Isorhamnetin prevents H2O2‑induced oxidative stress in human retinal pigment epithelial cells.

Isorhamnetin, a 3‑O‑methylated metabolite of quercetin, exhibits antioxidant effects. However, to the best of our knowledge, no study to date has focused on the effects of isorhamnetin on retinal pigment epithelium (RPE) cells, and its underlying molecular mechanisms. Therefore, the present study aimed to examine the potential protective effect of isorhamnetin against oxidative stress in human RPE cells. The results demonstrated that pretreatment of RPE cells with isorhamnetin significantly protected cell viability against oxidative stress. In addition, isorhamnetin pretreatment inhibited hydrogen peroxide (H2O2)‑induced reactive oxygen species (ROS) production and caspase‑3 activation in RPE cells. Furthermore, isorhamnetin pretreatment significantly increased the phosphorylation of phosphoinositide 3‑kinase (PI3K) and AKT serine/threonine kinase 1 (Akt) in RPE cells exposed to H2O2, compared with cells treated with H2O2 alone. Taken together, the present results demonstrated that isorhamnetin protected human RPE cells from oxidative stress‑induced cell death, and this effect was associated with activation of the PI3K/Akt signaling pathway. Thus, isorhamnetin may be considered as a potential antioxidant useful for the prevention of age‑related macular degeneration.