2.4. Cell viability assay
The H22 cells were seeded at a concentration of 1 × 105 cells/mL
in a volume of 0.1 mL in 96-well plates in the presence of CSP
(0–400 g/ml) for 24, 48 and 72 h, the growth inhibitory effect was
determined by measuring MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-
diphenyltetrazolium bromide) assay [30,31]. Briefly, each well was
added 20 L of 5 mg/mL of MTT and incubated for another 4 h. Then
the culture media were removed, 150 L of DMSO was added to
each well. Absorbance at 490 nm was detected by microplate ELISA
reader. The inhibition ratio of H22 cell proliferation was calculated
as follows: inhibitory ratio (%) = 1 − average absorbance of treated
group/average absorbance of control group × 100%.
2