Annexin V-FITC/PI apoptosis assay

The in vitro effect of genistein on A549 cell viability was determined by performing an Annexin V-FITC/PI assay. Briefly, A549 cells were plated onto a 6-well plate at a density of 1×10⁶ cells/well. Subsequently, A549 cells were exposed to different concentrations of genistein (0, 25, 50 and 100 µM) for 2 days. A total of 5 µl Annexin V-FITC (5 µg/ml) and 5 µl PI (1 µg/ml) was added and incubated for 10 min at room temperature in the dark. Then, cell apoptosis was examined using a flow cytometer (FC 500; Beckman Coulter, Inc., Brea, CA, USA).