Abstract

Malaria is a major debilitating disease caused by Plasmodium species and spread by female Anopheles mosquitoes. This research was conducted to determine the efficacy of ethanolic leaf extracts of Ricinus communis L. against Plasmodium berghei (NK65) infection in mice. Phytochemical components of the extract were analyzed and elucidated in order to reveal the constituents with antimalarial potentials. The safety of the extract in the experimental mice was ascertained by determining the median lethal dose (LD50). Result of the phytochemical screening revealed the presence of compounds notable for antimalarial effects such as alkaloids, flavonoids and anthraquinones. From the findings, it was established that a dosage of 141.42 mg/kg of the extract represents the acute lethal dose (LD50) in mice. Hence, three separate doses of the extract (10, 20 and 40 mg/kg) were prepared for the curative test. All the three doses portrayed a remarkable antimalarial activity as compared to the standard reference drug (chloroquine, 5 mg/kg). The extract dosage of 20 mg/kg showed the highest average suppression of 81.6% among the treatments. No significant differences were however observed among the treated groups (P>0.05). On the other hand, a highly significant difference was observed between the treated and control groups (P≤0.001). The leaf extracts of R. communis thus possess antimalarial properties and is therefore recommended as a new candidate for antimalarial drug development.

Key words: Ricinus communis, chloroquine, phytochemical compound, antimalaria, dose, Plasmodium berghei.