In-vitro antibacterial effect of selected medicinal plant extracts.

The antibacterial activities of five important plant species were selected and tested in turbidometric methods in a microplate reader. The various solvent (methanol, ethyl acetate, and chloroform) extracts of Morus Alba. L (leaves), Mangifera indica. (L.) (leaves) Eugenia jambolana. L (Fruits), Albizzia lebbeck. L (bark), Gymnema sylvestris R. br (leaves) and isolated gymnemic acid were evaluated for antibacterial activity against B. cereus, E.coli, P. mirabilis P. aeruginosa Staphylococcus aureus and Salmonella typhi. Methanolic extracts was showed significant activity against all the tested bacteria followed by ethyl acetate and chloroform extracts. Albizzia lebbeck was observed 66%, Eugenia jambolana 56.12%, Gymnema sylvestris 59.21% and gymnemic acid 58.33% antibacterial activity against E.coli. Albizzia lebbeck showed 67.36% against Bacillus cereus, 55% against Proteus mirabilis and it was less significant in Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella typhi. In case of Salmonella typhi, the tested plant extracts activity were not significant. Gymnemic acid was showed 68.33% against Staphylococcus aureus, Comparison of the inhibitory activity of the plant extracts with gentamicin (positive reference standard) revealed that methanol extracts of Morus Alba (68.25%), Eugenia jambolana (66.33%), Gymnema sylvestris (65.33%) and gymnemic acid (68.33%) were significantly higher than that of the antibiotics tested against Staphylococcus aureus. The described method is a rapid, homogeneous, cost effective and easy-to-perform system for screening of new potential antimicrobial agents in drug discovery.