Abstract
Purpose:
It has been demonstrated that polyphenolic compounds display antioxidant properties and are attributed to protect against age-related macular degeneration (AMD). Grape seed extract (GSE) and pine bark extracts (PBE) provide a concentrated source of polyphenols that have antioxidant capacity. The objective of this study was to investigate the differential cytoprotective effect of two polyphenolic compounds against oxidative stress-induced cell damage in cultured human retinal pigment epithelial (RPE) cells.
Methods:
Cultured ARPE-19 cells were incubated with GSE from Vitis vinifera or PBE from Pinus radiata (0.05, 0.1, 0.5, 1, 5 and 10 ㎍/㎖, respectively for 24 hours and were treat with hydrogen peroxide (H2O2, 0.4 mM) for 24 hour 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 by H2DCFDA fluorescence.
Results:
The percentage of viable RPE cells was significantly lower in cultures treated with H2O2 0.4 mM than in control cultures. Both GSE and PBE significantly reduced H2O2-induced cell death in a dose dependent manner. GSE and PBE at 0.5, 1, 5 and 10 ㎍/㎖ significantly reduced cell mortality due to the treatment with H2O2. Cytoprotective effect between GSE and PBE was not significantly different in same concentration. Intracellular ROS production increased significantly in cultures treated with H2O2 0.4 mM compared to control cultures. There was a significant dose dependent decrease in intracellular ROS levels after treatment of RPE with GSE or PBE.
Conclusions:
GSE and PBE, natural polyphenolic compounds, are equally able to protect RPE cells from H2O2-induced oxidative stress and to reduce intracellular ROS production by scavenging free radicals. This suggests potential effect of polyphenolic compounds against retinal diseases associated with oxidative stress including AMD.