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Topical Collection "Recent Advances in Flavors and Fragrances"

A topical collection in Molecules (ISSN 1420-3049). This collection belongs to the section "Natural Products Chemistry".

Editor

Prof. Dr. Luca Forti
Website
Collection Editor
Department of Life Sciences, University of Modena & Reggio Emilia, via G. Campi 183, Modena 41125, Italy
Interests: biocatalysis-biotransformations in organic synthesis; natural product chemistry; recovery of biologically active molecules from plant and marine matrices; polyphenols; application of yeast in organic synthesis; VOCs producing yeasts

Topical Collection Information

Dear Colleagues,

Flavors and fragrances find widespread applications in food, beverages, cosmetics, detergents, and pharmaceutical products. Industrially, world-wide production is estimated to be valued at US$ 20 billion.

The majority of these products are prepared through chemical synthesis or by extraction from plants. However, the employment of new biotechnological processes has increased considerably in the last few years. Because different enantiomers of chiral odorants, flavors or fragrances can show different sensorial properties (in terms of odor quality and/or intensity), their specific synthesis is valuable. Recently, much effort in R&D has been devoted to the identification of the active enantiomers of potent odorants and to their efficient chiral synthesis. In this context, biotechnology (biotransformations using microorganisms and isolated enzymes) represents a useful tool for catalyzing a large number of stereochemical transformations. Furthermore, all major facets of society and economic activities support the choice of environmentally friendly processes, and consumers have developed a preference for ‘natural’ or ‘organic’ products, thus developing a market for flavors and fragrances of biotechnological origin.

For this issue, we would like to publish original research articles or reviews on all aspects of flavor and fragrance, including isolation and sampling, chemical analyses, preparation, and delivery systems. Articles covering a wide range of topics, such as flavors, fragrances, aromas, essential oils, volatiles, biosynthesis, biotransformation, biotechnology, biological activities, biodegradation, computer-aided flavors, and fragrances design are welcomed for inclusion in this Topical Collection of Molecules.

This Topical Collection will offer an attractive forum for academia as well as for industry to present the state of the art on all aspects of flavors and fragrances. I strongly encourage authors to submit papers for this Topical Collection, within the scope of Molecules.

Prof. Dr. Luca Forti
Collection Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the collection website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

 

Keywords

  • flavors
  • fragrances
  • aroma
  • essential oil
  • isolation and sampling
  • chemical analysis
  • chiral recognition
  • synthesis
  • biotechnology
  • biotransformation
  • biocatalysis
  • delivery system
  • computer aided design

Published Papers (78 papers)

2020

Jump to: 2019, 2018, 2017, 2016, 2015

Open AccessArticle
Bacterial Biotransformation of Oleic Acid: New Findings on the Formation of γ-Dodecalactone and 10-Ketostearic Acid in the Culture of Micrococcus luteus
Molecules 2020, 25(13), 3024; https://doi.org/10.3390/molecules25133024 - 02 Jul 2020
Abstract
Microbial conversion of oleic acid (1) to form value-added industrial products has gained increasing scientific and economic interest. So far, the production of natural lactones with flavor and fragrance properties from fatty acids by non-genetically modified organisms (non-GMO) involves whole cells [...] Read more.
Microbial conversion of oleic acid (1) to form value-added industrial products has gained increasing scientific and economic interest. So far, the production of natural lactones with flavor and fragrance properties from fatty acids by non-genetically modified organisms (non-GMO) involves whole cells of bacteria catalyzing the hydration of unsaturated fatty acids as well as yeast strains responsible for further β-oxidation processes. Development of a non-GMO process, involving a sole strain possessing both enzymatic activities, significantly lowers the costs of the process and constitutes a better method from the customers’ point of view regarding biosafety issues. Twenty bacteria from the genus of Bacillus, Comamonas, Dietzia, Gordonia, Micrococcus, Pseudomonas, Rhodococcus and Streptomyces were screened for oxidative functionalization of oleic acid (1). Micrococcus luteus PCM525 was selected as the sole strain catalyzing the one-pot transformation of oleic acid (1) into natural valuable peach and strawberry-flavored γ-dodecalactone (6) used in the food, beverage, cosmetics and pharmaceutical industries. Based on the identified products formed during the process of biotransformation, we clearly established a pathway showing that oleic acid (1) is hydrated to 10-hydroxystearic acid (2), then oxidized to 10-ketostearic acid (3), giving 4-ketolauric acid (4) after three cycles of β-oxidation, which is subsequently reduced and cyclized to γ-dodecalactone (6) (Scheme 1). Moreover, three other strains (Rhodococcus erythropolis DSM44534, Rhodococcus ruber PCM2166, Dietzia sp. DSM44016), with high concomitant activities of oleate hydratase and alcohol dehydrogenase, were identified as efficient producers of 10-ketostearic acid (3), which can be used in lubricant and detergent formulations. Considering the prevalence of γ-dodecalactone (6) and 10-ketostearic acid (3) applications and the economic benefits of sustainable management, microbial bioconversion of oleic acid (1) is an undeniably attractive approach. Full article
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Open AccessArticle
Essential Oils as Natural Biocides in Conservation of Cultural Heritage
Molecules 2020, 25(3), 730; https://doi.org/10.3390/molecules25030730 - 07 Feb 2020
Cited by 2
Abstract
Essential oils (EOs) have been known for a long time, and they are used in several fields such as medicine and aromatherapy, as well as in the food and pharmaceutical industries. In the last decade, EOs have also been applied to contrast the [...] Read more.
Essential oils (EOs) have been known for a long time, and they are used in several fields such as medicine and aromatherapy, as well as in the food and pharmaceutical industries. In the last decade, EOs have also been applied to contrast the biodeterioration of cultural heritage, representing a powerful resource in green conservation strategies. In this study, an integrated approach based on microscopic observation, in vitro culture, and molecular investigation was preliminarily employed to identify biological systems colonizing wooden artworks. In order to contrast the biodeterioration processes induced by fungal colonization (Aspergillus flavus) or insect infestation (Anobium punctatum), wooden artworks were exposed to the volatile compound of Origanum vulgare or Thymus vulgaris essential oils (EOs), the chemical composition of which was determined by GC–MS using both polar and apolar columns. Artwork exposure was performed in ad-hoc-assembled “clean chambers.” Evaluating the effects on biological systems, the compatibility with artwork constitutive materials, and the lack of negative effects on human health and environmental pollution, the use of EOs as a valid alternative to traditional biocides must be considered. Full article
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Open AccessArticle
The In Vitro Activity of Essential Oils against Helicobacter Pylori Growth and Urease Activity
Molecules 2020, 25(3), 586; https://doi.org/10.3390/molecules25030586 - 29 Jan 2020
Cited by 1
Abstract
The anti-H. pylori properties of 26 different commercial essential oils were examined in vitro by MIC (minimal inhibitory concentration) determination for the reference strain H. pylori ATCC 43504. We selected 9 essential oils with different anti-Helicobacter activities and established their phytochemical [...] Read more.
The anti-H. pylori properties of 26 different commercial essential oils were examined in vitro by MIC (minimal inhibitory concentration) determination for the reference strain H. pylori ATCC 43504. We selected 9 essential oils with different anti-Helicobacter activities and established their phytochemical composition and urease inhibition activities. Phytochemical analysis of the selected essential oils by GC-MS method and antioxidant activity were performed. The phenol red method was used to screen the effect of essential oils on urease activity expressed as IC50 (the half of maximal inhibitory concentration). The most active essential oils, with MIC = 15.6 mg/L, were thyme, lemongrass, cedarwood and lemon balm oils; MIC = 31.3 mg/L—oregano oil; MIC = 62.5 mg/L—tea tree oil; MIC = 125 mg/L—pine needle, lemon and silver fir oils with bactericidal effect. Urease activity was inhibited by these oils with IC50 ranged from 5.3 to > 1049.9 mg/L. The most active was cedarwood oil (IC50 = 5.3 mg/L), inhibiting urease at sub-MIC concentrations (MIC = 15.6 mg/L). The statistical principal component analysis allowed for the division of the oils into three phytochemical groups differing in their anti-H. pylori activity. To summarize, the activity in vitro of the five essential oils silver fir, pine needle, tea tree, lemongrass, and cedarwood oils against H. pylori was found in this paper for the first time. The most active against clinical strains of H. pylori were cedar wood and oregano oils. Moreover, cedarwood oil inhibited the urease activity at subinhibitory concentrations. This essential oil can be regarded as a useful component of the plant preparations supporting the eradication H. pylori therapy. Full article
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Open AccessArticle
Apoptotic Effects on HL60 Human Leukaemia Cells Induced by Lavandin Essential Oil Treatment
Molecules 2020, 25(3), 538; https://doi.org/10.3390/molecules25030538 - 26 Jan 2020
Abstract
Recent scientific investigations have reported a number of essential oils to interfere with intracellular signalling pathways and to induce apoptosis in different cancer cell types. In this paper, Lavandin Essential Oil (LEO), a natural sterile hybrid obtained by cross-breeding L. angustifolia × L. [...] Read more.
Recent scientific investigations have reported a number of essential oils to interfere with intracellular signalling pathways and to induce apoptosis in different cancer cell types. In this paper, Lavandin Essential Oil (LEO), a natural sterile hybrid obtained by cross-breeding L. angustifolia × L. latifolia, was tested on human leukaemia cells (HL60). Based on the MTT results, the reduced cell viability of HL60 cells was further investigated to determine whether cell death was related to the apoptotic process. HL60 cells treated for 24 h with LEO were processed by flow cytometry, and the presence of Annexin V was measured. The activation of caspases-3 was evaluated by western blot and immunofluorescence techniques. Treated cells were also examined by scanning and transmission electron microscopy to establish the possible occurrence of morphological alterations during the apoptotic process. LEO main compounds, such as linalool, linalyl acetate, 1,8-cineole, and terpinen-4-ol, were also investigated by MTT and flow cytometry analysis. The set of obtained results showed that LEO treatments induced apoptosis in a dose-dependent, but not time-dependent, manner on HL60 cells, while among LEO main compounds, both terpinen-4-ol and linalyl acetate were able to induce apoptosis. Full article
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Open AccessArticle
Fatty Acids, Volatile and Sensory Profile of Multigrain Biscuits Enriched with Spent Malt Rootles
Molecules 2020, 25(3), 442; https://doi.org/10.3390/molecules25030442 - 21 Jan 2020
Cited by 2
Abstract
Spent malt rootlets, a by-product of the brewing industry, are a rich source of protein, essential amino acids, healthy fats, polyphenols and minerals, and could be a new promising type of raw material from the nutritional, economic, sensory, and technical perspectives. However, their [...] Read more.
Spent malt rootlets, a by-product of the brewing industry, are a rich source of protein, essential amino acids, healthy fats, polyphenols and minerals, and could be a new promising type of raw material from the nutritional, economic, sensory, and technical perspectives. However, their specific aroma profile could limit their addition in baked products. The aim of this work was to study the effect of spent malt rootlets addition on volatile derivatives of enriched biscuits in relation to their sensory profile. For this purpose, spent malt rootlets and enriched biscuits (0–25% spent malt rootlets added) were analyzed by GC-MS techniques, in order to obtain their fatty acids methyl esters and volatile compounds profile, while for the sensory analysis a nine-point hedonic score test was used. The results of this study reveal the fatty acids and volatile profile of spent malt rootlets and of the enriched biscuits with spent malt rootlets pointing out the contribution of fatty acids to the generation of aroma compounds. The influence of different aroma compounds on the consumer’s preferences was studied and the optimum level addition of spent malt rootlets in multigrain biscuits was found to be 15%. Full article
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2019

Jump to: 2020, 2018, 2017, 2016, 2015

Open AccessArticle
Ayapana triplinervis Essential Oil and Its Main Component Thymohydroquinone Dimethyl Ether Inhibit Zika Virus at Doses Devoid of Toxicity in Zebrafish
Molecules 2019, 24(19), 3447; https://doi.org/10.3390/molecules24193447 - 23 Sep 2019
Cited by 3
Abstract
Zika virus (ZIKV) is an emerging mosquito-borne virus of medical concern. ZIKV infection may represent a serious disease, causing neonatal microcephaly and neurological disorders. Nowadays, there is no approved antiviral against ZIKV. Several indigenous or endemic medicinal plants from Mascarene archipelago in Indian [...] Read more.
Zika virus (ZIKV) is an emerging mosquito-borne virus of medical concern. ZIKV infection may represent a serious disease, causing neonatal microcephaly and neurological disorders. Nowadays, there is no approved antiviral against ZIKV. Several indigenous or endemic medicinal plants from Mascarene archipelago in Indian Ocean have been found able to inhibit ZIKV infection. The purpose of our study was to determine whether essential oil (EO) from Reunion Island medicinal plant Ayapana triplinervis, whose thymohydroquinone dimethyl ether (THQ) is the main component has the potential to prevent ZIKV infection in human cells. Virological assays were performed on human epithelial A549 cells infected with either GFP reporter ZIKV or epidemic viral strain. Zebrafish assay was employed to evaluate the acute toxicity of THQ in vivo. We showed that both EO and THQ inhibit ZIKV infection in human cells with IC50 values of 38 and 45 µg/mL, respectively. At the noncytotoxic concentrations, EO and THQ reduced virus progeny production by 3-log. Time-of-drug-addition assays revealed that THQ could act as viral entry inhibitor. At the antiviral effective concentration, THQ injection in zebrafish does not lead to any signs of stress and does not impact fish survival, demonstrating the absence of acute toxicity for THQ. From our data, we propose that THQ is a new potent antiviral phytocompound against ZIKV, supporting the potential use of medicinal plants from Reunion Island as a source of natural and safe antiviral substances against medically important mosquito-borne viruses. Full article
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Open AccessArticle
Flowering Stage and Daytime Affect Scent Emission of Malus ioensis “Prairie Rose”
Molecules 2019, 24(13), 2356; https://doi.org/10.3390/molecules24132356 - 26 Jun 2019
Abstract
Flowering crabapple is an important ornamental flower. It is vital to understand the floral scent properties and the associated release dynamics for carrying out fragrant flower breeding or floral regulation of crabapple. Static headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry was used [...] Read more.
Flowering crabapple is an important ornamental flower. It is vital to understand the floral scent properties and the associated release dynamics for carrying out fragrant flower breeding or floral regulation of crabapple. Static headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry was used to detect the volatile compounds in Malus ioensis “Prairie Rose” flowers at different flowering stages and at different day-night time. The results showed that methylheptenone, phenylethanol, geranylacetone, 2-(4-methoxyphenyl)ethanol, α-cedrene were the major compounds in M. ioensis “Prairie Rose”, but the compounds released during different stages and different day-night time were significantly different (P < 0.0001). A total of 25 volatile compounds were identified from the four flowering stages. The floral scents in the initial and flowering stages were the most similar (dissimilarity 0.21). The main compounds in these two stages were geranylacetone and methylheptenone, and the contents of geranylacetone and phenylethanol were positively correlated with the flowering stages. From the bud stage to the end of flowering, the total amount of volatile compounds released showed an initial increase followed by a decrease and the amounts of compounds released during the initial flowering stage were the highest. The aliphatic and benzenoids content was significant higher in the daytime than at night. A total of 15 compounds were detected in the five time periods. Methylheptenone and phenylethanol were particularly released in the 10:00–12:00 and 15:00–17:00 time periods. There were only three common compounds among the five time periods and the types of flower volatiles released during the daytime were obviously higher than those released at night. From the nocturnal to diurnal, the amount of flower volatiles released first increased, then decreased, and the release reached a peak between 10 am and 12 noon, which was consistent with the pollination biological characteristics of Malus flowers. Our findings are important for understanding the mechanism of insect visits to crabapple and the regulation of crabapple flower scent. Full article
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Open AccessArticle
Distinctive Formation of Volatile Compounds in Fermented Rice Inoculated by Different Molds, Yeasts, and Lactic Acid Bacteria
Molecules 2019, 24(11), 2123; https://doi.org/10.3390/molecules24112123 - 05 Jun 2019
Cited by 1
Abstract
Rice has been fermented to enhance its application in some foods. Although various microbes are involved in rice fermentation, their roles in the formation of volatile compounds, which are important to the characteristics of fermented rice, are not clear. In this study, diverse [...] Read more.
Rice has been fermented to enhance its application in some foods. Although various microbes are involved in rice fermentation, their roles in the formation of volatile compounds, which are important to the characteristics of fermented rice, are not clear. In this study, diverse approaches, such as partial least squares-discriminant analysis (PLS-DA), metabolic pathway-based volatile compound formations, and correlation analysis between volatile compounds and microbes were applied to compare metabolic characteristics according to each microbe and determine microbe-specific metabolites in fermented rice inoculated by molds, yeasts, and lactic acid bacteria. Metabolic changes were relatively more activated in fermented rice inoculated by molds compared to other microbes. Volatile compound profiles were significantly changed depending on each microbe as well as the group of microbes. Regarding some metabolic pathways, such as carbohydrates, amino acids, and fatty acids, it could be observed that certain formation pathways of volatile compounds were closely linked with the type of microbes. Also, some volatile compounds were strongly correlated to specific microbes; for example, branched-chain volatiles were closely link to Aspergillus oryzae, while Lactobacillus plantarum had strong relationship with acetic acid in fermented rice. This study can provide an insight into the effects of fermentative microbes on the formation of volatile compounds in rice fermentation. Full article
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2018

