Lannea acida plants belong to the family Anacardiaceae. It has been used locally to treat and manage diseases that are contagious. Due to the recent increase in the resistance of malaria parasite to synthetic drugs the search for alternative treatment approach from plant sources is in urgent dimension. The antiplasmodial activity of mice was investigated with L. acida bark extracts. The study of the acute toxicity of the extract was used to determine lethal dose (LD50). Suppressive activity of the extract was examined for five consecutive days with the extracts doses and chloroquine as the control drug, curative was infected for five days prior treatment, while the prophylactic groups were pretreated daily for five days before inoculation of 1×107 chloroquine-sensitive Plasmodium berghei infected erythrocyte intraperitoneally. Five mice were in each group of 5 groups. Whilst, the Control group was administered with 10 ml distilled water/kg; 100, 200, and 400 mg extract/kg weight were administered for the experimental groups, and chloroquine 5 mg/kg body weight respectively, All doses of the extract produced substantial, dose reliant, chemo suppressive activity against the parasite in the suppressive, curative and prophylactic tests as compared with chloroquine treated mice. A lengthen mean survival time of the treated mice was observed as compared to the untreated mice. The oral median lethal dose (LD₅₀) of the extract in mice was 5000 mg/kg body weight. Empirical results of the study showed that the L. acida bark extract is harmless. It has a potent antimalarial property which could be of future importance in malaria management and antimalarial drug design.

Keywords: Lannea acida, antiplasmodial, Plasmodium berghei, medicinal plant.