Abstract
Xanthium brasilicum Vell. (Asteraceae) aerial part water, methanolic and chloroformic extracts were investigated for their antimalarial activity in vitro against 3 different Plasmodium falciparum strains. The IC50 of the above mentioned extracts against P. falciparum Nf54 was 3.1, 1.2 and 5.7 mu g/ml respectively, the IC50 against P. falciparum FCM17 was 7.4, 3.9 and 21.0 mu g/ml respectively and the IC50 against P. falciparum locally isolated strain was 3.9, 2.3 and 10.3 mu g/ml respectively. The methanolic extract was administered orally to group of mice artificially infected with P. yoelii N67 at a dose of 500 mg/kg/day for 4 days. Zero parasitaemia was observed after the sixth day from the infection upwards. The acute and subchronic toxicity of the X brasilicum methanolic extract proved that the plant is non. toxic to the albino rats up to the dose 1500 mg/kg body weight. The plant methanolic extract revealed negative activity against heme-histidine rich protein (HRP) of P. falciparum.