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Biological effects of extracts obtained from Stryphnodendron adstringens on Herpetomonas samuelpessoai
We report the effect of Stryphnodendron adstringens on the trypanosomatid Herpetomonas samuelpessoai. The parasites were grown at 28ÂșC in a chemically defined medium containing crude extract and fractions at concentrations from 100 to 5000 ”g/ml obtained from S. adstringens. Concentrations of 500, 1000, 2500, and 5000 ”g/ml both crude extract and semi-purified fraction progressively inhibited the protozoans' growth. At a concentration of 100 ”g/ml, crude extract or a semi-purified (F3) fraction did not affect the growth of the protozoans. The F3-9 - F3-12 sub-fractions, at a concentration of 1000 ”g/ml, also showed increased inhibitory activity on H. samuelpessoai. The IC50 of the crude extract and the F3 fraction were 538 and 634 ”g/ml, respectively. Ultrastructural and enzymatic alterations in the trypanosomatids were also evaluated. H. samuelpessoai cultivated in the presence of IC50 crude extract showed considerable ultrastructural alterations, such as marked mitochondrial swelling with a large number of cristae and evident Golgi complex vesiculation, as observed by transmission electron microscopy. Cells exposed to 538 ”g/ml of crude extract at 28ÂșC for 72 h, showed decreased activity of the enzyme succinate cytochrome c reductase, a typical mitochondrion marker, as compared to untreated cell