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In this study, antimicrobial activity of the essential oil (EO) and extracts of Himalayan-thyme (Thymus linearis Benth.) was evaluated against nine pathogenic microbial strains using disc diffusion and microdilution broth assays. The chemical composition of the EO was determined by gas chromatography-flame ionisation detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The molecular mechanism of action of the EO was investigated against three pathogenic bacteria (Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis) and three fungal strains (Candida albicans, Candida glabrata, and Candida tropicalis) using the assays of protein leakage, and DNA and RNA leakage through the membrane. Major components of the EO were thymol (54.9%), γ-terpinene (16.6%) and p- cymene (5.2%). The EO showed broad-spectrum potent antibacterial and antifungal activity (MIC 240–990 µg/mL) against test strains. The EO damaged cell membranes and altered cell membrane permeability of test microorganisms. The EO showed a time- and dose-dependent bactericidal and fungicidal effect. It could act as a promising antimicrobial agent due to its short killing time. [ABSTRACT FROM AUTHOR]

This study was framed to assess the essential oil yield and quality of four varieties of palmarosa (Cymbopogon martinii (Roxb.) Wats. var. motia Burk, viz. Trishna, Tripta, PRC-1 and CIMAP-Harsh under the salt affected soil with intervention of arbuscular mycorrhizal fungi (AMF). The essential oil yield (7.04-12.70 g kg-1 fresh biomass) and geraniol yield (5.71-10.56 g kg-1 fresh biomass) were significantly affected by the variety, soil type and AMF inoculation. Altogether, twenty-eight constituents, representing 96.90-99.43% of the total oil compositions were identified using Gas chromatography (GC)-flame ionisation detection and GC-mass spectrometry techniques. Major constituents of the oils of different varieties were geraniol (76.73-83.28%), geranyl acetate (6.60-13.06%), linalool (0.90-3.00%), (2E,6Z)-farnesol (0.80-3.00%), geranial (0.30-2.03%), myrcene (0.54-2.00%), (E)-β-ocimene (0.43-1.95%), (E)-caryophyllene (0.30-1.30%) and geranyl hexanoate (0.31-1.20%). Significantly higher essential oil and geraniol yields were observed in var. Tripta due to AMF intervention (Funneliformis mosseae and Glomus aggregatum). [ABSTRACT FROM AUTHOR]

The comminution and distillation time are two important factors, which affect the essential oil yield and/or composition of aromatic plants significantly. To find out the suitable comminution process and optimum distillation time for isolation of essential oil fromAcorus calamusL., an experiment was conducted. The comminuted rhizomes (sliced and powdered) were hydrodistilled for different durations and their yields and compositions were compared. Distillation of uncomminuted rhizome for 8 hours gave 2.37% of essential oil. However, in comminuted rhizomes, yield varied from 2.27 to 6.60% under different distillation durations. The resulting essential oils were analyzed using GC-FID and GC-MS. Twenty-seven constituents, representing 94.7–97.2% of the total oil compositions were identified. Major constituents of the oils were (Z)-asarone (84.8–91.2%), and (E)-asarone (2.5–5.2%). The comminution and distillation time showed noteworthy effect on the essential oil yield; however, they showed no major change on the essential oil composition ofA. calamus. It was concluded that powdering of dried rhizomes and effecting distillation for 4 hours are appropriate parameters for extracting maximum essential oil fromA. calamusat laboratory scale.ABSTRACT FROM PUBLISHERCopyright of Journal of Essential Oil Research is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. [ABSTRACT FROM AUTHOR]

Essential oils isolated fromArtemisia gmeliniiWeb. ex Stechm,Artemisia roxburghianaBess. var.purpurascens(Jacq.) Hook andArtemisia maritimaL. were analyzed using gas chromatography (GC) and GC–mass spectrometry (GC–MS).Artemisia gmelinii,A. roxburghianaandA. maritimayielded 1.43%, 0.77–0.90% and 1.67% essential oil, respectively. In all, ninety-two constituents, representing 95.6–99.1% of the total oil compositions of differentArtemisiaspp., were identified. Major constituents ofA. gmeliniioil were artemisia ketone (40.7%),cis-chrysanthenyl acetate (21.3%), 1,8-cineole (11.0%) and pinocarvone (8.9%). The oil ofA. roxburghianacontained borneol (2.1–18.5%), α-thujone (0.2–13.1%), artemisia alcohol (5.2–11.6%), β-eudesmol (5.0–11.6%), eucarvone (2.0–8.9%), caryophyllene oxide (3.5–8.8%), 1,8-cineole (3.2–8.1%),cis-sabinene hydrate (4.5–7.1%),cis-chrysanthenyl acetate (0.2–5.4%) and terpinen-4-ol (2.2–5.2%) as main constituents. However, the oil ofA. maritimawas rich in thujones (α-thujone 72.1%, β-thujone 8.4%). The oils of the investigatedArtemisiaspp. showed considerable variations in their chemical compositions compared with earlier reports. [ABSTRACT FROM PUBLISHER]