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Special Issue "Essential Oils: Chemistry and Bioactivity"

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

Deadline for manuscript submissions: closed (31 May 2017)

Special Issue Editor

Guest Editor
Prof. Olga Tzakou

School of Pharmacy, National and Kapodistrian University of Athens, Department of Pharmacognosy and Chemistry of Natural Products, Athens, Greece
E-Mail
Interests: chemical analysis of essential oils; chemotaxonomic studies of plant taxa (interpopulation differentiation and identification of diagnostic markers); evaluation of bioactivity (larvicidal, insect repellent, antifungal, etc.)

Special Issue Information

Dear Colleagues,

Essential oils are odorous products usually of a very complex composition, which frequently exhibit significant fluctuations, displaying seasonal and geographical variations. In nature, their physiological role is important in the protection of plants as antivirals, antibacterial, antifungals, insecticides and also against herbivores, by reducing their appetite for the producing plants. Additionally, they may attract insects to favor the dispersion of pollen and seeds, or repel unfavorable insects. Essential oils have a long history of use in traditional medicine as antimicrobial agents. Besides their antimicrobial activity, they exhibit various biological activities including antiinflammatory, analgesic, antioxidant, antidiabetic, spasmolytic, sedative, cancer suppressive, insecticidal, insect repellent, etc.

This Special Issue aims to attract contributions on all aspects of the chemistry and bioactivity of essential oils, as well as on new methodologies for their isolation. Still there is a challenge to further explore the range of their biological effects and their potential applications in medicine and agriculture among others.

Prof. Olga Tzakou
Guest Editor

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Keywords

•    isolation of essential oils
•    chemical analysis
•    chemodiversity
•    chemotaxonomy
•    biological activities
•    ecological functions

Published Papers (19 papers)

