Avaliação da atividade leishmanicida de plantas medicinais de interesse ao Sistema Único de Saúde

Abstract

Leishmaniasis is a endemic parasitosis that afflict 102 countries and territorie, it is caused by a protozoan of the genus Leishmania and transmitted by the phelobotomine. The disease has different clinical forms, from skin lesions to systemic involvement. The therapeutic arsenal for the treatment of leishmaniasis is very limited, due to low security and the high resistance indices. Faced with the need to develop new leishmanicidal drugs more efficient and safer, it was proposed in this work to investigate the leishmanicidal activity of aqueous extractive solutions of 10 medicinal plants mentioned in the RENISUS list. For that, the cytotoxic potential of the plants was evaluated by cell viability assay using MTT (3- [4,5-dimethyl-thiazol-2-yl] -2,5- diphenyltetrazolium bromide), the leishmanicidal activity against the amastigote forms of Leishmania amazonensis and Leishmania chagasi, the identification of the selectivity of these plants and the immunomodulatory effect through the production of nitric oxide. The results obtained were considered significant when * p <0.05, and expressed as mean ± standard error of the mean. The significance levels between experimental groups and positive or negative controls were evaluated in the Prisma® software, utlizying the analysis of variance ANOVA and post test of Tukey. The results of the cell viability assay showed that of the 10 medicinal plants evaluated, only Solanum paludosum induced a cytotoxic effect on the host cell, with IC50 31.7 ± 0.1 μg / mL, the others showed no cytotoxic effect up to the maximum concentration tested, 100 μg / mL. In the antiamastigote test, were active against L. amazonensis amastigotes the species Stryphnodendron astringens (IC50> 100 μg / mL and maximum effect of 53.0 ± 4.0%), Equisetum arvense (IC50 82.3 ± 1.5 μg / mL and maximum effect of 51.8 ± 0.3%), Chenopodium ambrosioides (IC50 68.4 ± 1.9 μg / mL and maximum effect of 60.6 ± 1.3%) and Solanum paludosum (CI50 19.7 ± 2.6 μg / mL and maximum effect of 79.7 ± 3.7%). Besides that, the Solanum paludosum plant also showed activity against L. chagasi, with IC50 9.3 ± 0.9 μg / mL and a maximum effect of 73.7 ± 3.8%. As for the production of nitric oxide, the plants Cynara scolymus, Passiflora alata, Polygonum acre, Solanum paludosum and Copaifera langsdorffii induced an increase in cultures of cells infected with L. amazonensis, the plants Equisetum arvense and Chenopodium ambrosioides induced an increase in nitric oxide in cultures of cells infected with L. chagasi, and the plant Stryphnodrendon induced the increase of nitric oxide in the cultures of both species. It is worth mentioning that the results obtained so far, support the continuity of studies for a more detailed investigation about the mechanism of action of these natural products.