MACROFILARICIDAL ACTIVITY OF THE STEMBARK OF STREBLUS-ASPER AND ITS MAJOR ACTIVE CONSTITUENTS

The crude extract of the stembark of Streblus asper, a traditionally used medicinal plant of India, revealed significant macrofilaricidal activity against Litomosoides carinii and Brugia malayi in rodents. The study revealed two cardiac glycosides, K029 (asperoside) and K030 (strebloside) of the extract to be responsible for antifilarial activity. Of the two glycosides, the more effective macrofilaricide was K029 which was active at 50 mg/kg orally against L. carinii (> 90%), B. malayi (> 70%), and Acanthocheilonema viteae (> 70%) in their respective hosts. The glycosides were also active in vitro against all the three filarial species. Significantly weak activity was detected in glycon and aglycon portions of the parent glycosides (K029 and K030). Several cardiac glycosides of other origins did not show any comparable antifilarial efficacy. The aglycosidic portion of the extract, however, showed poor adulticidal activity (44.5% activity at 1 g/kg against L. carinil). The present finding, thus, opens up the possibility of generating new leads in the development of novel macrofilaricides.