and Md. Azizur

ABSTRACT: The phytochemical screening of the bark of Albizia lebbeck (L) showed positive test for tannin, alkaloid, flavonoid, terpenoid, phlabotannin, saponin, steroid and cardiac glycoside. In this article an attempt was made for biological studies (the antimicrobial activity, cytotoxicityand free radical-scavenging activity) of different extracts (hexane, methanol, ethyl acetate, water and butanol extract) of the bark of Albizia lebbeck. The antimicrobial sensitivity of the extracts was tested using the disc diffusion method. The cytotoxic effects of five extracts (hexane, methanol, ethyl acetate, water and butanol extract) of the bark of Albizia lebbbeck were carried out. Free radical scavenging activity of the bark of Albizia lebbeck was performed. All the extracts showed moderate anti microbial activity and gram positive bacteria were more sensitive than gram negative bacteria. Significant cytotoxic activity was noticed and hexane extract was found the most lethal to brine shrimp nauplii. This result revealed that the highest cytotoxic constituent may be non polar in nature. Good fre