Flow cytometric analysis of cell apoptosis

The Annexin V/propidium iodide (PI) assay was performed according to the manufacturer's instructions (Invitrogen, USA). Briefly, SGC-7901 cells were plated into 6-well plates (Corning, USA) and incubated for 48 h with baicalein (0, 15, 30, and 60 μmol/L). The cells were collected, washed with cold PBS, centrifuged and resuspended in 100 μl binding buffer containing 2.5 μl FITC-conjugated Annexin V and 1 μl 100 μg/ml PI. The cells were incubated for 15 min at room temperature in the dark. A total of 10 000 events were collected by flow cytometry (BD, San Diego, USA).