RESUMO
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.