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Research

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Open AccessArticle Antioxidant and Anticancer Activities of Essential Oil from Gannan Navel Orange Peel
Molecules 2017, 22(8), 1391; doi:10.3390/molecules22081391
Received: 28 July 2017 / Revised: 20 August 2017 / Accepted: 21 August 2017 / Published: 22 August 2017
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Abstract
China is one of the leading producers of citrus in the world. Gannan in Jiangxi Province is the top navel orange producing area in China. In the present study, an essential oil was prepared by cold pressing of Gannan navel orange peel followed
[...] Read more.
China is one of the leading producers of citrus in the world. Gannan in Jiangxi Province is the top navel orange producing area in China. In the present study, an essential oil was prepared by cold pressing of Gannan navel orange peel followed by molecular distillation. Its chemical composition was analyzed by GC-MS. Twenty four constituents were identified, representing 97.9% of the total oil. The predominant constituent was limonene (74.6%). The anticancer activities of this orange essential oil, as well as some of its major constituents, were investigated by MTT assay. This essential oil showed a positive effect on the inhibition of the proliferation of a human lung cancer cell line A549 and prostate cancer cell line 22RV-1. Some of the oil constituents displayed high anticancer potential and deserve further study. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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Open AccessArticle Composition and Antioxidant, Antienzymatic and Antimicrobial Activities of Volatile Molecules from Spanish Salvia lavandulifolia (Vahl) Essential Oils
Molecules 2017, 22(8), 1382; doi:10.3390/molecules22081382
Received: 21 June 2017 / Revised: 14 August 2017 / Accepted: 18 August 2017 / Published: 21 August 2017
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Abstract
The current study describes the composition of Salvia lavandulifolia (Vahl) essential oils (SlEOs) obtained from plants cultivated in Murcia (Spain), as determined by gas chromatography. Relative and absolute concentrations, the enantiomeric ratios of chiral compounds and the in vitro antioxidant, antienzymatic and antimicrobial
[...] Read more.
The current study describes the composition of Salvia lavandulifolia (Vahl) essential oils (SlEOs) obtained from plants cultivated in Murcia (Spain), as determined by gas chromatography. Relative and absolute concentrations, the enantiomeric ratios of chiral compounds and the in vitro antioxidant, antienzymatic and antimicrobial activities are described. The main components of the SlEOs were camphor, 1,8-cineole, camphene and α-pinene, and the main enantiomers were (+)-camphor and (−)-camphene. The activities against free radicals and the capacity to reduce and chelate metallic ions were measured. SlEO-3 showed the highest activity in ORAC, DPPH, ABTS and reducing power methods, while SlEO-1 exhibited the highest chelating power. The activity of lipoxygenase and acetylcholinesterase could be inhibited by all the SlEOs, being bornyl acetate and limonene the most active individual compounds against lipoxygenase and 1,8-cineole against acetylcholinesterase. SlEOs and some individual compounds inhibited Escherichia coli, Staphylococcus aureus and Candida albicans. These results increase our knowledge of SlEOs and, particularly, provide for the first time a complete characterization of SlEOs from Murcia, Spain, while proposing possible biotechnological uses for them. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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Open AccessArticle Myrcia splendens (Sw.) DC. (syn. M. fallax (Rich.) DC.) (Myrtaceae) Essential Oil from Amazonian Ecuador: A Chemical Characterization and Bioactivity Profile
Molecules 2017, 22(7), 1163; doi:10.3390/molecules22071163
Received: 30 May 2017 / Revised: 30 June 2017 / Accepted: 6 July 2017 / Published: 12 July 2017
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Abstract
In this study, we performed the chemical characterization of Myrcia splendens (Sw.) DC. (Myrtaceae) essential oil from Amazonian Ecuador and the assessment of its bioactivity in terms of cytotoxic, antibacterial, and antioxidant activity as starting point for possible applicative uses. M. splendens essential
[...] Read more.
In this study, we performed the chemical characterization of Myrcia splendens (Sw.) DC. (Myrtaceae) essential oil from Amazonian Ecuador and the assessment of its bioactivity in terms of cytotoxic, antibacterial, and antioxidant activity as starting point for possible applicative uses. M. splendens essential oil, obtained by hydro-distillation, was analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) and Gas Chromatography-Flame Ionization Detector (GC-FID): the major components were found to be trans-nerolidol (67.81%) and α-bisabolol (17.51%). Furthermore, we assessed the cytotoxic activity against MCF-7 (breast), A549 (lung) human tumor cell lines, and HaCaT (human keratinocytes) non-tumor cell line through 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) test: promising results in terms of selectivity and efficacy against the MCF-7 cell line (IC50 of 5.59 ± 0.13 μg/mL at 48 h) were obtained, mainly due to α-bisabolol. Furthermore, antibacterial activity against Gram positive and negative bacteria were performed through High Performance Thin Layer Chromatography (HPTLC) bioautographic assay and microdilution method: trans-nerolidol and β-cedren-9-one were the main molecules responsible for the low antibacterial effects against human pathogens. Nevertheless, interesting values of Minimum Inhibitory Concentration (MIC) were noticeable against phytopathogen strains. Radical scavenging activity performed by HPTLC bioautographic and spectrophotometric 1,1-diphenyl-2-picrylhydrazyl (DPPH) approaches were negligible. In conclusion, the essential oil revealed a good potential for plant defense and anti-cancer applications. