Analysis of the toxic effect of harmane, norharmane and harmine on T. gondii growth. Human foreskin fibroblast (HFF) monolayers were infected with fresh tachyzoites (2.5×104) for 1 h and incubated with different doses of βCs and followed by microscope observation until monolayer lysis (cell lysis in combination with extracellular tachyzoites). Data are presented as the day post-infection (p.i.) on which complete monolayer lysis was observed by microscope visualization. The panel is representative of three independent experiments performed in duplicate. All the experiments presented similar results. Sulfadiazine (5 mM) was used as a control of T. gondii growth inhibitory drugs and showed no monolayer lysis at day 10 p.i.