Journal of Pharmaceutical Research International

Introduction: Malaria is a life threatening disease caused by infection of red cells by Plasmodium parasites and is very prevalent due to emergence of resistance to the parasites. The plant Callichilia stenopetala Stapf (family Apocynaceae) is commonly used by traditional practitioners in South-East part of Nigeria as a remedy for the treatment of malaria, “re-current” fever and other ailments. The aim of this study was to investigate antimalarial activities and phytochemical constituents of this plant.

Methods: The methanol extract of root bark of Callichilia stenopetala was suspended in water and partitioned between hexane, chloroform and ethyl acetate successively to obtain various fractions. A four–day suppressive and curative techniques were used to determine parasite inhibition. Antiplasmodial effect of the crude extract and the fractions against early infection was evaluated in chloroquine sensitive Plasmodium berghei berghei NK-65 infected mice. The two most active chemosuppressive fractions (hexane and chloroform) were studied for their effect against established infection using curative test procedure. Phytochemical analysis of the extract was carried out using standard procedures and oral acute toxicity in mice was also evaluated. 

Results: The phytochemical analysis showed the presence of alkaloids, saponins, steroidal and phenolic compounds. Anthraquinones and cardiac glycosides were not detected. At a dose of 8000 mgkg^-1, no mortalities or evidence of adverse effects was observed in acute toxicity test. The crude extract, the hexane fraction and the chloroform fraction demonstrated intrinsic chemosuppressive antimalarial properties that were dose-dependent. The tested fractions produced significant (p < 0.05), dose dependent activity against the parasite in the curative test compared with the standard drug chloroquine.

Conclusion: The results uphold the folkloric use of C. stenopetala root bark as antimalarial agent. The plant could be considered as a potential source of new antimalarial whose activity resides mainly in the hexane fraction.