In vitro and in vivo evaluation of the antitrypanosomal activity of fractions of Holarrhena africana

The aqueous extract of young leaves of Holarrhena africana, a plant used in the Nigerian traditional medicine, exhibited good activity against Trypanosoma brucei spp. The extract was fractionated and eight fractions were obtained. One fraction designated as HaF5 showed in vitro activity against Trypanosoma brucei rhodesiense with an IC50 value of 0.785 μg/mg and no overt cytotoxicity against L-6 cells. Fraction HaF5 was tested in vivo at two doses and found to exhibit in vivo efficacy in Trypanosoma brucei brucei infected mice leading to a complete disappearance of parasitaemia followed by a relapse.