Antibacterial properties of an Indian traditional medicinal plant, Rhynchosia scarabaeoides (L.) DC. (Fabaceae)

Rhynchosia scarabaeoides (L.) DC plant parts are extensively used by traditional healers in India to treat a variety of bacterial diseases, such as dysentery, diarrohea and skin disorders. This article reports the antibacterial activities of n-hexane, ethyl acetate and ethanol extracts belonging to the leaf, stem and root parts of R. scarabaeoides against five bacterial strains, Bacillus subtilis, Escherichia coli, Klebseilla pneumonia, Proteus vulgaris and Staphylococcus aureus, using an agar gel diffusion method. The range of inhibition zone (IZ) was found to be 15-24 mm and the minimum inhibitory activity (MIC) was found to be 1 mL/well. The IZ was found to be higher in ethyl acetate extracts while this was moderate in ethanol extracts, and no activity was seen with n-hexane extracts or root extracts. The MIC value of leaf ethyl acetate extract was found to be 1 mg against bacterial strains P. vulgaris and S. aureus, whereas 2 mg was found against B. subtilis, K. pneumoniae and E. coli. These results support the traditional usage of R. scarabaeoides plant parts in the treatment of bacterial infections. Interestingly, this plant was screened for antibacterial activity for the first time and was found to be active. Detailed chemical investigations are, therefore, warranted.