Jump to: 2020, 2019, 2017, 2016, 2015

Open AccessArticle
Comparative Chemical Profiles of Essential Oils and Hydrolate Extracts from Fresh Flowers of Eight Paeonia suffruticosa Andr. Cultivars from Central China
Molecules 2018, 23(12), 3268; https://doi.org/10.3390/molecules23123268 - 10 Dec 2018
Cited by 2
Abstract
Paeonia suffruticosa Andr. is a famous ornamental and aromatic plant with hundreds of cultivars in China. The objective of this work was to investigate comparative chemical profiles of essential oils and hydrolate extracts from eight P. suffruticosa Andr. cultivars from Central China. The [...] Read more.
Paeonia suffruticosa Andr. is a famous ornamental and aromatic plant with hundreds of cultivars in China. The objective of this work was to investigate comparative chemical profiles of essential oils and hydrolate extracts from eight P. suffruticosa Andr. cultivars from Central China. The percentages of hydrocarbons in hydrolate extracts (≤1.1%) were significantly lower than those in the essential oils (29.8–63.7%). The percentages of oxygenated compounds in hydrolate extracts (98.3–99.8%) were significantly higher than those in the essential oils (34.8–69.6%). Multivariate analyses with hierarchical clusters and principal components further indicated the chemical differences between essential oils and hydrolate extracts. Due to predominance of oxygenated compounds and almost trace level of hydrocarbons, P. suffruticosa Andr. hydrolate extracts could be good alternatives to the essential oils. Moreover, distribution of major oxygenated compounds in hydrolate extracts varied with cultivars. Hydrolate extracts from ’SHT’, ’WLPS’ and ’BXT’ presented chemotypes of methylated phenols (65.0%), 2-phenylethanol (64.4%) and geraniol + citronellol + nerol (59.9%), respectively. Those from five other cultivars presented somewhat mixed chemotypes. These results were further confirmed by quantitative evaluation relative to the major oxygenated compounds. The outcome of this work will promote applications of P. suffruticosa Andr. hydrolate extracts in fragrances and cosmetics. Full article
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Open AccessArticle
Chemical and Biological Evaluation of Essential Oils from Cardamom Species
Molecules 2018, 23(11), 2818; https://doi.org/10.3390/molecules23112818 - 30 Oct 2018
Cited by 5
Abstract
To highlight the importance of the spices in the Mediterranean diet, the aim of the paper was to study the essential oil compositions and to clarify the potential differences in the biological activities of the three cardamom species. In the study, we compared [...] Read more.
To highlight the importance of the spices in the Mediterranean diet, the aim of the paper was to study the essential oil compositions and to clarify the potential differences in the biological activities of the three cardamom species. In the study, we compared the phytochemical profiles and biological activities of essential oils from Elettaria cardamomum, Aframomum corrorima and Amomum subulatum. The oils were analyzed using the GC and GC/MS techniques and were mainly constituted of the oxygenated monoterpenes which represents 71.4%, 63.0%, and 51.0% of all compounds detected in E. cardamomum, A. corrorima and A. subulatum essential oils, respectively, 1,8-cineole was the main common compound between the tree tested volatile oil. The essential oils showed significant antimicrobial activity against Gram-positive and Gram-negative microorganisms tested especially the fungal strains. The Ethiopian cardamom was the most active essential oil with fungal growth inhibition zone ranging from 12.67 to 34.33 mm, MICs values ranging from 0.048 to 0.19 mg/mL, and MBCs values from 0.19 to 1.75 mg/mL. The three tested essential oils and their main component (1,8-cineole) significantly increased the production of elastase and protease production, and motility in P. aeruginosa PAO1 in a dose dependent manner. In fact, at 10 mg/mL concentration, the three essential oils showed more than 50% of inhibition of elastolytic and proteolytic activities in P. aeruginosa PAO1. The same oils inhibited also the violacein production in C. violaceum strain. It was also noticed that at high concentrations, the A. corrorima essential oil significantly inhibited the germination of radish. A thorough knowledge of the biological and safety profiles of essential oils can produce applications of economic importance. Full article
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Open AccessArticle
Bioformation of Volatile and Nonvolatile Metabolites by Saccharomycopsis fibuligera KJJ81 Cultivated under Different Conditions—Carbon Sources and Cultivation Times
Molecules 2018, 23(11), 2762; https://doi.org/10.3390/molecules23112762 - 25 Oct 2018
Cited by 5
Abstract
Saccharomycopsis fibuligera KJJ81 isolated from nuruk is an amylolytic yeast that is widely used as a microbial starter in various fermented foods. Volatile and nonvolatile metabolites of S. fibuligera KJJ81 were investigated according to different carbon sources and cultivation times using a nontargeted [...] Read more.
Saccharomycopsis fibuligera KJJ81 isolated from nuruk is an amylolytic yeast that is widely used as a microbial starter in various fermented foods. Volatile and nonvolatile metabolites of S. fibuligera KJJ81 were investigated according to different carbon sources and cultivation times using a nontargeted metabolomic approach. Partial-least-squares discriminant analysis was applied to determine the major metabolites, which were found to be closely related to the clustering and discrimination of S. fibuligera KJJ81 samples. Some volatile metabolites derived from phenylalanine, such as 2-phenylethanol, 2-phenylethyl acetate, and ethyl phenylacetate, were predominantly found in cultivation medium containing glucose (YPD medium). In addition, the level of 2-phenylethanol increased continuously with the cultivation time. In terms of nonvolatile metabolites, carbohydrates (mannose, arabitol, and mannitol), fatty acids (palmitic acid and stearic acid), organic acids (oxalic acid and succinic acid), and amino acids (isoleucine, serine, alanine, glutamic acid, glycine, proline, phenylalanine, and threonine) were the main contributors to S. fibuligera KJJ81 samples cultivated in YPD medium according to cultivation time. These results show that the formation of volatile and nonvolatile metabolites of S. fibuligera KJJ81 can be significantly affected by both the carbon sources and the cultivation time. Full article
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Open AccessArticle
Lavandula angustifolia Essential Oil and Linalool Counteract Social Aversion Induced by Social Defeat
Molecules 2018, 23(10), 2694; https://doi.org/10.3390/molecules23102694 - 19 Oct 2018
Cited by 5
Abstract
Many vegetable extracts, essential oils, and their main constituents are active on the Central Nervous System (CNS). In fact, they have been used as sedatives, hypnotics, or tranquilizers for their activity in treating CNS disorders. In this research, we studied the possible activities [...] Read more.
Many vegetable extracts, essential oils, and their main constituents are active on the Central Nervous System (CNS). In fact, they have been used as sedatives, hypnotics, or tranquilizers for their activity in treating CNS disorders. In this research, we studied the possible activities of Lavandula angustifolia (LA) essential oil and of its main constituent, linalool, as anti-stress compounds on anxiety and social interaction and their in vitro effects on proteins (pERK and PKA) involved in the transmission of the signal. An acute intraperitoneal injection of linalool (100 mg/kg) and of LA essential oil (200 mg/kg) reduced motor activity without any anxiolytic effect, but significantly increased social interaction. Stressed mice, after being exposed to a social defeat encounter, showed heightened anxiety and social avoidance. Acute administration of LA essential oil blocked stress-induced anxiety, while linalool showed no effects. However, both compounds were capable of reversing social aversion, acting as antidepressant agents. Our results showed that linalool inhibits pERK and PKA expression in the SH-SY5Y cell, but no effect was detected with the LA essential oil. Therefore, the LA essential oil and linalool may be considered as useful alternative tools to the available traditional treatments for social stress-induced mental illnesses. Full article
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Open AccessArticle
Differential Accumulation of Aroma Compounds in Normal Green and Albino-Induced Yellow Tea (Camellia sinensis) Leaves
Molecules 2018, 23(10), 2677; https://doi.org/10.3390/molecules23102677 - 18 Oct 2018
Cited by 6
Abstract
Tea (Camellia sinensis) cultivars with green leaves are the most widely used for making tea. Recently, tea mutants with white or yellow young shoots have attracted increasing interest as raw materials for making “high-quality” tea products. Albino teas are generallycharacterized as [...] Read more.
Tea (Camellia sinensis) cultivars with green leaves are the most widely used for making tea. Recently, tea mutants with white or yellow young shoots have attracted increasing interest as raw materials for making “high-quality” tea products. Albino teas are generallycharacterized as having metabolites of relatively high amino acid content and lower catechin content. However, little is known about aroma compounds in albino tea leaves. Herein, we compared original normal leaves (green) and light-sensitive albino leaves (yellow) of cv. Yinghong No. 9. GC-MS was employed to analyze endogenous tea aroma compounds and related precursors. Quantitative real time PCR was used to measure expression levels of genes involved in biosyntheses of tea aromas.The total contents of most endogenous free tea aromas, including aroma fatty acid derivatives, aroma terpenes, and aroma phenylpropanoids/benzenoids, and their glycosidically bound aroma compounds, were lower in yellow leaves than in green leaves. The content of the key precursor geranyl diphosphate (GDP) and expression levels of key synthetic genes involved in the formation of linalool, a major aroma compound in cv. Yinghong No. 9, were investigated. Linalool content was lower in albino-induced yellow leaves, which was due to the lower GDP content compared with normal green leaves. Full article
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Open AccessArticle
Chromobacterium violaceum and Pseudomonas aeruginosa PAO1: Models for Evaluating Anti-Quorum Sensing Activity of Melaleuca alternifolia Essential Oil and Its Main Component Terpinen-4-ol
Molecules 2018, 23(10), 2672; https://doi.org/10.3390/molecules23102672 - 17 Oct 2018
Cited by 8
Abstract
The problem of antibiotic resistance among pathogens encourages searching for novel active molecules. The aim of the research was to assay the anti-quorum sensing (anti-QS) and antibiofilm potential of Melaleuca alternifolia essential oil and its main constituent, terpinen-4-ol, to prevent the infections due [...] Read more.
The problem of antibiotic resistance among pathogens encourages searching for novel active molecules. The aim of the research was to assay the anti-quorum sensing (anti-QS) and antibiofilm potential of Melaleuca alternifolia essential oil and its main constituent, terpinen-4-ol, to prevent the infections due to methicillin-resistant Staphylococcus aureus strains as an alternate to antibiotics. The tea tree oil (TTO) was evaluated for its potential in inhibiting QS-dependent phenomena such as violacein production in Chromobacterium violaceum, swarming motility of Pseudomonas aeruginosa PAO1, and biofilm formation in MRSA strains on glass. The results showed that terpinen-4-ol was able to inhibit MRSA strain biofilm formation on the glass strips by 73.70%. TTO inhibited the violacein production at a mean inhibitory concentration (MIC) value of 0.048 mg/mL by 69.3%. At 100 µg/mL TTO and terpinen-4-ol exhibited inhibition in swarming motility of PAO1 by 33.33% and 25%, respectively. TTO revealed anti-QS and anti-biofilm activities at very low concentrations, but it could be further investigated for new molecules useful for the treatment of MRSA infections. Full article
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Open AccessArticle
Chemical Composition of Myrtle (Myrtus communis L.) Berries Essential Oils as Observed in a Collection of Genotypes
Molecules 2018, 23(10), 2502; https://doi.org/10.3390/molecules23102502 - 29 Sep 2018
Cited by 3
Abstract
Myrtle (Myrtus communis L.) is a shrub spontaneously growing in the Mediterranean area. The leaf and fruit content of essential oils and phenolic compounds justify the wide use of the plant as medicinal and aromatic. Because of overexploitation of wild plants, a [...] Read more.
Myrtle (Myrtus communis L.) is a shrub spontaneously growing in the Mediterranean area. The leaf and fruit content of essential oils and phenolic compounds justify the wide use of the plant as medicinal and aromatic. Because of overexploitation of wild plants, a domestication process is in progress in different regions and the influence of the genotype variability on the chemical composition of fruit essential oils may be useful to breeding programs. Consequently, the analysis performed on a selected group of candidate clones growing in the same field collection in Sardinia is the object of this report. Forty-seven selections provided fully ripe fruits for essential oil extraction by hydrodistillation and Gas Chromatography-Mass Spectrometry (GC-MS) analysis. Only five candidate clones showed white fruits. The highest yield of essential oil was observed in the LAC31 genotype with 0.55 g·kg−1, while the samples BOS1, MON5, RUM4, RUM10, V4 and V8 showed values above 0.20 g·kg−1 and most of the genotypes under 0.10 g·kg−1. Geranyl acetate was the compound with the highest relative abundance. The second compound for relative abundance was the 1,8-cineole. Other compounds with high relative abundance were α-terpinyl acetate, methyleugenol, linalool, α-terpineol, β-caryophyllene, α-humulene, Trans-caryophyllene oxide, and humulene epoxide II. Full article
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Open AccessCommunication
Chemical Composition of Essential Oil of Leaves from Lippia schaueriana Mart. Collected in the Caatinga Area
Molecules 2018, 23(10), 2480; https://doi.org/10.3390/molecules23102480 - 27 Sep 2018
Cited by 5
Abstract
Lippia schaueriana Mart. (Verbenaceae) is an endemic species of Caatinga with a restricted distribution to the states of Bahia and Pernambuco, which presents itself as a potential source of raw material for extraction of essential oil and exploitation by the chemical and pharmaceutical [...] Read more.
Lippia schaueriana Mart. (Verbenaceae) is an endemic species of Caatinga with a restricted distribution to the states of Bahia and Pernambuco, which presents itself as a potential source of raw material for extraction of essential oil and exploitation by the chemical and pharmaceutical industries. Considering that there are no reports in the literature of research carried out with this species, this paper aimed to establish—for the first time—the chemical composition of its essential oil. The essential oil of the dry leaves at room temperature was obtained by hydrodistillation after 3 h of extraction and the phytochemical analyzes were done by gas chromatography coupled to mass spectrometry (GC/MS). The main compounds found in the oil of leaves were piperitone oxide (51.25%), caryophyllene (17.76%), limonene (8.06%), spathulenol (6.63%), and piperitone (2.90%). The piperitone oxide is a compound described in the literature that shows antinociceptive, cardiovascular, analgesic, and relaxing activities, as well as fungicidal and insecticidal effect, which gives it an interesting potential for the alternative control of agricultural pests. Full article
Open AccessArticle
Comparative Analysis of Chemical Composition, Anti-Inflammatory Activity and Antitumor Activity in Essential Oils from Siegesbeckia orientalis, S. glabrescens and S. pubescens with an ITS Sequence Analysis
Molecules 2018, 23(9), 2185; https://doi.org/10.3390/molecules23092185 - 30 Aug 2018
Cited by 5
Abstract
Herba Siegesbeckiae (HS), derived from the aerial parts of three plants, Siegesbeckia orientalis (SO), S. glabrescens (SG), and S. pubescens (SP), has been used for the treatment of inflammatory diseases in China for centuries. In the present study, hydrodistillation was applied to extract [...] Read more.
Herba Siegesbeckiae (HS), derived from the aerial parts of three plants, Siegesbeckia orientalis (SO), S. glabrescens (SG), and S. pubescens (SP), has been used for the treatment of inflammatory diseases in China for centuries. In the present study, hydrodistillation was applied to extract essential oils from dried SO, SG, and SP aerial parts, and chemical composition analysis by gas chromatography–mass spectrometry (GC-MS) led to the identification of a total of 148 compounds (56 in SO, 62 in SG, and 59 in SP). The main components in the essential oils of SO, SG, and SP differed significantly. In vitro anti-inflammatory activity assays showed that SP essential oils (IC50, 0.97 μg/mL) significantly reduced the ability of lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages to release NO, and the SO essential oil (IC50, 14.99 μg/mL) was better than the others at inhibiting the LPS-induced release of cytokine IL-6. Furthermore, the essential oils exhibited antitumor activities (IC50, 37.72–123.16 μg/mL) against Hep3B (liver) and Hela (cervical) cells. Linear regression analysis showed that, caryophyllene oxide peak area percentages showed remarkably high negative correlation coefficients with IC50 values of Hep3B and Hela cytotoxicity, which suggested the contribution of this compound on the cancer cell cytotoxicity of three essential oils. Finally, the ITS1-5.8S-ITS2 region was amplified and sequenced in order to generate genomic reference sequences for each plant. These can be used to identify the origins of the plants, and will assist other research studies related to these three plants. Full article
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Open AccessArticle
Flavor Compounds in Pixian Broad-Bean Paste: Non-Volatile Organic Acids and Amino Acids
Molecules 2018, 23(6), 1299; https://doi.org/10.3390/molecules23061299 - 29 May 2018
Cited by 5
Abstract
Non-volatile organic acids and amino acids are important flavor compounds in Pixian broad-bean paste, which is a traditional Chinese seasoning product. In this study, non-volatile organic acids, formed in the broad-bean paste due to the metabolism of large molecular compounds, are qualitatively and [...] Read more.
Non-volatile organic acids and amino acids are important flavor compounds in Pixian broad-bean paste, which is a traditional Chinese seasoning product. In this study, non-volatile organic acids, formed in the broad-bean paste due to the metabolism of large molecular compounds, are qualitatively and quantitatively determined by high-performance liquid chromatography (HPLC). Amino acids, mainly produced by hydrolysis of soybean proteins, were determined by the amino acid automatic analyzer. Results indicated that seven common organic acids and eighteen common amino acids were found in six Pixian broad-bean paste samples. The content of citric acid was found to be the highest in each sample, between 4.1 mg/g to 6.3 mg/g, and malic acid were between 2.1 mg/g to 3.6 mg/g ranked as the second. Moreover, fumaric acid was first detected in fermented bean pastes albeit with a low content. For amino acids, savory with lower sour taste including glutamine (Gln), glutamic acid (Glu), aspartic acid (Asp) and asparagines (Asn) were the most abundant, noted to be 6.5 mg/g, 4.0 mg/g, 6.4 mg/g, 4.9 mg/g, 6.2 mg/g and 10.2 mg/g, and bitter taste amino acids followed. More importantly, as important flavor materials in Pixian broad-bean paste, these two groups of substances are expected to be used to evaluate and represent the flavor quality of Pixian broad-bean paste. Moreover, the results revealed that citric acid, glutamic acid, methionine and proline were the most important flavor compounds. These findings are agreat contribution for evaluating the quality and further assessment of Pixian broad-bean paste. Full article
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Open AccessArticle
Multi-Response Extraction Optimization Based on Anti-Oxidative Activity and Quality Evaluation by Main Indicator Ingredients Coupled with Chemometric Analysis on Thymus quinquecostatus Celak
Molecules 2018, 23(4), 957; https://doi.org/10.3390/molecules23040957 - 19 Apr 2018
Cited by 3
Abstract
Thymus quinquecostatus Celak is a species of thyme in China and it used as condiment and herbal medicine for a long time. To set up the quality evaluation of T. quinquecostatus, the response surface methodology (RSM) based on its 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical [...] Read more.
Thymus quinquecostatus Celak is a species of thyme in China and it used as condiment and herbal medicine for a long time. To set up the quality evaluation of T. quinquecostatus, the response surface methodology (RSM) based on its 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was introduced to optimize the extraction condition, and the main indicator components were found through an UPLC-LTQ-Orbitrap MSn method. The ethanol concentration, solid-liquid ratio, and extraction time on optimum conditions were 42.32%, 1:17.51, and 1.8 h, respectively. 35 components having 12 phenolic acids and 23 flavonoids were unambiguously or tentatively identified both positive and negative modes to employ for the comprehensive analysis in the optimum anti-oxidative part. A simple, reliable, and sensitive HPLC method was performed for the multi-component quantitative analysis of T. quinquecostatus using six characteristic and principal phenolic acids and flavonoids as reference compounds. Furthermore, the chemometrics methods (principal components analysis (PCA) and hierarchical clustering analysis (HCA)) appraised the growing areas and harvest time of this herb closely relative to the quality-controlled. This study provided full-scale qualitative and quantitative information for the quality evaluation of T. quinquecostatus, which would be a valuable reference for further study and development of this herb and related laid the foundation of further study on its pharmacological efficacy. Full article
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Open AccessReview
Effects of Basal Defoliation on Wine Aromas: A Meta-Analysis
Molecules 2018, 23(4), 779; https://doi.org/10.3390/molecules23040779 - 28 Mar 2018
Cited by 2
Abstract
Basal defoliation, as one of the most common viticulture management practices to modify fruit zone microclimates, has been widely applied aiming at improving wine quality. Wine aroma contributes greatly to wine quality, yet the effects of basal defoliation on wine aromas show discrepancies [...] Read more.
Basal defoliation, as one of the most common viticulture management practices to modify fruit zone microclimates, has been widely applied aiming at improving wine quality. Wine aroma contributes greatly to wine quality, yet the effects of basal defoliation on wine aromas show discrepancies according to previous studies. This study is a meta-analysis performed to dissect the factors related to the influence of basal defoliation on volatile compounds in wine. Timing of basal defoliation plays an important role in the concentration of varietal aromas in wine. Pre-veraison defoliation induces an increase in β-damascenone and linalool as well as a reduction in 3-isobutyl-2-methoxypyrazine (IBMP). The effects of basal defoliation on certain volatile compounds relative to fermentation aromas in wine (1-hexanol, β-phenylethanol, 2-phenylethyl acetate, decanoic acid, and ethyl octanoate) depend on grape maturity. There are also other factors, such as cultivar and climate conditions, that might be responsible for the effect of basal defoliation on wine aromas. The concentrations of isobutanol, isoamyl alcohol, hexanoic acid, and octanoic acid as well as ethyl isobutyrate, ethyl hexanoate, ethyl isovalerate, and ethyl decanoate in wine are not markedly affected by basal defoliation. Due to limited studies included in this meta-analysis, more trials are needed to confirm the current findings. Full article
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Open AccessArticle
A Novel Approach for Microbial Synthesis of Enantiomerically Pure Whisky Lactones Based on Solid-State Fermentation
Molecules 2018, 23(3), 659; https://doi.org/10.3390/molecules23030659 - 14 Mar 2018
Cited by 1
Abstract
In this study, solid-state fermentation (SSF) was proposed as an alternative approach to obtain optically pure forms of one of the most common aroma compounds, whisky lactone. Filamentous fungi were used for enantioselective hydrolysis of a racemate of trans and cis whisky lactones, [...] Read more.
In this study, solid-state fermentation (SSF) was proposed as an alternative approach to obtain optically pure forms of one of the most common aroma compounds, whisky lactone. Filamentous fungi were used for enantioselective hydrolysis of a racemate of trans and cis whisky lactones, utilizing rapeseed cake as a growth medium. Among the tested fungi, Fusarium oxysporum AM13 and Papularia rosea AM17 were chosen for further studies. Various process parameters, including temperature, moisture content of solid media, and substrate concentration were optimized to maximize the efficiency of the kinetic resolution process. After optimization of the culture conditions (33 °C temperature, 60% moisture content, and substrate concentration of 3 mg/g oilseed cake), F. oxysporum AM13 resolved a mixture of trans-(+)-(4S,5R) and cis-(+)-(4R,5R) whisky lactones with enantiomeric excess (ee), ee > 99% and ee = 98%, respectively. This study presents an inexpensive and environmentally friendly method for the production of enantiomerically pure aroma lactones via the solid-state fermentation of oilseed cake. The results revealed that SSF is an effective method for acquiring highly valued and industrially demanded compounds with negligible economic cost. Full article
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Open AccessArticle
GC-MS Analysis of the Composition of the Essential Oil from Dendranthema indicum Var. Aromaticum Using Three Extraction Methods and Two Columns
Molecules 2018, 23(3), 576; https://doi.org/10.3390/molecules23030576 - 04 Mar 2018
Cited by 6
Abstract
Dendranthema indicum var. aromaticum, which is an aromatic plant with a strong and special fragrance throughout the whole plant, is used for the treatment of colds and headaches, and as a mosquito repellant in Shennongjia, Hubei province, China. To analyze the composition [...] Read more.
Dendranthema indicum var. aromaticum, which is an aromatic plant with a strong and special fragrance throughout the whole plant, is used for the treatment of colds and headaches, and as a mosquito repellant in Shennongjia, Hubei province, China. To analyze the composition of the essential oil from this medicinal herb, we developed a gas chromatography-mass Spectrometry (GC-MS) method including microwave-assisted extraction, hydrodistillation and direct headspace analysis in two different stationary phase columns. In total, 115 volatile compounds were identified, of which 90 compounds were identified using Rxi-5MS and 78 using HP-INNOWAX. Our results revealed that the oil was mainly composed of five categories of compound: oxygenated monoterpenes (28.76–78.10%), oxygenated sesquiterpenes (4.27–38.06%), sesquiterpenes (3.22–11.57%), fatty hydrocarbons (1.65–9.81%) and monoterpenes (0–3.32%). The major constituents are α-thujone, β-thujone, cis-sabinol, sabinyl acetate and (-)-neointermedeol.However, the essential oil composition in the published literature differs significantly. Therefore, a cluster analysis was carried out using the top ten compositions in the reported literature as well as this study, using Minitab software. To provide detailed information on plant origin, the ITS1-5.8s-ITS2 region was amplified and sequenced (Accession No. MF668250). Besides, in order to provide a macroscopic view of the chemical composition, the biosynthetic pathway of the main components was summarized according to the Kyoto Encyclopedia of Genes and Genomes (KEGG) database and the published literatures. Full article
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Open AccessReview
Neuroprotective Effects and Mechanisms of Tea Bioactive Components in Neurodegenerative Diseases
Molecules 2018, 23(3), 512; https://doi.org/10.3390/molecules23030512 - 25 Feb 2018
Cited by 16
Abstract
As the population ages, neurodegenerative diseases such as Parkinson’s disease (PD) and Alzheimer’s disease (AD) impose a heavy burden on society and families. The pathogeneses of PD and AD are complex. There are no radical cures for the diseases, and existing therapeutic agents [...] Read more.
As the population ages, neurodegenerative diseases such as Parkinson’s disease (PD) and Alzheimer’s disease (AD) impose a heavy burden on society and families. The pathogeneses of PD and AD are complex. There are no radical cures for the diseases, and existing therapeutic agents for PD and AD have diverse side effects. Tea contains many bioactive components such as polyphenols, theanine, caffeine, and theaflavins. Some investigations of epidemiology have demonstrated that drinking tea can decrease the risk of PD and AD. Tea polyphenols can lower the morbidity of PD and AD by reducing oxidative stress and regulating signaling pathways and metal chelation. Theanine can inhibit the glutamate receptors and regulate the extracellular concentration of glutamine, presenting neuroprotective effects. Additionally, the neuroprotective mechanisms of caffeine and theaflavins may contribute to the ability to antagonize the adenosine receptor A2AR and the antioxidant properties, respectively. Thus, tea bioactive components might be useful for neuronal degeneration treatment in the future. In the present paper, the neuro protection and the mechanisms of tea and its bioactive components are reviewed. Moreover, the potential challenges and future work are also discussed. Full article
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Open AccessArticle
Development of Volatile Compounds during Hydrolysis of Porcine Hemoglobin with Papain
Molecules 2018, 23(2), 357; https://doi.org/10.3390/molecules23020357 - 08 Feb 2018
Cited by 2
Abstract
There is a growing market for the use of hydrolysates from animal side-streams for production of high-protein supplements. However, there can be issues with development of off-flavors, either due to the raw material in question or due to the hydrolysis process itself. This [...] Read more.
There is a growing market for the use of hydrolysates from animal side-streams for production of high-protein supplements. However, there can be issues with development of off-flavors, either due to the raw material in question or due to the hydrolysis process itself. This study examined the development of volatile compounds during hydrolysis of hemoglobin. Briefly, porcine hemoglobin was hydrolyzed by 0.5% papain for up to 5 h, and the development of volatile compounds was analyzed via gas chromatography-mass spectrometry. The results showed that there was significant development of a number of volatile compounds with time, e.g., certain Maillard reaction and lipid oxidation products, which are likely candidates for the aroma development during hydrolysis. Furthermore, it was shown that development of a number of the volatiles was due to the hydrolysis process, as these compounds were not found in a control without enzyme. Full article
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Open AccessArticle
High Add Valued Application of Turpentine in Crop Production through Structural Modification and QSAR Analysis
Molecules 2018, 23(2), 356; https://doi.org/10.3390/molecules23020356 - 08 Feb 2018
Cited by 3
Abstract
Turpentine is a volatile component of resin, which is an abundant forest resource in Southern China. As one of the most important components, the integrated application of β-pinene has been studied. The broad-spectrum evaluation of β-pinene and its analogues has, therefore, been necessary. [...] Read more.
Turpentine is a volatile component of resin, which is an abundant forest resource in Southern China. As one of the most important components, the integrated application of β-pinene has been studied. The broad-spectrum evaluation of β-pinene and its analogues has, therefore, been necessary. In an attempt to expand the scope of agro-activity trials, the preparation and the evaluation of the herbicidal activity of a series of β-pinene analogues against three agricultural herbs were carried out. In accordance with the overall herbicidal activity, it is noteworthy that compounds 6k, 6l, and 6m demonstrated extreme activity with IC50 values of 0.065, 0.065, and 0.052 mol active ingredients/hectare against E. crus-galli. The preliminary structure–activity relationship (SAR) was analyzed and the compounds with the appropriate volatility and substituent type that had beneficial herbicidal activity were analyzed. Simultaneously, the quantitative structure–activity relationship (QSAR) model was built and the most important structural features were indicated, which was, to a certain extent, in line with the SAR study. The study aimed to study the application of the forest resource turpentine in agriculture as a potential and alternative approach for comprehensive utilization. Full article
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Open AccessArticle
Effect of Temperature on Flavor Compounds and Sensory Characteristics of Maillard Reaction Products Derived from Mushroom Hydrolysate
Molecules 2018, 23(2), 247; https://doi.org/10.3390/molecules23020247 - 26 Jan 2018
Cited by 12
Abstract
Maillard reaction products (MRPs) were prepared from mushroom hydrolysate (MH) by heating with d-xylose and l-cysteine at various temperatures (100 °C–140 °C) for 2 h at a pH of 7.4. The sensory characteristics of MH and MRPs were evaluated by panelists [...] Read more.
Maillard reaction products (MRPs) were prepared from mushroom hydrolysate (MH) by heating with d-xylose and l-cysteine at various temperatures (100 °C–140 °C) for 2 h at a pH of 7.4. The sensory characteristics of MH and MRPs were evaluated by panelists and volatile compounds were analyzed by GC/MS. Additionally, partial least squares regression (PLSR) was performed to analyze the correlation between quantitative sensory characteristics and GC/MS data. GC/MS results revealed that higher reaction temperature resulted in more nitrogen and sulfur containing compounds in MRPs while alcohols, ketones and aldehydes were the major flavor compounds obtained in MH. PLSR results showed that 3-phenylfuran and 2-octylfuran were the compounds responsible for the caramel-like flavor; 1-octen-3-ol, (E)-2-octen-1-ol and geranyl acetone were significantly and positively correlated to mushroom-like flavor, whereas, 2-thiophene-carboxaldehyde, 2,5-thiophenedicarboxaldehyde and 3-methylbutanal positively affected MRPs meat-like attribute. Overall, 125 °C was identified as the optimal temperature for preparing MRPs with abundant volatile compounds and favorable sensory characteristics; the concentration of free amino acids and 5′-GMP, which are associated with the umami taste, in MRPs derived under 125 °C were 3 to 4 times higher than those in MH. Full article
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2017

