Piceatannol inhibits cell proliferation. (A) U2OS cells were treated with various concentrations of piceatannol for 72 h and cell proliferation was assessed using CCK-8 assay kit. (B) Cells were incubated with 0, 40 and 60μM for 24 and 48 h and finally 1X104 cells were counted by flow cytometry. (C) Cell proliferation was measured by colony forming assay. The data is expressed as mean ± S.D. from three independent experiments. *p<0.05, **p<0.01, ***p< 0.001 significantly different compared with control.