Resumo

HAMUY, R et al. Determination of the in vitro sensitivity of different Trypanosoma cruzi strains to benznidazole and the leaf extract of the plant Zanthoxylum chiloperone. Mem. Inst. Investig. Cienc. Salud [online]. 2013, vol.11, n.2, pp.16-25. ISSN 1812-9528.

The in vitro sensitivity of ten Trypanosoma cruzi strains to benznidazole and the leaf extract of the plant Zanthoxylum chiloperone was evaluated. Epimastigotes forms of strains that belonged to different lineages, different geographic origin, including three from Paraguay and isolated from different hosts (humans, triatomines, wild animals) were used. The degree of sensitivity to the drug and vegetal extract was estimated by the lysis percentage of the parasites at 24 and 48 hs of exposure. It was observed a wide range of variation in the lysis percentages between strains from 22.2% to 90.8% at a benznidazole concentration of 200 µg/mL, finding a strain without sensitivity to the drug. In relation to the vegetal extract, three concentrations were tested, 500, 700 and 900 µg/mL, observing variations in the lysis percentages between strains with the two first concentrations, between 2.1% and 100%, and with total lysis in all strains at the concentration of 900 µg/mL. Association was not observed between the diversity of responses to the compounds and the strain classification, geographic origin and host type.The observed differences emphasizes the heterogeneity of the natural populations of T. cruzi, an important aspect to be considered in the sensitivity studies of chemotherapics and in the primary screenings of new antichagasic drugs. It should also be remarked the efficacy of the vegetal extract on different strains of this parasite.

Palavras-chave : Trypanosoma cruzi; benznidazole; in vitro; sensitivity; Zanthoxylum chiloperone.

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