646 Activated-Grape Seed Extract (AGSE) inhibits oxidative stress and demethylation of PP2A in human skin

Abstract

Environmental stimuli attack the skin daily resulting in oxidative stress and the generation of reactive oxygen species (ROS) and inflammation. One pathway that regulates oxidative stress in skin involves Protein phosphatase 2A (PP2A), a phosphatase that has been previously linked to Alzheimer’s Disease and aging. Oxidative stress bursts via hydrogen peroxide (H2O2) and Ultraviolet A (UVA) treatments have previously been shown to dramatically decrease PP2A methylation in human dermal fibroblasts (HDFs), moreover, in vivo studies demonstrate that oxidative stress induces PP2A inactivation. Thus, we hypothesize, agents that increase PP2A methylation and activity will promote skin health and combat aging. To discover novel inhibitors of PP2A demethylation activity, we screened a small library of ∼30 natural botanical extracts. We discovered Grape Seed Extract (GSE), which has previously been reported to have several benefits for skin to be one of the most potent PP2A demethylating extracts (IC50 = 0.96 μg/mL). Via several fractionation and extraction steps, we developed a novel grape seed extract called Activated-Grape Seed Extract (AGSE) which is enriched for PP2A-activating flavonoids resulting in a ∼5-fold increased potency (IC50 = 0.22 μg/mL) in preventing PP2A demethylation when compared to commercial GSE. We then investigated the antioxidant potential of AGSE and demonstrate it dose-dependently protects PP2A against oxidative stress-induced demethylation in HDFs by reducing ROS levels in cell-based and cell-free assays equal to or better than Vitamin C, E and Ferulic acid. Moreover, AGSE shows anti-inflammatory activity, dose-dependently inhibiting UVA induced IL-6 release in HDFs and TPA IL-8 release from NHEKs. These results demonstrate that AGSE is a novel, multi-functional extract that modulates methylation of PP2A with increased potency as compared to commercial GSE and supports the hypothesis of PP2A as a master regulator for oxidative stress signaling and aging in skin.