Study on the antimicrobial activities of the extracts and their main fractions from Vitex negundo Linn. stem

Different extraction methods were employed to extract antimicrobial compounds from Vitex negundo Linn. stem by using different organic solvent systems. The extracts from Vitex negundo Linn. stem were primarily separated by column chromatography with D3520 macroporous resin. The results showed that the inhibitory effects of the extracts on bacteria to be used in our experiments were influenced by the polar of solvents which we chose and the ethanol extract was obviously showed better antimicrobial activity than that of chloroform and water extracts. However,no significant difference was found on the various extraction methods. Interestingly,extracts of Vitex negundo Linn. stem showed better inhibitory effects on the growth of Staphylococcus aureus than on other microorganisms. Moreover,after macroporous resin D3520 chromatography,the extracts were separated into 9 fractions,which they showed different antibacterial activities on Staphylococcus aureu.