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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Open AccessArticle In Vitro Anti-Leishmanial Activity of Essential Oils Extracted from Vietnamese Plants
Molecules 2017, 22(7), 1071; doi:10.3390/molecules22071071
Received: 4 May 2017 / Revised: 21 June 2017 / Accepted: 22 June 2017 / Published: 27 June 2017
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Abstract
Leishmania mexicana is one of the pathogens causing cutaneous leishmaniasis which is associated with patient morbidity. In our researches for new safe and effective treatments, thirty-seven essential oils (EOs) extracted from Vietnamese plants were screened in vitro for the first time on Leishmania
[...] Read more.
Leishmania mexicana is one of the pathogens causing cutaneous leishmaniasis which is associated with patient morbidity. In our researches for new safe and effective treatments, thirty-seven essential oils (EOs) extracted from Vietnamese plants were screened in vitro for the first time on Leishmania mexicana mexicana (Lmm) promastigotes at the maximum concentration of 50 nL/mL. Active EOs were also analyzed for cytotoxicity on mammalian cell lines (WI38, J774) and their selectivity indices (SI) were calculated. Their composition was determined by GC-MS and GC-FID. Our results indicated that EOs extracted from Cinnamomum cassia, Zingiber zerumbet, Elsholtzia ciliata and Amomum aromaticum, possessed a moderate anti-leishmanial activity, with IC50 values of 2.92 ± 0.08, 3.34 ± 0.34, 8.49 ± 0.32 and 9.25 ± 0.64 nL/mL respectively. However, they also showed cytotoxicity with SI < 10. The most promising EO was extracted from Ocimum gratissimum, displaying an IC50 of 4.85 ± 1.65 nL/mL and SI > 10. It contained 86.5% eugenol, which was demonstrated to be effective on Lmm with IC50 of 2.57 ± 0.57 nL/mL and not toxic on mammalian cells, explaining the observed activity. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
Open AccessArticle The Effects of Selected Sesquiterpenes from Myrica rubra Essential Oil on the Efficacy of Doxorubicin in Sensitive and Resistant Cancer Cell Lines
Molecules 2017, 22(6), 1021; doi:10.3390/molecules22061021
Received: 10 May 2017 / Accepted: 16 June 2017 / Published: 20 June 2017
Cited by 2 | PDF Full-text (4489 KB) | HTML Full-text | XML Full-text
Abstract
β-caryophyllene oxide (CAO), α-humulene (HUM), trans-nerolidol (NER) and valencene (VAL) are constituents of the essential oil of Myrica rubra (MEO), which has significant antiproliferative effect in various cancer cell lines. In the present study, we compared the antiproliferative effect of these sesquiterpenes alone
[...] Read more.
β-caryophyllene oxide (CAO), α-humulene (HUM), trans-nerolidol (NER) and valencene (VAL) are constituents of the essential oil of Myrica rubra (MEO), which has significant antiproliferative effect in various cancer cell lines. In the present study, we compared the antiproliferative effect of these sesquiterpenes alone and in combination with the cytostatic drug doxorubicin (DOX) in cancer cell lines with different sensitivity to DOX. Two ovarian cancer cell lines (sensitive A2780 and partly resistant SKOV3) and two lymphoblast cancer cell lines (sensitive CCRF/CEM and completely resistant CEM/ADR) were used. The observed effects varied among sesquiterpenes and also differed in individual cell lines, with only VAL being effective in all the cell lines. A strong synergism of DOX with NER was found in the A2780 cells, while DOX acted synergistically with HUM and CAO in the SKOV3 cells. In the CCRF/CEM cells, a synergism of DOX with CAO and NER was observed. In resistant CEM/ADR cells, sesquiterpenes did not increase DOX efficacy, although they significantly increased accumulation of DOX (up to 10-times) and rhodamine-123 (substrate of efflux transporter ABCB1) within cancer cells. In conclusion, the tested sesquiterpenes were able to improve DOX efficacy in the sensitive and partly resistant cancer cells, but not in cells completely resistant to DOX. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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Open AccessArticle Laurus nobilis: Composition of Essential Oil and Its Biological Activities
Molecules 2017, 22(6), 930; doi:10.3390/molecules22060930
Received: 10 May 2017 / Revised: 30 May 2017 / Accepted: 1 June 2017 / Published: 3 June 2017
Cited by 1 | PDF Full-text (973 KB) | HTML Full-text | XML Full-text
Abstract
Laurus nobilis is native to the southern Mediterranean region and cultivated mainly in Europe and the USA as an ornamental and medicinal plant. The chemical composition of the essential oil (EO) from leaves of L. nobilis, collected in Southern Italy, was studied by
