The Antimicrobial activityof Essential Oil of Zataria multiflora Boiss and Satureja khuzestanica and their Stability

Introduction: some plants show antimicrobial activity against wide range of microorganism.the aim of this study was to investigate the antimicrobial activity and stability of zataria multiflora boiss and satureja khuzestanica essential oil (eo). materials and methods: first, these plants (zataria multiflora boiss and satureja khuzestanica) were collected, verified by a botanist, dried, and grinded. then, hydro-distallation method was used, to obtain eo from each one. their antimicrobial activity of each eo was evaluated by micro dilution broth method. for stability test, the surfaces (stone, mdf, and steel) were cleaned by 70% ethanol, and then separately incubated with each eo. then, all were dried, and incubated for 12, 24 and 36 hours at room temperature. after incubation, sampling was done, inoculated on nutrient agar. finally, the number of colonies grown on each plate was counted. results: the mic50 of both eo was 3.1%. but, the mic90 of zataria multiflora boiss eo against all strains was 12.5%, except escherichia coli which was 6.2%. also, the mic90 of satureja khuzestanica eo against all strains was 12.5%, except aspergillus niger which was 6.2%. both eos had high stability until 36 hours on the stone and steel. in case of mdf, eos were stable until 24 hours. no significant difference was observed between stability of zataria multiflora boiss and satureja khuzestanica eo. conclusion: it can be concluded that zataria multiflora boiss and satureja khuzestanica eo have approximately same antimicrobial activity and stability. since both eos have high antimicrobial property, they can be applied to remove microbes from different sources.