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Exclusive Feature Papers in Natural Products Chemistry

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Natural Products Chemistry".

Deadline for manuscript submissions: closed (31 December 2022) | Viewed by 58406

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Department of Odontostomatologic and Specialized Clinical Sciences, Sez-Biochimica, Faculty of Medicine, Università Politecnica delle Marche, Via Ranieri 65, 60100 Ancona, Italy
Interests: nutrition; periodontal diseases/periodontitis; oxidative stress; nutrition; aging; mitochondrial function and diseases; berries (strawberry, blueberry, bilberry, cranberry, etc.); olive oil (dietary fats); honey; polyphenols; flavonoids; antioxidants; apoptosis
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Guest Editor
Department of Chemistry, Biology and Biotechnology, University of Perugia, Via del Giochetto, 06126 Perugia, Italy
Interests: cancer chemoprevention; nutrition; olive oil; polyphenols; natural bioactive compounds; antioxidants; oxidative stress; genotoxicity; mutagenicity; apoptosis; cell cycle regulation
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Laboratory of Food Chemistry and Technology, School of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
Interests: natural products' chemistry, bioactivity, and applications; olive tree products and byproducts; olive oil chemistry; analysis and quality; phytochemical analysis; nutrients and bioactive compounds; bioaccessibility and bioavailability; antioxidants as food preservatives; structure–antioxidant activity relationships
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Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, SA, Italy
Interests: natural products; food chemistry and analytical chemistry; clinical nutrition; phytochemistry and phytotherapy; supplement and nutraceutical formulation
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleague,

It is our pleasure to announce a new Special Issue entitled “Exclusive Feature Papers in Natural Products Chemistry.” This is a collection of important high-quality papers (including both original research articles and comprehensive review papers) published in an open access format that have been written by Editorial Board Members or prominent scholars invited by the Editorial Office and the Guest Editors. This Special Issue aims to discuss emerging knowledge or new cutting-edge developments in the Natural Products Chemistry research field through selected works in the hope of making a great research contribution to the community. We intend for this Special Issue to be the best forum for disseminating excellent research findings and sharing innovative ideas in the field.

Prof. Dr. Maurizio Battino
Dr. Francesco Cacciola
Prof. Dr. Milen I. Georgiev
Prof. Dr. Vincenzo De Feo
Dr. Roberto Fabiani
Prof. Dr. Maria Z. Tsimidou
Prof. Dr. Luca Rastrelli
Guest Editors

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Keywords

  • natural products
  • natural extracts
  • plant secondary metabolism
  • phytochemical analysis
  • nutrients and bioactive compounds
  • bioaccessibility and bioavailability
  • antioxidants
  • anti-inflammatories
  • antitumor and antiviral potentials

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Related Special Issue

Published Papers (18 papers)

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14 pages, 1999 KiB  
Article
Use of Trifluoro-Acetate Derivatives for GC-MS and GC-MS/MS Quantification of Trace Amounts of Stera-3β,5α,6β-Triols (Tracers of Δ5-Sterol Autoxidation) in Environmental Samples
by Claude Aubert and Jean-François Rontani
Molecules 2023, 28(4), 1547; https://doi.org/10.3390/molecules28041547 - 6 Feb 2023
Viewed by 1810
Abstract
Stera-3β,5α,6β-triols make useful tracers of the autoxidation of Δ5-sterols. These compounds are generally analyzed using gas chromatography–mass spectrometry (GC-MS) after silylation. Unfortunately, the 5α hydroxyl groups of these compounds, which are not derivatized by conventional silylation reagents, substantially alter the chromatographic [...] Read more.
Stera-3β,5α,6β-triols make useful tracers of the autoxidation of Δ5-sterols. These compounds are generally analyzed using gas chromatography–mass spectrometry (GC-MS) after silylation. Unfortunately, the 5α hydroxyl groups of these compounds, which are not derivatized by conventional silylation reagents, substantially alter the chromatographic properties of these derivatives, thus ruling out firm quantification of trace amounts. In this work, we developed a derivatization method (trifluoroacetylation) that enables derivatization of the three hydroxyl groups of 3β,5α,6β-steratriols. The derivatives thus formed present several advantages over silyl ethers: (i) better stability, (ii) shorter retention times, (iii) better chromatographic properties and (iv) mass spectra featuring specific ions or transitions that enable very low limits of detection in selected ion monitoring (SIM) and multiple reaction monitoring (MRM) modes. This method, validated with cholesta-3β,5α,6β-triol, was applied to several environmental samples (desert dusts, marine sediments and particulate matter) and was able to quantify trace amounts of 3β,5α,6β-steratriols corresponding to several sterols: not only classical monounsaturated sterols (e.g., cholesterol, campesterol and sitosterol) but also, and for the first time, di-unsaturated sterols (e.g., stigmasterol, dehydrocholesterol and brassicasterol). Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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15 pages, 2287 KiB  
Article
μ-Raman Determination of Essential Oils’ Constituents from Distillates and Leaf Glands of Origanum Plants
by Elli Kampasakali, Alexandros Nakas, Dimitrios Mertzanidis, Stella Kokkini, Andreana N. Assimopoulou and Dimitrios Christofilos
Molecules 2023, 28(3), 1221; https://doi.org/10.3390/molecules28031221 - 26 Jan 2023
Cited by 2 | Viewed by 2216
Abstract
A novel, inexpensive and simple experimental setup for collecting μ-Raman spectra of volatile liquids in very small quantities was developed. It takes advantage of capillary forces to detain minute volatile liquid volumes. Spectra of volatile and even scattering or absorbing media can [...] Read more.
