Identification of anti-babesial activity for four ethnoveterinary plants in vitro

A commonly available Babesia caballi culture system was utilized for anti-babesial screening of four commonly used ethnoveterinary plants, Rhoiscissus tridentata, Elephantorrhiza elephantina, Aloe marlothii and Urginea sanguinea, in vitro. Well-established B. caballi cultures were initially incubated with either imidocarb diproprionate and diminazene aceturate to validate the model, where after the studies were performed on the four plants. Effectivity was established as the degree of inhibition using a colour change method as well as by evaluating percentage parasitized cells on thin culture smears and calculating the degree of residual infectivity. The model was effective in demonstrating the in vitro efficacy of the well known anti-babesial drugs imidocarb and diminazene indicating an EC50 value of 0.08 and 0.3 mu g/ml, respectively. Only the E. elephantina rhizomes acetone extracts were effective at a concentration of 100 mu g/ml. It was also shown that the colour change method of evaluation was not very sensitive for determining activity of crude plant extracts. (c) 2005 Elsevier B.V. All rights reserved.