Azadiracta indica, Carica papaya, Morinda lucida and Alstonia boonei are common medicinal plants used widely in Nigeria for the treatment of malaria and other life threatening ailments. The research investigated the antiplasmodial effect of the four botanical extract in Plasmodium berghei infected mice. One hundred and fifty five healthy BALB/c mice of average weight 13.5g were divided into four main groups of thirty mice each and six sub groups of five mice. The control group had five mice. Experimented mice in each group were inoculated intraperitoneally with Plasmodium berghei parasitized red blood cell, followed by daily administration of the six ethanolic extract of A. boonei, M. lucida and C. papaya and A. indica at concentrations of 20, 40, 80, 120, 240 and 300mg/kg/bw. The control group was placed on normal saline alone using the methods of peters 4 days suppressive test. The results showed significant (p<0.05) suppression of Plasmodium berghei load in mice infected which is dose dependent. The tolerance level of each of the extract was tested and LC50 was observed at 80mg/kg/bw for A. boonei, M. lucida and C. papaya, 120mg/kg/bw for A.indica. In conclusion, the extracts possess potent antimalarial substances and may therefore offer a potential drug that is safe, effective and affordable.

Keywords: Antimalarial, P.berghei, A.indica, BALB/c mice, Plant extracts