Antimalarial and analgesic activities of ethanolic leaf extract of Panicum maximum.

Objective: To evaluate antiplasmodial and analgesic activities of ethanolic leaf extract/fractions of Panicum maximum.

Methods: The crude leaf extract (47-190 mg/kg) and fractions (chloroform, ethyl acqeous and methanol; 96 mg/kg) of Panicum maximum were investigated for antiplasmodial activity against chloroquine sensitive Plasmodium berghei infections in mice and for analgesic activity against chemical and heat-induced pains. The antiplasmodial activity during early and established infections as well as prophylactic were investigated. Artesunate at 5 mg/kg and pyrimethamine at 1.2 mg/kg were used as positive controls. Analgesic activity of the crude extract/fractions was also evaluated against acetic acid, formalin and heat-induced pains.

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 compared with control (P<0.001). The activities of extract/fractions were incomparable to that of the standard drugs (Artesunate and pyrimethamine). On chemically and thermally-induced pains, the extract inhibited acetic acid and formalin-induced inflammation as well as hot plate-induced pain in mice. These inhibitions were statistically significant (P<0.001) and in a dose-dependent fashion.

Conclusions: Panicum maximum leaf extract has antiplasmodial and analgesic activities which may in part be mediated through the chemical constituents of the plant.