Brine shrimp lethality assay as a prescreening system for anti-Trypanosoma cruzi activity.

With the aim of finding an acceptable method for selecting plant extracts to be assayed against the infective blood form of Trypanosoma cruzi, the causative agent of Chagas' disease (American trypanosomiasis), two different strategies were compared: a) screening only medicinal species and b) pre-screening random collected species in the brine shrimp lethality assay (BSLA). Fifty-two plants belonging to the Asteraceae family, including eighteen medicinal species, were collected and their ethanol extracts assayed against both T. cruzi and Artemia salina (brine shrimp). The proportion of trypanocidal extracts among the medicinal species and among the random collection did not differ significantly. On the other hand, the proportion of trypanocidal extracts among those that presented LC(50) of less than 100 ppm to A. salina was four times higher than among the medicinal species.