Abstract: The present study, was conducted to evaluate in vitro antibacterial properties of Essential Oil (EO) from endemic plants, thyme (Thymus vulgaris) and mint (Mentha piperita) ageist Escherichia coli O157:H7. Antibacterial screening was done by Disk Diffusion (DD), Minimal Inhibitory Concentration (MIC) and Minimum Bactericide Concentration (MBC) methods. About 3.9 And 7.8 μg mL-1concentrations of thyme EO were required in order to achieving the MIC and MBC. These indexes for mint EO was 15.6 and 31.2 μg mL-1in E. coli O157:H7. In DD assay (500 μg disk-1 concentration) thyme and mint were shown 35±1.4 and 13±1.5 mm inhibition zone. The chemical composition of hydro distilled EOs of thyme and mint was analyzed by Gas Chromatography-Mass Spectrometry (GC/MS). A total of 36 compounds of thyme and 23 compounds of mint, representing 93.62 and 90.69% of the oils were identified: Thymol (18.12%), Carvacrol (12.11%), p-Cymene (15.12%) in thyme and α-Terpinene (20.11%), Pipertitinone oxaide (17.10%) and trans-Carveol (19.48%) in mint, were the main components of the oils. Results here show that the EOs of thyme and mint possess antibacterial activity and therefore, it could be used as a natural preservative ingredient in food and/or pharmaceutical industries against E.coli O157:H7.
Saeed Sadigh Eteghad , Hamid Mirzaei , Saeed Farzam Pour and Saeed Kahnamui , 2009. Inhibitory Effects of Endemic Thymus vulgaris and Mentha piperita Essential Oils on Escherichia coli O157:H7. Research Journal of Biological Sciences, 4: 340-344.