Effect of curcuminoids on cell proliferation. A) Cell survival (%) after incubating HeLa cells in media without curcumin (○) or with media prepared with solid curcumin at concentrations of 10 (□), 20 (▽), 30 (△), 40 (◇), or 50 μM (+). The initial seeding density of the HeLa cells was about 20% confluence for all cells, which was assigned the relative value of 100%. Cells were counted daily for three days and the data points represent average cell numbers from four different viewing fields with standard deviations (error bars). B) Same as in panel A, except that cells were incubated in media prepared either without curcumin (●) or with medium prepared with DMSO-dissolved curcumin at concentrations of 10 (■), 20 (▼), 30 (▲), 40 (◆), or 50 μM (●).