Uchôa, Adriana FerreiraDantas Junior, Dalmo Monteiro2025-07-152025-07-152025-06-26DANTAS JUNIOR, Dalmo Monteiro. Atividade leishmanicida do extrato e frações proteicas das sementes de Tephrosia toxicaria (Sw.) Pers. Sobre os promastigotos de Leishmania infantum. Orientadora: Adriana Ferreira Uchôa. 2025. 50 f. Trabalho de Conclusão de Curso (Graduação em Biomedicina) – Departamento de Biologia Celular e Genética, Universidade Federal do Rio Grande do Norte, Natal, 2025.https://repositorio.ufrn.br/handle/123456789/64378Leishmaniasis, a disease caused by a protozoan from the genus Leishmania, has different clinical forms, including visceral, cutaneous, and mucocutaneous. In Brazil, the Visceral form, the most serious and caused mostly by Leishmania infantum, is known for its increased periculocity because of the scarcity of treatment options, drug toxicity, and resistance. In this context, botanical extracts emerge as a source of promising therapeutic adjuvants, due to their vast repertoire of biomolecules with biological activity, such as proteins. In this study, the leishmanicidal potential of the seed crude extract of Tephrosia toxicaria (Sw.) Pers., na tropical leguminosae, known as "Caiena's Timbo", was evaluated. The leishmanicidal potential previously confirmed by our group enhanced our more detailed investigation of the fractions of this extract and its potential modes of action against the promastigote of L. infantum. The extract were obtained by aquous extraction of the T. toxicaria's seed flour, in the 1:5 (w/v) proportion, followed by a proteic fractioning with amonium sulfate precipitation, in the following saturation range: 0-25% (F1), 25-50% (F2), 50-75% (F3) e 75-100% (F4). These fractions were characterized in terms of their protein and phenol compounds content, as well as the detection of lectin and Protease Inhibitors (PIs). The leishmanicidal activity as evaluated by a resazurin reduction assay, exposing promastigotes of L. infantum to varying concentrations of the extract and fractions, ranging from 1000 to 0,1 μg/mL. The results show a leishmanicidal activity higher in the fractions than the crude extract, possibly because of the higher concentration of soluble proteins and PI's, in reason of the fractioning method. The fractions F2 to F4 displayed an inhibition above 50% in the 0,1 μg/mL concentration, the lowest tested, surpassing the crude extract, which got 30% inhibition at the same concentration. The morphological analysis revealed changes in the cellular structure of the parasite after treatment with the fractions, including plasmatic membrane irregularities and flagellum disorganization, indicating un impact on the cell integrity. Fraction F3 is highlighted here because of its cell changes caused, suggesting a leishmanicidal effect alongside the inhibition of cellular physiological processes, which may be inhibited by the fraction. It is hypothesized that the presence of PI's in the fractions may contribute to the reduction of cell viability and morphological changes observed, as proteases play a fundamental role in the physiology of Leishmania. Further future investigations will contribute to the validation of this hypothesis and will explore the potential use of these fractions and isolated molecules as candidates for the development of new therapeutic strategies.pt-BRAttribution 3.0 Brazilhttp://creativecommons.org/licenses/by/3.0/br/CalazarExtratos botânicosLeishmanioseProteasesTimbóBotanic extractsCalazarLeishmaniasisTimbóbachelorThesisCIENCIAS BIOLOGICAS::BIOQUIMICA::QUIMICA DE MACROMOLECULAS::PROTEINAS