Essential Oils of Plants (Chemical Composition, Variation and Properties)

A special issue of Plants (ISSN 2223-7747). This special issue belongs to the section "Phytochemistry".

Deadline for manuscript submissions: closed (28 February 2021) | Viewed by 46772

Special Issue Editors


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Guest Editor
Dpto. Biodiversity Ecology and Evolution, Faculty of Biology, Complutense University of Madrid, 28040 Madrid, Spain
Interests: essential oils; chemical composition; seasonal variation; chemotypes; antibacterial activity; antifungal activity
Special Issues, Collections and Topics in MDPI journals
School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
Interests: essential oils chemistry; the oil’s relationship to the botany of the species; insect chemistry; natural product chemistry
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Essential oils are important for the plants that produce them as well as the humans that have learnt to extract and use them since the beginning of civilization. Nowadays, their constituent secondary metabolites are not only very important for the fragrance industry but also for the chemical and pharmaceutical industries. Essential oils have numerous uses and knowledge related to essential oils is implicated in most fields of research: biology, ecology, genetic, conservation, climatic change, medicine, etc. For this Special Issue, we invite you to contribute with papers toward updating the knowledge on this incredible topic.

Dr. Jésus Palá-Pául
Dr. Joe Brophy
Guest Editors

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Keywords

  • essential oils
  • chemical composition
  • seasonal variation
  • chemotypes
  • antibacterial activity
  • antifungal activity

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Published Papers (13 papers)

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Research

16 pages, 1723 KiB  
Article
Chemical Composition and Biological Activity of Salvia officinalis L. Essential Oil
by Zvonimir Jažo, Mateo Glumac, Vlatka Paštar, Sanida Bektić, Mila Radan and Ivana Carev
Plants 2023, 12(9), 1794; https://doi.org/10.3390/plants12091794 - 27 Apr 2023
Cited by 7 | Viewed by 3652
Abstract
In our study, we investigated the chemical composition and cytotoxic activity of essential oils isolated from Dalmatian sage (Salvia officinalis L.) collected along the Adriatic coast of Croatia. Scanning electron microscopy (SEM) was used to examine the morphology of the stem and [...] Read more.
In our study, we investigated the chemical composition and cytotoxic activity of essential oils isolated from Dalmatian sage (Salvia officinalis L.) collected along the Adriatic coast of Croatia. Scanning electron microscopy (SEM) was used to examine the morphology of the stem and leaf surfaces. Essential oil excretory glands were detected on both the leaves and stem surfaces. The essential oils were isolated by hydrodistillation, and their chemical composition was determined by gas chromatography and mass spectrometry (GC-MS). Sage essential oils were mixtures of terpene compounds, among which the most common were: α- and β-thujone, camphor, and 1,8-cineol. Cytotoxic activity was tested using MTS assay on multiple cell lines: normal and immortalized fibroblasts (HF77FA and HDF-Tert), immortalized lung line (BEAS-2B), and breast adenocarcinoma (MDA-MB-231). The growth of treated cells was determined relative to control conditions without treatment. The immortalized lung line was the least resistant to the activity of the essential oils, whereas immortalized fibroblasts were the most resistant. Statistical analysis has connected the cytotoxic effect and chemical composition of the studied essential oils. To the best of our knowledge, this work is the first testing of the cytotoxic activity of S. officinalis EO’s on the BEAS-2B, HF77FA, and HDF-Tert cell lines. The presented data on essential oil chemical composition and cytotoxic effect on 4 types of human cells supports pharmacotherapeutic potential this plant is known to have. Full article
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15 pages, 984 KiB  
Article
Chemical Variability of Peel and Leaf Essential Oils in the Citrus Subgenus Papeda (Swingle) and Few Relatives
by Clémentine Baccati, Marc Gibernau, Mathieu Paoli, Patrick Ollitrault, Félix Tomi and François Luro
Plants 2021, 10(6), 1117; https://doi.org/10.3390/plants10061117 - 31 May 2021
Cited by 13 | Viewed by 3329
Abstract
The Papeda Citrus subgenus includes several species belonging to two genetically distinct groups, containing mostly little-exploited wild forms of citrus. However, little is known about the potentially large and novel aromatic diversity contained in these wild citruses. In this study, we characterized and [...] Read more.
