Antibacterial activity of Carum copticum essential oil against Pectobacterium carotovorum subsp. carotovorum and Escherichia coli in nutrient broth medium

Due to the adverse effects of agricultural pesticides on biological ecosystems، biological control of plant pathogens by using natural antimicrobial compounds such as essential oils and extracts of medicinal plants could be a necessity. Essential oil of carum copticum، is rich in antibacterial compounds particularly thymol. The aim of this study was to determine the minimum inhibitory and bactericidal concentration of Carum copticum essential oil against Pectobacterium carotovorum subsp. carotovorum as a plant pathogen and E. coli as a human pathogen in nutrient broth medium. In this study chemical compounds of Carum copticum essential oil were identified by GC-MS. Carum copticum essential oil at concentrations including 0. 004 to 4 % were prepared in nutrient broth medium. Antibacterial activity of essential oil in comparison with gentamicin antibiotic was determined by using 6 mm impregnated filter paper disks in agar diffusion method. The minimum inhibitory concentration (MIC) of Carum copticum essential oil against tested bacteria was determined by macrobroth dilution method. The MBC was determined by using cultivation method in nutrient agar medium. Zone of growth inhibition for Pectobacterium carotovorum varied from 5. 7± 0. 14 to 27. 4 ± 0. 95 mm while for E. coli it ranged from 6. 4 ± 0. 55 to 33. 1 ± 0. 95 mm in the order of increasing concentrations from 0. 004 to 4%. The MIC and MBC of Carum copticum essential oil against Pectobacterium carotovorum and E. coli were recorded as 0. 5% and 1% and 0. 125% and 0. 25%، respectively. Regarding the results of this research، plant essential oils can be a good alternative to chemical control of human and plant bacterial pathogens.