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Open AccessArticle
Cytotoxicity of the Defensive Secretion from the Medicinal Insect Blaps rynchopetera
Molecules 2018, 23(1), 10; https://doi.org/10.3390/molecules23010010 - 21 Dec 2017
Cited by 9
Abstract
Blaps rynchopetera Fairmaire has long been used as a folk medicine by the Yi and Bai ethnic groups in China to treat fever, cough, gastritis, boils, and tumors. In the present study, the cytotoxicity of the defensive secretion (TDS) of B. rynchopetera against [...] Read more.
Blaps rynchopetera Fairmaire has long been used as a folk medicine by the Yi and Bai ethnic groups in China to treat fever, cough, gastritis, boils, and tumors. In the present study, the cytotoxicity of the defensive secretion (TDS) of B. rynchopetera against AGS Caco-2, HepG2 U251 and Bel-7402 was tested, and the results revealed that TDS had potent cytotoxicity against testing cells with IC50 values of 45.8, 17.4, 53.6, 98.4 and 23.4 μg/mL, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis was employed to clarify the cytotoxic constituents in TDS of B. rynchopetera and five volatile compounds, including 2-ethyl-2,5-cyclohexadiene-1,4-dione (3, 31.00%), 1-tridecene (5, 28.02%), 2-methyl-2,5-cyclohexadiene-1,4-dione (2, 22.86%), hydroquinone (4, 1.33%), and p-benzoquinone (1, 1.01%), were identified. Chemical constituent investigation on TDS further supported the presence of 5 above compounds. A cytotoxic assay indicated that compounds 1, 2, 3 and 4 exhibited significant cytotoxicity against the testing cell lines, implying that benzoquinones and hydroquinone played important roles in the cytotoxicity of TDS of B. rynchopetera. TDS is a cytotoxic natural material and further studies investigating mechanisms and inhibitory activities on other cell lines is warranted. Full article
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Open AccessArticle
Disaccharides: Influence on Volatiles and Phenolics of Sour Cherry Juice
Molecules 2017, 22(11), 1939; https://doi.org/10.3390/molecules22111939 - 09 Nov 2017
Cited by 4
Abstract
The food industry is continuously developing ingredients, processing methods and packaging materials to improve the quality of fruit products. The aim of this work was to study the effect of sugars, a common ingredient in the food industry, on phenolics and volatiles of [...] Read more.
The food industry is continuously developing ingredients, processing methods and packaging materials to improve the quality of fruit products. The aim of this work was to study the effect of sugars, a common ingredient in the food industry, on phenolics and volatiles of sour cherry juice. Sucrose, trehalose and maltose chemical isomers were chosen for this investigation. All sugars influenced the evaluated parameters. Samples with maltose addition had lower, while samples with sucrose and trehalose addition had higher anthocyanin content than the control sample. Generally, trehalose had a higher positive effect on volatiles with the desired flavor note. Full article
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Open AccessArticle
Discriminative Analysis of Different Grades of Gaharu (Aquilaria malaccensis Lamk.) via 1H-NMR-Based Metabolomics Using PLS-DA and Random Forests Classification Models
Molecules 2017, 22(10), 1612; https://doi.org/10.3390/molecules22101612 - 25 Sep 2017
Cited by 10
Abstract
Gaharu (agarwood, Aquilaria malaccensis Lamk.) is a valuable tropical rainforest product traded internationally for its distinctive fragrance. It is not only popular as incense and in perfumery, but also favored in traditional medicine due to its sedative, carminative, cardioprotective and analgesic effects. The [...] Read more.
Gaharu (agarwood, Aquilaria malaccensis Lamk.) is a valuable tropical rainforest product traded internationally for its distinctive fragrance. It is not only popular as incense and in perfumery, but also favored in traditional medicine due to its sedative, carminative, cardioprotective and analgesic effects. The current study addresses the chemical differences and similarities between gaharu samples of different grades, obtained commercially, using 1H-NMR-based metabolomics. Two classification models: partial least squares-discriminant analysis (PLS-DA) and Random Forests were developed to classify the gaharu samples on the basis of their chemical constituents. The gaharu samples could be reclassified into a ‘high grade’ group (samples A, B and D), characterized by high contents of kusunol, jinkohol, and 10-epi-γ-eudesmol; an ‘intermediate grade’ group (samples C, F and G), dominated by fatty acid and vanillic acid; and a ‘low grade’ group (sample E and H), which had higher contents of aquilarone derivatives and phenylethyl chromones. The results showed that 1H- NMR-based metabolomics can be a potential method to grade the quality of gaharu samples on the basis of their chemical constituents. Full article
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Open AccessFeature PaperArticle
One-Pot Multi-Enzymatic Synthesis of the Four Stereoisomers of 4-Methylheptan-3-ol
Molecules 2017, 22(10), 1591; https://doi.org/10.3390/molecules22101591 - 22 Sep 2017
Cited by 4
Abstract
The use of pheromones in the integrated pest management of insects is currently considered a sustainable and environmentally benign alternative to hazardous insecticides. 4-Methylheptan-3-ol is an interesting example of an insect pheromone, because its stereoisomers are active towards different species. All four possible [...] Read more.
The use of pheromones in the integrated pest management of insects is currently considered a sustainable and environmentally benign alternative to hazardous insecticides. 4-Methylheptan-3-ol is an interesting example of an insect pheromone, because its stereoisomers are active towards different species. All four possible stereoisomers of this compound were prepared from 4-methylhept-4-en-3-one by a one-pot procedure in which the two stereogenic centres were created during two sequential reductions catalysed by an ene-reductase (ER) and an alcohol dehydrogenase (ADH), respectively. Full article
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Open AccessFeature PaperArticle
Chemical and Antimicrobial Analyses of Sideritis romana L. subsp. purpurea (Tal. ex Benth.) Heywood, an Endemic of the Western Balkan
Molecules 2017, 22(9), 1395; https://doi.org/10.3390/molecules22091395 - 23 Aug 2017
Cited by 9
Abstract
A comprehensive study on essential oil and different solvent extracts of Sideritis romana L. subsp. purpurea (Tal. ex Benth.) Heywood (Lamiaceae) from Montenegro is reported. The gas chromatography-mass spectrometry analysis of the essential oil revealed a total of 43 components with bicyclogermacrene (23.8%), [...] Read more.
A comprehensive study on essential oil and different solvent extracts of Sideritis romana L. subsp. purpurea (Tal. ex Benth.) Heywood (Lamiaceae) from Montenegro is reported. The gas chromatography-mass spectrometry analysis of the essential oil revealed a total of 43 components with bicyclogermacrene (23.8%), germacrene D (8%), (E)-caryophyllene (7.9%) and spathulenol (5.5%) as the major ones. Sesquiterpenoid group was found to be the most dominant one (64.8%), with 19.9% of the oxygenated forms. In the crude methanol extract of the investigated plant, obtained by Sohhlet exraction, the total phenol content was 14.7 ± 0.4 mg of GA/g, the total flavonoids were 0.29 ± 0.03% expressed as hyperoside percentage, whereas the total tannins content was 0.22 ± 0.04% expressed as pyrogallol percentage. For the antimicrobial activity determination, the following microorganisms have been used: methicillin-susceptible Staphylococcus aureus (MSSA (American Type Culture Collection (ATCC) 29213)) and methicillin-resistant S. aureus (MRSA (clinical strain)), Escherichia coli (ATCC 25922), carbapenem-susceptible Klebsiella pneumoniae (clinical strain), carbapenem-resistant K. pneumoniae (clinical strain) and Candida albicans (ATCC 14053). The essential oil showed high potency against MSSA and MRSA, both at high (~5 × 105 CFU/mL) and low (~5 × 103 CFU/mL) inoculum. With respect to MSSA, the minimal inhibitory concentration (MIC) value was 0.307 mg/mL, with bactericidal activity obtained at 0.615 mg/mL, while, in the case of MRSA, the MIC and minimal bactericidal concentration (MBC) values were 0.076 and 0.153 mg/mL, respectively. Regarding anti-Candida albicans activity, the MIC value was 2.46 mg/mL without reaching fungicidal activity. In addition to the observed essential oil efficacy, different solvent extracts were analyzed for their antimicrobial activity. Similarly to the essential oil, thehighest efficacy was observed against both MSSA and MRSA strains, at high and low inoculums, in the case of the 1,2-dichloroethane and methanol extracts. A potent fungicidal activity has been also found for the n-hexane and 1,2-dichloroethane extracts. It can be concluded that Sideritis romana L. subsp. purpurea (Tal. ex Benth.) Heywood provides a wide range of application in different fields such as phytochemistry, pharmacology, toxicology or pharmacognosy. Full article
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Open AccessReview
β-Ocimene, a Key Floral and Foliar Volatile Involved in Multiple Interactions between Plants and Other Organisms
Molecules 2017, 22(7), 1148; https://doi.org/10.3390/molecules22071148 - 13 Jul 2017
Cited by 20
Abstract
β-Ocimene is a very common plant volatile released in important amounts from the leaves and flowers of many plant species. This acyclic monoterpene can play several biological functions in plants, by potentially affecting floral visitors and also by mediating defensive responses to herbivory. [...] Read more.
β-Ocimene is a very common plant volatile released in important amounts from the leaves and flowers of many plant species. This acyclic monoterpene can play several biological functions in plants, by potentially affecting floral visitors and also by mediating defensive responses to herbivory. The ubiquity and high relative abundance of β-ocimene in the floral scents of species from most plant families and from different pollination syndromes (ranging from generalism to specialism) strongly suggest that this terpenoid may play an important role in the attraction of pollinators to flowers. We compiled abundant evidence from published studies that supports β-ocimene as a generalist attractant of a wide spectrum of pollinators. We found no studies testing behavioural responses of pollinators to β-ocimene, that could directly demonstrate or deny the function of β-ocimene in pollinator attraction; but several case studies support that the emissions of β-ocimene in flowers of different species follow marked temporal and spatial patterns of emission, which are typical from floral volatile organic compound (VOC) emissions that are involved in pollinator attraction. Furthermore, important β-ocimene emissions are induced from vegetative plant tissues after herbivory in many species, which have relevant functions in the establishment of tritrophic interactions. We thus conclude that β-ocimene is a key plant volatile with multiple relevant functions in plants, depending on the organ and the time of emission. Experimental behavioural studies on pure β-ocimene conducted with pollinating insects will be necessary to prove the assumptions made here. Full article
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Open AccessArticle
Sensory Characteristics and Volatile Components of Dry Dog Foods Manufactured with Sorghum Fractions
Molecules 2017, 22(6), 1012; https://doi.org/10.3390/molecules22061012 - 17 Jun 2017
Cited by 7
Abstract
Descriptive sensory analysis and gas chromatography-mass spectrometry (GC-MS) with a modified headspace solid-phase microextraction (SPME) method was performed on three extruded dry dog food diets manufactured with different fractions of red sorghum and a control diet containing corn, brewer’s rice, and wheat as [...] Read more.
Descriptive sensory analysis and gas chromatography-mass spectrometry (GC-MS) with a modified headspace solid-phase microextraction (SPME) method was performed on three extruded dry dog food diets manufactured with different fractions of red sorghum and a control diet containing corn, brewer’s rice, and wheat as a grain source in order to determine the effect of sorghum fractions on dry dog food sensory properties. The aroma compounds and flavor profiles of samples were similar with small differences, such as higher toasted aroma notes, and musty and dusty flavor in the mill-feed sample. A total of 37 compounds were tentatively identified and semi-quantified. Aldehydes were the major group present in the samples. The total volatile concentration was low, reflecting the mild aroma of the samples. Partial least squares regression was performed to identify correlations between sensory characteristics and detected aroma compounds. Possible relationships, such as hexanal and oxidized oil, and broth aromatics were identified. Volatile compounds were also associated with earthy, musty, and meaty aromas and flavor notes. This study showed that extruded dry dog foods manufactured with different red sorghum fractions had similar aroma, flavor, and volatile profiles. Full article
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Open AccessArticle
Effect of Selected Mercapto Flavor Compounds on Acrylamide Elimination in a Model System
Molecules 2017, 22(6), 888; https://doi.org/10.3390/molecules22060888 - 31 May 2017
Abstract
The effect of four mercapto flavor compounds (1,2-ethanedithiol, 1-butanethiol, 2-methyl-3-furanthiol, and 2-furanmethanethiol) on acrylamide elimination were investigated in model systems. The obtained results showed that mercaptans assayed were effective in elimination arylamide in a model system. Their reactivities for decreasing acrylamide content depended [...] Read more.
The effect of four mercapto flavor compounds (1,2-ethanedithiol, 1-butanethiol, 2-methyl-3-furanthiol, and 2-furanmethanethiol) on acrylamide elimination were investigated in model systems. The obtained results showed that mercaptans assayed were effective in elimination arylamide in a model system. Their reactivities for decreasing acrylamide content depended on mercaptan’s molecular structure and acrylamide disappearance decreased in the following order: 1,2-ethanedithiol > 2-methyl-3-furanthiol > 1-butanethiol > 2-furanmethanethiol. Mercaptans were added to acrylamide to produce the corresponding 3-(alkylthio) propionamides. This reaction was irreversible and only trace amounts of acrylamide were formed by thermal heating of 3-(alkylthio) propanamide. Although a large amount disappeared, only part of the acrylamide conversed into 3-(alkylthio) propionamides. All of these results constitute a fundamental proof of the complexity of the reactions involved in the removal of free acrylamide in foods. This implies mercapto flavor/aroma may directly or indirectly reduce the level of acrylamide in food processing. This study could be regarded as a pioneer contribution on acrylamide elimination in a model system by the addition of mercapto flavor compounds. Full article
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Open AccessArticle
Impact of a Microbial Cocktail Used as a Starter Culture on Cocoa Fermentation and Chocolate Flavor
Molecules 2017, 22(5), 766; https://doi.org/10.3390/molecules22050766 - 09 May 2017
Cited by 14
Abstract
Chocolate production suffered a vast impact with the emergence of the “witches’ broom” disease in cocoa plants. To recover cocoa production, many disease-resistant hybrid plants have been developed. However, some different cocoa hybrids produce cocoa beans that generate chocolate with variable quality. Fermentation [...] Read more.
Chocolate production suffered a vast impact with the emergence of the “witches’ broom” disease in cocoa plants. To recover cocoa production, many disease-resistant hybrid plants have been developed. However, some different cocoa hybrids produce cocoa beans that generate chocolate with variable quality. Fermentation of cocoa beans is a microbiological process that can be applied for the production of chocolate flavor precursors, leading to overcoming the problem of variable chocolate quality. The aim of this work was to use a cocktail of microorganisms as a starter culture on the fermentation of the ripe cocoa pods from PH15 cocoa hybrid, and evaluate its influence on the microbial communities present on the fermentative process on the compounds involved during the fermentation, and to perform the chocolate sensorial characterization. According to the results obtained, different volatile compounds were identified in fermented beans and in the chocolate produced. Bitterness was the dominant taste found in non-inoculated chocolate, while chocolate made with inoculated beans showed bitter, sweet, and cocoa tastes. 2,3-Butanediol and 2,3-dimethylpyrazine were considered as volatile compounds making the difference on the flavor of both chocolates. Saccharomyces cerevisiae UFLA CCMA 0200, Lactobacillus plantarum CCMA 0238, and Acetobacter pasteurianus CCMA 0241 are proposed as starter cultures for cocoa fermentation. Full article
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Open AccessArticle
The Emission of the Floral Scent of Four Osmanthus fragrans Cultivars in Response to Different Temperatures
Molecules 2017, 22(3), 430; https://doi.org/10.3390/molecules22030430 - 08 Mar 2017
Cited by 9
Abstract
Floral scent is an important part of volatile organic compounds (VOCs) emitted from plants, and is influenced by many environmental and endogenous factors. To investigate the influence of temperature on the emission of the floral scent of Osmanthus fragrans, the number of [...] Read more.
Floral scent is an important part of volatile organic compounds (VOCs) emitted from plants, and is influenced by many environmental and endogenous factors. To investigate the influence of temperature on the emission of the floral scent of Osmanthus fragrans, the number of chemical compounds and their relative release amounts from four cultivars of O. fragrans under different temperature treatments, were identified using the solid-phase microextraction (SPME) technique and gas chromatography-mass spectrometry (GC-MS) in this study. Results revealed that the numbers and release amounts of floral scent components were significantly influenced by different temperatures, and depend on different cultivars and different types of compounds. Overall, most cultivars had the largest number of chemical compounds in 19 °C and the numbers of chemical compounds decreased with the increase or decrease in the temperature. Alcohols and ketones were the two main kinds of compounds responding to temperature change. The response of a specific chemical compound to temperature change was different in four cultivars. Generally, linalool, α-ionone, β-ionone, and γ-decalactone accounted for the highest proportion in the nine main compounds, and changes of these four chemical compounds to different temperatures had obvious contributions to the floral scent of O. fragrans. The results obtained provide evidence that temperatures can greatly influence the emission of floral scent. Full article
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Open AccessReview
Microbial Contribution to Wine Aroma and Its Intended Use for Wine Quality Improvement
Molecules 2017, 22(2), 189; https://doi.org/10.3390/molecules22020189 - 24 Jan 2017
Cited by 68
Abstract
Wine is a complex matrix that includes components with different chemical natures, the volatile compounds being responsible for wine aroma quality. The microbial ecosystem of grapes and wine, including Saccharomyces and non-Saccharomyces yeasts, as well as lactic acid bacteria, is considered by [...] Read more.
Wine is a complex matrix that includes components with different chemical natures, the volatile compounds being responsible for wine aroma quality. The microbial ecosystem of grapes and wine, including Saccharomyces and non-Saccharomyces yeasts, as well as lactic acid bacteria, is considered by winemakers and oenologists as a decisive factor influencing wine aroma and consumer’s preferences. The challenges and opportunities emanating from the contribution of wine microbiome to the production of high quality wines are astounding. This review focuses on the current knowledge about the impact of microorganisms in wine aroma and flavour, and the biochemical reactions and pathways in which they participate, therefore contributing to both the quality and acceptability of wine. In this context, an overview of genetic and transcriptional studies to explain and interpret these effects is included, and new directions are proposed. It also considers the contribution of human oral microbiota to wine aroma conversion and perception during wine consumption. The potential use of wine yeasts and lactic acid bacteria as biological tools to enhance wine quality and the advent of promising advice allowed by pioneering -omics technologies on wine research are also discussed. Full article
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Open AccessArticle
Volatile Compound Profiling by HS-SPME/GC-MS-FID of a Core Olive Cultivar Collection as a Tool for Aroma Improvement of Virgin Olive Oil
Molecules 2017, 22(1), 141; https://doi.org/10.3390/molecules22010141 - 14 Jan 2017
Cited by 10
Abstract
Virgin olive oil (VOO) is the only food product requiring official sensory analysis to be classified in commercial categories, in which the evaluation of the aroma plays a very important role. The selection of parents, with the aim of obtaining new cultivars with [...] Read more.
Virgin olive oil (VOO) is the only food product requiring official sensory analysis to be classified in commercial categories, in which the evaluation of the aroma plays a very important role. The selection of parents, with the aim of obtaining new cultivars with improved oil aroma, is of paramount importance in olive breeding programs. We have assessed the volatile fraction by headspace-solid-phase microextraction/gas chromatography-mass spectrometry-flame ionization detection (HS-SPME/GC-MS-FID) and the deduced aroma properties of VOO from a core set of olive cultivars (Core-36) which possesses most of the genetic diversity found in the World Olive Germplasm Collection (IFAPA Alameda del Obispo) located in Cordoba, Spain. The VOO volatile fractions of Core-36 cultivars display a high level of variability. It is mostly made of compounds produced from polyunsaturated fatty acids through the lipoxygenase pathway, which confirms to be a general characteristic of the olive species (Olea europaea L.). The main group of volatile compounds in the oils was six straight-chain carbon compounds derived from linolenic acid, some of them being the main contributors to the aroma of the olive oils according to their odor activity values (OAV). The high level of variability found for the volatile fraction of the oils from Core-36 and, therefore, for the aroma odor notes, suggest that this core set may be a very useful tool for the choice of optimal parents in olive breeding programs in order to raise new cultivars with improved VOO aroma. Full article
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Open AccessArticle
Optimization of the Production of 1-Phenylethanol Using Enzymes from Flowers of Tea (Camellia sinensis) Plants
Molecules 2017, 22(1), 131; https://doi.org/10.3390/molecules22010131 - 13 Jan 2017
Cited by 4
Abstract
1-Phenylethanol (1PE) can be used as a fragrance in food flavoring and cosmetic industries and as an intermediate in the pharmaceutical industry. 1PE can be synthesized from acetophenone, and the cost of 1PE is higher than the cost of acetophenone. Therefore, it is [...] Read more.
1-Phenylethanol (1PE) can be used as a fragrance in food flavoring and cosmetic industries and as an intermediate in the pharmaceutical industry. 1PE can be synthesized from acetophenone, and the cost of 1PE is higher than the cost of acetophenone. Therefore, it is important to establish an effective and low-cost approach for producing 1PE. Our previous studies found that tea (Camellia sinensis) flowers, which are an abundant and waste resource, contained enzymes that could transform acetophenone to 1PE. In the present study, we extracted crude enzymes from tea flowers and optimized the production conditions of 1PE using response surface methodology. The optimized conditions were an extraction pH of 7.0, a reaction pH of 5.3, a reaction temperature of 55 °C, a reaction time of 100 min, a coenzyme NADPH concentration of 3.75 μmol/mL in the reaction assay, and a substrate acetophenone concentration of 1.25 μmol/mL in the reaction assay. The results provide essential information for future industrial 1PE production using plant-derived enzymes. Full article
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2016