The Papeda Citrus subgenus includes several species belonging to two genetically distinct groups, containing mostly little-exploited wild forms of citrus. However, little is known about the potentially large and novel aromatic diversity contained in these wild citruses. In this study, we characterized and compared the essential oils obtained from peels and leaves from representatives of both Papeda groups, and three related hybrids. Using a combination of GC, GC-MS, and 13C-NMR spectrometry, we identified a total of 60 compounds in peel oils (PO), and 76 compounds in leaf oils (LO). Limonene was the major component in almost all citrus PO, except for C. micrantha and C. hystrix, where β-pinene dominated (around 35%). LO composition was more variable, with different major compounds among almost all samples, except for two citrus pairs: C. micrantha/C. hystrix and two accessions of C. ichangensis. In hybrid relatives, the profiles were largely consistent with their Citrus/Papeda parental lineage. This high chemical diversity, not only among the sections of the subgenus Papeda, but also between species and even at the intraspecific level, suggests that Papeda may be an important source of aroma diversity for future experimental crosses with field crop species. Full article
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14 pages, 8652 KiB  
Article
Essential Oil of Croton zehntneri Prevents Conduction Alterations Produced by Diabetes Mellitus on Vagus Nerve
by Kerly Shamyra Silva-Alves, Francisco Walber Ferreira-da-Silva, Andrelina Noronha Coelho-de-Souza and José Henrique Leal-Cardoso
Plants 2021, 10(5), 893; https://doi.org/10.3390/plants10050893 - 28 Apr 2021
Cited by 9 | Viewed by 2244
Abstract
Autonomic diabetic neuropathy (ADN) is a complication of diabetes mellitus (DM), to which there is no specific treatment. In this study, the efficacy of the essential oil of Croton zehntneri (EOCz) in preventing ADN was evaluated in the rat vagus nerve. For the [...] Read more.
Autonomic diabetic neuropathy (ADN) is a complication of diabetes mellitus (DM), to which there is no specific treatment. In this study, the efficacy of the essential oil of Croton zehntneri (EOCz) in preventing ADN was evaluated in the rat vagus nerve. For the two fastest conducting myelinated types of axons of the vagus nerve, the conduction velocities and rheobase decreased, whilst the duration of the components of the compound action potential of these fibers increased. EOCz completely prevented these DM-induced alterations of the vagus nerve. Unmyelinated fibers were not affected. In conclusion, this investigation demonstrated that EOCz is a potential therapeutic agent for the treatment of ADN. Full article
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41 pages, 3811 KiB  
Article
The Diversity of Volatile Compounds in Australia’s Semi-Desert Genus Eremophila (Scrophulariaceae)
by Nicholas J. Sadgrove, Guillermo F. Padilla-González, Alison Green, Moses K. Langat, Eduard Mas-Claret, Dane Lyddiard, Julian Klepp, Sarah V. A.-M. Legendre, Ben W. Greatrex, Graham L. Jones, Iskandar M. Ramli, Olga Leuner and Eloy Fernandez-Cusimamani
Plants 2021, 10(4), 785; https://doi.org/10.3390/plants10040785 - 16 Apr 2021
Cited by 8 | Viewed by 3404
Abstract
Australia’s endemic desert shrubs are commonly aromatic, with chemically diverse terpenes and phenylpropanoids in their headspace profiles. Species from the genus Eremophila (Scrophulariaceae ex. Myoporaceae) are the most common, with 215 recognised taxa and many more that have not yet been described, widely [...] Read more.