[...] Read more.
Laurus nobilis is native to the southern Mediterranean region and cultivated mainly in Europe and the USA as an ornamental and medicinal plant. The chemical composition of the essential oil (EO) from leaves of L. nobilis, collected in Southern Italy, was studied by GC and GC-MS. In all, 55 compounds were identified, accounting for 91.6% of the total oil. 1,8-Cineole (31.9%), sabinene (12.2%), and linalool (10.2%) were the main components. Antimicrobial and antifungal activities of EO and 1,8-cineole were determined in vitro. The cytotoxicity of the EO was evaluated against SH-SY5Y cell line, as well as the influence of the EO on the expression of adenylate cyclase 1 (ADCY1), suggesting possible oil effects on the Central Nervous System. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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Open AccessArticle Antinociceptive Effect of the Essential Oil from Croton conduplicatus Kunth (Euphorbiaceae)
Molecules 2017, 22(6), 900; doi:10.3390/molecules22060900
Received: 18 April 2017 / Revised: 24 May 2017 / Accepted: 26 May 2017 / Published: 30 May 2017
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Abstract
Medicinal plants have been widely used in the treatment of chronic pain. In this study, we describe the antinociceptive effect of the essential oil from Croton conduplicatus (the EO 25, 50, and 100 mg/kg, i.p.), a medicinal plant native to Brazil. Antinociceptive activity
[...] Read more.
Medicinal plants have been widely used in the treatment of chronic pain. In this study, we describe the antinociceptive effect of the essential oil from Croton conduplicatus (the EO 25, 50, and 100 mg/kg, i.p.), a medicinal plant native to Brazil. Antinociceptive activity was investigated by measuring the nociception induced by acetic acid, formalin, hot plate and carrageenan. A docking study was performed with the major constituents of the EO (E-caryophyllene, caryophyllene oxide, and camphor). The EO reduced nociceptive behavior at all doses tested in the acetic acid-induced nociception test (p < 0.05). The same was observed in both phases (neurogenic and inflammatory) of the formalin test. When the hot-plate test was conducted, the EO (50 mg/kg) extended the latency time after 60 min of treatment. The EO also reduced leukocyte migration at all doses, suggesting that its antinociceptive effect involves both central and peripheral mechanisms. Pretreatment with glibenclamide and atropine reversed the antinociceptive effect of the EO on the formalin test, suggesting the involvement of KATP channels and muscarinic receptors. The docking study revealed a satisfactory interaction profile between the major components of the EO and the different muscarinic receptor subtypes (M2, M3, and M4). These results corroborate the medicinal use of C. conduplicatus in folk medicine. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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Open AccessArticle Growth Inhibition of Sulfate-Reducing Bacteria in Produced Water from the Petroleum Industry Using Essential Oils
Molecules 2017, 22(4), 648; doi:10.3390/molecules22040648
Received: 8 March 2017 / Revised: 13 April 2017 / Accepted: 15 April 2017 / Published: 19 April 2017
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Abstract
Strategies for the control of sulfate-reducing bacteria (SRB) in the oil industry involve the use of high concentrations of biocides, but these may induce bacterial resistance and/or be harmful to public health and the environment. Essential oils (EO) produced by plants inhibit the
[...] Read more.
Strategies for the control of sulfate-reducing bacteria (SRB) in the oil industry involve the use of high concentrations of biocides, but these may induce bacterial resistance and/or be harmful to public health and the environment. Essential oils (EO) produced by plants inhibit the growth of different microorganisms and are a possible alternative for controlling SRB. We aimed to characterize the bacterial community of produced water obtained from a Brazilian petroleum facility using molecular methods, as well as to evaluate the antimicrobial activity of EO from different plants and their major components against Desulfovibrio alaskensis NCIMB 13491 and against SRB growth directly in the produced water. Denaturing gradient gel electrophoresis revealed the presence of the genera Pelobacter and Marinobacterium, Geotoga petraea, and the SRB Desulfoplanes formicivorans in our produced water samples. Sequencing of dsrA insert-containing clones confirmed the presence of sequences related to D. formicivorans. EO obtained from Citrus aurantifolia, Lippia alba LA44 and Cymbopogon citratus, as well as citral, linalool, eugenol and geraniol, greatly inhibited (minimum inhibitory concentration (MIC) = 78 µg/mL) the growth of D. alaskensis in a liquid medium. The same MIC was obtained directly in the produced water with EO from L. alba LA44 (containing 82% citral) and with pure citral. These findings may help to control detrimental bacteria in the oil industry. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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Open AccessArticle The Effect of Citrus Essential Oils and Their Constituents on Growth of Xanthomonas citri subsp. citri
