In vitro effect of four herbal plants on the motility of Brugia malayi microfilariae.

BACKGROUND & OBJECTIVE Disease burden due to lymphatic filariasis is disproportionately high despite mass drug administration with conventional drugs. Usage of herbal drugs in traditional medicine is quite well known but largely empirical. Hence the present study was designed to screen the in vitro antifilarial effect of four herbal plants on Brugia malayi. METHODS Motility of microfilariae of B. malayi after incubation for 48 h with aqueous/methanol extracts of Vitex negundo L. (roots), Butea monosperma L. (roots and leaves), Ricinus communis L. (leaves), and Aegle marmelos Corr. (leaves) was explored in the concentration range of 20 to 100 ng/ml for possible antifilarial effect by comparing with suitable solvent control. RESULTS Butea monosperma leaves and roots, Vitex negundo root and Aegle marmelo leaves showed significant inhibition of motility of microfilariae as compared to controls whereas inhibitory activity demonstrated by Ricinus communis L. leaves was not significant. Antifilarial effects imparted by all these extracts were found to be a function of their relative concentrations. Inhibitory concentrations (IC(50)) for the plant extracts with significant antifilarial activity against Brugia malayi microfilariae in in vitro system have been derived to be 82, 83 and 70 ng/ml for Vitex negundo L., Butea monosperma L. and Aegle marmelos Corr. respectively. INTERPRETATION & CONCLUSION The present study recorded significant antifilarial effect of all plant extracts studied except for Ricinus communis L. leaves and contributes to the development of database for novel drug candidates for human lymphatic filariasis.