A novel, inexpensive and simple experimental setup for collecting μ-Raman spectra of volatile liquids in very small quantities was developed. It takes advantage of capillary forces to detain minute volatile liquid volumes. Spectra of volatile and even scattering or absorbing media can be measured more effectively. The method is used to facilitate the collection of intensity-consistent Raman spectra from a series of reference compounds present in Origanum essential oils, in order to quantify their constituents by multiple linear regression. Wild grown Origanum plants, collected from five different regions in Greece and taxonomically identified as O. onites, O. vulgare subsp. hirtum and O. vulgare subsp. vulgare, were appropriately distilled to acquire their essential oils. Comparison of the Raman results with those from headspace gas chromatography–mass spectrometry (HS GC-MS) confirmed the successful relative quantification of the most abundant essential oil constituents, highlighting the similarities and differences of the three Origanum taxa examined. Finally, it is demonstrated that directly measuring the leaf peltate glandular hairs yields exploitable results to identify the main components of the essential oil they contain, underlining the potential of in situ (field or industry) measurements utilizing microscope-equipped portable Raman spectrometers. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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10 pages, 733 KiB  
Article
Bioactive Clerodane Diterpenoids from the Leaves of Casearia coriacea Vent
by Allison Ledoux, Carla Hamann, Olivier Bonnet, Kateline Jullien, Joëlle Quetin-Leclercq, Alembert Tchinda, Jacqueline Smadja, Anne Gauvin-Bialecki, Erik Maquoi and Michel Frédérich
Molecules 2023, 28(3), 1197; https://doi.org/10.3390/molecules28031197 - 25 Jan 2023
Cited by 5 | Viewed by 2228
Abstract
Casearia coriacea Vent., an endemic plant from the Mascarene Islands, was investigated following its antiplasmodial potentialities highlighted during a previous screening. Three clerodane diterpene compounds were isolated and identified as being responsible for the antiplasmodial activity of the leaves of the plant: caseamembrin [...] Read more.
Casearia coriacea Vent., an endemic plant from the Mascarene Islands, was investigated following its antiplasmodial potentialities highlighted during a previous screening. Three clerodane diterpene compounds were isolated and identified as being responsible for the antiplasmodial activity of the leaves of the plant: caseamembrin T (1), corybulosin I (2), and isocaseamembrin E (3), which exhibited half maximal inhibitory concentrations (IC50) of 0.25 to 0.51 µg/mL. These compounds were tested on two other parasites, Leishmania mexicana mexicana and Trypanosoma brucei brucei, to identify possible selectivity in one of them. Although these products possess both antileishmanial and antitrypanosomal properties, they displayed selectivity for the malaria parasite, with a selectivity index between 6 and 12 regarding antitrypanosomal activity and between 25 and 100 regarding antileishmanial activity. These compounds were tested on three cell lines, breast cancer cells MDA-MB-231, pulmonary adenocarcinoma cells A549, and pancreatic carcinoma cells PANC-1, to evaluate their selectivity towards Plasmodium. This has not enabled us to establish selectivity for Plasmodium, but has revealed the promising activity of compounds 13 (IC50 < 2 µg/mL), particularly against pancreatic carcinoma cells (IC50 < 1 µg/mL). The toxicity of the main compound, caseamembrin T (1), was then evaluated on zebrafish embryos to extend our cytotoxicity study to normal, non-cancerous cells. This highlighted the non-negligible toxicity of caseamembrin T (1). Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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20 pages, 3386 KiB  
Article
Optimizing the Distillation of Greek Oregano—Do Process Parameters Affect Bioactive Aroma Constituents and In Vitro Antioxidant Activity?
by Alexandros Nakas, Georgia Giannarelli, Ioannis Fotopoulos, Eirini Chainoglou, Aikaterini Peperidou, Konstantinos N. Kontogiannopoulos, Artemis Tsiaprazi-Stamou, Vasilios Varsamis, Helen Gika, Dimitra Hadjipavlou-Litina and Andreana N. Assimopoulou
Molecules 2023, 28(3), 971; https://doi.org/10.3390/molecules28030971 - 18 Jan 2023
Cited by 4 | Viewed by 1756
Abstract
The aim of the present work was to optimize the conditions of the distillation process at a pilot scale to maximize the yield of specific bioactive compounds of the essential oil of oregano cultivated in Greece, and subsequently to study the in vitro [...] Read more.
