Estudo Pré-clínico com microemulsões de via tópica contendo produtos bioativos como alternativa terapêutica para a Leishmaniose Cutânea

Abstract

Cutaneous leishmaniasis is a neglected disease that mainly affects developing countries, from underdeveloped and developing countries. The infection is caused by parasites of the genus Leishmania and presents a wide spectrum of clinical manifestations, which are classified as cutaneous or mucocutaneous. Currently, the recommended treatment in Brazil consists of the use of meglumine antimoniate, pentamidine isethionate, amphotericin B and liposomal amphotericin B, however these drugs have limited efficacy and high toxicity. In this sense, medicinal plants have aroused the interest of the scientific community, due to the therapeutic potential of secondary metabolites present in different plant species. Thus, the present study aims to develop microemulsion formulations containing the dichloromethane fraction of Libidibia ferrea and the phenolic compound methyl gallate to evaluate them in a preclinical study as a therapeutic alternative for cutaneous leishmaniasis, with the aim of optimizing the therapeutic protocol of patients diagnosed with this disease. Initially, in vitro biological assays of antileishmania activity in amastigotes were carried out, as well as the evaluation of cytotoxicity in RAW cells. Then, the antileishmania activity was investigated in in vivo assays with microemulsion formulations containing the dichloromethane fraction (DCM) of Libidibia ferrea and methyl gallate submitted to the treatment of golden hamsters infected with Leishmania (Leishmania) amazonensis monotherapeutically and associated with Glucantime® via IM and IL. Preliminary results demonstrated that the substances did not present cytotoxicity in RAW264.7 macrophages; the dichloromethane fraction of L. ferrea was more effective in inhibiting RAW264.7 macrophage infection and the methanolic extract induced greater IL-6 secretion by murine macrophages. In the in vivo study, there was a significant reduction in the volume of the lesion in animals treated with the association of the dichloromethane fraction + 20 mg/Sb/Kg/day of intralesional Glucantime®, but there was no clinical and parasitological cure, in the biochemical analysis there was a significant difference during the course of treatment on the values obtained for creatine kinase and urea. The microemulsion with methyl gallate showed stability and efficacy in controlling the evolution of leishmaniatic lesions and parasitic load in golden hamsters infected with L. (L.) amazonensis when compared to the control group. Thus, the association of the microemulsion containing the dichloromethane fraction of L. ferrea with Glucantime® and the microemulsion containing methyl gallate showed promise in reducing leishmaniatic lesions.