Australia’s endemic desert shrubs are commonly aromatic, with chemically diverse terpenes and phenylpropanoids in their headspace profiles. Species from the genus Eremophila (Scrophulariaceae ex. Myoporaceae) are the most common, with 215 recognised taxa and many more that have not yet been described, widely spread across the arid parts of the Australian continent. Over the years, our research team has collected multiple specimens as part of a survey to investigate the chemical diversity of the genus and create leads for further scientific enquiry. In the current study, the diversity of volatile compounds is studied using hydrodistilled essential oils and leaf solvent extracts from 30 taxa. Several rare terpenes and iridoids were detected in chemical profiles widely across the genus, and three previously undescribed sesquiterpenes were isolated and are assigned by 2D NMR—E-11(12)-dehydroisodendrolasin, Z-11-hydroxyisodendrolasin and 10-hydroxydihydro-α-humulene acetate. Multiple sampling from Eremophila longifolia, Eremophila arbuscular, Eremophila latrobei, Eremophila deserti, Eremophila sturtii, Eremophila oppositifolia and Eremophila alternifolia coneys that species in Eremophila are highly chemovariable. However, taxa are generally grouped according to the expression of (1) furanosesquiterpenes, (2) iridoids or oxides, (3) mixtures of 1 and 2, (4) phenylpropanoids, (5) non-furanoid terpenes, (6) mixtures of 4 and 5, and less commonly (7) mixtures of 1 and 5. Furthermore, GC–MS analysis of solvent-extracted leaves taken from cultivated specimens conveys that many heavier ‘volatiles’ with lower vapour pressure are not detected in hydrodistilled essential oils and have therefore been neglected in past chemical studies. Hence, our data reiterate that chemical studies of the genus Eremophila will continue to describe new metabolites and that taxon determination has limited predictive value for the chemical composition. Full article
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8 pages, 1299 KiB  
Article
The Essential Oil Composition of Trachymene incisa Rudge subsp. incisa Rudge from Australia
by Jesús Palá-Paúl, Lachlan M. Copeland and Joseph J. Brophy
Plants 2021, 10(3), 601; https://doi.org/10.3390/plants10030601 - 23 Mar 2021
Cited by 1 | Viewed by 2393
Abstract
Trachymene incisa subsp. incisa is an Australian endemic taxon that varies greatly in the abundance and length of the leaf trichomes. The essential oil composition of five populations of this subspecies, three corresponding to the typical glabrous form and two of the particularly [...] Read more.
Trachymene incisa subsp. incisa is an Australian endemic taxon that varies greatly in the abundance and length of the leaf trichomes. The essential oil composition of five populations of this subspecies, three corresponding to the typical glabrous form and two of the particularly hairy variant, has been analyzed in an attempt to determinate if that variability is also reflected in their composition. The oils have been extracted by hydrodistillation and analyzed by Gas Chromatography (GC) and Gas Chromatography coupled to Mass Spectrometry (GC–MS). The essential oils of T. incisa subsp. incisa were characterized by the high amount of sesquiterpenes that were the major fraction. The sesquiterepene hydrocarbons were significantly higher in the hairy variant in comparison to the glabrous one. According to the main compound, three different chemotypes were found: I.—β-selinene + bicyclogermacrene and II.—γ-bisabolene + α-pinene for the typical glabrous variant and III.—bicyclogermacrene + β-caryophyllene for the hairy variant. Full article
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17 pages, 1183 KiB  
Article
Chemical Characterization of Marrubium vulgare Volatiles from Serbia
by Milica Aćimović, Stefan Ivanović, Katarina Simić, Lato Pezo, Tijana Zeremski, Jelena Ovuka and Vladimir Sikora
Plants 2021, 10(3), 600; https://doi.org/10.3390/plants10030600 - 23 Mar 2021
Cited by 8 | Viewed by 3065
Abstract
Marrubium vulgare is a cosmopolitan medicinal plant from the Lamiaceae family, which produces structurally highly diverse groups of secondary metabolites. A total of 160 compounds were determined in the volatiles from Serbia during two investigated years (2019 and 2020). The main components were [...] Read more.
