Trypanocidal activity of South American Vernonieae (Asteraceae) extracts and its sesquiterpene lactones.

Chagas disease is caused by and affects the poorest population in the Americas. Fourteen plant extracts and seventeen sesquiterpene lactones from the tribe Vernonieae (Asteraceae), were evaluated for the first time against . Cytotoxicity employing HeLa cells was also assessed. The best results were obtained with leaves and flowers rinse extracts from (E-1 and E-3) and (E-11 and E-13), with IC values <2 µg/mL, being E-1 the most active (IC = 0.8 µg/mL). Additionally, these extracts displayed a good selectivity (SI > 10). The most active sesquiterpene lactones, isolated from the extracts, were 2 (2methoxy-2,5-epoxy-8-methacryloxygermacra-3Z,11(13)-dien-6,12-olide) and 6 (2ethoxy-2,5-epoxy-8-angeloxygermacra-3Z,11(13)-dien-6,12-olide) from and 12 (8α-methacryloxyhirsutinolide 13-O-acetate) from , with IC of 1.5, 2.1 and 2.0 µM, respectively. These compounds showed SI values >14, better than those of the reference drug nifurtimox. Plants living in South American ecosystems could become a potential source of trypanocidal agents.