ANTIPLASMODIAL ACTIVITY OF ALKALOID FRACTION OF THE METHANOL ROOT EXTRACT OF ANDROPOGON SCHIRENSIS HOCHST (POACEA) IN PLASMODIUM BERGHEI INFECTED MICE

Abstract

Malaria is one of the major health problems in Nigeria and the increasing number of drug-resistant Plasmodium
species continue to be a major concern. Andropogon schirensis is a perennial plant that is used traditionally in the
treatment of malaria and dysentery. This study evaluated the in-vivo antiplasmodial activity of the alkaloid fraction
of the methanol root extract of Andropogon schirensis in Plasmodium berghi infected mice. Gas chromatography-
mass spectrometry analysis was carried out to identify the compounds present in the alkaloid fraction. Acute oral
toxicity was conducted using OECD 425 guideline. The alkaloid fraction at tested doses of 250, 500 and 1000
mg/kg was evaluated for in-vivo antiplasmodial activity using suppressive, curative and prophylactic tests in
Plasmodium berghi infected mice. Packed cell volume of each mouse was measured after the curative test and the
mice were observed for twenty-eight days to determine the mean survival time. Gas chromatography-mass
spectrometry analysis revealed the presence of seventeen bioactive compounds. The oral median lethal dose (LD50)
of the alkaloid fraction was estimated to be greater than 5,000 mg/kg. The alkaloid fraction at the tested doses of
250, 500 and 1,000 mg/kg showed significant (p<0.001) parasitaemia suppression of 51.18, 72.25 and 72.90%
respectively in the suppressive test and 61.63, 67.71 and 70.49% respectively in the curative test. The fraction
prevented malaria induced changes in packed cell volume and the mean survival time of the mice at all the tested
doses after the curative test was over twenty-eight days. The fraction showed significant (p<0.001) parasitaemia
suppression of 43.19, 49.50 and 65.61% respectively in the prophylactic test. The study showed that the alkaloid
fraction has good suppressive and curative antiplasmodial activity with moderate prophylactic activity. These results
suggest that the plant possesses antimalarial activity which may be due to the presence of bioactive compounds.