Marrubium vulgare is a cosmopolitan medicinal plant from the Lamiaceae family, which produces structurally highly diverse groups of secondary metabolites. A total of 160 compounds were determined in the volatiles from Serbia during two investigated years (2019 and 2020). The main components were E-caryophyllene, followed by germacrene D, α-humulene and α-copaene. All these compounds are from sesquiterpene hydrocarbons class which was dominant in both investigated years. This variation in volatiles composition could be a consequence of weather conditions, as in the case of other aromatic plants. According to the unrooted cluster tree with 37 samples of Marrubium sp. volatiles from literature and average values from this study, it could be said that there are several chemotypes: E-caryophyllene, β-bisabolene, α-pinene, β-farnesene, E-caryophyllene + caryophyllene oxide chemotype, and diverse (unclassified) chemotypes. However, occurring polymorphism could be consequence of adaptation to grow in different environment, especially ecological conditions such as humidity, temperature and altitude, as well as hybridization strongly affected the chemotypes. In addition, this paper aimed to obtain validated models for prediction of retention indices (RIs) of compounds isolated from M. vulgare volatiles. A total of 160 experimentally obtained RIs of volatile compounds was used to build the prediction models. The coefficients of determination were 0.956 and 0.964, demonstrating that these models could be used for predicting RIs, due to low prediction error and high r2. Full article
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13 pages, 901 KiB  
Article
The Volatile Phytochemistry of Monarda Species Growing in South Alabama
by Sims K. Lawson, Prabodh Satyal and William N. Setzer
Plants 2021, 10(3), 482; https://doi.org/10.3390/plants10030482 - 4 Mar 2021
Cited by 15 | Viewed by 3502
Abstract
The genus Monarda (family Lamiaceae) contains 22 species of which three are native to southern Alabama, M. citriodora, M. fistulosa, and M. punctata. Several species of Monarda have been used in traditional medicines of Native Americans, and this present study [...] Read more.
The genus Monarda (family Lamiaceae) contains 22 species of which three are native to southern Alabama, M. citriodora, M. fistulosa, and M. punctata. Several species of Monarda have been used in traditional medicines of Native Americans, and this present study is part of an ongoing project to add to our understanding of Native American pharmacopeia. Plant material from M. citriodora, M. fistulosa, and M. punctata was collected in south Alabama and the essential oils obtained by hydrodistillation. The essential oils were analyzed by gas chromatographic techniques to determine the chemical compositions as well as enantiomeric distributions. The compounds thymol, carvacrol, p-cymene, and their derivatives were the primary terpenoid components found in the essential oils. The known biological activities of these compounds are consistent with the traditional uses of Monarda species to treat wounds, skin infections, colds, and fevers. Full article
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18 pages, 688 KiB  
Article
Validation of Qualitative Broth Volatilization Checkerboard Method for Testing of Essential Oils: Dual-Column GC–FID/MS Analysis and In Vitro Combinatory Antimicrobial Effect of Origanum vulgare and Thymus vulgaris against Staphylococcus aureus in Liquid and Vapor Phases
by Marie Netopilova, Marketa Houdkova, Klara Urbanova, Johana Rondevaldova and Ladislav Kokoska
Plants 2021, 10(2), 393; https://doi.org/10.3390/plants10020393 - 18 Feb 2021
Cited by 8 | Viewed by 3654
Abstract
Combinatory action of antimicrobial agents such as essential oils (EOs) show to be an effective strategy to overcome the problem with increasing antibiotic resistance of microorganisms, including Staphylococcus aureus. The objective of this study was to evaluate in vitro antimicrobial interactions between [...] Read more.
