In vitro antibacterial activity of Venda medicinal plants

Ethanolic and aqueous extracts of ten medicinal plants used in folklore medicine in Venda (South Africa) were screened for their in vitro activity against some Gram-positive and Gram-negative pathogenic bacteria using the disc diffusion method. Root and stembark extracts of Datura stramonium at a concentration of 50mg ml^-1 were inhibitory to most of the organisms with a diameter of zone of inhibition of growth ranging from 12-19mm. Warburgia salutaris was also inhibitory to most of the bacteria with a diameter of zone of inhibition of growth ranging from 8-17mm at a concentration of 50mg ml ^-1. A range of 10-16mm was observed for Peltophorum africanum at a concentration of 40mg ml^-1 against the Gram-negative bacteria tested. Other plants showed moderate or no activity, compared to a 30μg ml ^-1 oxytetracycline control antibiotic. The use of these plants by the indigenes of Venda against diseases apparently caused by these organisms may be of some value.