Molecules 2017, 22(4), 591; doi:10.3390/molecules22040591
Received: 13 January 2017 / Revised: 5 April 2017 / Accepted: 5 April 2017 / Published: 14 April 2017
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Abstract
Citrus bacterial canker (CBC) caused by Xanthomonas citri subsp. citri (Xcc), is the most devastating of the citrus diseases worldwide. During our study, we found that Essential oils (EOs) of some citrus cultivars are effective on Xcc. Therefore, it prompted
[...] Read more.
Citrus bacterial canker (CBC) caused by Xanthomonas citri subsp. citri (Xcc), is the most devastating of the citrus diseases worldwide. During our study, we found that Essential oils (EOs) of some citrus cultivars are effective on Xcc. Therefore, it prompted us to determine the plant metabolites responsible for the antibacterial properties. We obtained EOs from some locally cultivated citrus by using a Clevenger apparatus and their major constituents were identified by gas chromatography/mass spectrometry (GC-MS). The effect of Citrus aurantium, C. aurantifolia, Fortunella sp. EOs and their major constituents were evaluated against Xcc-KVXCC1 using a disk diffusion assay. Minimal inhibitory and bactericidal concentration of the EOs and their constituents were determined using the broth microdilution method. C. aurantium, C. aurantifolia Eos, and their major constituents including citral, linalool, citronellal, geraniol, α-terpineol, and linalyl acetate indicated antibacterial effects against Xcc. The C. aurantifolia EO and citral showed the highest antibacterial activity among the tested EOs and constituents with inhibition zones of 15 ± 0.33 mm and 16.67 ± 0.88 mm, respectively. Synergistic effects of the constituents were observed between α-terpineol-citral, citral-citronellal, citral-geraniol, and citronellal-geraniol by using a microdilution checkerboard assay. Transmission electron microscopy revealed that exposure of Xcc cells to citral caused cell wall damage and altered cytoplasmic density. We introduced C. aurantifolia and C. aurantium EOs, and their constituents citral, α-terpineol, citronellal, geraniol, and linalool as possible control agents for CBC. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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Open AccessArticle Bergamot Essential Oil Attenuates Anxiety-Like Behaviour in Rats
Molecules 2017, 22(4), 614; doi:10.3390/molecules22040614
Received: 15 March 2017 / Revised: 7 April 2017 / Accepted: 9 April 2017 / Published: 11 April 2017
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Abstract
Preclinical studies have recently highlighted that bergamot essential oil (BEO) is endowed with remarkable neurobiolological effects. BEO can affect synaptic transmission, modulate electroencephalographic activity and it showed neuroprotective and analgesic properties. The phytocomplex, along with other essential oils, is also widely used in
[...] Read more.
Preclinical studies have recently highlighted that bergamot essential oil (BEO) is endowed with remarkable neurobiolological effects. BEO can affect synaptic transmission, modulate electroencephalographic activity and it showed neuroprotective and analgesic properties. The phytocomplex, along with other essential oils, is also widely used in aromatherapy to minimize symptoms of stress-induced anxiety and mild mood disorders. However, only limited preclinical evidences are actually available. This study examined the anxiolytic/sedative-like effects of BEO using an open field task (OFT), an elevated plus-maze task (EPM), and a forced swimming task (FST) in rats. This study further compared behavioural effects of BEO to those of the benzodiazepine diazepam. Analysis of data suggests that BEO induces anxiolytic-like/relaxant effects in animal behavioural tasks not superimposable to those of the DZP. The present observations provide further insight to the pharmacological profile of BEO and support its rational use in aromatherapy. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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Open AccessArticle Essential Oil Composition and Bioactivities of Waldheimia glabra (Asteraceae) from Qinghai-Tibet Plateau
Molecules 2017, 22(3), 460; doi:10.3390/molecules22030460
Received: 26 December 2016 / Accepted: 11 March 2017 / Published: 13 March 2017
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Abstract
Waldheimia glabra is traditionally used as incense and as an anti-influenza drug by Tibetans in China. Here, we collected W. glabra from the Gangs Rinpoche mountain at an altitude of 5200 m, and analyzed its essential oil by gas chromatography-mass spectrometry (GC-MS) combined
[...] Read more.
Waldheimia glabra is traditionally used as incense and as an anti-influenza drug by Tibetans in China. Here, we collected W. glabra from the Gangs Rinpoche mountain at an altitude of 5200 m, and analyzed its essential oil by gas chromatography-mass spectrometry (GC-MS) combined with the retention indices (RI). Twenty-seven compounds, representing 72.4% of the total essential oil, were identified, including α-bisabolol (20.2%), valeranone (11.8%), chamazulene (9.9%), spathulenol (8.2%), β-caryophyllene (6.1%), and caryophyllene oxide (5.2%). Bioactivity evaluation of the essential oil revealed that it exhibited potent anti-influenza effect on viruses H3N2 and anti-inflammatory effect by inhibiting the lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 macrophages, but no anti-complementary activity. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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Open AccessArticle Chemical Composition, Antioxidant, Antimicrobial and Cytotoxic Activities of Essential Oil from Premna microphylla Turczaninow
