Ethno-veterinary medicine: screening of Nigerian medicinal plants for trypanocidal properties

Trypanosoma congolense and T. brucei bloodstream form parasites were propag ated axenically in suitable standard media at 34 degreesC. The effects of 3 3 plant extracts, fractions and pure compounds were evaluated on two clones of T. brucei and drug-sensitive and multi-drug-resistant clones of T. cong olense. The cytotoxic activity of the trypanocidal extracts was' also evalu ated on calf aorta endothelial cells in vitro. Of the extracts tested, 22% killed T. congolense IL 1180 at a concentration of 100 mug/ml while 18% kil led 90-100% of T. brucei ILTat 1.4 at the same concentration. However, 6% o f the active extracts killed 93% of a dyskinetoplastid form of T. brucei IL Tat 1.1, indicating that the intact kinetoplast is a target of some of the compounds tested against drug sensitive trypanosomes, 66.7%, had trypanoci dal activity on a multi-drug-re-Of the 12 extracts that displayed activity- resistant clone, T. congolense IL 3338. The extracts of Eugenia uniflora, A cacia artaxacantha, Terminalia ivorensis, T. superba and Alchornea cordifol ia had median lethal concentrations of between 13 and 69 mug/ml on both the drug-sensitive, IL 1180 and multi-drug-resistant clone, IL 3338. The media n lethal doses of the active plant extracts on the calf aorta endothelial c ells varied between I 12 and 13 750 mug/ml while the calculated selective i ndices ranged between 0.71 and 246.8 indicating bright prospects for the de velopment of some of these extracts as potential trypanocidal agents. (C) 2 001 Elsevier Science Ireland Ltd. All rights reserved.