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Open AccessArticle
Chemical Studies of Yellow Tamarillo (Solanum betaceum Cav.) Fruit Flavor by Using a Molecular Sensory Approach
Molecules 2016, 21(12), 1729; https://doi.org/10.3390/molecules21121729 - 16 Dec 2016
Cited by 6
Abstract
The odor-active volatile compounds of yellow tamarillo fruit (S. betaceum Cav.) were identified and quantified by using a sensomics approach, combining a gentle volatile extraction (solvent-assisted flavor evaporation (SAFE)), gas chromatography-mass spectrometry (GC-MS), and sensory analyses (gas chromatography-olfactometry (GC-O) and aroma extract [...] Read more.
The odor-active volatile compounds of yellow tamarillo fruit (S. betaceum Cav.) were identified and quantified by using a sensomics approach, combining a gentle volatile extraction (solvent-assisted flavor evaporation (SAFE)), gas chromatography-mass spectrometry (GC-MS), and sensory analyses (gas chromatography-olfactometry (GC-O) and aroma extract dilution analysis (AEDA)). The medium-term purpose of this work is to evaluate the change of odor-active volatiles during processing. Thus, (Z)-3-hexenal, hexanal, and ethyl butanoate were identified as key aroma compounds of yellow tamarillo. The C6-aliphatic compounds, aliphatic esters, and terpenols were characterized as the volatiles responsible for the herbal-green, fruity, and fresh-mint odor notes of this variety, respectively. Additionally, one non-volatile compound contributing to the residual bitter taste of this fruit was isolated by a bioguided (taste sensory analyses) fractionation. The freeze-dried fruit was sequentially liquid-liquid partitioned with solvents of different polarity, and then the ethyl acetate fraction was submitted to size exclusion chromatography. Then, its structure was elucidated as rosmarinic acid, by using common spectroscopic methods (mass spectrometry (MS) and nuclear magnetic resonance (NMR)). The amount of rosmarinic acid was quantified as 46.17 ± 1.20 mg/100 g of dried fruit, by the external standard method. Its bitter taste threshold value was determined by using the 3AFC (alternative forced choice) method to be 37.00 ± 1.25 mg/L. Full article
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Open AccessArticle
Laurus nobilis, Zingiber officinale and Anethum graveolens Essential Oils: Composition, Antioxidant and Antibacterial Activities against Bacteria Isolated from Fish and Shellfish
Molecules 2016, 21(10), 1414; https://doi.org/10.3390/molecules21101414 - 22 Oct 2016
Cited by 22
Abstract
Several bacterial strains were isolated from wild and reared fish and shellfish. The identification of these strains showed the dominance of the Aeromonas hydrophila species in all seafood samples, followed by Staphylococcus spp., Vibrio alginolyticus, Enterobacter cloacae, Klebsiella ornithinolytica, Klebsiella [...] Read more.
Several bacterial strains were isolated from wild and reared fish and shellfish. The identification of these strains showed the dominance of the Aeromonas hydrophila species in all seafood samples, followed by Staphylococcus spp., Vibrio alginolyticus, Enterobacter cloacae, Klebsiella ornithinolytica, Klebsiella oxytoca and Serratia odorifera. The isolates were studied for their ability to produce exoenzymes and biofilms. The chemical composition of the essential oils from Laurus nobilis leaves, Zingiber officinale rhizomes and Anethum graveolens aerial parts was studied by GC and GC/MS. The essential oils’ antioxidant and antibacterial activities against the isolated microorganisms were studied. Low concentrations of the three essential oils were needed to inhibit the growth of the selected bacteria and the lowest MBCs values were obtained for the laurel essential oil. The selected essential oils can be used as a good natural preservative in fish food due to their antioxidant and antibacterial activities. Full article
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Open AccessArticle
Chemical Composition and in Vitro Antimicrobial, Cytotoxic, and Central Nervous System Activities of the Essential Oils of Citrus medica L. cv. ‘Liscia’ and C. medica cv. ‘Rugosa’ Cultivated in Southern Italy
Molecules 2016, 21(9), 1244; https://doi.org/10.3390/molecules21091244 - 18 Sep 2016
Cited by 11
Abstract
Citrus medica cv. ‘liscia’ and C. medica cv. ‘rugosa’ are two taxa of citron, belonging to the biodiversity of South Italy, in particular of Amalfi Coast, in the Campania region. The chemical composition of the essential oils (EOs) from fruit peels of both [...] Read more.
Citrus medica cv. ‘liscia’ and C. medica cv. ‘rugosa’ are two taxa of citron, belonging to the biodiversity of South Italy, in particular of Amalfi Coast, in the Campania region. The chemical composition of the essential oils (EOs) from fruit peels of both C. medica cultivars was studied by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analyses. In all, 100 compounds were identified, 82 for C. medica cv. ‘liscia’, accounting for 91.4% of the total oil, and 88 for C. medica cv. ‘rugosa’, accounting for 92.0% of the total oil. Monoterpene hydrocarbons are the main constituents in both oils of C. medica cv. ‘liscia’ (79.1%) and C. medica cv. ‘rugosa’ (80.2%). In both oils, limonene (67.2%–62.8%) and camphene (8.5%–10.9%) are the main constituents. The antimicrobial activity of the EOs was assayed against some bacterial strains: Bacillus cereus (DSM 4313), Bacillus cereus (DSM 4384), Staphylococcus aureus (DSM 25693), Pseudomonas aeruginosa (ATCC 50071), and Escherichia coli (DSM 8579). Low concentrations of C. medica cv. ‘rugosa’ EO showed an inhibitory effect on P. aeruginosa and higher concentrations inhibited more B. cereus (4384) and E. coli than S. aureus. The cytotoxicity of the EO was evaluated against SH-SY5Y cell line. The influence of the EO on the expression of adenylate cyclase 1 (ADCY1) was also studied. The antimicrobial activity registered confirm their traditional uses as food preserving agents and led us to hypothesize the possible use of these oils as antimicrobials. The alterations in ADCY1 expression suggested a role for limonene in effects on the central nervous system. Full article
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Open AccessArticle
Chemical Composition, Antibacterial and Phytotoxic Activities of Peganum harmala Seed Essential Oils from Five Different Localities in Northern Africa
Molecules 2016, 21(9), 1235; https://doi.org/10.3390/molecules21091235 - 15 Sep 2016
Cited by 9
Abstract
Peganum harmala L., also known as Syrian rue or Pègano, is a herbaceous plant belonging to the Zygohpyllaceae family, and is widely used in traditional medicine. The chemical composition of essential oils of P. harmala seeds from five different regions of Northern Africa [...] Read more.
Peganum harmala L., also known as Syrian rue or Pègano, is a herbaceous plant belonging to the Zygohpyllaceae family, and is widely used in traditional medicine. The chemical composition of essential oils of P. harmala seeds from five different regions of Northern Africa (Algeria, Egypt, Libya, Morocco and Tunisia) was studied by GC and GC-MS analyses. A total of 105 compounds were identified, the main components being oxygenated monoterpenes and oxygenated sesquiterpenes. Eugenol is the main component in all oils. The antimicrobial activity of the essential oils was assayed against some bacterial strains: Staphylococcus aureus (DSM 25693), Bacillus cereus (DSM 4313), Bacillus cereus (DSM4384), Escherichia coli (DMS 857) and Pseudomonas aeruginosa (ATCC 50071). All the oils showed different inhibitory activity. In the twentieth century this is an important result; we need possible new botanical drugs because the problem of resistance to antimicrobial drugs has become apparent. Moreover, the essential oils were evaluated for their possible in vitro phytotoxic activity against germination and initial radicle growth of Raphanus sativus L., Lepidium sativum L., and Ruta graveolens L. The results showed that both germination and radical elongation were sensitive to the oils. Full article
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Open AccessArticle
Elucidation of Differential Accumulation of 1-Phenylethanol in Flowers and Leaves of Tea (Camellia sinensis) Plants
Molecules 2016, 21(9), 1106; https://doi.org/10.3390/molecules21091106 - 23 Aug 2016
Cited by 7
Abstract
1-Phenylethanol (1PE) is a major aromatic volatile in tea (Camellia sinensis) flowers, whereas it occurs in a much smaller amounts in leaves. Enzymes involved in the formation of 1PE in plants and the reason why 1PE differentially accumulates in plants is [...] Read more.
1-Phenylethanol (1PE) is a major aromatic volatile in tea (Camellia sinensis) flowers, whereas it occurs in a much smaller amounts in leaves. Enzymes involved in the formation of 1PE in plants and the reason why 1PE differentially accumulates in plants is unknown. In the present study, enzymes in the last step leading from acetophenone to 1PE were isolated from tea flowers by traditional biochemical chromatography. The two types of partially purified enzymes were proposed to be responsible for formations of (R)-1PE and (S)-1PE, respectively. Tea leaves also contained such enzymes having equivalent activities with flowers. Stable isotope labeling experiments indicated that weak transformation from l-phenylalanine to acetophenone in leaves mainly resulted in little occurrence of 1PE in leaves. This study provided an example that differential distribution of some metabolites in plant tissues was not only determined by enzyme(s) in the last step of metabolite formation, but also can be due to substrate availability. Full article
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Open AccessArticle
Integrated Analysis of the Wood Oil from Xanthocyparis vietnamensis Farjon & Hiep. by Chromatographic and Spectroscopic Techniques
Molecules 2016, 21(7), 840; https://doi.org/10.3390/molecules21070840 - 27 Jun 2016
Cited by 3
Abstract
In order to get better knowledge about the volatiles produced by Xanthocyparis vietnamensis, a species recently discovered in Vietnam, its wood oil has been analyzed by a combination of chromatographic (GC, CC) and spectroscopic (GC-MS, 13C-NMR) techniques. Forty components that accounted for [...] Read more.
In order to get better knowledge about the volatiles produced by Xanthocyparis vietnamensis, a species recently discovered in Vietnam, its wood oil has been analyzed by a combination of chromatographic (GC, CC) and spectroscopic (GC-MS, 13C-NMR) techniques. Forty components that accounted for 87.9% of the oil composition have been identified. The composition is dominated by nootkatene (20.7%), 11,12,13-tri-nor-eremophil-1(10)-en-7-one (17.2%), γ-eudesmol (5.1%), nootkatone (4.7%), valencene (3.5%) and 13-nor-eremophil-1(10)-en-11-one (2.6%). The structure of two new compounds—10-epi-nor-γ-eudesmen-11-one and 12-hydroxy-isodihydroagarofuran—has been elucidated, while 11,12,13-tri-nor-eremophil-1(10)-en-7-ol is reported as a natural product for the first time. The composition of X. vietnamensis wood oil varied drastically from those of leaf oils, dominated by hedycaryol (34.4%), phyllocladene (37.8%) or by pimara-6(14)-15-diene (19.4%). Full article
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Open AccessArticle
Analysis of Odorants in Marking Fluid of Siberian Tiger (Panthera tigris altaica) Using Simultaneous Sensory and Chemical Analysis with Headspace Solid-Phase Microextraction and Multidimensional Gas Chromatography-Mass Spectrometry-Olfactometry
Molecules 2016, 21(7), 834; https://doi.org/10.3390/molecules21070834 - 25 Jun 2016
Cited by 6
Abstract
Scent-marking is the most effective method of communication in the presence or absence of a signaler. These complex mixtures result in a multifaceted interaction triggered by the sense of smell. The objective was to identify volatile organic compound (VOC) composition and odors emitted [...] Read more.
Scent-marking is the most effective method of communication in the presence or absence of a signaler. These complex mixtures result in a multifaceted interaction triggered by the sense of smell. The objective was to identify volatile organic compound (VOC) composition and odors emitted by total marking fluid (MF) associated with Siberian tigers (Panthera tigris altaica). Siberian tiger, an endangered species, was chosen because its MF had never been analyzed. Solid phase microextraction (SPME) for headspace volatile collection combined with multidimensional gas chromatography-mass spectrometry-olfactometry for simultaneous chemical and sensory analyses were used. Thirty-two VOCs emitted from MF were identified. 2-acetyl-1-pyrroline, the sole previously identified compound responsible for the “characteristic” odor of P. tigris MF, was identified along with two additional compounds confirmed with standards (urea, furfural) and four tentatively identified compounds (3-methylbutanamine, (R)-3-methylcyclopentanone, propanedioic acid, and 3-hydroxybutanal) as being responsible for the characteristic aroma of Siberian tiger MF. Simultaneous chemical and sensory analyses improved characterization of scent-markings and identified compounds not previously reported in MF of other tiger species. This research will assist animal ecologists, behaviorists, and zookeepers in understanding how scents from specific MF compounds impact tiger and wildlife communication and improve management practices related to animal behavior. Simultaneous chemical and sensory analyses is applicable to unlocking scent-marking information for other species. Full article
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Open AccessArticle
Antispasmodic Effects and Action Mechanism of Essential Oil of Chrysactinia mexicana A. Gray on Rabbit Ileum
Molecules 2016, 21(6), 783; https://doi.org/10.3390/molecules21060783 - 16 Jun 2016
Cited by 5
Abstract
The Chrysactinia mexicana A. Gray (C. mexicana) plant is used in folk medicine to treat fever and rheumatism; it is used as a diuretic, antispasmodic; and it is used for its aphrodisiac properties. This study investigates the effects of the essential oil of [...] Read more.
The Chrysactinia mexicana A. Gray (C. mexicana) plant is used in folk medicine to treat fever and rheumatism; it is used as a diuretic, antispasmodic; and it is used for its aphrodisiac properties. This study investigates the effects of the essential oil of C. mexicana (EOCM) on the contractility of rabbit ileum and the mechanisms of action involved. Muscle contractility studies in vitro in an organ bath to evaluate the response to EOCM were performed in the rabbit ileum. EOCM (1–100 µg·mL−1) reduced the amplitude and area under the curve of spontaneous contractions of the ileum. The contractions induced by carbachol 1 µM, potassium chloride (KCl) 60 mM or Bay K8644 1 µM were reduced by EOCM (30 µg·mL−1). Apamin 1 µM and charybdotoxin 0.01 µM decreased the inhibition induced by EOCM. The d-cAMP 1 µM decreased the inhibition induced by EOCM. l-NNA 10 µM, Rp-8-Br-PET-cGMPS 1 µM, d,l-propargylglycine 2 mM, or aminooxyacetic acid hemihydrochloride 2 mM did not modify the EOCM effect. In conclusion, EOCM induces an antispasmodic effect and could be used in the treatment of intestinal spasms or diarrhea processes. This effect would be mediated by Ca2+, Ca2+-activated K+ channels and cAMP. Full article
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Open AccessArticle
Antimicrobial Activity and Modulatory Effect of Essential Oil from the Leaf of Rhaphiodon echinus (Nees & Mart) Schauer on Some Antimicrobial Drugs
Molecules 2016, 21(6), 743; https://doi.org/10.3390/molecules21060743 - 08 Jun 2016
Cited by 13
Abstract
Background: Rhaphiodon echinus is a weed plant used in the Brazilian folk medicinal for the treatment of infectious diseases. In this study, the essential oil of R. echinus leaf was investigated for its antimicrobial properties. Methods: The chemical constituents of the [...] Read more.
Background: Rhaphiodon echinus is a weed plant used in the Brazilian folk medicinal for the treatment of infectious diseases. In this study, the essential oil of R. echinus leaf was investigated for its antimicrobial properties. Methods: The chemical constituents of the essential oil were characterized by GC-MS. The antimicrobial properties were determined by studying by the microdilution method the effect of the oil alone, and in combination with antifungal or antibiotic drugs against the fungi Candida albicans, Candida krusei and Candida tropicalis and the microbes Escherichia coli, Staphylococcus aureus and Pseudomonas. In addition, the iron (II) chelation potential of the oil was determined. Results: The results showed the presence of β-caryophyllene and bicyclogermacrene in major compounds, and revealed a low antifungal and antibacterial activity of the essential oil, but a strong modulatory effect on antimicrobial drugs when associated with the oil. The essential oil showed iron (II) chelation activity. Conclusions: The GC-MS characterization revealed the presence of monoterpenes and sesquiterpenes in the essential oil and metal chelation potential, which may be responsible in part for the modulatory effect of the oil. These findings suggest that essential oil of R. echinus is a natural product capable of enhancing the antibacterial and antifungal activity of antimicrobial drugs. Full article
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Open AccessReview
Nerolidol: A Sesquiterpene Alcohol with Multi-Faceted Pharmacological and Biological Activities
Molecules 2016, 21(5), 529; https://doi.org/10.3390/molecules21050529 - 28 Apr 2016
Cited by 79
Abstract
Nerolidol (3,7,11-trimethyl-1,6,10-dodecatrien-3-ol) is a naturally occurring sesquiterpene alcohol that is present in various plants with a floral odor. It is synthesized as an intermediate in the production of (3E)-4,8-dimethy-1,3,7-nonatriene (DMNT), a herbivore-induced volatile that protects plants from herbivore damage. Chemically, nerolidol [...] Read more.
