CONICET | Buscador de Institutos y Recursos Humanos

Nowadays and since more than 40 years, the therapeutic options for Chagasdisease are limited to two drugs (benznidazol and nifurtimox) with variable efficacy and serious adverse effects. Recently, we have described the isolation and the trypanocidal activity of different sesquiterpene lactones (STLs) from the species Smallanthussonchifolius. The aim of this work was to determine the trypanocidal activity of the ethanolic extract of this plant in order to evaluate its potentiality as a phytotherapeutic agent (herbal medicine). Trypanocidal activity was evaluated in different forms of T. cruzi. Parasites were incubated in the presence of the extract (0-100µg/ml) and the IC50value was estimated. Citotoxicity was analyzed by MTT in Vero cells. In order to study the modeof action of the extract,epimastigotes were stained with acridine orange and observed in a fluorescence microscope. As positive control parasites were treated with H2O2. The chemical composition of the extract was analyzed by chromatographic techniques) and by infrared spectroscopy.Preliminary results, showed the presence of terpenic compounds, possibly STLs. For T. cruziepimastigotes(72h, 28°C) andtrypomastigotes(24h, 37°C).,IC50values of 7.4 µg/ml and 16.5 µg/ml were obtained, respectively. Inatrial simulating blood banks, the CI50value for tripomastigotes (24h, 4°C)was 8.5 µg/ml MTT assay showed a value of CC50 of 448.3 µg/ml. Regarding the mechanism of action studied with acridine orange, we observed that in high concentrations (IC90) the extract cause a type of cell death ?apoptosis-like?, whereas when the parasites were treated with the IC50concentration, morphologic changes, such as the formation of acidic bodies and some death, were observed. These results showed that the ethanolic extract of S.sonchifolius is active against the different forms of T. cruzi. Further studies are being carried out in order toidentify the compounds responsible of the observed activity.