Antimalarial activity of Gomphostemma crinitum leaf extracts

Antimalarial efficacy of Gomphostemma crinitum leaf extracts were studied in vitro against the chloroquine-sensitive MRC-02 strain of Plasmodium falciparum. The CHCl(3) extract (IC(50) 37.28 mu g/mL) was found to be better than the aqueous extract (IC(50) 111.4 mu g/mL). The major compound present in CHCl(3) extract was coded as GC-7 (12,17-diacetoxy, 15-hydroxy, 2-oxo, 3, 13 E (14)-diene clerodane). Seasonal variation of GC-7 was studied and correlated to the antimalarial efficacy of the crude extracts of leaves collected in different months. GC-7 was found to be the only regular compound present in G. crinitum leaves throughout the year. A good correlation between antimalarial efficacy (IC(50) 9.3 mu g/mL) and concentration of GC-7 in crude extracts was observed. The mode of action of GC-7 was found to be different from that of chloroquine.