Evaluation of the Antimalarial Activity of Ethanol Extracts of the Leaves of Three Plant Species Collected from Yayu Coffee Forest Biosphere Reserve, Southwest Ethiopia

OBJECTIVE: In the attempt of searching for potential plant derived antimalarial medicines, the aim of the present study was to examine In vivo antimalarial efficacy of crude ethanol extracts of the leaves of Croton macrostachyus, Ruta chalepensis and Vernonia amygdalina using chloroquine (CQ) sensitive strains of Plasmodium berghei in Swiss albino mice. METHODS: To ascertain the safety level of the plant materials, crude extracts underwent oral acute toxicity assessments whereby mice received up to a single dose of 3000 mg/kg. Peter's four day standard antimalarial suppressive test was carried out to determine growth inhibition of parasitemia at tested doses of 400, 600, and 800 mg/kg of the extracts. Survival time of experimental mice and preliminary phytochemical screenings of the extracts were also done according to the standard procedures. RESULTS: Extracts of the plant materials did not produce severe acute toxic effects in mice that received up to 3000 mg/kg in a single dose. Although complete clearance was not recorded, extracts of the plant materials produced dose dependent suppression of the parasitemia. The highest growth inhibition recorded was by extract of V. amygdalina (61.44%) followed by C. macrostachyus (59.3%) at 800 mg/kg of tested doses. Whereas, complete parasitemia clearance was attributed in mice treated with 25 mg/kg of CQ. In addition, survival time of experimental mice was recorded and the result showed mice treated with the extracts lived longer than the corresponding negative controls. The phytochemical screening of the extracts revealed the presence of antimalarial active constituents such as alkaloids, saponins, cardiac glycosides, flavonoids, terpenoids, steroids, phenols, and tannins. CONCLUSION: The present study, therefore, suggests that crude ethanol extracts of C. macrostachyus, R. chalepensis, and V. amygdalina are safe and rich with active secondary metabolites which have promising antimalarial effects.