2.6. MTT assay
Cell viability is determined by the MTTassay. Cells
were seeded at a density of 104 in 0.2 ml of medium
into each well of 96-well plates. After 18 h of incubation,
the cells were washed with PBS and cultured
for 24 h with 200 ml of FBS-free DMEM, together with
the indicated concentrations of A. radix extract.
Then, the medium was removed and 100 ml of MTT
[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium
bromide] (1 mg/ml) (Sigma—Aldrich, St.
Louis, MO) in PBS was added. At the end of 4 h
incubation, the plates were centrifuged, and the
untransformed MTT was removed. After 100 ml of
absolute ethanol was added to each well, the plates
were shaken for 5 min. The optical density at
570 nm was determined using an ELISA reader.
The cell viability rates were calculated from the
OD readings and are represented as percentages of
the control value (untreated cells).