Grape seed-derived polyphenols (GSPs) provide a concentrated source of polyphenols having antioxidant capacity. In this study we investigated the cytoprotective effect of GSP against oxidative stress-induced cell damage in cultured human retinal pigment epithelial (RPE) cells.

Cultured adult retinal pigment epithelium (ARPE)-19 cells were incubated with GSP from Vitis vinifera (0.1, 0.5, 1, 5 or 10 µg/mL) for 24 hours and treated with hydrogen peroxide (H₂O₂, 0.4 mM) for 24 hours to induce oxidative stress. Cell viability was measured using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Intracellular reactive oxygen species (ROS) was quantified using 2',7'-dichlorofluorescein diacetate (DCF-DA) fluorescence.

The percentage of viable RPE cells was significantly lower in cultures treated with H₂O₂ 0.4 mM than in control cultures. GSP significantly reduced H₂O₂-induced cell death in a dose dependent manner. GSP at 0.1, 0.5, 1, 5 and 10 µg/mL significantly reduced cell mortality due to the treatment with H₂O₂. Intracellular ROS production increased significantly in cultures treated with H₂O₂ 0.4 mM compared with control. There was a significant dose-dependent decrease in intracellular ROS levels after treatment of RPE with GSP.

GSP, a natural polyphenolic compound, can protect RPE cells from H₂O₂-induced oxidative stress and reduce intracellular ROS production by scavenging free radicals. This suggests potential effects of polyphenolic compounds against retinal diseases associated with oxidative stress.