Rat skeletal myoblasts (L-6 cells) were seeded in 96-well microtiter plates at 2000 cells/well in 100 μL RPMI 1640 medium with 10% FBS and 2 mM l-glutamine. After 24 h the medium was removed and replaced by 100 μl per well containing 5000 trypomastigote forms of T. cruzi Tulahuen strain C2C4 containing the β-galactosidase (Lac Z) gene . After 48 h the medium was removed from the wells and replaced by 100 μl fresh medium. Extracts were dissolved in 5% DMSO at 0.2 mg/mL. 5 μL of the sample solution were added to the wells so that the test concentration was 10 μg/mL.