Federal University of Pará. Institute of Health Sciences. Postgraduate Program in Pharmaceutical Innovation. Belém, PA, BrazilMinistério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, BrasilFederal University of Pará. Institute of Biological Sciences. Postgraduate Program in Biology of Infectious and Parasitic Agents. Belém, PA, Brazil / Federal University of Pará. Institute of Biological Sciences. Postgraduate Program in Biodiversity and Biotechnology of the BIONORTE Network. Belém, PA, BrazilMinistério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, BrasilMinistério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, BrasilMinistério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, BrasilFederal University of Pará. Institute of Biological Sciences. Postgraduate Program in Biodiversity and Biotechnology of the BIONORTE Network. Belém, PA, BrazilFederal University of Ouro Preto. School of Pharmacy. Ouro Preto, MG, BrazilFederal University of Pará. Institute of Health Sciences. Postgraduate Program in Pharmaceutical Innovation. Belém, PA, BrazilFederal University of Pará. Institute of Biological Sciences. Postgraduate Program in Biodiversity and Biotechnology of the BIONORTE Network. Belém, PA, Brazil / Federal University of Pará. Institute of Biological Sciences. Oxidative Stress Research Laboratory. Belém, PA, BrazilFederal University of Pará. Institute of Health Sciences. Postgraduate Program in Pharmaceutical Innovation. Belém, PA, Brazil / Federal University of Pará. Institute of Biological Sciences. Postgraduate Program in Biodiversity and Biotechnology of the BIONORTE Network. Belém, PA, BrazilThis study evaluated the morphological changes caused by fractions and subfractions, obtained from barks of Aspidosperna nitidum, against L. (L.) amazonensis promastigotes. The ethanolic extract (EE) obtained through the maceration of trunk barks was subjected to an acid–base partition, resulting the neutral (FN) and the alkaloid (FA) fractions, and fractionation under refux, yielded hexane (FrHEX), dichloromethane (FrDCL), ethyl acetate (FrACoET), and methanol (FrMEOH) fractions. The FA was fractionated and three subfractions (SF5-6, SF8, and SF9) were obtained and analyzed by HPLC–DAD and 1 H NMR. The antipromastigote activity of all samples was evaluated by MTT, after that, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for the active fractions were performed. Chromatographic analyzes suggest the presence of alkaloids in EE, FN, FA, and FrDCL. The fractionation of FA led to the isolation of the indole alkaloid dihydrocorynantheol (SF8 fractions). The SF5-6, dihydrocorynantheol and SF-9 samples were active against promastigotes, while FrDCL was moderately active. The SEM analysis revealed cell rounding and changes in the fagellum of the parasites. In the TEM analysis, the treated promastigotes showed changes in fagellar pocket and kinetoplast, and presence of lipid inclusions. These results suggest that alkaloids isolated from A. nitidum are promising as leishmanicidal
