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

Trypanosoma congolense and T. brucei bloodstream form parasites were propagated axenically in suitable standard media at 34 degreesC. The effects of 33 plant extracts, fractions and pure compounds were evaluated on two clones of T. brucei and drug-sensitive and multi-drug-resistant clones of T. congolense. The cytotoxic activity of the trypanocidal extracts was' also evaluated 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% killed 90-100% of T. brucei ILTat 1.4 at the same concentration. However, 6% of 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 trypanocidal activity on a multi-drug-re-Of the 12 extracts that displayed activity-resistant clone, T. congolense IL 3338. The extracts of Eugenia uniflora, Acacia artaxacantha, Terminalia ivorensis, T. superba and Alchornea cordifolia 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 median lethal doses of the active plant extracts on the calf aorta endothelial cells varied between I 12 and 13 750 mug/ml while the calculated selective indices ranged between 0.71 and 246.8 indicating bright prospects for the development of some of these extracts as potential trypanocidal agents. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.