The aim of the present work was to optimize the conditions of the distillation process at a pilot scale to maximize the yield of specific bioactive compounds of the essential oil of oregano cultivated in Greece, and subsequently to study the in vitro antioxidant activity of these oils. Steam distillation was conducted at an industrial distillery and a Face-Centered Composite (FCC) experimental design was applied by utilizing three distillation factors: time, steam pressure and temperature. Essential oil composition was determined by static headspace gas chromatography–mass spectrometry (HS–GC/MS). To obtain a comprehensive profile of the essential oils, instrumental parameters were optimized, including sample preparation, incubation conditions, sampling process, injection parameters, column thermal gradient and MS conditions. With the applied GC-MS method, more than 20 volatile compounds were identified in the headspace of the oregano essential oils and their relative percentages were recorded. Carvacrol was the most prominent constituent under all distillation conditions applied. Data processing revealed time as the main factor which most affected the yield. The Desired Space (DSc) was determined by conducting a three-dimensional response surface analysis of the independent and dependent variables, choosing yields of thymol and carvacrol as optimization criteria. The in vitro antioxidant activity of the essential oils of all samples was measured in terms of the interaction with the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) after 20 and 60 min. The most prominent essential oils at different distillation conditions were also tested as inhibitors of lipid peroxidation. Higher % values of carvacrol and thymol were correlated to higher antioxidant activity. Evaluating the impact of the distillation conditions on the in vitro results, it seems that lower pressure, less time and higher temperature are crucial for enhanced antioxidant activities. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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12 pages, 1825 KiB  
Article
Synthesis and Pesticidal Activity of New Niacinamide Derivatives Containing a Flexible, Chiral Chain
by Zhe-Cheng Wei, Qiao Wang, Li-Jing Min, Joanna Bajsa-Hirschel, Charles L. Cantrell, Liang Han, Cheng-Xia Tan, Jian-Quan Weng, Yu-Xin Li, Na-Bo Sun, Stephen O. Duke and Xing-Hai Liu
Molecules 2023, 28(1), 47; https://doi.org/10.3390/molecules28010047 - 21 Dec 2022
Cited by 3 | Viewed by 2398
Abstract
Natural products are a source for pesticide or drug discovery. In order to discover lead compounds with high fungicidal or herbicidal activity, new niacinamide derivatives derived from the natural product niacinamide, containing chiral flexible chains, were designed and synthesized. Their structures were confirmed [...] Read more.
Natural products are a source for pesticide or drug discovery. In order to discover lead compounds with high fungicidal or herbicidal activity, new niacinamide derivatives derived from the natural product niacinamide, containing chiral flexible chains, were designed and synthesized. Their structures were confirmed by 1H NMR, 13C NMR and HRMS analysis. The fungicidal and herbicidal activities of these compounds were tested. The fungicidal activity results demonstrated that the compound (S)-2-(2-chloronicotinamido)propyl-2-methylbenzoate (3i) exhibited good fungicidal activity (92.3% inhibition) against the plant pathogen Botryosphaeria berengriana at 50 μg/mL and with an EC50 of 6.68 ± 0.72 μg/mL, which is the same as the positive control (fluxapyroxad). Compound 3i was not phytotoxic and could therefore be used as a fungicide on crops. Structure-activity relationships (SAR) were studied by molecular docking simulations with the succinate dehydrogenase of the fungal mitochondrial respiratory chain. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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15 pages, 1791 KiB  
Article
Valorization of Citrus Reticulata Peels for Flavonoids and Antioxidant Enhancement by Solid-State Fermentation Using Aspergillus niger CGMCC 3.6189
by Daniel Mamy, Yuanyuan Huang, Nelson Dzidzorgbe Kwaku Akpabli-Tsigbe, Maurizio Battino and Xiumin Chen
Molecules 2022, 27(24), 8949; https://doi.org/10.3390/molecules27248949 - 15 Dec 2022
Cited by 10 | Viewed by 2983
Abstract
The bioactive components and bioactivities of citrus peel can be enhanced with microbial fermentation. Accordingly, this study investigated the ability of Aspergillus niger CGMCC3.6189 to accumulate flavonoids in Citrus reticulata peel powder (CRPP) by solid-state fermentation (SSF). Under the optimal SSF conditions including [...] Read more.
The bioactive components and bioactivities of citrus peel can be enhanced with microbial fermentation. Accordingly, this study investigated the ability of Aspergillus niger CGMCC3.6189 to accumulate flavonoids in Citrus reticulata peel powder (CRPP) by solid-state fermentation (SSF). Under the optimal SSF conditions including 80% moisture, 30 °C, pH 4.0, 4 × 107 spores/g d.w. CRPP, and 192 h, the total phenolic content (TPC), total flavonoid content (TFC), and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activities of fermented CRPP significantly increased by 70.0, 26.8, 64.9, and 71.6%, respectively. HPLC analysis showed that after fermentation, the contents of hesperidin, nobiletin, and tangeretin were significantly increased from 19.36, 6.31, and 2.91 mg/g to 28.23, 7.78, and 3.49 mg/g, respectively, while the contents of ferulic acid and narirutin were decreased under the optimal fermentation conditions. Fermentation time is one of the most important factors that affect the accumulation of flavonoids and antioxidant activity; however, extended fermentation time increased the darkness of CRPP color. Therefore, our study provides a feasible and effective SSF method to increase the bioactive components and the antioxidant activity of CRPP that may be used in food, nutraceutical, and medicinal industries. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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14 pages, 14935 KiB  
Article
Comparative Volatilomic Profile of Three Finger Lime (Citrus australasica) Cultivars Based on Chemometrics Analysis of HS-SPME/GC–MS Data
by Rosaria Cozzolino, José S. Câmara, Livia Malorni, Giuseppe Amato, Ciro Cannavacciuolo, Milena Masullo and Sonia Piacente
Molecules 2022, 27(22), 7846; https://doi.org/10.3390/molecules27227846 - 14 Nov 2022
Cited by 7 | Viewed by 2382
Abstract
Finger lime is receiving growing attention as an ingredient of gastronomic preparations of haute cuisine for its delicious flavor and fragrance and for its appealing aspect. Volatile compounds play a crucial role in determining the organoleptic characteristics of the fruit and its pleasantness [...] Read more.
