In vivo comparative antimalarial evaluation of three solvent leaf extracts of Anthocleista djalonensis against Plasmodium berghei

Abstract

Solvent selection critically influences the yield and quality of bioactive compounds extracted from medicinal plants.  Local gin appears to be the most widely used solvent for preparing herbal extracts locally in Nigeria, despite the side effects and toxicity. This study compared the in vivo antimalarial activity of three solvent extracts (95% ethanol, water, and local gin (78% alcohol) from Anthocleista djalonensis leaves against Plasmodium berghei ANKA strain. The extracts were obtained by cold maceration. Oral actute toxicity (LD₅₀) was evaluated using modified Lorke’s (1983) method with doses up to 5000 mg/kg.  Antimalarial efficacy was assessed using the 4-day suppressive and curative tests in infected mice at doses of 50, 100, 200, 400, and 800 mg/kg. The ethanol extract proved to be toxic (LD₅₀ = 4472 mg/kg), while the local gin and aqueous extracts were non-toxic (LD₅₀  > 5000 mg/kg). In the suppressive assay, all extracts significantly reduced parasitemia and prolonged the survival, with the local gin extract at 800 mg/kg showing the uppermost suppression (96.82%), surpassing the ethanol (94.54%) and aqueous (94.33%) extracts, and displaying  no statistically significant difference (p < 0.05) from the positive control at the same dose. In the curative assay, the local gin extract at 800 mg/kg offered the greatest curative action and survival time, with a clear dose-dependent response detected for all extracts. These findings confirm the plant’s strong antimalarial properties, with solvent choice influencing results. The local gin was most effective, confirming its traditional use, while water attained slightly lower efficacy with decreased toxicity.