Antibacterial activity of flavonoids of Withania somnifera L.

Abstract

Context: Flavonoids from different parts (leaf, stem, root and fruits) of Withania somnifera have been screened for antibacterial activity against Enterobacter aerogens, Bacillus subtilis, Klebsiella pneumoniae, Raoultella planticola and Agrobacterium tumefaciens. Materials and Methods: Disc diffusion assay (DDA) was performed for antimicrobial screening. Minimum inhibitory concentration (MIC), minimum bactericidal (MBC) and total activity (TA) of extracts found sensitive against test pathogens have also been evaluated. Results and Conclusions: Most susceptible microorganisms in the present study were R. planticola and A. tumefaciens, which had shown susceptibility for almost all the extracts tested. Thereafter sensitive was shown by K. pneumoniae, B. subtilis, E. aerogens. However, highest inhibition zone was observed for E. aerogens (IZ 25.5 mm; AI 1.159 ± 0.023) followed by R. planticola (IZ 22 mm; AI 0.733 ± 0.133). Antimicrobial activity of flavonoids extracts of W. somnifera were carried out to validate the use of traditional medicinal herb and the results of this study tend to give credence to the common use of W. sominfera plant. The study provide platform for further studies in plant, so as to pinpoint specific alkaloids and/or flavonoids responsible for antimicrobial activity and might open new vistas in the therapeutic use of the plant in allopathy medicine too. Key words: Antibacterial activity, flavonoids, minimum bactericidal, minimum inhibitory concentration, W. somnifera