Effects of Bilberry (Vaccinium myrtillus) Anthocyanins on Apoptosis and Oxidative Stress‐Induced Responses in Cultured Retinal Pigment Epithelial Cells

Abstract

Inflammation and oxidative stress play a significant role in age-related macular degeneration pathogenesis. Anthocyanins from bilberry are purported to be cytoprotective. Using human retinal pigment epithelial (RPE) cell in vitro we found that bilberry anthocyanins are taken up by RPE cells. Bilberry extract is capable of inhibiting intracellular increases in radical generation by H2O2 treatment but did not altering H2O2 induced BCL2 and BAX expression, mitochondrial function, or cell death. Other in vitro studies have shown differences between individual anthocyanidins (aglycones) and their corresponding anthocyanins (glycosides) with regard to bioactivities, e.g., modulation of tyrosine kinases. To test the concept that anthocyanins, like other polyphenolic compounds may induce antioxidant/electrophile response element (ARE/EpRE) regulated genes, heme oxygenase-1 (HO-1) and glutathione S-transferase (GSTpi) proteins were analyzed by Western blot analysis. HO-1 and GSTpi mRNA expression levels were determined by real-time reverse transcriptase–PCR. HO-1 and GSTp1 were up regulated by bilberry anthocyanins. HO-1 may contribute to protection of the RPE cell by its anti-inflammatory properties. The phase II detoxifying enzyme GST may contribute to increased oxidative stress defenses by enhancing glutathione levels.