Molecules 2017, 22(3), 381; doi:10.3390/molecules22030381
Received: 31 January 2017 / Accepted: 26 February 2017 / Published: 28 February 2017
Cited by 1 | PDF Full-text (231 KB) | HTML Full-text | XML Full-text
Abstract
Premna microphylla Turczaninow, an erect shrub, was widely used in Chinese traditional medicine to treat dysentery, appendicitis, and infections. In this study, the essential oil from P. microphylla Turcz. was obtained by hydrodistillation and analyzed by GC (Gas Chromatography) and GC-MS (Gas Chromatography-Mass
[...] Read more.
Premna microphylla Turczaninow, an erect shrub, was widely used in Chinese traditional medicine to treat dysentery, appendicitis, and infections. In this study, the essential oil from P. microphylla Turcz. was obtained by hydrodistillation and analyzed by GC (Gas Chromatography) and GC-MS (Gas Chromatography-Mass Spectrometer). Fifty-six compounds were identified in the oil which comprised about 97.2% of the total composition of the oil. Major components of the oil were blumenol C (49.7%), β-cedrene (6.1%), limonene (3.8%), α-guaiene (3.3%), cryptone (3.1%), and α-cyperone (2.7%). Furthermore, we assessed the in vitro biological activities displayed by the oil obtained from the aerial parts of P. microphylla, namely the antioxidant, antimicrobial, and cytotoxic activities. The antioxidant activity of the essential oil was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. For this, the IC50 value was estimated to be 0.451 mg/mL. The essential oil of P. microphylla exhibited considerable antibacterial capacity against Escherichia coli with an MIC (Minimum Inhibitory Concentration) value of 0.15 mg/mL, along with noticeable antibacterial ability against Bacillus subtilis and Staphylococcus aureus with an MIC value of 0.27 mg/mL. However, the essential oil did not show significant activity against fungus. The oil was tested for its cytotoxic activity towards HepG2 (liver hepatocellular cells) and MCF-7 Cells (human breast adenocarcinoma cell line) using the MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) assay, and exerted cytotoxic activity with an IC50 of 0.072 and 0.188 mg/mL for 72 h. In conclusion, the essential oil from P. microphylla is an inexpensive but favorable resource with strong antibacterial capacity as well as cytotoxic activity. Thus, it has the potential for utilization in the cosmetics and pharmaceutical industries. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
Open AccessArticle Essential Oil of Aristolochia trilobata: Synthesis, Routes of Exposure, Acute Toxicity, Binary Mixtures and Behavioral Effects on Leaf-Cutting Ants
Molecules 2017, 22(3), 335; doi:10.3390/molecules22030335
Received: 17 January 2017 / Revised: 10 February 2017 / Accepted: 15 February 2017 / Published: 25 February 2017
Cited by 2 | PDF Full-text (2441 KB) | HTML Full-text | XML Full-text
Abstract
Plants of the genus Aristolochia have been frequently reported as important medicinal plants. Despite their high bioactive potential, to date, there are no reports of their effects on leaf-cutting ants. Therefore, the present study aimed to evaluate the insecticidal activity of the essential
[...] Read more.
Plants of the genus Aristolochia have been frequently reported as important medicinal plants. Despite their high bioactive potential, to date, there are no reports of their effects on leaf-cutting ants. Therefore, the present study aimed to evaluate the insecticidal activity of the essential oil of Aristolochia trilobata and its major components on Atta sexdens and Acromyrmex balzani, two species of leaf-cutting ants. The bioassays were performed regarding routes of exposure, acute toxicity, binary mixtures of the major components and behavioral effects. Twenty-five components were identified in the essential oil of A. trilobata using a gas chromatographic system equipped with a mass spectrometer and a flame ionization detector. The components found in higher proportions were sulcatyl acetate, limonene, p-cymene and linalool. The essential oil of A. trilobata and its individual major components were efficient against A. balzani and A. sexdens workers when applied by fumigation. These components showed fast and efficient insecticidal activity on ants. The components acted synergistically and additively on A. balzani and A. sexdens, respectively, and caused a strong repellency/irritability in the ants. Thus, our results demonstrate the great potential of the essential oil of A. trilobata and its major components for the development of new insecticides. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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Open AccessArticle The Essential Oil of Monarda didyma L. (Lamiaceae) Exerts Phytotoxic Activity in Vitro against Various Weed Seed
Molecules 2017, 22(2), 222; doi:10.3390/molecules22020222
Received: 3 January 2017 / Accepted: 27 January 2017 / Published: 2 February 2017