Combinatory action of antimicrobial agents such as essential oils (EOs) show to be an effective strategy to overcome the problem with increasing antibiotic resistance of microorganisms, including Staphylococcus aureus. The objective of this study was to evaluate in vitro antimicrobial interactions between Origanum vulgare and Thymus vulgaris EOs against various S.aureus strains in both liquid and vapor phases using the broth volatilization checkerboard method. Fractional inhibitory concentrations (FICs) were determined for both liquid and vapor phases, and the composition of EOs was analyzed by gas chromatography-mass spectrometry using dual-column/dual-detector gas chromatograph. Results of oregano and thyme EOs combination showed additive effects against all S. aureus strains in both phases. In several cases, sums of FICs were lower than 0.6, which can be considered a strong additive interaction. The lowest FICs obtained were 0.53 in the liquid phase and 0.59 in the gaseous phase. Chemical analysis showed that both EOs were composed of many compounds, including carvacrol, thymol, γ-terpinene, and p-cymene. This is the first report on oregano and thyme EOs interactions against S. aureus in the vapor phase. It also confirms the accuracy of the broth volatilization checkerboard method for the evaluation of combinatory antimicrobial effects of EOs in the vapor phase. Full article
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16 pages, 353 KiB  
Article
Effect of Essential Oils on the Release of TNF-α and CCL2 by LPS-Stimulated THP‑1 Cells
by Maria Graça Miguel, Carina Isabel da Silva, Luana Farah, Fernão Castro Braga and Ana Cristina Figueiredo
Plants 2021, 10(1), 50; https://doi.org/10.3390/plants10010050 - 28 Dec 2020
Cited by 12 | Viewed by 4073
Abstract
Plants and their constituents have been used to treat diverse ailments since time immemorial. Many plants are used in diverse external and internal formulations (infusions, alcoholic extracts, essential oils (EOs), etc.) in the treatment of inflammation-associated diseases, such as those affecting the respiratory [...] Read more.
Plants and their constituents have been used to treat diverse ailments since time immemorial. Many plants are used in diverse external and internal formulations (infusions, alcoholic extracts, essential oils (EOs), etc.) in the treatment of inflammation-associated diseases, such as those affecting the respiratory tract or causing gastrointestinal or joint problems, among others. To support the traditional uses of plant extracts, EOs have been assessed for their alleged anti-inflammatory properties. However, the effect of EOs on the release of cytokines and chemokines has been much less reported. Considering their traditional use and commercial relevance in Portugal and Angola, this study evaluated the effect of EOs on the in vitro inhibition of the cytokine tumor necrosis factor-α (TNF-α) and the chemokine (C-C motif) ligand 2 (CCL2) by lipopolysaccharide (LPS)-stimulated human acute monocytic leukemia cells (THP-1 cells). Twenty EOs extracted from eighteen species from seven families, namely from Amaranthaceae (Dysphania ambrosioides), Apiaceae (Foeniculum vulgare), Asteraceae (Brachylaena huillensis, Solidago virgaurea), Euphorbiaceae (Spirostachys africana), Lamiaceae (Lavandula luisieri, Mentha cervina, Origanum majorana, Satureja montana, Thymbra capitata, Thymus mastichina, Thymus vulgaris, Thymus zygis subsp. zygis), Myrtaceae (Eucalyptus globulus subsp. maidenii, Eucalyptus radiata, Eucalyptus viminalis) and Pinaceae (Pinus pinaster) were assayed for the release of CCL2 and TNF-α by LPS-stimulated THP-1 cells. B. huillensis, S. africana, S. montana, Th. mastichina and Th. vulgaris EOs showed toxicity to THP-1 cells, at the lowest concentration tested (10 μg/mL), using the tetrazolium dye assay. The most active EOs in reducing TNF-α release by LPS-stimulated THP-1 cells were those of T. capitata (51% inhibition at 20 μg/mL) and L. luisieri (15–23% inhibition at 30 μg/mL and 78–83% inhibition at 90 μg/mL). L. luisieri EO induced a concentration-dependent inhibition of CCL2 release by LPS‑stimulated THP-1 cells (23%, 54% and 82% inhibition at 10, 30 and 90 μg/mL, respectively). These EOs are potentially useful in the management of inflammatory diseases mediated by CCL2 and TNF‑α, such as atherosclerosis and arthritis. Full article
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26 pages, 3403 KiB  
Article
Prostanthera (Lamiaceae) as a ‘Cradle of Incense’: Chemophenetics of Rare Essential Oils from Both New and Forgotten Australian ‘Mint Bush’ Species
by Nicholas J. Sadgrove, Guillermo F. Padilla-González, Ian R. H. Telford, Ben W. Greatrex, Graham L. Jones, Rose Andrew, Jeremy J. Bruhl, Moses K. Langat, Ingrid Melnikovova and Eloy Fernandez-Cusimamani
Plants 2020, 9(11), 1570; https://doi.org/10.3390/plants9111570 - 13 Nov 2020
Cited by 10 | Viewed by 3200
Abstract
The highly aromatic Australian mint bushes from the genus Prostanthera Labill. produce a high yield of essential oil on hydrodistillation. Together with its rich history, horticultural potential, iconic flowers, and aromatic leaves, it achieves high ornamental and culinary value. Species in the genus [...] Read more.