Finger lime is receiving growing attention as an ingredient of gastronomic preparations of haute cuisine for its delicious flavor and fragrance and for its appealing aspect. Volatile compounds play a crucial role in determining the organoleptic characteristics of the fruit and its pleasantness for consumers. The aim of the present study was to investigate the volatile profiles by headspace solid phase micro-extraction (HS-SPME) coupled to gas chromatography–mass spectrometry (GC–MS) in the peel and, for the first time, in the pulp of three Australian finger lime cultivars grown in Sicily (southern Italy): Pink Pearl, Sanguinea, and Faustrime, allowing to overall identify 84 volatile organic compounds (VOCs). The analytical data showed that the three cultivars were characterized by distinct volatile chemotypes: limonene/sabinene/bicyclogermacrene in the Pink Pearl, limonene/γ-terpinene/bicyclogermacrene in the Sanguinea, and limonene/β-phellandrene/γ-terpinene in the Faustrime. Moreover, some volatiles, found exclusively in one cultivar, could be considered potential markers of the individual cultivar. PCA allowed us to clearly discriminate the samples into three clusters: the first related to the Sanguinea peel, the second to the Faustrime peel, and a third group associated with the Pink Pearl peel along with the pulp of the three cultivars. Accordingly, the VOCs that mostly contributed to the differentiation of the three finger lime cultivars were also identified. Among them, D-limonene, sabinene γ-terpinene, α-pinene, α-phellandrene, β-myrcene, p-cymene, linalool, δ-elemene, ledene, bicyclogermacrene β-citronellol, α-bergamotene, α-caryophillene, and β-bisabolene, have been previously reported to exhibit important biological activities, suggesting that these cultivars, in addition to possessing unique volatile profiles, can show promise for several applications in pharmaceutical and food industry, namely for development of functional foods. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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12 pages, 2481 KiB  
Article
Bioassay-Guided Isolation of Iridoid Glucosides from Stenaria nigricans, Their Biting Deterrence against Aedes aegypti (Diptera: Culicidae), and Repellency Assessment against Imported Fire Ants (Hymenoptera: Formicidae)
by Fazila Zulfiqar, Abbas Ali, Zulfiqar Ali and Ikhlas A. Khan
Molecules 2022, 27(20), 7053; https://doi.org/10.3390/molecules27207053 - 19 Oct 2022
Cited by 2 | Viewed by 1649
Abstract
In our natural product screening program, we screened natural products for their repellency and toxicity against insect vectors. Methanolic extract of aerial parts of Stenaria nigricans (Lam.), with no published chemistry, was tested for repellency against mosquitoes and imported hybrid fire ants. Methanolic [...] Read more.
In our natural product screening program, we screened natural products for their repellency and toxicity against insect vectors. Methanolic extract of aerial parts of Stenaria nigricans (Lam.), with no published chemistry, was tested for repellency against mosquitoes and imported hybrid fire ants. Methanolic extracts showed biting deterrence similar to DEET (N,N-diethyl-3-methylbenzamide) against Aedes aegypti L. Based on this activity, the crude extract was fractionated into chloroform, ethyl acetate, and methanol subfractions. The active methanolic subfraction was further fractionated into 13 subfractions. These fractions were tested for their biting deterrence against Ae. Aegypti. Active subfractions were further characterized to identify the compounds responsible for this activity. Four undescribed iridoid glucosides (14) and three previously reported compounds (57) were isolated from active subfractions and tested for their biting deterrent activity. Based on BDI values, compounds 2, 3, 6, and 7, with biting deterrence similar to DEET, showed the potential to be used as repellents against mosquitoes. In an in vitro digging bioassay, none of these compounds showed any repellency against hybrid imported fire ants at a dose of 125 µg/g. This is the first report of biting deterrence and repellency of S. nigricans extract and its pure compounds, iridoid glucosides against mosquitoes and imported fire ants. Further studies will be conducted to explore the repellent potential of these compounds in different formulations under field conditions. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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17 pages, 755 KiB  
Article
Chemical Composition and Phytotoxic, Antibacterial and Antibiofilm Activity of the Essential Oils of Eucalyptus occidentalis, E. striaticalyx and E. stricklandii
by Marwa Khammassi, Flavio Polito, Ismail Amri, Sana Khedhri, Lamia Hamrouni, Filomena Nazzaro, Florinda Fratianni and Vincenzo De Feo
Molecules 2022, 27(18), 5820; https://doi.org/10.3390/molecules27185820 - 8 Sep 2022
Cited by 20 | Viewed by 2786
Abstract
The Eucalyptus genus (Myrtaceae) is characterized by a richness in essential oils (EO) with multiple biological activities. This study reports the chemical composition and the phytotoxic and antimicrobial activities of the EOs from Tunisian E.occidentalis, E.striaticalyx and E.stricklandii. [...] Read more.
