Protective Effects of Blueberry Anthocyanins against H2O2-Induced Oxidative Injuries in Human Retinal Pigment Epithelial Cells

Blueberry anthocyanins are considered protective of eye health because of their recognized antioxidant properties. In this study, blueberry anthocyanin extract (BAE), malvidin (Mv), malvidin-3-glucoside (Mv-3-glc), and malvidin-3-galactoside (Mv-3-gal) all reduced H2O2-induced oxidative stress by decreasing the levels of reactive oxygen species and malondialdehyde and increasing the levels of superoxide dismutase, catalase, and glutathione peroxidase in human retinal pigment epithelial cells. BAE and the anthocyanin standards enhanced cell viability from 63.69 +/- 3.36 to 86.57 +/- 6.92% (BAE), 115.72 +/- 23.41% (Mv), 98.15 +/- 9.39% (Mv-3-glc), and 127.97 +/- 20.09% (Mv-3-gal) and significantly inhibited cell apoptosis (P < 0.01 for all). Mitogen-activated-protein-kinase pathways, including ERK1/2 and p38, were involved in the bioactivities. In addition, the anthocyanins decreased vascular-endothelial-cell-growth-factor levels and activated Akt-signal pathways. These combined results supported the hypothesis that blueberry anthocyanins could inhibit the induction and progression of age-related macular degeneration (AMD) through antioxidant mechanisms.