Ex vivo trypanocidal activity of 1-(2-hydroxybenzylidene)thiosemicarbazide against Trypanosoma equiperdum

•A thiosemicarbazone derivate showed a dose-dependent effect on T. equiperdum.•The compound exhibits an IC50 value lower than the drug commonly used.•A substitution of a hydroxyl group could increase the anti-trypanocidal activity. Trypanosoma equiperdum is the causative agent of dourine, a venereal disease in horses and donkeys. This parasite has a widely distribution, is found in Africa, Asia, Southern and Eastern Europe, Russia, Mexico and Venezuela. The T. equiperdum is morphologically indistinguishable to other Trypanozoon species, however differs from other mammalian trypanosomes due to the fact that it is primarily a tissue parasite, generating cutaneous plaques, swelling of genitalia and neurological signs. The aim of this study was to evaluate the trypanocidal effectiveness of a set of derivatives of thiosemicarbazones on a T. equiperdum ex vivo culture. All compounds appeared to have trypanocidal activity, however one of them shown better solubility and a dose-dependent effect. The median inhibitory concentration (IC50) was 1.2μM. The selected compound exhibits a greater inhibitory activity than diminazene aceturate, a common drug for animal trypanosomosis treatment.