Inhibitory activities of Brassica nigra , Cinnamomum cassia (Blume) and Cuminum cyminum towards Escherichia coli and Staphylococcus aureus

摘要

Three Indian spices, namely Brassica nigra, Cinnamomum cassia (Blume) and Cuminum cyminum were examined independently, in their different forms (aqueous extracts, essential oils and powdered), for antibacterial potentials against Escherichia coli (MTCC1687) and Staphylococcus aureus (MTCC5021). Spice agar method was opted for investigating antibacterial potentials of powdered spice samples. Minimum inhibitory concentrations of the powdered spice samples were also determined. It was the concentration of spice sample that arrested the growth of test bacteria upto 80 % level of the total incubation period of 30 days. Agar well assay was followed for screening of antibacterial potentials of aqueous extracts and essential oils Results revealed that essential oils of spices arrested bacterial strains most effectively followed by powdered forms, while aqueous extracts were found ineffective. Among powdered spice samples tested, C. cassia (Blume) most effectively arrested test bacterial strains and among essential oils under investigation B. nigra displayed widest growth inhibitory zones towards microbes under observation. It was also noticed that S. aureus was more susceptible towards test substances as compared to E.coli.