Flavonoids are yellow pigments widely distributed as their glycosides obtained from plant sources. Flavonoids may delay or prevent the onset of diseases such as cancer induced by free radicals. In the present work, the air dried leaves of Crotalaria grahamiana belongs to Papilionaceae is chosen for phytochemical and pharmacological studies. Aqueous extract was prepared and fractionated with benzene, diethyl ether and ethyl acetate. Ether fraction results Kaempferol (aglycone) and Ethyl acetate fraction results Populnin (glycoside). The structure was ascertained by UV, NMR, PC and chemical reactions. Ethyl acetate concentrate has been tested for its anti-bacterial activity using two species of bacteria namely staphylococcus aureus and Escherichia coli for two different drug concentrations. The result shows that it is potent enough to act against both Gram positive and Gram negative organisms. The SRBC membrane stabilization studies on the ethyl acetate soluble of Crotalaria grahamiana
showed destabilization property at lower concentrations. At 75μg the stabilizing effects is observed in the compound. This capacity persists up to 100μg. Beyond that concentration the drug is unable to contain the membrane.