The Eucalyptus genus (Myrtaceae) is characterized by a richness in essential oils (EO) with multiple biological activities. This study reports the chemical composition and the phytotoxic and antimicrobial activities of the EOs from Tunisian E.occidentalis, E.striaticalyx and E.stricklandii. The EOs were analyzed using GC/MS and their phytotoxicities were assessed against the germination and seedling growth of Sinapis arvensis, Trifolium campestre and Lolium rigidum. Antimicrobial activity was investigated against both Gram-negative (Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumannii) and Gram-positive (Staphylococcus aureus and Listeria monocytogenes) bacteria. The inhibition of biofilm formation and its metabolism was determined at different times. All EOs were rich in oxygenated monoterpenes (36.3–84.8%); the EO of E.occidentalis was rich in sesquiterpenes, both oxygenated and hydrocarbon (40.0% and 15.0%, respectively). Eucalyptol was the main constituent in all samples. The EOs showed phytotoxic activity on seed germination and seedling growth, depending both on chemical composition and weed. The EOs show a remarkable antibacterial potential resulting in a significant inhibition of the formation of bacterial biofilm and its metabolism, depending on the EO and the strain, with activity on the mature biofilm as well. Therefore, these Eucalyptus EOs could have potential applications both in the food and health fields. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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11 pages, 2139 KiB  
Article
Comparative Study of Antimicrobial and Antioxidant Potential of Olea ferruginea Fruit Extract and Its Mediated Selenium Nanoparticles
by Hammad Ul Hassan, Naveed Iqbal Raja, Fozia Abasi, Ansar Mehmood, Rahmatullah Qureshi, Zahid Manzoor, Muhammad Shahbaz and Jarosław Proćków
Molecules 2022, 27(16), 5194; https://doi.org/10.3390/molecules27165194 - 15 Aug 2022
Cited by 18 | Viewed by 2406
Abstract
Nanotechnology, the science of the recent era, has diverse applications in agriculture. Selenium (Se) is a non-metal and an essential micronutrient for animals and humans. In this study, selenium nanoparticles (SeNPs) were biosynthesized by using Olea ferruginea fruit extracts. The size, shape, chemical [...] Read more.
Nanotechnology, the science of the recent era, has diverse applications in agriculture. Selenium (Se) is a non-metal and an essential micronutrient for animals and humans. In this study, selenium nanoparticles (SeNPs) were biosynthesized by using Olea ferruginea fruit extracts. The size, shape, chemical nature, and identification of functional groups involved in the synthesis of SeNPs were studied by UV-visible spectroscopy, Scanning Electron Microscope (SEM), and Fourier Transform Infra-Red (FTIR) spectrometry. SeNP synthesis was confirmed by an absorption peak at 258 nm by UV-visible spectroscopy. SEM showed that SeNPs were spherical, smooth, and between 60 and 80 nm in size. FTIR spectrometry confirmed the presence of terpenes, alcohols, ketones, aldehydes, and esters as well as phyto-constituents, such as alkaloids and flavonoids, that possibly act as reducing or capping agents of SeNPs in an aqueous solution of Olea ferruginea. Antimicrobial activity was examined against bacterial pathogens, such as Klebsiella pneumonia, Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermitis, as well as fungal pathogens, such as Aspergillus niger and Fusarium oxysporum, by using the well-diffusion method. Antioxidant activity was observed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, ABTs assay, and reducing power assay. At a higher concentration of 400 ppm, biosynthesized SeNPs showed an inhibition zone of 20.5 mm, 20 mm, 21 mm, and 18.5 mm against Klebsiella pneumonia, Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermitis, respectively. Similarly, SeNPs also demonstrated a zone of inhibition against Aspergillus niger and Fusarium oxysporum of 17.5 and 21 mm, respectively. In contrast to Olea ferruginea fruit extracts, Olea ferruginea-mediated SeNPs demonstrated strong antimicrobial activity. By performing the DPPH, ABTs, and reducing power assay, SeNPs showed 85.2 ± 0.009, 81.12 ± 0.007, and 80.37 ± 0.0035% radical scavenging potential, respectively. The present study could contribute to the drug development and nutraceutical industries. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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21 pages, 3184 KiB  
Article
Exogenous Application of Green Titanium Dioxide Nanoparticles (TiO2 NPs) to Improve the Germination, Physiochemical, and Yield Parameters of Wheat Plants under Salinity Stress
by Nilofar Mustafa, Naveed Iqbal Raja, Noshin Ilyas, Fozia Abasi, Muhammad Sheeraz Ahmad, Maria Ehsan, Asma Mehak, Imran Badshah and Jarosław Proćków
Molecules 2022, 27(15), 4884; https://doi.org/10.3390/molecules27154884 - 30 Jul 2022
Cited by 25 | Viewed by 3316
Abstract
Agriculture is the backbone of every developing country. Among various crops, wheat (Triticum aestivum L.) belongs to the family Poaceae and is the most important staple food crop of various countries. Different biotic (viruses, bacteria and fungi) and abiotic stresses (water logging, [...] Read more.