The highly aromatic Australian mint bushes from the genus Prostanthera Labill. produce a high yield of essential oil on hydrodistillation. Together with its rich history, horticultural potential, iconic flowers, and aromatic leaves, it achieves high ornamental and culinary value. Species in the genus express highly diverse and chemically unique essential oils that demonstrate intra- and inter-specific patterns that have inspired taxonomic reinterpretation for over a hundred years. Previous studies have conveyed that phenoplastic expression of volatiles creates chemotypes within taxa, adding complexity to chemophenetic exploration. The current study chemically characterised essential oils from 64 highly aromatic specimens, representative of 25 taxa, giving yields as high as >2% g/g. The chemical profiles of essential oils are diverse, but generally include 1,8-cineole and signatory compounds such as sesquiterpene oxides, caryophyllene oxide, kessane and cis-dihydroagarofuran; sesquiterpene alcohols, globulol, epiglobulol, maaliol, prostantherol, spathulenol and ledol; and monoterpene derivatives of common scaffolds, borneol, bornyl acetate, bornanone, linalool and linalyl acetate. As in previous studies, analysis of chemical data confirms that the chemistry strongly agrees with taxonomic classifications. Importantly, as in classical taxonomy, the current chemical study complemented morphological analysis but conveys chemovariation, obscuring the taxonomic agreement. Nevertheless, variation within taxa may be due to environmental factors, meaning that cultivation of species in gardens will create different chemical profiles as compared to those published here. Full article
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10 pages, 844 KiB  
Article
The Flower Essential Oil of Dalea mutisii Kunth (Fabaceae) from Ecuador: Chemical, Enantioselective, and Olfactometric Analyses
by Gianluca Gilardoni, Mayra Montalván, Mariana Ortiz, Diego Vinueza and José Vinicio Montesinos
Plants 2020, 9(10), 1403; https://doi.org/10.3390/plants9101403 - 21 Oct 2020
Cited by 15 | Viewed by 2603
Abstract
An essential oil was distilled with 0.25% yield from fresh flowers of Dalea mutisii Kunth, a native species mainly growing in the Andean region of Ecuador. A total of 50 compounds were identified, and most of them were quantified. The chemical composition was [...] Read more.
An essential oil was distilled with 0.25% yield from fresh flowers of Dalea mutisii Kunth, a native species mainly growing in the Andean region of Ecuador. A total of 50 compounds were identified, and most of them were quantified. The chemical composition was characterized by the prevalence of monoterpene hydrocarbons (>90%). Major components were α-pinene (42.9%), β-pinene (15.1%), β-phellandrene (12.6%), myrcene (6.7%), and (Z)-β-ocimene (5.4%). The essential oil was then submitted to enantioselective analysis, with a 2,3-diethyl-6-tert-butyldimethylsilyl-β-cyclodextrin-based capillary column. An enantiomeric excess was measured for (1R,5R)-(+)-α-pinene (91.6%), (1R,5R)-(+)-β-pinene (15.2%), (R)-(−)-α-phellandrene (4.8%), and (R)-(−)-β-phellandrene (88.8%), whereas (R)-(+)-limonene was enantiomerically pure. A gas chromatography–olfactometry (GC–O) analysis was additionally carried out on this pleasantly fragrant essential oil, following an aroma extract dilution analysis (AEDA) approach. Main odorants were α-pinene, β-pinene, α-phellandrene, and (Z)-β-ocimene, with dilution factors (FD) of 8, 4, 2, and 2, respectively. Full article
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37 pages, 3592 KiB  
Article
Essential Oils of Zingiber Species from Vietnam: Chemical Compositions and Biological Activities
by Le Thi Huong, Nguyen Thanh Chung, Trinh Thi Huong, Ly Ngoc Sam, Nguyen Huy Hung, Isiaka Ajani Ogunwande, Do Ngoc Dai, Le Duy Linh and William N. Setzer
Plants 2020, 9(10), 1269; https://doi.org/10.3390/plants9101269 - 26 Sep 2020
Cited by 21 | Viewed by 4718
Abstract
Mosquito-borne diseases are a large problem in Vietnam as elsewhere. Due to environmental concerns regarding the use of synthetic insecticides as well as developing insecticidal resistance, there is a need for environmentally-benign alternative mosquito control agents. In addition, resistance of pathogenic microorganisms to [...] Read more.
