Cells were plated in 96-well plates
24 h before treatment and continuously exposed to different concentrations
of compounds. After 20 h,MTT(10 μL, 5mg/mL)was added to each
well, which were incubated for another 24 h. Then DMSO(100 μL) was
added to each well. Finally, the OD value of each well was recorded at
570 nm. The results were expressed as the percentage of inhibition
that produced a reduction in the absorbance by the treatment of the
compounds compared to the controls.