Figure 6. Effect of curcumin on H₂O₂-induced apoptosis. Retinal pigment epithelium (RPE) cells were pretreated with 15 µM curcumin and 10 µM CoPP for 3 h. About 10 µM ZnPP was added to cells preprocessed for 1 h after 2 h pretreatment with 15 µM curcumin. Cells were then treated with 1000 µM H₂O₂ for 3 h. Apoptotic cells were detected with Annexin V-FITC staining and analyzed with flow cytometry. A: (a) dimethyl sulfoxide (DMSO), (b) DMSO + H₂O₂, (c) curcumin (15 µM) + H₂O₂, (d) curcumin (15 µM) + H₂O₂ +ZnPP (10 µM), (e) CoPP (10 µM) + H₂O₂. B: Columns, percentage of Annexin V positive cells for indicated conditions. Each bar represents the mean±SD of three independent experiments (*p<0.05)