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Abstract
The chemical composition of the essential oil of the flowering aerial parts of Monarda didyma L. cultivated in central Italy was analyzed by Gas Chromatography/Mass Spectrometry (GC/MS). The major compounds of the oil were thymol (59.3%), p-cymene (10.3%), terpinolene (9.2%), δ-3-carene (4.4%), myrcene
[...] Read more.
The chemical composition of the essential oil of the flowering aerial parts of Monarda didyma L. cultivated in central Italy was analyzed by Gas Chromatography/Mass Spectrometry (GC/MS). The major compounds of the oil were thymol (59.3%), p-cymene (10.3%), terpinolene (9.2%), δ-3-carene (4.4%), myrcene (3.7%), and camphene (3.4%). The essential oil was tested in vitro for its anti-germination activity against Papaver rhoeas L., Taraxacum officinale F. H. Wigg., Avena fatua L., Raphanus sativus L. and Lepidium sativum L. seeds, demonstrating good inhibitory activity in a dose-dependent way. The exposure of the employed weed seeds to M. didyma essential oil and thymol solution (59.3%) increased the level of hydrogen peroxide (H2O2) and malondialdehyde (MDA), markers of oxidative stress, in emerging 5-day-old rootlets. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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Open AccessArticle Essential Oil Extraction, Chemical Analysis and Anti-Candida Activity of Calamintha nepeta (L.) Savi subsp. glandulosa (Req.) Ball—New Approaches
Molecules 2017, 22(2), 203; doi:10.3390/molecules22020203
Received: 28 November 2016 / Accepted: 24 January 2017 / Published: 26 January 2017
Cited by 5 | PDF Full-text (2809 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A comprehensive study on essential oils extracted from different Calamintha nepeta (L.) Savi subsp. glandulosa (Req.) Ball samples from Tarquinia (Italy) is reported. In this study, the 24-h steam distillation procedure for essential oil preparation, in terms of different harvesting and extraction times,
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A comprehensive study on essential oils extracted from different Calamintha nepeta (L.) Savi subsp. glandulosa (Req.) Ball samples from Tarquinia (Italy) is reported. In this study, the 24-h steam distillation procedure for essential oil preparation, in terms of different harvesting and extraction times, was applied. The Gas chromatography–mass spectrometry (GC/MS) analysis showed that C. nepeta (L.) Savi subsp. glandulosa (Req.) Ball essential oils from Tarquinia belong to the pulegone-rich chemotype. The analysis of 44 samples revealed that along with pulegone, some other chemicals may participate in exerting the related antifungal activity. The results indicated that for higher activity, the essential oils should be produced with at least a 6-h steam distillation process. Even though it is not so dependent on the period of harvesting, it could be recommended not to harvest the plant in the fruiting stage, since no significant antifungal effect was shown. The maximum essential oil yield was obtained in August, with the highest pulegone percentage. To obtain the oil with a higher content of menthone, September and October should be considered as the optimal periods. Regarding the extraction duration, vegetative stage material gives the oil in the first 3 h, while material from the reproductive phase should be extracted at least at 6 or even 12 h. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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Open AccessReview Essential Oils and Their Constituents: An Alternative Source for Novel Antidepressants
Molecules 2017, 22(8), 1290; doi:10.3390/molecules22081290
Received: 6 July 2017 / Revised: 31 July 2017 / Accepted: 31 July 2017 / Published: 3 August 2017
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Abstract
Depression is a disease that has affected a high proportion of the world’s population and people of different ages, incapacitating them from good performance at work and in social relationships, and causing emotional disorders to millions of families. Therefore, the search for new
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Depression is a disease that has affected a high proportion of the world’s population and people of different ages, incapacitating them from good performance at work and in social relationships, and causing emotional disorders to millions of families. Therefore, the search for new therapeutic agents is considered a priority for the discovery of more effective forms of treatment. In this review, studies of essential oils and their constituents in experimental models related to depression are discussed. The mechanisms of action of the oils and the presence of psychoactive constituents in their chemical compositions are discussed. The data in the review show the therapeutic potential of essential oils and their chemical constituents for use in depressive disorders. Advanced studies using humans are needed to confirm the antidepressant properties described in animals. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
Open AccessReview Essential Oils of Oregano: Biological Activity beyond Their Antimicrobial Properties
Molecules 2017, 22(6), 989; doi:10.3390/molecules22060989
Received: 25 May 2017 / Revised: 8 June 2017 / Accepted: 10 June 2017 / Published: 14 June 2017
