ABSTRACT
Thyme [Zataria multiflora Bois.] Penny voyel [Mentha pulegium L.] Origanum [Origanum vulgare L.] and Fennel [Foeniculum vulgare Miller] are the Iranian traditional spice which are widely used in the country. Following the recent efforts to look for healthy remedies with antimicrobial potential, the effects of essential oils of these medicinal plants were investigated on Salmonella typhimurum. Chemical composition and antimicrobial effects of essential oils from plants were evaluated on Salmonella typhimurum and compared with five antibiotics enrofloxacin, chloramphenicle, erythromycin, oxytetracyclin and flumequin. The essential oils of the leavs and stems are obtained from each plants by hydrodistillation and clevenger and analyzed by GC/MS. The results of this study show that Thyme oil, compared to flumequin, oxytetracyclin and erythromycin is more effective [P<0.5]. Essential oil of Penny voyel is more effective than oxytetracyclin and erythromycin. Among essential oil of plants, Thymol oil with minimal inhibitory concentration [MIC] 156.5 micro g/ml and minimal bactericidal concentration [MBC] 312.5 micro g/ml had the best result against Salmonella typhimurum. Chemicial compounds: Thymol, Carvacrol and alpha -terpinen were found in Z. multiflora, M. pulegium, O. vulgar and F. vulgare by GC analyse. Considering the significant antibacterial effect of essential oil of Z. multiflora on effect on Salmonella typhimurum in invitro, it is recommened that, the therapeutic effect of this essential oil be studied in invivo