Antimalarial activities of butanol and ethylacetate fractions of Combretum nigricans leaf

Objective: To evaluate the antimalarial activity of the ethylacetate and butanol fractions of Combretum nigricans (C. nigricans) leaf extract in mice. Methods: C. nigricans solvent (butanol and ethylacetate) fractions were screened for their phytochemical constituents using standard procedures illustrated by Harborne and Evans. The Peters’ 4-day suppressive test against early malaria infection, Rane’s curative test against established malaria and prophylactic test for residual activity were employed for evaluating the antimalarial potential in mice. Results: The phytochemical screening revealed the presence of alkaloids, terpenoids, saponins, and flavonoids in both fractions at different intensity. Both fractions exhibited significant antimalarial activity in all test models (P<0.05). The ethylacetate fraction of C. nigricans had better chemosuppressive and curative effects compared to the butanol fraction, which however, elicited a better chemoprophylactic effect. The chemosuppressive effect of C. nigricans ethylacetate fraction (200-800 mg/kg) was 77.6%, 69.1% and 86.1%; curative effect was 62.3%, 71.3% and 72.4%; while the chemoprophylactic activity was 32.1%, 48.6% and 61.2% respectively. C. nigricans butanol fraction (200-800 mg/kg) had 40.3%, 54.1% and 69.1% chemosuppression; 26.2%, 36.9% and 34.5% curative effect; and 48.4%, 70.0% and 87.4% chemoprophylaxis. Conclusions: Both solvent fractions of C. nigricans possess antimalarial activity, and may be useful at different stages of malaria therapy.