Nerolidol (3,7,11-trimethyl-1,6,10-dodecatrien-3-ol) is a naturally occurring sesquiterpene alcohol that is present in various plants with a floral odor. It is synthesized as an intermediate in the production of (3E)-4,8-dimethy-1,3,7-nonatriene (DMNT), a herbivore-induced volatile that protects plants from herbivore damage. Chemically, nerolidol exists in two geometric isomers, a trans and a cis form. The usage of nerolidol is widespread across different industries. It has been widely used in cosmetics (e.g., shampoos and perfumes) and in non-cosmetic products (e.g., detergents and cleansers). In fact, U.S. Food and Drug Administration (FDA) has also permitted the use of nerolidol as a food flavoring agent. The fact that nerolidol is a common ingredient in many products has attracted researchers to explore more medicinal properties of nerolidol that may exert beneficial effect on human health. Therefore, the aim of this review is to compile and consolidate the data on the various pharmacological and biological activities displayed by nerolidol. Furthermore, this review also includes pharmacokinetic and toxicological studies of nerolidol. In summary, the various pharmacological and biological activities demonstrated in this review highlight the prospects of nerolidol as a promising chemical or drug candidate in the field of agriculture and medicine. Full article
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Open AccessArticle
Effect of Food Emulsifiers on Aroma Release
Molecules 2016, 21(4), 511; https://doi.org/10.3390/molecules21040511 - 22 Apr 2016
Cited by 6
Abstract
This study aimed to determine the influence of different emulsifiers or xanthan-emulsifier systems on the release of aroma compounds. Solid-phase microextraction (SPME) and GC-MS were used to study the effects of varying concentrations of xanthan gum, sucrose fatty acid ester, Tween 80 and [...] Read more.
This study aimed to determine the influence of different emulsifiers or xanthan-emulsifier systems on the release of aroma compounds. Solid-phase microextraction (SPME) and GC-MS were used to study the effects of varying concentrations of xanthan gum, sucrose fatty acid ester, Tween 80 and soybean lecithin on the release of seven aroma compounds. The effects of the emulsifier systems supplemented with xanthan gum on aroma release were also studied in the same way. The results showed varying degrees of influence of sucrose fatty acid ester, soybean lecithin, Tween 80 and xanthan gum on the release of aroma compounds. Compared with other aroma compounds, ethyl acetate was more likely to be conserved in the solution system, while the amount of limonene released was the highest among these seven aroma compounds. In conclusion, different emulsifiers and complexes showed different surface properties that tend to interact with different aroma molecules. The present studies showed that the composition and structure of emulsifiers and specific interactions between emulsifiers and aroma molecules have significant effects on aroma release. Full article
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Open AccessCommunication
PTR-MS Characterization of VOCs Associated with Commercial Aromatic Bakery Yeasts of Wine and Beer Origin
Molecules 2016, 21(4), 483; https://doi.org/10.3390/molecules21040483 - 12 Apr 2016
Cited by 25
Abstract
In light of the increasing attention towards “green” solutions to improve food quality, the use of aromatic-enhancing microorganisms offers the advantage to be a natural and sustainable solution that did not negatively influence the list of ingredients. In this study, we characterize, for [...] Read more.
In light of the increasing attention towards “green” solutions to improve food quality, the use of aromatic-enhancing microorganisms offers the advantage to be a natural and sustainable solution that did not negatively influence the list of ingredients. In this study, we characterize, for the first time, volatile organic compounds (VOCs) associated with aromatic bakery yeasts. Three commercial bakery starter cultures, respectively formulated with three Saccharomyces cerevisiae strains, isolated from white wine, red wine, and beer, were monitored by a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS), a direct injection analytical technique for detecting volatile organic compounds with high sensitivity (VOCs). Two ethanol-related peaks (m/z 65.059 and 75.080) described qualitative differences in fermentative performances. The release of compounds associated to the peaks at m/z 89.059, m/z 103.075, and m/z 117.093, tentatively identified as acetoin and esters, are coherent with claimed flavor properties of the investigated strains. We propose these mass peaks and their related fragments as biomarkers to optimize the aromatic performances of commercial preparations and for the rapid massive screening of yeast collections. Full article
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Open AccessArticle
Antibacterial Activity and Action Mechanism of the Essential Oil from Enteromorpha linza L. against Foodborne Pathogenic Bacteria
Molecules 2016, 21(3), 388; https://doi.org/10.3390/molecules21030388 - 21 Mar 2016
Cited by 24
Abstract
Foodborne illness and disease caused by foodborne pathogenic bacteria is continuing to increase day by day and it has become an important topic of concern among various food industries. Many types of synthetic antibacterial agents have been used in food processing and food [...] Read more.
Foodborne illness and disease caused by foodborne pathogenic bacteria is continuing to increase day by day and it has become an important topic of concern among various food industries. Many types of synthetic antibacterial agents have been used in food processing and food preservation; however, they are not safe and have resulted in various health-related issues. Therefore, in the present study, essential oil from an edible seaweed, Enteromorpha linza (AEO), was evaluated for its antibacterial activity against foodborne pathogens, along with the mechanism of its antibacterial action. AEO at 25 mg/disc was highly active against Bacillus cereus (12.3–12.7 mm inhibition zone) and Staphylococcus aureus (12.7–13.3 mm inhibition zone). The minimum inhibitory concentration and minimum bactericidal concentration values of AEO ranged from 12.5–25 mg/mL. Further investigation of the mechanism of action of AEO revealed its strong impairing effect on the viability of bacterial cells and membrane permeability, as indicated by a significant increase in leakage of 260 nm absorbing materials and K+ ions from the cell membrane and loss of high salt tolerance. Taken together, these data suggest that AEO has the potential for use as an effective antibacterial agent that functions by impairing cell membrane permeability via morphological alternations, resulting in cellular lysis and cell death. Full article
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Open AccessArticle
Screening of Satureja subspicata Vis. Honey by HPLC-DAD, GC-FID/MS and UV/VIS: Prephenate Derivatives as Biomarkers
Molecules 2016, 21(3), 377; https://doi.org/10.3390/molecules21030377 - 21 Mar 2016
Cited by 6
Abstract
The samples of Satureja subspicata Vis. honey were confirmed to be unifloral by melissopalynological analysis with the characteristic pollen share from 36% to 71%. Bioprospecting of the samples was performed by HPLC-DAD, GC-FID/MS, and UV/VIS. Prephenate derivatives were shown to be dominant by [...] Read more.
The samples of Satureja subspicata Vis. honey were confirmed to be unifloral by melissopalynological analysis with the characteristic pollen share from 36% to 71%. Bioprospecting of the samples was performed by HPLC-DAD, GC-FID/MS, and UV/VIS. Prephenate derivatives were shown to be dominant by the HPLC-DAD analysis, particularly phenylalanine (167.8 mg/kg) and methyl syringate (MSYR, 114.1 mg/kg), followed by tyrosine and benzoic acid. Higher amounts of MSYR (3–4 times) can be pointed out for distinguishing S. subspicata Vis. honey from other Satureja spp. honey types. GC-FID/MS analysis of ultrasonic solvent extracts of the samples revealed MSYR (46.68%, solvent pentane/Et2O 1:2 (v/v); 52.98%, solvent CH2Cl2) and minor abundance of other volatile prephenate derivatives, as well as higher aliphatic compounds characteristic of the comb environment. Two combined extracts (according to the solvents) of all samples were evaluated for their antioxidant properties by FRAP and DPPH assay; the combined extracts demonstrated higher activity (at lower concentrations) in comparison with the average honey sample. UV/VIS analysis of the samples was applied for determination of CIE Lab colour coordinates, total phenolics (425.38 mg GAE/kg), and antioxidant properties (4.26 mmol Fe2+/kg (FRAP assay) and 0.8 mmol TEAC/kg (DDPH assay)). Full article
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Open AccessArticle
Comparison of the Profile and Composition of Volatiles in Coniferous Needles According to Extraction Methods
Molecules 2016, 21(3), 363; https://doi.org/10.3390/molecules21030363 - 17 Mar 2016
Cited by 6
Abstract
The enantiomeric distribution and profile of volatiles in plants, which affect the biological and organoleptic properties, can be varied depending on extraction methods as well as their cultivars. The secondary volatile components of the needles of three conifer cultivars (Chamaecyparispisifera, Chamaecyparisobtusa [...] Read more.
The enantiomeric distribution and profile of volatiles in plants, which affect the biological and organoleptic properties, can be varied depending on extraction methods as well as their cultivars. The secondary volatile components of the needles of three conifer cultivars (Chamaecyparispisifera, Chamaecyparisobtusa, and Thujaorientalis) were compared. Furthermore, the effects of three different extraction methods—solid-phase microextraction (SPME), steam distillation (SD), and solvent extraction (SE)—on the composition and enantiomeric distribution of those volatiles were elucidated. Monoterpene hydrocarbons predominated in all samples, and the compositions of sesquiterpenes and diterpenes differed according to the cultivar. In particular, the yields of oxygenated monoterpenes and sesquiterpenes were greatest for SD, whereas those of sesquiterpenes and diterpenes were highest for SE. On the other hand, more monoterpenes with higher volatility could be obtained with SPME and SD than when using SE. In addition, the enantiomeric composition of nine chiral compounds found in three cultivars differed according to their chemotype. There were also some differences in the yielded oxygenated monoterpenes and sesquiterpene hydrocarbons, but not monoterpene hydrocarbons, according to the extraction method. These results demonstrate that the extraction methods used as well as the cultivars influence the measured volatile profiles and enantiomeric distribution of coniferous needle extracts. Full article
Open AccessArticle
Fumigant Toxicity of Lamiaceae Plant Essential Oils and Blends of Their Constituents against Adult Rice Weevil Sitophilus oryzae
Molecules 2016, 21(3), 361; https://doi.org/10.3390/molecules21030361 - 16 Mar 2016
Cited by 18
Abstract
To find a new and safe alternative to conventional insecticides, we evaluated the fumigant toxicity of eight Lamiaceae essential oils and their constituents against the adult rice weevil Sitophilus oryzae. Of the eight species tested, hyssop (Hyssopus offcinalis), majoram ( [...] Read more.
To find a new and safe alternative to conventional insecticides, we evaluated the fumigant toxicity of eight Lamiaceae essential oils and their constituents against the adult rice weevil Sitophilus oryzae. Of the eight species tested, hyssop (Hyssopus offcinalis), majoram (Origanum majorana), and Thymus zygis essential oils showed strong fumigant toxicity against S. oryzae adults at 25 mg/L air concentration. Constituents of active essential oils were analyzed by gas chromatography coupled to flame ionization detector (FID) and gas chromatography-mass spectrometry. A total of 13, 15, and 17 compounds were identified from hyssop, majoram, and Thymus zygis essential oils, respectively. Pinocamphone and isopinocamphone were isolated by open column chromatography. Among the test compounds, pinocamphone and isopinocamphone showed the strongest fumigant toxicity against S. oryzae. Sabinene hydrate, linalool, α-terpineol, and terpinen-4-ol exhibited 100% fumigant toxicity against S. oryzae at 3.9 mg/L air concentration. The measured toxicity of the artificial blends of the constituents identified in hyssop, majoram, and Thymus zygis oils indicated that isopinocamphone, terpine-4-ol, and linalool were major contributors to the fumigant toxicity of the artificial blend, respectively. Full article
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Open AccessReview
Recent Advances in Volatiles of Teas
Molecules 2016, 21(3), 338; https://doi.org/10.3390/molecules21030338 - 11 Mar 2016
Cited by 38
Abstract
Volatile compounds are important components of tea aroma, a key attribute of sensory quality. The present review examines the formation of aromatic volatiles of various kinds of teas and factors influencing the formation of tea volatiles, including tea cultivar, growing environment and agronomic [...] Read more.
Volatile compounds are important components of tea aroma, a key attribute of sensory quality. The present review examines the formation of aromatic volatiles of various kinds of teas and factors influencing the formation of tea volatiles, including tea cultivar, growing environment and agronomic practices, processing method and storage of tea. The determination of tea volatiles and the relationship of active-aroma volatiles with the sensory qualities of tea are also discussed in the present paper. Full article
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Open AccessArticle
Expression and Functional Activity of the Human Bitter Taste Receptor TAS2R38 in Human Placental Tissues and JEG-3 Cells
Molecules 2016, 21(3), 306; https://doi.org/10.3390/molecules21030306 - 03 Mar 2016
Cited by 15
Abstract
Bitter taste receptors (TAS2Rs) are expressed in mucous epithelial cells of the tongue but also outside the gustatory system in epithelial cells of the colon, stomach and bladder, in the upper respiratory tract, in the cornified squamous epithelium of the skin as well [...] Read more.
Bitter taste receptors (TAS2Rs) are expressed in mucous epithelial cells of the tongue but also outside the gustatory system in epithelial cells of the colon, stomach and bladder, in the upper respiratory tract, in the cornified squamous epithelium of the skin as well as in airway smooth muscle cells, in the testis and in the brain. In the present work we addressed the question if bitter taste receptors might also be expressed in other epithelial tissues as well. By staining a tissue microarray with 45 tissue spots from healthy human donors with an antibody directed against the best characterized bitter taste receptor TAS2R38, we observed an unexpected strong TAS2R38 expression in the amniotic epithelium, syncytiotrophoblast and decidua cells of the human placenta. To analyze the functionality we first determined the TAS2R38 expression in the placental cell line JEG-3. Stimulation of these cells with diphenidol, a clinically used antiemetic agent that binds TAS2Rs including TAS2R38, demonstrated the functionality of the TAS2Rs by inducing calcium influx. Restriction enzyme based detection of the TAS2R38 gene allele identified JEG-3 cells as PTC (phenylthiocarbamide)-taster cell line. Calcium influx induced by PTC in JEG-3 cells could be inhibited with the recently described TAS2R38 inhibitor probenecid and proved the specificity of the TAS2R38 activation. The expression of TAS2R38 in human placental tissues points to further new functions and hitherto unknown endogenous ligands of TAS2Rs far beyond bitter tasting. Full article
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Open AccessReview
Chemistry and Pharmacology of Citrus sinensis
Molecules 2016, 21(2), 247; https://doi.org/10.3390/molecules21020247 - 22 Feb 2016
Cited by 21
Abstract
Presently the search for new drugs from natural resources is of growing interest to the pharmaceutical industry. Natural products have been the source of new drugs since ancient times. Plants are a good source of secondary metabolites which have been found to have [...] Read more.
Presently the search for new drugs from natural resources is of growing interest to the pharmaceutical industry. Natural products have been the source of new drugs since ancient times. Plants are a good source of secondary metabolites which have been found to have beneficial properties. The present study is a review of the chemistry and pharmacology of Citrus sinensis. This review reveals the therapeutic potential of C. sinensis as a source of natural compounds with important activities that are beneficial for human health that could be used to develop new drugs. Full article
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Open AccessReview
Recent Advances in the Emission and Functions of Plant Vegetative Volatiles
Molecules 2016, 21(2), 124; https://doi.org/10.3390/molecules21020124 - 22 Jan 2016
Cited by 40
Abstract
Plants synthesize and emit a large variety of volatile organic compounds, which possess extremely important ecological functions. In most case, most plant volatiles are liquids, rather than gases, at room temperature. Some volatiles are emitted “on demand” when plants, especially vegetative parts, are [...] Read more.
Plants synthesize and emit a large variety of volatile organic compounds, which possess extremely important ecological functions. In most case, most plant volatiles are liquids, rather than gases, at room temperature. Some volatiles are emitted “on demand” when plants, especially vegetative parts, are exposed to abiotic or biotic stress. In this review, we summarize some of the highlights of plant vegetative volatile emission and functions research published during the past few years. Full article
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2015

