In vitro activity of selected medicinal plants in Kenya on Trypanosoma evansi
Trypanosomiasis, a protozoan disease causes morbidity and death to humans and severely limits livestock production in endemic areas. It occurs predominantly in Africa, South America and Asia. Although chemotherapy has been used to control the disease, cases of drug resistance by trypanosomes are a major problem and prospects of vaccine development are remote. Herbal medicines have been claimed to be effective in the control of the disease in endemic areas. This study evaluated the in vitro activity of plant extracts of selected indigenous Kenyan plants on T. evansi. Test extracts included Azadirachta indica (neem), Prunus africana, Bidens pilosa, Physalis peruviana, Senna didymobotyra and Croton megalocarpus. 96- Well micro titer plates were used and trypanocidal activity was evaluated in vitro by calculating minimum inhibitory concentrations (MIC) of respective extracts. Of the 27 extracts evaluated, chloroform extracts of Azadirachta indica leaves had the highest activity (minimum inhibitory concentration of 18.75 μg/ml). Other extracts showed activity on the parasite in vitro at concentrations that were much higher than chloroformic extract of A. indica. This study has confirmed the hypothesis that some plants used in Kenya to control trypanosomiasis have trypanocidal potential.
Keywords: African trypanosomosis, Medicinal plants, Anti-trypanosomal activity, In vitro model.