We report the effect of
Stryphnodendron adstringens
on the trypanosomatid
Herpetomonas samuelpessoai
. The parasites were grown at 28°C in a chemically defined medium containing crude extract and fractions at concentrations from 100 to 5000 μg/ml obtained from
S. adstringens. Concentrations of 500, 1000, 2500, and 5000 μg/ml both crude extract and semi-purified fraction progressively inhibited the protozoans´ growth. At a concentration of 100 μg/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 μg/ml, also showed increased inhibitory activity on H. samuelpessoai. The IC
50 of the crude extract and the F3 fraction were 538 and 634 μg/ml, respectively. Ultrastructural and enzymatic alterations in the trypanosomatids were also evaluated. H. samuelpessoai cultivated in the presence of IC
50 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 μg/ml of crude extract at 28°C for 72 h, showed decreased activity of the enzyme succinate cytochrome c reductase, a typical mitochondrion marker, as compared to untreated cells