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Open AccessReview
Chemical Composition and Biological Activities of Fragrant Mexican Copal (Bursera spp.)
Molecules 2015, 20(12), 22383-22394; https://doi.org/10.3390/molecules201219849 - 12 Dec 2015
Cited by 8
Abstract
Copal is the Spanish word used to describe aromatic resins from several genera of plants. Mexican copal derives from several Bursera spp., Protium copal, some Pinus spp. (e.g., P. pseudostrobus) and a few Fabaceae spp. It has been used for centuries [...] Read more.
Copal is the Spanish word used to describe aromatic resins from several genera of plants. Mexican copal derives from several Bursera spp., Protium copal, some Pinus spp. (e.g., P. pseudostrobus) and a few Fabaceae spp. It has been used for centuries as incense for religious ceremonies, as a food preservative, and as a treatment for several illnesses. The aim of this review is to analyze the chemical composition and biological activity of commercial Mexican Bursera copal. Full article
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Open AccessArticle
Essential Oil Composition, Antioxidant, Cytotoxic and Antiviral Activities of Teucrium pseudochamaepitys Growing Spontaneously in Tunisia
Molecules 2015, 20(11), 20426-20433; https://doi.org/10.3390/molecules201119707 - 16 Nov 2015
Cited by 17
Abstract
The chemical composition, antioxidant, cytotoxic and antiviral activities of the essential oil obtained by hydrodistillation from the aerial parts of Teucrium pseudochamaepitys (Lamiaceae) collected from Zaghouan province of Tunisia are reported. The essential oil was analyzed by gas chromatography equipped with a flame [...] Read more.
The chemical composition, antioxidant, cytotoxic and antiviral activities of the essential oil obtained by hydrodistillation from the aerial parts of Teucrium pseudochamaepitys (Lamiaceae) collected from Zaghouan province of Tunisia are reported. The essential oil was analyzed by gas chromatography equipped with a flame ionization detector (GC-FID) and gas chromatography coupled with mass spectrometry (GC/MS). Thirty-one compounds were identified representing 88.6% of the total essential oil. Hexadecanoic acid was found to be the most abundant component (26.1%) followed by caryophyllene oxide (6.3%), myristicin (4.9%) and α-cubebene (3.9%). The antioxidant capacity of the oil was measured on the basis of the scavenging activity to the stable 2,2-diphenyl-1-picrylhydrazyl (DPPH). The IC50 value of the oil was evaluated as 0.77 mg·mL−1. In addition, the essential oil was found to possess moderate cytotoxic effects on the HEp-2 cell line (50% cytotoxic concentration (CC50) = 653.6 µg·mL−1). The potential antiviral effect was tested against Coxsackievirus B (CV-B), a significant human and mouse pathogen that causes pediatric central nervous system disease, commonly with acute syndromes. The reduction of viral infectivity by the essential oil was measured using a cytopathic (CPE) reduction assay. Full article
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Open AccessArticle
The Occurrence of Propyl Lactate in Chinese Baijius (Chinese Liquors) Detected by Direct Injection Coupled with Gas Chromatography-Mass Spectrometry
Molecules 2015, 20(10), 19002-19013; https://doi.org/10.3390/molecules201019002 - 19 Oct 2015
Cited by 12
Abstract
As one of the oldest distillates in the world, flavor compounds of Chinese Baijiu (Chinese liquor) were extremely complex. Propyl lactate was firstly detected by direct injection and gas chromatography-mass spectrometry (GC-MS) in 72 Chinese Baijius. The objectives were to detect the contents [...] Read more.
As one of the oldest distillates in the world, flavor compounds of Chinese Baijiu (Chinese liquor) were extremely complex. Propyl lactate was firstly detected by direct injection and gas chromatography-mass spectrometry (GC-MS) in 72 Chinese Baijius. The objectives were to detect the contents of propyl lactate and evaluate its contribution to the aroma of Chinese Baijiu based on odor activity values (OAVs). The levels of propyl lactate in these distillates were determined by internal standard method and selective ion monitoring (SIM), which ranged from 0.050 to 1.900 mg∙L−1 under investigation. Its detection threshold was determined by Three-Alternative Forced-Choice (3-AFC) and curve fitting (CF), which was 0.740 mg∙L−1 in 38% ethanol solution. The contribution of propyl lactate on the aroma of these distillate drinks was evaluated by their odor activity values (OAVs), which varied from 0.066 to 4.440. The OAVs of propyl lactate were found to exceed 1 in 13 Chinese Baijius, including 50° Jingzhi Guniang 5 years (4.440), 52° Jingzhi Guniang 10 years (3.024), Jingyanggang (2.568), Xianghe Ronghe Shaofang (2.313), and 1956 Laolang (1.431), which indicated that propyl lactate was one of odor-active components in these Chinese Baijius. Full article
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Open AccessArticle
Contribution of Bacillus Isolates to the Flavor Profiles of Vanilla Beans Assessed through Aroma Analysis and Chemometrics
Molecules 2015, 20(10), 18422-18436; https://doi.org/10.3390/molecules201018422 - 09 Oct 2015
Cited by 2
Abstract
Colonizing Bacillus in vanilla (Vanilla planifolia Andrews) beans is involved in glucovanillin hydrolysis and vanillin formation during conventional curing. The flavor profiles of vanilla beans under Bacillus-assisted curing were analyzed through gas chromatography-mass spectrometry, electronic nose, and quantitative sensory analysis. The [...] Read more.
Colonizing Bacillus in vanilla (Vanilla planifolia Andrews) beans is involved in glucovanillin hydrolysis and vanillin formation during conventional curing. The flavor profiles of vanilla beans under Bacillus-assisted curing were analyzed through gas chromatography-mass spectrometry, electronic nose, and quantitative sensory analysis. The flavor profiles were analytically compared among the vanilla beans under Bacillus-assisted curing, conventional curing, and non-microorganism-assisted curing. Vanilla beans added with Bacillus vanillea XY18 and Bacillus subtilis XY20 contained higher vanillin (3.58% ± 0.05% and 3.48% ± 0.10%, respectively) than vanilla beans that underwent non-microorganism-assisted curing and conventional curing (3.09% ± 0.14% and 3.21% ± 0.15%, respectively). Forty-two volatiles were identified from endogenous vanilla metabolism. Five other compounds were identified from exogenous Bacillus metabolism. Electronic nose data confirmed that vanilla flavors produced through the different curing processes were easily distinguished. Quantitative sensory analysis confirmed that Bacillus-assisted curing increased vanillin production without generating any unpleasant sensory attribute. Partial least squares regression further provided a correlation model of different measurements. Overall, we comparatively analyzed the flavor profiles of vanilla beans under Bacillus-assisted curing, indirectly demonstrated the mechanism of vanilla flavor formation by microbes. Full article
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Open AccessArticle
Characterization of Fatty Acid, Amino Acid and Volatile Compound Compositions and Bioactive Components of Seven Coffee (Coffea robusta) Cultivars Grown in Hainan Province, China
Molecules 2015, 20(9), 16687-16708; https://doi.org/10.3390/molecules200916687 - 14 Sep 2015
Cited by 23
Abstract
Compositions of fatty acid, amino acids, and volatile compound were investigated in green coffee beans of seven cultivars of Coffea robusta grown in Hainan Province, China. The chlorogenic acids, trigonelline, caffeine, total lipid, and total protein contents as well as color parameters were [...] Read more.
Compositions of fatty acid, amino acids, and volatile compound were investigated in green coffee beans of seven cultivars of Coffea robusta grown in Hainan Province, China. The chlorogenic acids, trigonelline, caffeine, total lipid, and total protein contents as well as color parameters were measured. Chemometric techniques, principal component analysis (PCA), hierarchical cluster analysis (HCA), and analysis of one-way variance (ANOVA) were performed on the complete data set to reveal chemical differences among all cultivars and identify markers characteristic of a particular botanical origin of the coffee. The major fatty acids of coffee were linoleic acid, palmitic acid, oleic acid, and arachic acid. Leucine (0.84 g/100 g DW), lysine (0.63 g/100 g DW), and arginine (0.61 g/100 g DW) were the predominant essential amino acids (EAAs) in the coffee samples. Seventy-nine volatile compounds were identified and semi-quantified by HS-SPME/GC-MS. PCA of the complete data matrix demonstrated that there were significant differences among all cultivars, HCA supported the results of PCA and achieved a satisfactory classification performance. Full article
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Open AccessArticle
Extractions of Oil from Descurainia sophia Seed Using Supercritical CO2, Chemical Compositions by GC-MS and Evaluation of the Anti-Tussive, Expectorant and Anti-Asthmatic Activities
Molecules 2015, 20(7), 13296-13312; https://doi.org/10.3390/molecules200713296 - 22 Jul 2015
Cited by 10
Abstract
Descurainia sophia is widely distributed in China and is one of the most troublesome annual weeds. It has diverse medicinal usage. D. sophia has abundant oil, making it an important oil plant in China. The main goal of this study was to obtain [...] Read more.
Descurainia sophia is widely distributed in China and is one of the most troublesome annual weeds. It has diverse medicinal usage. D. sophia has abundant oil, making it an important oil plant in China. The main goal of this study was to obtain the maximum yield of the oil by an optimal selection of supercritical fluid extraction parameters. According to the central composite design and response surface methodology for supercritical fluid extraction method, a quadratic polynomial model was used to predict the yield of D. sophia seed oil. A series of runs was performed to assess the optimal extraction conditions. The results indicated that the extraction pressure had the greatest impact on oil yield within the range of the operating conditions studied. A total of approximately 67 compounds were separated in D. sophia seed oil by GC-MS, of which 51 compounds represented 98.21% of the total oils, for the first time. This study was also aimed at evaluating the anti-asthmatic, anti-tussive and expectorant activities in vivo of D. sophia seed oil which supplied for further research on bioactive constituents and pharmacological mechanisms. Full article
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Open AccessReview
Recent Advances in the Synthesis of Carotenoid-Derived Flavours and Fragrances
Molecules 2015, 20(7), 12817-12840; https://doi.org/10.3390/molecules200712817 - 15 Jul 2015
Cited by 15
Abstract
Carotenoids are important isoprenoid compounds whose oxidative degradation produces a plethora of smaller derivatives, called apocarotenoids, which possess a range of different chemical structures and biological activities. Among these natural products, compounds having less than 15 carbon atoms in their frameworks are often [...] Read more.
Carotenoids are important isoprenoid compounds whose oxidative degradation produces a plethora of smaller derivatives, called apocarotenoids, which possess a range of different chemical structures and biological activities. Among these natural products, compounds having less than 15 carbon atoms in their frameworks are often relevant flavours or fragrances and their manufacturing represents an important economic resource for chemical companies. The strict correlation between stereochemical structure and odour has made the stereospecific synthesis of the latter biological active compounds increasingly important. In this review, the recent advances on the synthesis of the most relevant carotenoid-derived flavours and fragrances are discussed. In particular, the new synthetic methods that have given new and innovative perspectives from a scientific standpoint and the preparative approaches that might possess industrial importance are described thoroughly. Full article
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Open AccessArticle
Chemical Composition and Antioxidant and Antibacterial Activities of an Essential Oil Extracted from an Edible Seaweed, Laminaria japonica L.
Molecules 2015, 20(7), 12093-12113; https://doi.org/10.3390/molecules200712093 - 02 Jul 2015
Cited by 28
Abstract
Laminaria japonica L. is among the most commonly consumed seaweeds in northeast Asia. In the present study, L. japonica essential oil (LJEO) was extracted by microwave-hydrodistillation and analyzed by gas chromatography and mass spectroscopy. LJEO contained 21 volatile compounds, comprising 99.76% of the [...] Read more.
Laminaria japonica L. is among the most commonly consumed seaweeds in northeast Asia. In the present study, L. japonica essential oil (LJEO) was extracted by microwave-hydrodistillation and analyzed by gas chromatography and mass spectroscopy. LJEO contained 21 volatile compounds, comprising 99.76% of the total volume of the essential oil, primarily tetradeconoic acid (51.75%), hexadecanoic acid (16.57%), (9Z,12Z)-9,12-Octadecadienoic acid (12.09%), and (9Z)-hexadec-9-enoic acid (9.25%). Evaluation of the antibacterial potential against three foodborne pathogens, Bacillus cereus ATCC 10876, Escherichia coli O157:H7 ATCC 43890, and Staphylococcus aureus ATCC 49444, revealed that LJEO at a concentration of 25 mg/paper disc exerted high antibacterial activity against S. aureus (11.5 ± 0.58 mm inhibition zone) and B. cereus (10.5 ± 0.57 mm inhibition zone), but no inhibition of E. coli O157:H7. LJEO also displayed DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical scavenging activity (80.45%), superoxide anion scavenging activity (54.03%), and ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical and hydroxyl radical scavenging at 500 µg/mL. Finally, LJEO showed high inhibition of lipid peroxidation with strong reducing power. In conclusion, LJEO from edible seaweed is an inexpensive but favorable resource with strong antibacterial capacity as well as free radical scavenging and antioxidant activity; therefore, it has the potential for use in the food, cosmetics, and pharmaceutical industries. Full article
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Open AccessArticle
Characterization of Volatile Compounds of Eleven Achillea Species from Turkey and Biological Activities of Essential Oil and Methanol Extract of A. hamzaoglui Arabacı & Budak
Molecules 2015, 20(6), 11432-11458; https://doi.org/10.3390/molecules200611432 - 22 Jun 2015
Cited by 24
Abstract
According to distribution of genus Achillea, two main centers of diversity occur in S.E. Europe and S.W. Asia. Diversified essential oil compositions from Balkan Peninsula have been numerously reported. However, report on essential oils of Achillea species growing in Turkey, which is [...] Read more.
According to distribution of genus Achillea, two main centers of diversity occur in S.E. Europe and S.W. Asia. Diversified essential oil compositions from Balkan Peninsula have been numerously reported. However, report on essential oils of Achillea species growing in Turkey, which is one of the main centers of diversity, is very limited. This paper represents the chemical compositions of the essential oils obtained by hydrodistillation from the aerial parts of eleven Achillea species, identified simultaneously by gas chromatography and gas chromatography-mass spectrometry. The main components were found to be 1,8-cineole, p-cymene, viridiflorol, nonacosane, α-bisabolol, caryophyllene oxide, α-bisabolon oxide A, β-eudesmol, 15-hexadecanolide and camphor. The chemical principal component analysis based on thirty compounds identified three species groups and a subgroup, where each group constituted a chemotype. This is the first report on the chemical composition of A. hamzaoglui essential oil; as well as the antioxidant and antimicrobial evaluation of its essential oil and methanolic extract. Full article
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Open AccessArticle
Microwave-Assisted Synthesis of Cinnamyl Long Chain Aroma Esters
Molecules 2015, 20(6), 10594-10603; https://doi.org/10.3390/molecules200610594 - 08 Jun 2015
Cited by 2
Abstract
Cinnamyl long chain aroma esters were prepared by using the conventional and microwave-assisted methods. The esterification reaction of naturally occurring 3-phenyl-prop-2-en-1-ol and different chain lengths acidic and diol reagents was carried out at the temperature of 140 °C under solvent free conditions. As [...] Read more.
Cinnamyl long chain aroma esters were prepared by using the conventional and microwave-assisted methods. The esterification reaction of naturally occurring 3-phenyl-prop-2-en-1-ol and different chain lengths acidic and diol reagents was carried out at the temperature of 140 °C under solvent free conditions. As acidic reagents, oxolane-2,5-dione, oxane-2,6-dione, hexanedioic acid and decanedioic acid were applied. Ethane-1,2-diol and 2,2ʹ-[oxybis(2,1-ethandiyloxy)]diethanol were used as diol reagents. The synthesis of high molecular mass cinnamyl esters under conventional method conditions requires a long time to obtain high yields. The studies confirm that by using microwave irradiation, it is possible to reduce the reaction times to only 10–20 min. The structures of prepared esters were confirmed on the basis of FTIR, 1H-NMR and 13C-NMR. In addition, the newly obtained cinnamyl long chain esters were tested for their thermal properties. The TG studies proved the high thermal resistance of the obtained esters under inert and oxidative conditions. Full article
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Open AccessReview
Non-Conventional Yeasts Whole Cells as Efficient Biocatalysts for the Production of Flavors and Fragrances
Molecules 2015, 20(6), 10377-10398; https://doi.org/10.3390/molecules200610377 - 04 Jun 2015
Cited by 19
Abstract
The rising consumer requests for natural flavors and fragrances have generated great interest in the aroma industry to seek new methods to obtain fragrance and flavor compounds naturally. An alternative and attractive route for these compounds is based on bio-transformations. In this review, [...] Read more.
The rising consumer requests for natural flavors and fragrances have generated great interest in the aroma industry to seek new methods to obtain fragrance and flavor compounds naturally. An alternative and attractive route for these compounds is based on bio-transformations. In this review, the application of biocatalysis by Non Conventional Yeasts (NCYs) whole cells for the production of flavor and fragrances is illustrated by a discussion of the production of different class of compounds, namely Aldehydes, Ketones and related compounds, Alcohols, Lactones, Terpenes and Terpenoids, Alkenes, and Phenols. Full article
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Open AccessArticle
An Effective Quality Control of Pharmacologically Active Volatiles of Houttuynia cordata Thunb by Fast Gas Chromatography-Surface Acoustic Wave Sensor
Molecules 2015, 20(6), 10298-10312; https://doi.org/10.3390/molecules200610298 - 03 Jun 2015
Cited by 4
Abstract
Fast gas chromatography-surface acoustic wave sensor (GC/SAW) has been applied for the detection of the pharmacological volatiles emanated from Houttuynia cordata Thunb which is from South Korea. H. cordata Thunb with unpleasant and fishy odors shows a variety of pharmacological activities such as [...] Read more.
Fast gas chromatography-surface acoustic wave sensor (GC/SAW) has been applied for the detection of the pharmacological volatiles emanated from Houttuynia cordata Thunb which is from South Korea. H. cordata Thunb with unpleasant and fishy odors shows a variety of pharmacological activities such as anti-microbial, anti-inflammatory, anti-cancer, and insect repellent. The aim of this study is to show a novel quality control by GC/SAW methodology for the discrimination of the three different parts of the plant such as leaves, aerial stems, and underground stems for H. cordata Thunb. Sixteen compounds were identified. β-Myrcene, cis-ocimene and decanal are the dominant volatiles for leaves (71.0%) and aerial stems (50.1%). While, monoterpenes (74.6%) are the dominant volatiles for underground stems. 2-Undecanone (1.3%) and lauraldehyde (3.5%) were found to be the characteristic components for leaves. Each part of the plant has its own characteristic fragrance pattern owing to its individual chemical compositions. Moreover, its individual characteristic fragrance patterns are conducive to discrimination of the three different parts of the plant. Consequently, fast GC/SAW can be a useful analytical method for quality control of the different parts of the plant with pharmacological volatiles as it provides second unit analysis, a simple and fragrant pattern recognition. Full article
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Open AccessArticle
Chemical Composition and Antioxidant Activity of Essential Oil of Six Pinus Taxa Native to China
Molecules 2015, 20(5), 9380-9392; https://doi.org/10.3390/molecules20059380 - 21 May 2015
Cited by 14
Abstract
The essential oils obtained by steam distillation from needles of six China endemic Pinus taxa (P. tabulaeformis, P. tabulaeformis f. shekanensis, P. tabulaeformis var. mukdensis, P. tabulaeformis var. umbraculifera, P. henryi and P [...] Read more.
The essential oils obtained by steam distillation from needles of six China endemic Pinus taxa (P. tabulaeformis, P. tabulaeformis f. shekanensis, P. tabulaeformis var. mukdensis, P. tabulaeformis var. umbraculifera, P. henryi and P. massoniana) were analysed by GC/MS. A total of 72 components were separated and identified by GC/MS from the six taxa. The major constituents of the essential oils were: α-pinene (6.78%–20.55%), bornyl acetale (3.32%–12.71%), β-caryophellene (18.26%–26.31%), α-guaiene (1.23%–8.19%), and germacrene D (1.26%–9.93%). Moreover, the essential oils were evaluated for antioxidant potential by three assays (DPPH, FRAP and ABTS) and tested for their total phenolic content. The results showed that all essential oils exhibited acceptable antioxidant activities and these strongly suggest that these pine needles may serve as a potential source of natural antioxidants for food and medical purposes. Full article
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Open AccessReview
A Comprehensive Review on the Phytochemical Constituents and Pharmacological Activities of Pogostemon cablin Benth.: An Aromatic Medicinal Plant of Industrial Importance
Molecules 2015, 20(5), 8521-8547; https://doi.org/10.3390/molecules20058521 - 12 May 2015
Cited by 79
Abstract
Pogostemon cablin Benth. (patchouli) is an important herb which possesses many therapeutic properties and is widely used in the fragrance industries. In traditional medicinal practices, it is used to treat colds, headaches, fever, nausea, vomiting, diarrhea, abdominal pain, insect and snake bites. In [...] Read more.
Pogostemon cablin Benth. (patchouli) is an important herb which possesses many therapeutic properties and is widely used in the fragrance industries. In traditional medicinal practices, it is used to treat colds, headaches, fever, nausea, vomiting, diarrhea, abdominal pain, insect and snake bites. In aromatherapy, patchouli oil is used to relieve depression, stress, calm nerves, control appetite and to improve sexual interest. Till now more than 140 compounds, including terpenoids, phytosterols, flavonoids, organic acids, lignins, alkaloids, glycosides, alcohols, aldehydes have been isolated and identified from patchouli. The main phytochemical compounds are patchouli alcohol, α-patchoulene, β-patchoulene, α-bulnesene, seychellene, norpatchoulenol, pogostone, eugenol and pogostol. Modern studies have revealed several biological activities such as antioxidant, analgesic, anti-inflammatory, antiplatelet, antithrombotic, aphrodisiac, antidepressant, antimutagenic, antiemetic, fibrinolytic and cytotoxic activities. However, some of the traditional uses need to be verified and may require standardizing and authenticating the bioactivity of purified compounds through scientific methods. The aim of the present review is to provide comprehensive knowledge on the phytochemistry and pharmacological activities of essential oil and different plant extracts of patchouli based on the available scientific literature. This information will provide a potential guide in exploring the use of main active compounds of patchouli in various medical fields. Full article
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Open AccessReview
Cymbopogon Species; Ethnopharmacology, Phytochemistry and the Pharmacological Importance
Molecules 2015, 20(5), 7438-7453; https://doi.org/10.3390/molecules20057438 - 23 Apr 2015
Cited by 60
Abstract
Cymbopogon genus is a member of the family of Gramineae which are herbs known worldwide for their high essential oil content. They are widely distributed across all continents where they are used for various purposes. The commercial and medicinal uses of the various [...] Read more.
Cymbopogon genus is a member of the family of Gramineae which are herbs known worldwide for their high essential oil content. They are widely distributed across all continents where they are used for various purposes. The commercial and medicinal uses of the various species of Cymbopogon are well documented. Ethnopharmacology evidence shows that they possess a wide array of properties that justifies their use for pest control, in cosmetics and as anti-inflammation agents. These plants may also hold promise as potent anti-tumor and chemopreventive drugs. The chemo-types from this genus have been used as biomarkers for their identification and classification. Pharmacological applications of Cymbopogon citratus are well exploited, though studies show that other species may also useful pharmaceutically. Hence this literature review intends to discuss these species and explore their potential economic importance. Full article
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Open AccessArticle
A Three-Enzyme-System to Degrade Curcumin to Natural Vanillin
Molecules 2015, 20(4), 6640-6653; https://doi.org/10.3390/molecules20046640 - 14 Apr 2015
Cited by 10
Abstract
The symmetrical structure of curcumin includes two 4-hydroxy-3-methoxyphenyl substructures. Laccase catalyzed formation of a phenol radical, radical migration and oxygen insertion at the benzylic positions can result in the formation of vanillin. As vanillin itself is a preferred phenolic substrate of laccases, the [...] Read more.
The symmetrical structure of curcumin includes two 4-hydroxy-3-methoxyphenyl substructures. Laccase catalyzed formation of a phenol radical, radical migration and oxygen insertion at the benzylic positions can result in the formation of vanillin. As vanillin itself is a preferred phenolic substrate of laccases, the formation of vanillin oligomers and polymers is inevitable, once vanillin becomes liberated. To decelerate the oligomerization, one of the phenolic hydroxyl groups was protected via acetylation. Monoacetyl curcumin with an approximate molar yield of 49% was the major acetylation product, when a lipase from Candida antarctica (CAL) was used. In the second step, monoacetyl curcumin was incubated with purified laccases of various basidiomycete fungi in a biphasic system (diethyl ether/aqueous buffer). A laccase from Funalia trogii (LccFtr) resulted in a high conversion (46% molar yield of curcumin monoacetate) to vanillin acetate. The non-protected vanillin moiety reacted to a mixture of higher molecular products. In the third step, the protecting group was removed from vanillin acetate using a feruloyl esterase from Pleurotus eryngii (PeFaeA) (68% molar yield). Alignment of the amino acid sequences indicated that high potential laccases performed better in this mediator and cofactor-free reaction. Full article
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Open AccessArticle
Chemical Composition and Biological Activities of the Essential Oil of Skimmia laureola Leaves
Molecules 2015, 20(3), 4735-4745; https://doi.org/10.3390/molecules20034735 - 16 Mar 2015
Cited by 8
Abstract
The composition of the essential oil from leaves of Skimmia laureola was determined by GC and GC-MS. Twenty-eight components were identified, accounting for 93.9% of the total oil. The oil is mainly composed of monoterpenes (93.5%), of which monoterpene hydrocarbons and oxygenated monoterpenes [...] Read more.
The composition of the essential oil from leaves of Skimmia laureola was determined by GC and GC-MS. Twenty-eight components were identified, accounting for 93.9% of the total oil. The oil is mainly composed of monoterpenes (93.5%), of which monoterpene hydrocarbons and oxygenated monoterpenes represent 11.0% and 82.5%, respectively. Sesquiterpenes constitute only 0.3% of the total oil. Linalyl acetate is the main component (50.5%), with linalool (13.1%), geranyl acetate (8.5%) and cis-p-menth-2-en-1-ol (6.2%) as other principal constituents. The essential oil showed a significant antispasmodic activity, in a dose range of 0.03–10 mg/mL. The essential oil also possesses antibacterial and antifungal activities against some pathogenic strains. The phytotoxic and cytotoxic activities were also assessed. Full article
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Open AccessArticle
Nutritional Value and Volatile Compounds of Black Cherry (Prunus serotina) Seeds
Molecules 2015, 20(2), 3479-3495; https://doi.org/10.3390/molecules20023479 - 17 Feb 2015
Cited by 10
Abstract
Prunus serotina (black cherry), commonly known in Mexico as capulín, is used in Mexican traditional medicine for the treatment of cardiovascular, respiratory, and gastrointestinal diseases. Particularly, P. serotina seeds, consumed in Mexico as snacks, are used for treating cough. In the present study, [...] Read more.
Prunus serotina (black cherry), commonly known in Mexico as capulín, is used in Mexican traditional medicine for the treatment of cardiovascular, respiratory, and gastrointestinal diseases. Particularly, P. serotina seeds, consumed in Mexico as snacks, are used for treating cough. In the present study, nutritional and volatile analyses of black cherry seeds were carried out to determine their nutraceutical potential. Proximate analysis indicated that P. serotina raw and toasted seeds contain mostly fat, followed by protein, fiber, carbohydrates, and ash. The potassium content in black cherry raw and toasted seeds is high, and their protein digestibility-corrected amino acid scores suggest that they might represent a complementary source of proteins. Solid phase microextraction and gas chromatography/flame ionization detection/mass spectrometry analysis allowed identification of 59 and 99 volatile compounds in the raw and toasted seeds, respectively. The major volatile compounds identified in raw and toasted seeds were 2,3-butanediol and benzaldehyde, which contribute to the flavor and odor of the toasted seeds. Moreover, it has been previously demonstrated that benzaldehyde possesses a significant vasodilator effect, therefore, the presence of this compound along with oleic, linoleic, and α-eleostearic fatty acids indicate that black cherry seeds consumption might have beneficial effects on the cardiovascular system. Full article
Open AccessArticle
Contact Toxicity and Repellency of the Essential Oil of Liriope muscari (DECN.) Bailey against Three Insect Tobacco Storage Pests
Molecules 2015, 20(1), 1676-1685; https://doi.org/10.3390/molecules20011676 - 20 Jan 2015
Cited by 12
Abstract
In order to find and develop new botanical pesticides against tobacco storage pests, bioactivity screening was performed. The essential oil obtained from the aerial parts of Liriope muscari was investigated by GC/MS and GC/FID. A total of 14 components representing 96.12% of the [...] Read more.
In order to find and develop new botanical pesticides against tobacco storage pests, bioactivity screening was performed. The essential oil obtained from the aerial parts of Liriope muscari was investigated by GC/MS and GC/FID. A total of 14 components representing 96.12% of the oil were identified and the main compounds in the oil were found to be methyl eugenol (42.15%) and safrole (17.15%), followed by myristicin (14.18%) and 3,5-dimethoxytoluene (10.60%). After screening, the essential oil exhibit potential insecticidal activity. In the progress of assay, it showed that the essential oil exhibited potent contact toxicity against Tribolium castaneum, Lasioderma serricorne and Liposcelis bostrychophila adults, with LD50 values of 13.36, 11.28 µg/adult and 21.37 µg/cm2, respectively. The essential oil also exhibited strong repellency against the three stored product insects. At the same concentrations, the essential oil was more repellent to T. castaneum than to L. serricorne adults. The results indicate that the essential oil of Liriope muscari has potential to be developed into a natural insecticide or repellent for controlling insects in stored tobacco and traditional Chinese medicinal materials. Full article

Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Type of the paper: Article
Tentative title: Apoptotic Effects on Human Leukaemia Cells Induced by Lavandin Essential Oil Treatment
Authors: Valentina Laghezza Masci1, Elisa Ovidi1, Anna Rita Taddei2, Giovanni Turchetti1, Antonio Tiezzi1, Pierluigi Giacomello3, Stefania Garzoli3,*
Affiliations: 1 Department for the Innovation in Biological, Agrofood and Forestal Systems, Tuscia University, Viterbo, Italy;
2 High Equipment Center, Tuscia University, Viterbo, Italy (A.R.T)
3 Department of Drug Chemistry and Technology, Sapienza University, Rome, Italy;
Abstract: Recently, scientific investigations reported that numerous essential oils interfere with intracellular signaling pathways inducing apoptosis in different cancer cell models. In this paper the effects of lavandin essential oil (LEO), a natural sterile hybrid (L.x intermedia var. Grosso) obtained by the crossing of L. angustifolia × L. latifolia, was analysed on human leukaemia cells (HL60). Based on MTT results, the reduced cell viability on HL60 cells was further investigated to determine whether the cell death was related to the apoptotic process. HL60 cells treated for 4 and 24 hours with LEO were processed by flow cytometry and the presence of annexin V investigated. Activation of caspases-3 was evaluated by western blot and immunofluorescence techniques. Scanning and transmission electron microscopy observations of treated cells visualized the morphological alteration induced during the apoptotic process. Investigations concerning LEO main compounds, such as linalool, linalyl acetate, eucalyptol and terpinen-4-ol were also performed.

