Sea buckthorn flavonoids protect RPE cells from UVB-induced oxidative damage

Natural flavonoids are believed to provide protection to retinal pigment epithelial (RPE) cells due to their well-established antioxidant properties. This study aims to evaluate the impact of sea buckthorn flavonoids on a UVB-induced oxidative damage model of RPE cells. The n-butanol extract fraction (Fr. NB) was identified as the most effective component from five different polar extracts using the ABTS method and an RPE cell oxidative stress model. Interestingly, HPLC analysis revealed that the main flavonoids in Fr. NB were rutin, Isorhamnetin-3-O-glucoside-7-O-rhamnoside (IR3G7R), and Isorhamnetin-3-O-glucoside (IR3G), all of which significantly increased cell viability. Both Fr. NB and the major flavonoids reduced oxidative damage by enhancing the activity of antioxidant enzymes and reducing levels of oxidative products and apoptosis. These findings suggest that sea buckthorn flavonoids may protect RPE cells from UVB-induced oxidative damage through an antioxidant mechanism, potentially offering health benefits for the human eye.