Cellular viability assay

Human CRC HCT116 cells (1×10³ cell/well) were seeded into 96-well plates and cultivated with negative control (PBS), 1, 10 or 100 µM berberine for 48 h at 37°C. MTT was added to a final concentration of 0.5 mg/ml 48 h subsequent to berberine treatment and HCT116 cells were incubated for an additional 4 h at 37°C. DMSO was then added into each well and incubated for a further 20 min. The optical density was measured at 570 nm with a microplate spectrophotometer.