Investigação da atividade Anti-Trypanosoma Cruzi de esteroides isolados de plantas e derivados sintéticos

Abstract

Chagas disease is a zoonosis caused by the hemoflagellate protozoan Trypanosoma cruzi, which affects millions of people in Latin America. Disease treatment is based on the use of two drugs, benznidazole and nifurtimox, which present low cure rates in the chronic phase of the disease as well as generating a number of adverse side effects. In this context, the development of new therapies for a better treatment of Chagas disease is necessary. In this study we investigated the anti-T.cruzi potential of physalins and betulinic acid, plant-based isolated steroids, in addition to synthetic derivatives from the latter, in in vitro assays. Our results demonstrate a high trypanocidal activity of physalins B and F and of the derivative BA5 against trypomastigote forms and on the processes of invasion and development of these on peritoneal macrophages. Electron microscopy revealed that physalin B or BA5 derivative treatment resulted in ultrastructural changes in the plasma membrane, Golgi apparatus, kinetoplast and endoplasmic reticulum of trypomastigotes forms. Additionally, these compounds contributed to the formation of atypical vacuoles in the appearance of myelin figures, which were labeled with MDC to confirm their identity as autophagic vacuoles. Flow cytometry analysis revealed that parasite death occurred mainly by necrosis. When combined with benznidazole, physalin B, physalin F or BA5 derivative, resulted in a higher anti-T. cruzi activity against amastigotes when compared to the compounds tested alone. These results indicate that steroids, such as physalins B and F and the derivative BA5, are potential candidates for an alternative treatment of Chagas disease.