Estudo in silico com possíveis alvos terapêuticos e in vitro anti-leishmania de derivados espiro-acridínicos

Abstract

Leishmaniasis is considered as a neglected disease by the World Health Organization, where Brazil is in the world statistics of countries with a higher prevalence of this pathology. This disease encompasses several clinical manifestations ranging from simple ulcerous cutaneous lesions to disfiguring mucocutaneous forms, and the visceral form of the disease, which can be fatal when left untreated. The treatment of leishmaniasis is done through the administration of pentavalent antimonials, which present several limitations, such as painful parenteral administration and high toxicity, being unsatisfactory, highlighting the importance in the development of new drugs that are able to decrease these effects. Therefore, this work proposes an in silico study with possible therapeutic targets and the evaluation of the anti-Leishmania activity in vitro of spiro-acridine compounds against the promastigote and amastigote forms of Leishmania infantum. In this study 10 spiro-acridine compounds of the AMTAC series were analyzed. In the in silico study, molecular docking with the enzymes Esterol 14-alpha dimethylase, Tripanotiona retutase and Topoisomerase I, using Hyper Chem v. 8.0 software. The three-dimensional structures of the enzymes used in molecular docking were obtained directly from the Protein Data Bank (PDB). All of the compounds showed interaction with the hydrogenated and / or hydrophobic bridges studied, which were significant. Regarding the evaluation of in vitro anti-Leishmania activity, evaluated using the colorimetric test of 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide, IC50 values of IC50 of 1.109 to 6.058 μg / mL were observed), except AMTAC 09 (IC 50> 400 μg / ml). The results of the compounds studied were better than the meglumine antimonial (IC50 = 25610 ± 1.46μg / ml). In this series, it was possible to observe the structure – activity relation of AMTAC 01 (IC50 = 2.039 ± 0.06 μg / ml), used as the base structure for the development of the various spiro-acridines studied, and AMTAC 11 (IC 50 = 1.109μg / mL), dimethylamino radical, seems to favor pharmacological activity, probably due to positive electron donors and lipophilic effects. As for the activity in the amastigote form of Leishmania infantum of the most active compounds, there is a significant activity of AMTAC 11 (EC50 = 0.974 ± 0.2 μg / mL), being greater than its positive controls, meglumine antimoniate (EC50 = 112,800 ± 12μg / ml) and amphotericin B (1.597 ± 0.26 μg / ml). In the molecular docking study, the spiro-acridine derivatives that presented the best interaction profile with the target were AMTAC 13 (R1 = NO2) and AMTAC14 (R3 = NO2) and also showed significant anti-Leishmania activity. None of the derivatives showed cytotoxicity to erythrocytes of human origin (HC50 => 400 μg / ml). Thus, we can conclude that spiro-acridine compounds have a potential effect against Leishmania, but more studies are needed to better understand of its possible mechanism of action.