Avaliação do efeito da combinação entre protolimonoides, provenientes do extrato etanólico de Guarea kunthiana, frente a viabilidade de formas epimastigotas de Trypanosoma cruzi

Abstract

Trypanosoma cruzi (Chagas, 1909) is a parasitic protozoan belonging to the Tripanosomatidae family and is the etiological agent of Chagas Disease or American Trypanosomiasis (Coura, 2002). According to the Pan American Health Organization (2021), CD, a neglected disease, still affects 6 to 8 million people in the Americas. In Brazil, the reference treatment is made with Benznidazole which, however, is not highly effective, especially in the chronic phase of the disease (Andrade, 1996; Coura, 2002). Thus, there is a need to look for new active compounds with the potential to make the parasites unfeasible. This way, it is known of the existence of biological activity related to limonoids and protolimonoids found in groups belonging to Meliaceae, such as the species Guarea kunthiana. (Roy & Saraf, 2006; Da Cruz, 2020). Therefore, the present study aimed to evaluate the effect of the combination of two protolimonoids (3β-Otigloylmeliantriol and Melianol) from the ethanol extract of the fruits of this plant, at in vitro growth of epimastigote forms of Trypanosoma cruzi. Thus a combination assay was performed with four concentrations of each protolimonoid which were defined based on the individual IC50 of the compounds. The cell viability of the parasites was determined employing an MTS assay (Henriques et. al, 2011) for 24h. In addition, the combination index (CI) of the compounds was determined, for later classification of synergism according to Chou (2006). Then, it was seen that protolimonoids 3 and 5 have a synergistic effect in combination, which enhances the activity of each compound on the in vitro growth of T. cruzi. The results obtained by this study are new in the literature, and they can certainly contribute to the search for new treatment possibilities for Chagas disease.