Antimicrobial activities of bharangin from Premna herbaceae Roxb. and bharangin monoacetate.

The root nodules of Premna herbaceae, which are being used in ayurvedic system of medicine as gantubharangi for curing several ailments, have been studied for antimicrobial activities. The major compound responsible for the biological activity is bharangin, a yellow colored compound extractable with hexane. Bharangin monoacetate prepared by acetylation of bharangin has been investigated along with bharangin for their antimicrobial activity against gram positive and gram negative bacteria and fungi. In general bharangin monoacetate showed more activity with MIC of 3-6 microg/ml when compared with bharangin, which has MIC of 10-25 microg/ml. The enhanced antibacterial activity is attributed to the presence of acetoxyl group in place of hydroxyl group present in the structure of bharangin. The activity is compared with standard gentamycin for bacteria and nystatin for fungi.