Agriculture is the backbone of every developing country. Among various crops, wheat (Triticum aestivum L.) belongs to the family Poaceae and is the most important staple food crop of various countries. Different biotic (viruses, bacteria and fungi) and abiotic stresses (water logging, drought and salinity) adversely affect the qualitative and quantitative attributes of wheat. Among these stresses, salinity stress is a very important limiting factor affecting the morphological, physiological, biochemical attributes and grain yield of wheat. This research work was carried out to evaluate the influence of phytosynthesized TiO2 NPs on the germination, physiochemical, and yield attributes of wheat varieties in response to salinity. TiO2 NPs were synthesized using TiO2 salt and a Buddleja asiatica plant extract as a reducing and capping agent. Various concentrations of TiO2 nanoparticles (20, 40, 60 and 80 mg/L) and salt solutions (NaCl) (100 and 150 mM) were used. A total of 20 mg/L and 40 mg/L improve germination attributes, osmotic and water potential, carotenoid, total phenolic, and flavonoid content, soluble sugar and proteins, proline and amino acid content, superoxide dismutase activity, and reduce malondialdhehyde (MDA) content at both levels of salinity. These two concentrations also improved the yield attributes of wheat varieties at both salinity levels. The best results were observed at 40 mg/L of TiO2 NPs at both salinity levels. However, the highest concentrations (60 and 80 mg/L) of TiO2 NPs showed negative effects on germination, physiochemical and yield characteristics and causes stress in both wheat varieties under control irrigation conditions and salinity stress. Therefore, in conclusion, the findings of this research are that the foliar application of TiO2 NPs can help to improve tolerance against salinity stress in plants. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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16 pages, 3526 KiB  
Article
Blending Technology Based on HPLC Fingerprint and Nonlinear Programming to Control the Quality of Ginkgo Leaves
by Zhe Liu, Guixin Li, Yu Zhang, Hongli Jin, Yucheng Liu, Jiatao Dong, Xiaonong Li, Yanfang Liu and Xinmiao Liang
Molecules 2022, 27(15), 4733; https://doi.org/10.3390/molecules27154733 - 25 Jul 2022
Cited by 4 | Viewed by 2431
Abstract
The breadth and depth of traditional Chinese medicine (TCM) applications have been expanding in recent years, yet the problem of quality control has arisen in the application process. It is essential to design an algorithm to provide blending ratios that ensure a high [...] Read more.
The breadth and depth of traditional Chinese medicine (TCM) applications have been expanding in recent years, yet the problem of quality control has arisen in the application process. It is essential to design an algorithm to provide blending ratios that ensure a high overall product similarity to the target with controlled deviations in individual ingredient content. We developed a new blending algorithm and scheme by comparing different samples of ginkgo leaves. High-consistency samples were used to establish the blending target, and qualified samples were used for blending. Principal component analysis (PCA) was used as the sample screening method. A nonlinear programming algorithm was applied to calculate the blending ratio under different blending constraints. In one set of calculation experiments, the result was blended by the same samples under different conditions. Its relative deviation coefficients (RDCs) were controlled within ±10%. In another set of calculations, the RDCs of more component blending by different samples were controlled within ±20%. Finally, the near-critical calculation ratio was used for the actual experiments. The experimental results met the initial setting requirements. The results show that our algorithm can flexibly control the content of TCMs. The quality control of the production process of TCMs was achieved by improving the content stability of raw materials using blending. The algorithm provides a groundbreaking idea for quality control of TCMs. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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23 pages, 1773 KiB  
Article
Biochemical and Molecular Investigation of the Effect of Saponins and Terpenoids Derived from Leaves of Ilex aquifolium on Lipid Metabolism of Obese Zucker Rats
by Natalia Pachura, Robert Kupczyński, Kamila Lewandowska, Maciej Włodarczyk, Marta Klemens, Piotr Kuropka, Renata Nowaczyk, Małgorzata Krzystek-Korpacka, Iwona Bednarz-Misa, Tomasz Sozański, Krystyna Pogoda-Sewerniak and Antoni Szumny
Molecules 2022, 27(11), 3376; https://doi.org/10.3390/molecules27113376 - 24 May 2022
Cited by 4 | Viewed by 2676
Abstract
Ilex paraguariensis, the holly tree, is a plant with recognized biological properties, whose aqueous infusions are known as “Yerba mate”, that regulate lipid metabolism, reduce obesity, and improve brain stimulation. In the present study, the effect of standardized saponin and terpenoid fractions [...] Read more.
