Gedunin and Photogedunin of Xylocarpus granatum possess antifilarial activity against human lymphatic filarial parasite Brugia malayi in experimental rodent host

Abstract

The present study is aimed to evaluate antifilarial activity of Xylocarpus granatum (fruit from Andaman) against human lymphatic filarial parasite Brugia malayi in vivo. The in vitro antifilarial activity has already been reported earlier for this mangrove plant which has traditionally been used against several ailments. Aqueous ethanolic crude extract, four fractions (Ethyl acetate fraction, n-butanol fraction, water soluble fraction and water insoluble fraction) and pure molecule/s of Xylocarpus granatum (fruit) were tested in vitro on adult worms and microfilariae (mf) of B. malayi and the active samples were further evaluated in vivo in B. malayi i.p. transplanted jird model (Meriones unguiculatus) and Mastomys coucha subcutaneously infected with infective larvae (L3). The crude aqueous ethanolic extract was active in vitro (IC50: adult=15.46 µg/ml; mf=13.17 µg/ml) and demonstrated 52.8% and 62.7% adulticidal and embryostatic effect on B. malayi respectively in mastomys at a dose of 5x250 mg/kg by oral route. The antifilarial activity was primarily localized in the ethyl acetate soluble fraction which revealed IC50 of 8.5 and 6.9 µg/ml in adult and mf respectively. This fraction possessed moderate adulticidal and embryostatic action in vivo in mastomys. Out of eight pure molecules isolated from the active fraction, two compounds Gedunin (IC50=0.239, CC50=212.5, SI=889.1) and Photogedunin (IC50=0.213, CC50=262.3, SI=1231.4) at 5x100 mg/kg by subcutaneous route revealed excellent adulticidal efficacy resulting in to the death of 80 % and 70 % transplanted adult B. malayi in the peritoneal cavity of jirds respectively in addition to noticeable microfilaricidal action on the day of autopsy. The findings reveal that the extract from the fruit Xylocarpus granatum contains promising in vitro and in vivo antifilarial activity against human lymphatic filarial parasite B. malayi which could be attributed to the presence of two pure compounds Gedunin and Photogedunin.