Chagas’ disease, caused by the intracellular protozoan Trypanosoma cruzi, is one of the most serious health
problems throughout South America. Despite the progress that has been made in the study of its biochemistry and
physiology, more efficient chemotherapies to control this parasitic infection are still lacking. In this paper we report the
trypanocidal and cytotoxic activities of a series of sesquiterpene lactones, isolated from Asteraceae medicinal plants. The
significant trypanocidal activity and high selectivity indexes found for many of the compounds evaluated, prompted us to
undertake a quantitative structure-activity relationship study. A model using 3D molecular descriptors allowed us to set up
a high correlation of the observed activity and the atomic spatial arrangement of these sesquiterpene lactones closely
related to steric parameters.