Ilex paraguariensis, the holly tree, is a plant with recognized biological properties, whose aqueous infusions are known as “Yerba mate”, that regulate lipid metabolism, reduce obesity, and improve brain stimulation. In the present study, the effect of standardized saponin and terpenoid fractions of a European taxon, Ilex aquifolium, on blood biochemical parameters in a rat model of metabolic disorder, (fa/fa) Zucker, are presented. The profiles of the volatile fractions of two species and six European varieties of Ilex were investigated. After selecting the best variety, the saponin and terpenoid fractions were isolated and standardized, and animals were fed 10 mg kg−1 b.w. for 8 weeks. A statistically significant decrease in liver adiposity was observed, confirmed by histology and quantitative identification (gas chromatography–mass spectrometry analyses of hepatic lipids. RT-qPCR analysis of gene expression in the aorta revealed that the administration of the terpenoid fraction downregulated LOX-1, suggesting a reduction in atherosclerotic stimuli. In addition, a statistically significant reduction (p < 0.05) in PPARγ for the saponin fraction was observed in the liver. The expression of the ACAT-1 gene in the liver, responsible for the formation of cholesterol esters, increased significantly in the group receiving the terpenoid fraction compared to the control, which was also confirmed by the analysis of individual blood biochemical parameters. The opposite effect was observed for saponins. Taking the above into account, it is shown for the first time that Ilex aquifolium can be a source of compounds that positively influence lipid metabolism. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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Review

Jump to: Research

22 pages, 2338 KiB  
Review
The Contribution of Theoretical Prediction Studies to the Antioxidant Activity Assessment of the Bioactive Secoiridoids Encountered in Olive Tree Products and By-Products
by Nikolaos Nenadis, Ioanna Pyrka and Maria Z. Tsimidou
Molecules 2023, 28(5), 2267; https://doi.org/10.3390/molecules28052267 - 28 Feb 2023
Cited by 8 | Viewed by 2136
Abstract
Assessment of the antioxidant activity of different types of natural compounds is a complex research area that encompasses various in vitro tests and in vivo studies. Sophisticated modern analytical tools permit the unambiguous characterization of the compounds present in a matrix. The contemporary [...] Read more.
Assessment of the antioxidant activity of different types of natural compounds is a complex research area that encompasses various in vitro tests and in vivo studies. Sophisticated modern analytical tools permit the unambiguous characterization of the compounds present in a matrix. The contemporary researcher, knowing the chemical structure of the compounds present, can carry out quantum chemical calculations that provide important physicochemical information assisting the prediction of antioxidant potential and the mechanism behind the activity of target compounds before further experimentation. The efficiency of calculations is steadily improved due to the rapid evolution of both hardware and software. It is possible, consequently, to study compounds of medium or even larger size, incorporating also models that simulate the liquid phase (solution). This review contributes to the establishment of theoretical calculations as an inherent part of the antioxidant activity assessment process, having as a case study the complex mixtures of olive bioactive secoiridoids (oleuropein, ligstroside, and related compounds). The literature indicates great variability in theoretical approaches and models used so far for only a limited number of this group of phenolic compounds. Proposals are made for standardization of methodology (reference compounds, DFT functional, basis set size, and solvation model) to facilitate comparisons and communication of findings. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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19 pages, 1719 KiB  
Review
Quality Control and Authentication of Argan Oils: Application of Advanced Analytical Techniques
by Meryeme El Maouardi, Mourad Kharbach, Yahya Cherrah, Kris De Braekeleer, Abdelaziz Bouklouze and Yvan Vander Heyden
Molecules 2023, 28(4), 1818; https://doi.org/10.3390/molecules28041818 - 15 Feb 2023
Cited by 4 | Viewed by 4254
Abstract
In addition to the nutritional and therapeutic benefits, Argan oil is praised for its unique bio-ecological and botanic interest. It has been used for centuries to treat cardiovascular issues, diabetes, and skin infections, as well as for its anti-inflammatory and antiproliferative properties. Argan [...] Read more.
In addition to the nutritional and therapeutic benefits, Argan oil is praised for its unique bio-ecological and botanic interest. It has been used for centuries to treat cardiovascular issues, diabetes, and skin infections, as well as for its anti-inflammatory and antiproliferative properties. Argan oil is widely commercialized as a result of these characteristics. However, falsifiers deliberately blend Argan oil with cheaper vegetable oils to make economic profits. This reduces the quality and might result in health issues for consumers. Analytical techniques that are rapid, precise, and accurate are employed to monitor its quality, safety, and authenticity. This review provides a comprehensive overview of studies on the quality assessment of Moroccan Argan oil using both untargeted and targeted approaches. To extract relevant information on quality and adulteration, the analytical data are coupled with chemometric techniques. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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14 pages, 355 KiB  
Review
The Molecular Weaponry Produced by the Bacterium Hafnia alvei in Foods
by José Ramos-Vivas, Olga Tapia, María Elexpuru-Zabaleta, Kilian Tutusaus Pifarre, Yasmany Armas Diaz, Maurizio Battino and Francesca Giampieri
Molecules 2022, 27(17), 5585; https://doi.org/10.3390/molecules27175585 - 30 Aug 2022
Cited by 9 | Viewed by 6088
Abstract
Hafnia alvei is receiving increasing attention from both a medical and veterinary point of view, but the diversity of molecules it produces has made the interest in this bacterium extend to the field of probiotics, the microbiota, and above all, to its presence [...] Read more.
