Banca de QUALIFICAÇÃO: MILLENA PATRÍCIO DO NASCIMENTO FERREIRA

IN VITRO LEISHMANICIDAL EVALUATION OF ORGANIC EXTRACT FROM THE MICROALGAE Tetradesmus obliquos

Microalgae; Bioactive compounds; Fatty acids; Leishmania

American Tegumentary Leishmaniasis (ATL) is a disease caused by protozoa of the genus Leishmania that causes ulcers in the skin and mucous membranes. Current treatments for leishmaniasis have limitations, such as side effects and high toxicity. The microalgae Tetradesmus obliquus has been studied due to the biotechnological potential of its metabolites, mainly lipids rich in fatty acids with healing activity. The objective of this study was to evaluate the potential of bioactives present in the organic extract of the microalgae T. obliquus against Leishmania braziliensis. The T. obliquus biomass was cultivated in BG-11 medium in Erlenmeyers flasks for 15 days until reaching its stationary phase of cell growth. After cultivation, the biomass was collected and stored at 4°C for later extraction. Extraction with ethanol solvent occurred in a ratio of 1:10 (w/v) where the mixture remained in contact for 48 hours. After evaporating the solvent, the lipid yield was determined. Promastigotes of L. braziliensis were expanded in culture in Schneider's medium containing 10% fetal bovine serum and the inhibitory concentration (IC50) was obtained at concentrations of 25, 50, 100 and 200 μg/mL. To determine the cytotoxicity of the extract, a cell viability test was performed through the MTT colorimetric assay with fibroblasts and peripheral blood mononuclear cells (PBMC) at concentrations of 7.8, 15.6, 31.25, 62.5, 125 and 250 µg/ml. The extract obtained a yield of 1.49% in the first extraction and 4.47% in the second extraction. It showed total inhibition of parasite cells at a concentration of 200 μg/mL and IC50 of 91 μg/mL. The in vitro cytotoxicity of the extract in PBMC cells showed viability of 100% at the tested concentrations (CC50 > 250 µg/mL). The in vitro cytotoxicity of the extract in fibroblasts induced cytotoxic effect in the cells during the treatment. In conclusion, T. obliquus lipid extracts are potential candidates for the development of antileishmanial drugs.