Preclinical Antimalarial Evaluation of Hunteria Umbellata Methanol Leaf Extract in Mice Infected with Plasmodium Berghei Nk65

The increasing ineffectiveness of conventional antimalarial therapies has led to the further exploration of medicinal plants for their antimalarial benefits. Herein, we assessed the acute toxicity and antimalarial potential of Hunteria umbellata leaf methanol extract in mice. As 2 of the 3 mice that were administered 2000 mg/kg b.wt. of the extract died in our acute toxicity study, a lower dose of 500 mg/kg. b.wt. was investigated. Treatment with 500 mg/kg. b.wt. of the extract resulted in the death of one out of three mice. Hence, the extract was deemed to be safe at doses less than 500 mg/kg b.wt. Following this, doses of 10, 50 and 100 mg/kg b.wt. were investigated for their antimalarial activity which was done using 25 male mice (6 – 8 wks. old) that were randomly distributed into 5 groups of 5 mice and infected with Plasmodium berghei NK65. Although the extract caused a dose-dependent decrease in parasite growth and inhibited parasite growth by 50% at a low dose of 85 mg/kg b.wt., mice that received higher doses of the extract died earlier than those that received lower doses. Thus, whereas our toxicity study suggests that the extract is only toxic at doses above 500 mg/kg b.wt., mice administered 100 mg/kg b.wt. in the antimalarial study died faster than those that received lower doses. Therefore, an exhaustive toxicity testing of the extract is advocated since acute toxicity study can only reveal immediate effects from short exposures unlike chronic tests which can reveal long-term impacts. Taken together, our results suggest that although H. umbellata leaf methanol extract has excellent antimalarial activity where alkaloids may be implicated, it may not be selective for the malaria parasite at high doses.