Fig. 4

Cell viability determined by MTT assay. A Different concentrations (100 and 500 μg/ml) of Tox-S from C. difficile (RT 001, RT 126, RT 084) and culture-filtrate of C. difficile ATCC 700057 were added to HT-29 cells for 4 h at 37 °C; B Different concentrations of capsaicin (10, 20, 50 and 75 µM) and curcumin (5, 10, 20, 30 and 60 µM) were added to HT-29 cells for 24 h at 37 °C. Data were presented as mean ± SD from three independent experiments. A P value of < 0.05 was considered as significant (*P < 0.05) by unpaired student’s t test statistical analysis