Abstract

The present study deals with the antimicrobial activity of the aqueous, acetone and petroleum ether extracts of the leaves, stem and root of Andrographis ovata Clarke, Aristolochia indica L., Eclipta prostrata L. and Gloriosa superba L., using agar diffusion method against human pathogens, such as Escherichia coli, Proteus vulgaris, Psudeomonas aeruginosa and Klebsiella pneumoniae. In the present investigation, all the extracts were found to be effective against four human bacterial species, E. coli, P. vulgaris, P. aeruginosa and K. pneumoniae, sensitive to all the plant extracts. The study suggests that the extract of the plant parts possesses potential broad spectrum antimicrobial activity. The antimicrobial activity of acetone extracts was found to be higher than that of distilled water extracts. However, the root extract showed more inhibitory effect than the stem and leaf extracts.

Key words: Medicinal plants, antimicrobial activity, plant extracts, growth inhibition, disc diffusion method.