In vivo antimalarial activity of ethanolic extract of leaves of Holarrhena floribunda (G. Don) Dur. and Schinz (Apocynaceae)

Holarrhena floribunda is a plant of wide usage in the Togolese folk medicine. A previous ethnobotanical survey on the latex plants of the Maritime region of the country revealed that this plant was included in several recipes curing malaria and microbial infections. Therefore this study aimed to seek for the effectiveness of the ethanolic extract of the plant in the treatment of malaria. The in vivo antimalarial activity was evaluated on Plasmodium berghei -infected mice using the four day suppressive test of Peters. Further, the acute toxic effects of the extract were monitored after a single oral dose (5,000 mg/kg body weight) administration in NMRI mice. The results indicated that the ethanolic extract of H. floribunda reduced significantly parasitaemia in a dose-dependent manner. The mean survival time of mice was also increased in a dose-dependent manner and the extract prevented the weight loss linked with the parasitaemia increase. In the acute toxicity assay the oral administration of the extract to the mice did not affect the relative weight of vital organs, and there were no sign of toxicity or death during the study period. The LD50 of the tested extract was found to be greater than 5,000 mg/kg, indicating its safety. This study demonstrates the antimalarial activities of leaves of H. floribunda and then, supports its medicinal use in the treatment of microbial infections. Keywords: Holarrhena floribunda, ethanolic extract, antimalarial, acute toxicity.