Evaluation of the Anti-malarial effect of the methanolic leaf extract of Vernonia glaberrima ( Asteraceae )

The emergence of drug-resistant strains has compromised the efficacy of several anti-malarial drugs, including the artemisinins. Many species of Vernonia, family Asteraceae, have been employed in traditional medicine for the management of diabetes mellitus, microbial infections and malaria. The anti-malarial effect of the methanolic leaf extract of Vernonia glaberrima was investigated using Chloroquine-sensitive Plasmodium berghei (NK65) infected mice, according to Riley and Peters curative test model. Three test groups of mice were orally administered with the suspension of the graded doses of the extract at 300, 150 and 75 mg/Kg body weight for four consecutive days; a reference drug, Chloroquine phosphate (5mg/Kg) group, and the negative control group (0.2ml distilled water) were similarly administered. The level of chemo-suppression obtained on the eighth day was a function of the reduction in parasitemia as estimated from the mice tail blood smear. The mean survival time (in days) for each group of mice was also determined over a period of 28 days postinfection. The results showed a dose-dependent chemo-suppression by the three extract groups 300, 150 and 75 mg/Kg at 62.1%, 54.3% and 32.2% respectively, while Chloroquine (5mg/Kg) exhibited a higher suppression at 73.4%. Only the Chloroquine and 300mg/kg groups produced statistically significant (p˂0.05) mean survival time of 19 and 17 days when compared to the negative control. The study demonstrated the anti-malarial effect of the leaf extract of V. glaberrima and lends credence to its ethno-medicinal use in treating malaria infection.