Detection of antibacterial activity in spent roots of two genotypes of aromatic grass Vetiveria zizanioides

Hexane extracts of inflorescence, intact roots and spent roots, upon hydrodistillation extracting the essential oil from Vetiveria zizanioides L. in two genotypes (gulabi and KS-1), were evaluated for antibacterial activity against wild-type and drug-resistant strains of Mycobacterium smegmatis and Escherichia coli using disk diffusion and micro-broth dilution methods. The hexane extracts of intact roots and spent roots after distillation of both varieties were found to show potent activity against the drug-resistant strains of M. smegmatis and E. coli . The minimum inhibitory concentration of the intact and spent root extracts of both varieties against M. smegmatis ranged from 62.5 to 250 mu g/ml, and for E. coli , the range was from 0.5 mg/ml to 60 mg/ml. Inflorescence in both cases was inactive in terms of antibacterial properties. The results showed that Vetiveria zizanioides cv gulabi has better inhibitory activity against drug-resistant strains of M. smegmatis and E. coli , as compared with KS-1. The results suggest DNA gyrase inhibitory action, because the strains resistant to quinolones due to gyrase mutations are sensitive to the extracts.