Hafnia alvei is receiving increasing attention from both a medical and veterinary point of view, but the diversity of molecules it produces has made the interest in this bacterium extend to the field of probiotics, the microbiota, and above all, to its presence and action on consumer foods. The production of Acyl Homoserine Lactones (AHLs), a type of quorum-sensing (QS) signaling molecule, is the most often-studied chemical signaling molecule in Gram-negative bacteria. H. alvei can use this communication mechanism to promote the expression of certain enzymatic activities in fermented foods, where this bacterium is frequently present. H. alvei also produces a series of molecules involved in the modification of the organoleptic properties of different products, especially cheeses, where it shares space with other microorganisms. Although some strains of this species are implicated in infections in humans, many produce antibacterial compounds, such as bacteriocins, that inhibit the growth of true pathogens, so the characterization of these molecules could be very interesting from the point of view of clinical medicine and the food industry. Lastly, in some cases, H. alvei is responsible for the production of biogenic amines or other compounds of special interest in food health. In this article, we will review the most interesting molecules that produce the H. alvei strains and will discuss some of their properties, both from the point of view of their biological activity on other microorganisms and the properties of different food matrices in which this bacterium usually thrives. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
45 pages, 5865 KiB  
Review
Natural Products Inhibitors of Monoamine Oxidases—Potential New Drug Leads for Neuroprotection, Neurological Disorders, and Neuroblastoma
by Narayan D. Chaurasiya, Francisco Leon, Ilias Muhammad and Babu L. Tekwani
Molecules 2022, 27(13), 4297; https://doi.org/10.3390/molecules27134297 - 4 Jul 2022
Cited by 36 | Viewed by 8791
Abstract
Monoamine oxidase inhibitors (MAOIs) are an important class of drugs prescribed for treatment of depression and other neurological disorders. Evidence has suggested that patients with atypical depression preferentially respond to natural product MAOIs. This review presents a comprehensive survey of the natural products, [...] Read more.
Monoamine oxidase inhibitors (MAOIs) are an important class of drugs prescribed for treatment of depression and other neurological disorders. Evidence has suggested that patients with atypical depression preferentially respond to natural product MAOIs. This review presents a comprehensive survey of the natural products, predominantly from plant sources, as potential new MAOI drug leads. The psychoactive properties of several traditionally used plants and herbal formulations were attributed to their MAOI constituents. MAO inhibitory constituents may also be responsible for neuroprotective effects of natural products. Different classes of MAOIs were identified from the natural product sources with non-selective as well as selective inhibition of MAO-A and -B. Selective reversible natural product MAOIs may be safer alternatives to the conventional MAOI drugs. Characterization of MAO inhibitory constituents of natural products traditionally used as psychoactive preparations or for treatment of neurological disorders may help in understanding the mechanism of action, optimization of these preparations for desired bioactive properties, and improvement of the therapeutic potential. Potential therapeutic application of natural product MAOIs for treatment of neuroblastoma is also discussed. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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24 pages, 22991 KiB  
Review
Biogenic Silver Nanoparticles as a Stress Alleviator in Plants: A Mechanistic Overview
by Fozia Abasi, Naveed Iqbal Raja, Zia Ur Rehman Mashwani, Muhammad Shoaib Amjad, Maria Ehsan, Nilofar Mustafa, Muhammad Haroon and Jarosław Proćków
Molecules 2022, 27(11), 3378; https://doi.org/10.3390/molecules27113378 - 24 May 2022
Cited by 27 | Viewed by 4268
Abstract
Currently, the growth and yield of crops are restrained due to an increase in the occurrence of ecological stresses globally. Biogenic generation of nanomaterials is an important step in the development of environmentally friendly procedures in the nanotechnology field. Silver-based nanomaterials are significant [...] Read more.
Currently, the growth and yield of crops are restrained due to an increase in the occurrence of ecological stresses globally. Biogenic generation of nanomaterials is an important step in the development of environmentally friendly procedures in the nanotechnology field. Silver-based nanomaterials are significant because of their physical, chemical, and biological features along with their plentiful applications. In addition to useful microbes, the green synthesized Ag nanomaterials are considered to be an ecologically friendly and environmentally biocompatible method for the enhancement of crop yield by easing stresses. In the recent decade, due to regular droughts, infrequent precipitation, salinity, and increased temperature, the climate alternation has changed certain ecological systems. As a result of these environmental changes, crop yield has decreased worldwide. The role of biogenic Ag nanomaterials in enhancing methylglyoxal detoxification, antioxidant defense mechanisms, and generating tolerance to stresses-induced ROS injury has been methodically explained in plants over the past ten years. However, certain studies regarding stress tolerance and metal-based nanomaterials have been directed, but the particulars of silver nanomaterials arbitrated stresses tolerance have not been well-reviewed. Henceforth, there is a need to have a good understanding of plant responses during stressful conditions and to practice the combined literature to enhance tolerance for crops by utilization of Ag nanoparticles. This review article illustrates the mechanistic approach that biogenic Ag nanomaterials in plants adopt to alleviate stresses. Moreover, we have appraised the most significant activities by exogenous use of Ag nanomaterials for improving plant tolerance to salt, low and high temperature, and drought stresses. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Natural Products Chemistry)
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