Clotrimazole, ketoconazole, and clodinafop-propargyl inhibit the in vitro growth of babesia bigemina and babesia bovis (Phylum Apicomplexa)

We evaluated the growth inhibitory efficacy of the imidazole derivatives, clotrimazole (CLT) and ketoconazole (KC), and the herbicide clodinafop- propargyl (CP), in in vitro cultures of Babesia bovis and B. bigemina. Clotrimazole was effective in a dose range of 15 to 60 μM (IC 50:11 and 23.5 μM), followed by KC (50 to 100 μM; IC 50 : 50 and 32 μM) and CP (500 μM; IC50 : 265 and 390 μM). In transmission electron microscopy, extensive damage was observed in the cytoplasm of drug-treated parasites. Combinations of CLT/KC, CLT/CP and CLT/KC/CP acted synergistically in both parasites. In contrast, the combination of KC/CP was exclusively effective in B. bovis, but not in B. bigemina