Protection of Chinese olive fruit extract and its fractions against advanced glycation endproduct-induced oxidative stress and pro-inflammatory factors in cultured vascular endothelial and human monocytic cells

Abstract

Accumulation of advanced glycation endproducts (AGEs) plays a pivotal role in the pathophysiology of diabetic complications. In this study, we evaluated the protective activities of water/ethanol (1:1, v/v) extract (WEE) and its fractions from Chinese olive (Canarium album L.) fruit on AGEs-induced endothelial dysfunction. The WEE and its fractions could scavenge free radicals, inhibit AGEs formation and reduce the overgeneration of AGEs-induced ROS in endothelial cells. They also increased AGEs-mediated loss of glutathione level and SOD activity. AGEs stimulated monocyte adhesion, ICAM-1 expression and IκBα phosphorylation, which were inhibited by WEE and its fractions. Furthermore, they reduced AGEs-induced inflammatory cytokines including TNFα, interleukin-1β and interleukin-6 level in monocytes. Nine compounds such as gallic acid, methyl gallate, ethyl gallate, scopoletin, ferulic acid, ellagic acid, and rutin were identified. These findings indicated that Chinese olive fruit attenuated AGEs-mediated endothelial dysfunction by ameliorating inflammation and oxidant stress responses via inhibiting NF-κB pathway.