MTT cell viability assay

The viability of the HepG2 cells was assessed by means of the [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] (MTT) colorimetric assay. The cells were plated on 96-well microtiter cell culture plates at 2 × 10⁴ cells/well for 24 h. After the indicated treatment, the cells were incubated at 37.0 °C for 3 h in a culture medium containing 10 mol L⁻¹ MTT in phosphate-buffered saline (PBS). The blue MTT formazan precipitate was then dissolved in 50 L of DMSO, and the absorbance was measured at 570 nm with a multi-well plate reader [57]. The cell viability was expressed as the percentage of the absorption values in the treated cells relative to the non-treated (control) cells. The data are presented as the means ± the standard error of three independent experiments.