Antiplasmodial and antipyretic studies on root extracts of Anthocleista djalonensis against Plasmodium berghei

Abstract

Objective To evaluate the antimalarial activities of ethanolic root extract/fractions of Anthocleista djalonensis ( A. djalonensis) in Plasmodium berghei ( P. berghei) infected mice. Methods A. djalonensis root extract (175–1 000 mg/kg) and fractions (chloroform, ethyl acetate and methanol; 250 and 500 mg/kg) were investigated for antiplasmodial activity against chloroquine-sensitive Plasmodium berghei infections in mice and for antipyretic activity against dinitrophenol, amphetamine and yeast-induced pyrexia. The antiplasmodial activity during early and established infections as well as prophylactic were investigated. Artesunate (5 mg/kg) and pyrimethamine (1.2 mg/kg) were used as positive controls. Antipyretic activity of the crude extract was also evaluated against dinitrophenol, amphetamine and yeast-induced pyrexia. Results The extract and its fractions dose-dependently reduced parasitaemia induced by chloroquine sensitive Plasmodium berghei infection in prophylactic, suppressive and curative models in mice. These reductions were statistically significant (P<0.001). They also improved the mean survival time from 13 to 28 days relative to control (P<0.001). The activities of extract/fractions were comparable to that of the standard drugs used (chloroquine and pyrimethamine). On pyrexia induced by dinitrophenol, amphetamine and yeast, the extract inhibited significantly (P<0.05 – 0.001) and in a dose-dependent fashion temperature rise caused by these pyrogens. Conclusions A. djalonensis root extract has antiplasmodial and antipyretic activities which may in part be mediated through the chemical constituents of the plant.