A study on antimicrobial activity and chemical compositions of essential oils from flowers of Lavandula Angutifolia and Salvia Officinalis

Abstract: Chemical composition and antimicrobial effects on E.coli and S.aureus of essential oils from Lavandula angustifolia and Salvia officinalis were studied. Disk diffusion method was conducted to evaluate the zone of microbial growth inhibition at 1, 1:2, 1:8 and 1:16 dilutions of the essential oils at four stages of zero (fresh oil), 1, 2 and 3 months post-extraction. The antimicrobial effect was also studied against 10^7/ml, 10^6/ml and 10^5/ml concentrations of microbial cells to find out Minimal Inhiitory Concentration (MIC) and Minimal Bactricidal Concentration (MBC). The essential oils were bactericidal against both the micro organisms. Comparatively, Gram negative bacterium. E.coli, was readily affected by the essential oil of Lavandula angustifolia and S.aureus was redily affected by the essential oil of Salvia officinalis. Chemical composition of the essential oils were analyzed by Gas. Chromatography and Mass Spectrometry (GC and GC/MS). Twelve common chemical compounds of ?-Humulene, ?-pinene, ?-pinene, ?-Thujene, 1,8-Camphene, Camphor, Cis-?-ocimene, Linalool, P-Cymene and Terpinene-4-ol were found at various concentrations in both the oils, most of which were monoterpenes. Major components of essential oil of Salvia officinalis were ?-pinene (16%), Berneol (9.4%), Glubulol (9.3%), ?-Humulene (8.4%), ?-Thujene (6.4), ?-Pinene (5.5%), Camphene (5%), and those of Lavandula angustifolia were Linalol (36.9%), 1,8-Cineole (16%), ?-Orneol (11.5%), Camphor (4.2%) and Terpinene-4-ol (4.19%). It seems that monoterpenes give antibacterial property to the essential oils. Keywords: Lavandula angutifolia, Salvia officinalis, Antimicrobial, Essential oil