Mosquito-borne diseases are a large problem in Vietnam as elsewhere. Due to environmental concerns regarding the use of synthetic insecticides as well as developing insecticidal resistance, there is a need for environmentally-benign alternative mosquito control agents. In addition, resistance of pathogenic microorganisms to antibiotics is an increasing problem. As part of a program to identify essential oils as alternative larvicidal and antimicrobial agents, the leaf, stem, and rhizome essential oils of several Zingiber species, obtained from wild-growing specimens in northern Vietnam, were acquired by hydrodistillation and investigated using gas chromatography. The mosquito larvicidal activities of the essential oils were assessed against Culex quinquefasciatus, Aedes albopictus, and Ae. aegypti, and for antibacterial activity against a selection of Gram-positive and Gram-negative bacteria, and for activity against Candida albicans. Zingiber essential oils rich in α-pinene and β-pinene showed the best larvicidal activity. Zingiber nudicarpum rhizome essential oil showed excellent antibacterial activity against Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus, with minimum inhibitory concentrations (MIC) of 2, 8, and 1 μg/mL, respectively. However, the major components, α-pinene and β-pinene, cannot explain the antibacterial activities obtained. Full article
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20 pages, 343 KiB  
Article
Premna Species in Vietnam: Essential Oil Compositions and Mosquito Larvicidal Activities
by Nguyen Huy Hung, Le Thi Huong, Nguyen Thanh Chung, Nguyen Cong Truong, Do Ngoc Dai, Prabodh Satyal, Thieu Anh Tai, Vu Thi Hien and William N Setzer
Plants 2020, 9(9), 1130; https://doi.org/10.3390/plants9091130 - 31 Aug 2020
Cited by 12 | Viewed by 4065
Abstract
Essential oils have emerged as viable alternatives to synthetic insecticides for control of mosquito-borne pathogens. The leaf essential oils of eight species of Premna (Lamiaceae) growing in central Vietnam have been obtained by hydrodistillation and analyzed by gas chromatography–mass spectrometry. Sesquiterpene hydrocarbons dominated [...] Read more.
Essential oils have emerged as viable alternatives to synthetic insecticides for control of mosquito-borne pathogens. The leaf essential oils of eight species of Premna (Lamiaceae) growing in central Vietnam have been obtained by hydrodistillation and analyzed by gas chromatography–mass spectrometry. Sesquiterpene hydrocarbons dominated most of the Premna essential oils, with the notable exception of Premnamekongensis from Ngoc Linh Nature Reserve, which had α-pinene as the major component. Larvicidal activities against Aedes aegypti have been determined and all of the Premna essential oils showed larvicidal activity with 24-h LC50 < 65 μg/mL. The leaf essential oils of Premnacambodiana from Chu Mom Ray National Park and Premnamekongensis from Ngoc Linh Nature Reserve showed the best larvicidal activities with 24-h LC50 of 16.8 and 18.0 μg/mL, respectively. The essential oil compositions and larvicidal activities of P. cambodiana, Premna flavescens, Premnamaclurei, P. mekongensis, and Premnapuberula are reported for the first time. Although the larvicidal activities of Premna leaf essential oils are promising, the essential oil yields are relatively low (0.10–0.25%). Full article
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