Investigations on Antibacterial Activity of Leaf Extracts of Azadirachta indica A. Juss (Meliaceae): A Traditional Medicinal Plant of India

The present study was carried out to screen and evaluate antimicrobial activity of leaf extracts of Azadirachta indica A. Juss. Petroleum ether, dichloromethane, chloroform, ethanol and aqueous extract of leaves of A. indica were tested against selected Gram positive and Gram negative bacterial species. Phytochemical leaf extracts of A. indica exhibited significant anti-bacterial activity against all the test microorganisms. However, inhibitory activities of the leaf extracts were both organism and solvent dependent. The leaf extracts limited the growth of both Grampositive and Gram-negative bacterial species tested. Among the different extracted used in the study, ethanolic and dichloromethane leaf extracts of A. indica were found to be more active towards the bacterial species used in the study. Further, the aqueous leaf extract was moderately active. However, petroleum ether and chloroform extracts were not effective against any of the organisms tested, but for Bacillus cereus where the chloroform extract was moderately active. Growth of Lactobacillus bulgaris was not inhibited by any of the tested leaf extracts of A. indica but for dichloromethane. The study shows that ethanolic and dichloromethane leaf extracts of A. indica can be used as a potential source of antimicrobial agents.