Figure 5. Effect of curcumin on reactive oxygen species (ROS) generation in retinal pigment epithelium (RPE) cells. Cells were separately pretreated with curcumin (15 μM) and CoPP as a heme oxygenase-1 (HO-1) activator for 3 h and then treated with 1000 μM H₂O₂ for 3 h. ROS levels treated with curcumin and those treated with CoPP decreased at a similar rate. To quantify cells with increased intracellular ROS levels, the percentages of fluorescent cells among the total cells were calculated and the means± SD were expressed from three separate experiments. *p<0.05, **p<0.01.