Investigations on the Antimalarial Properties of Cleistopholis patens (Annonaceae) Leaf Methanol Extract and Its Partitioned Fractions in Mice

Aim: The methanol extract and partitioned fractions of Cleistopholis patens leaf were evaluated for antiplasmodial activities with a view to establishing its antimalarial potential and identifying the most active partitioned fraction. Methods: The leaf was collected, authenticated, air-dried and powdered. The extract, prepared by maceration in methanol was tested (0-800 mg/kg) against P. berghei berghei in mice using Peter’s four-day test. Normal saline and Chloroquine (10 mg/kg) were negative and positive control respectively. Percentage parasitemia, percentage chemosuppression, effective doses, survival times and percentage survivors were the parameters used for the assessment. The extract was thereafter suspended in water and successively partitioned into n-hexane, dichloromethane and ethyl acetate and the resulting fractions and the aqueous phase were similarly tested at doses 10-80 mg/kg. Results: The methanol extract which was comparable (P=.06) in activity to chloroquine gave 1.05±0.09 percentage parasitemia, 77.45±4.39 percentage chemosuppression at 40 mg/kg and an ED50 and ED90 of 255.83±3.60 and 471.35±15.05 mg/kg. The most active n-hexane fraction elicited a percentage chemosuppression of 82%, 0.87 percentage parasitaemia at 80 mg/kg, moderately high percentage survivor and relatively low ED50 and ED90 of 28.87±5.29 and 56.30±8.44 mg/kg. Conclusion: The methanol extract of C. patens leaf is active against P. berghei berghei and the antimalarial compounds is likely to be concentrated in the n-hexane fraction.