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Abstract
Essential oils of oregano are widely recognized for their antimicrobial activity, as well as their antiviral and antifungal properties. Nevertheless, recent investigations have demonstrated that these compounds are also potent antioxidant, anti-inflammatory, antidiabetic and cancer suppressor agents. These properties of oregano essential oils
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Essential oils of oregano are widely recognized for their antimicrobial activity, as well as their antiviral and antifungal properties. Nevertheless, recent investigations have demonstrated that these compounds are also potent antioxidant, anti-inflammatory, antidiabetic and cancer suppressor agents. These properties of oregano essential oils are of potential interest to the food, cosmetic and pharmaceutical industries. The aim of this manuscript is to review the latest evidence regarding essential oils of oregano and their beneficial effects on health. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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Open AccessReview Calamintha nepeta (L.) Savi and its Main Essential Oil Constituent Pulegone: Biological Activities and Chemistry
Molecules 2017, 22(2), 290; doi:10.3390/molecules22020290
Received: 28 December 2016 / Accepted: 6 February 2017 / Published: 14 February 2017
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Abstract
Medicinal plants play an important role in the treatment of a wide range of diseases, even if their chemical constituents are not always completely recognized. Observations on their use and efficacy significantly contribute to the disclosure of their therapeutic properties. Calamintha nepeta (L.)
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Medicinal plants play an important role in the treatment of a wide range of diseases, even if their chemical constituents are not always completely recognized. Observations on their use and efficacy significantly contribute to the disclosure of their therapeutic properties. Calamintha nepeta (L.) Savi is an aromatic herb with a mint-oregano flavor, used in the Mediterranean areas as a traditional medicine. It has an extensive range of biological activities, including antimicrobial, antioxidant and anti-inflammatory, as well as anti-ulcer and insecticidal properties. This study aims to review the scientific findings and research reported to date on Calamintha nepeta (L.) Savi that prove many of the remarkable various biological actions, effects and some uses of this species as a source of bioactive natural compounds. On the other hand, pulegone, the major chemical constituent of Calamintha nepeta (L.) Savi essential oil, has been reported to exhibit numerous bioactivities in cells and animals. Thus, this integrated overview also surveys and interprets the present knowledge of chemistry and analysis of this oxygenated monoterpene, as well as its beneficial bioactivities. Areas for future research are suggested Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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Open AccessReview Chemical Variability and Biological Activities of Eucalyptus spp. Essential Oils
Molecules 2016, 21(12), 1671; doi:10.3390/molecules21121671
Received: 3 October 2016 / Revised: 20 November 2016 / Accepted: 28 November 2016 / Published: 7 December 2016
Cited by 4 | PDF Full-text (514 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Many plant species produce mixtures of odorous and volatile compounds known as essential oils (EOs). These mixtures play important roles in Nature and have been utilized by mankind for different purposes, such as pharmaceuticals, agrochemicals, aromatherapy, and food flavorants. There are more than
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Many plant species produce mixtures of odorous and volatile compounds known as essential oils (EOs). These mixtures play important roles in Nature and have been utilized by mankind for different purposes, such as pharmaceuticals, agrochemicals, aromatherapy, and food flavorants. There are more than 3000 EOs reported in the literature, with approximately 300 in commercial use, including the EOs from Eucalyptus species. Most EOs from Eucalyptus species are rich in monoterpenes and many have found applications in pharmaceuticals, agrochemicals, food flavorants, and perfumes. Such applications are related to their diverse biological and organoleptic properties. In this study, we review the latest information concerning the chemical composition and biological activities of EOs from different species of Eucalyptus. Among the 900 species and subspecies of the Eucalyptus genus, we examined 68 species. The studies associated with these species were conducted in 27 countries. We have focused on the antimicrobial, acaricidal, insecticidal and herbicidal activities, hoping that such information will contribute to the development of research in this field. It is also intended that the information described in this study can be useful in the rationalization of the use of Eucalyptus EOs as components for pharmaceutical and agrochemical applications as well as food preservatives and flavorants. Full article
(This article belongs to the Special Issue Essential Oils: Chemistry and Bioactivity)
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