Trypanocidal and leishmanicidal activities of flavonoids from argentine medicinal plants

In vitro trypanocidal and leishmanicidal activities of the flavonoids hispidulin, from Ambrosia tenuifolia, and santin, from Eupatorium buniifolium, are reported. A sensitive technique that takes advantage of (H-3)thymidine uptake by dividing trypanosomatids has been adjusted for quantification of the parasiticidal effect of the natural products. The IC50 values for hispidulin and santin on Trypanosoma cruzi epimastigotes were 46.7 and 47.4 mu M, respectively. On trypomastigotes, the IC50 values were 62.3 mu M for hispidulin and 42.1 mu M for santin. Hispidulin was more active than santin on promastigotes of Leishmania mexicana (IC50 = 6.0 mu M versus 32.5 mu M). No cytotoxic activity was observed on lymphoid cells, making hispidulin and santin potential lead compounds for the development of new natural drugs. This is the first report on the trypanocidal and leishmanicidal activities of these flavonoids and on the presence of santin in E. buniifolium.