Antiplasmodial activity of root extract and fractions of Croton zambesicus

Abstract

Aim of the study Antiplasmodial activity of root extract and fractions of Croton zambesicus were evaluated to ascertain the folkloric claim of its antimalarial activity and elucidate its antiplasmodial mechanism of action. Material and method The crude ethanolic root extract (27–81 mg/kg) and gradient fractions ( n- hexane, chloroform, ethyl acetate and methanol; 54 mg/kg) of Croton zambesicus were investigated for antiplasmodial activity against chloroquine - sensitive Plasmodium berghei infections in mice. The antiplasmodial activity during early and established infections as well as the prophylactic activity were investigated. Chloroquine (5 mg/kg) and pyrimethamine (1.2 mg/kg) were used as positive controls. Thin films made from tail blood of each mouse were used to assess the level of parasitaemia of the mice. Oxidant generation potentials of the crude extract and fractions was also evaluated to elucidate their mechanism of action. Results The crude root extract (27 – 81 mg/kg) demonstrated significant ( P < 0.01–0.001) schizonticidal activity during early and established infections and also had prophylactic activity. The activity was comparable to that of the standard drug used (chloroquine 5 mg/kg, pyrimethamine 1.2 mg/kg). Methanol, ethyl acetate and chloroform fractions had comparative in vivo antiplasmodial activity and oxidant generation potentials. Conclusion The antiplasmodial activity of this root extract and fractions which is likely to be through peroxidation confirms the folkloric use of this plant.