Type of the paper: Article
Tentative title: Essential oil as natural biocides in conservation of cultural heritage
Authors: Franco Palla*, Valentina Rotolo, Federica Mercurio
Laboratory of Biology and Biotechnology for Cultural Heritage, Department of Biological, Chemical and Pharmaceutical Science and Technologies, Via Archirafi 38, 90123, Palermo, Italy
Corrispondence: ; Tel.: 39 -91-23891224
Abstract: Essential Oils (EOs) is known since long time and their application are actually performed in several fields such as medicine and aromatherapy as well as in food and pharmaceutical industries. In the last decade EOs are also applied to contrast biodeterioration of cultural heritage, representing a powerful resource under a green conservation point of view. In this study an integrated approach, based on microscopy observation, in vitro culture and molecular investigation, has been preliminarily employed to identify microbial colonizers, followed by EOs application (directly or by fumigation) in order to suppressing artworks biodeterioration. Evaluated the compatibility with artwork constitutive materials, the lack of negative effects on human health and on environmental pollution represents the special feature of this valid alternative to traditional biocides.

Type of the paper: Article
Tentative title: The in vitro activity of a selected essential oils against Helicobacter pylori growth and urease activity
Authors: Izabela Korona-Glowniak1*, Anna Glowniak-Lipa1, Tomasz Baj2, Agnieszka Ludwiczuk3 and Anna Malm1
1Department of Pharmaceutical Microbiology, Medical University in Lublin, 1 Chodzki Str., 20-093 Lublin, Poland
2Department of Pharmacognosy, Medical University in Lublin, 1 Chodzki Str., 20-093 Lublin, Poland
*Corresponding author –
Abstract: During the last years due to increasing antimicrobial resistance of Helicobacter pylori, several studies have been performed in the aspect of searching for plants and plant extracts/constituents as anti-H. pylori. From 28 commercially available essential oils the most effective in inhibition in vitro on growth of the reference strain H. pylori ATCC 43504 by MIC (minimal inhibitory concentration) determination. Next, 9 essential oils with the highest anti-H. pylori activity were tested. Phytochemical analysis of the selected essential oils by GC-MS method and antioxidant activity were performed. The phenol red method was used to screen the effect of essential oils on urease activity expressed as IC50 (the half maximal inhibitory concentration).
The most active essential oils with MIC =15,6 mg/L were thyme, lemon grass, cedarwood and melissa oils; MIC = 31,3 mg/L – origanum oil; MIC = 62,5 mg/L – tee tree oil; MIC = 125 mg/L – pine, lemon and fir oils; the MBC/MIC ratio was 1-4, indicating their bactericidal effect. Urease activity was inhibited by these oils with IC50 ranged from 5.3 to >1049.9 mg/l. The most active was cedarwood oil (IC50 = 5.3 mg/l), inhibiting urease at sub-MIC concentrations (MIC = 15.6 mg/l). The statistical PCA analysis (principal component analysis) allowed for the division of the oils into three phytochemical groups differing in their anti-H. pylori activity. To summarize, the activity in vitro of the five essential oils: fir, pine, tee tree, lemon grass, and cedarwood oils against H. pylori was found in this paper for the first time. The most active against clinical strains of H. pylori were cedarwood and origanum oils. Besides, cedarwood oil inhibited the urease activity at sub-inhibitory concentrations. This essential oil can be regarded as a useful component of the plant preparations supporting the eradication H. pylori therapy.
Keywords: essential oils, Helicobacter pylori, antibacterial activity

Type of the paper: Article
Title: Chemical composition of leaf essential oils of navel oranges extracted by different methods and analyzed by GC-MS and GC-IMS
Authors: Shan Cao, Weihui Deng, Ke Liu, Jingyu Sun, Balian Zhong and Jiong Chun*
Abstract: Diaphorina citri is the vector of bacteria responsible for huanglongbing (citrus greening disease), a destructive disease in citrus. D. citri reproduces and develops only on the young leaves of its rutaceous host plants. In this study, young and old leaves of navel oranges which were affected by bacteria or not affected were extracted by hydrodistillation and supercritical CO2 extraction method. GC-MS and GC-IMS were used to analyze the chemical composition of leaf essential oils. GC-IMS was an effect method to identify the composition difference of young leaves. Our study may help develop new method for detection or find new attractants of D. citri for prevention of citrus greening disease.

Type of the paper: Review
Tentative Title: Antidiabetic Effect of Essential Oils: A Review
Authors: Simona Codruta Heghes1, Lorena Filip2, Oliviu Vostinaru3, *, Cristina Mogosan3, Doina Miere2, Cristina Adela Iuga1 and Mirela Moldovan4
Affiliation: 1 Department of Drug Analysis, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca 400349, Romania;
2 Department of Bromatology, Hygiene, Nutrition, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca 400349, Romania;
3 Department of Pharmacology, Physiology and Physiopathology, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca 400349, Romania;
4 Department of Dermopharmacy and Cosmetics, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca 400010, Romania;
*Correspondence:
Abstract: Diabetes mellitus is a metabolic disease characterized by the alteration of glucose homeostasis resulting in chronic hyperglycemia. Although current antidiabetic drugs may successfully control blood glucose level, their use is often associated with problematic side effects. Therefore, the development of new drug candidates is necessary for a better management of the disease. Among these potential new drug sources, aromatic plants rich in essential oils are very promising due to their diverse chemical composition and multiple mechanisms of action. This review describes a series of recent studies investigating the antidiabetic effect of essential oils from twenty-eight plant species belonging to nine botanical families. The pharmacological models used in the studies together with the putative mechanisms of action and the chemical composition of the essential oils are also detailed. The presented data clearly demonstrate the antidiabetic effect of the essential oils from the studied aromatic plant species. Further research is needed in order to ascertain the therapeutic importance of these findings.

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