Abstract: The protective effect of D-chiro-inositol-enriched tartary buckwheat bran extract (TBBE) on endothelial dysfunction was investigated in the current study. Endothelial cells and the aorta of rats were treated with palmitic acid (PA) alone or in combination with TBBE, and mice were fed a high fat diet (HFD) and then were either orally administered or not with TBBE. Results showed that TBBE at 0?50 μg/mL had no harmful effect on cells. TBBE at different concentrations inhibited reactive oxygen species (ROS) production and NADPH oxidase 4 (NOX4) activity in PA-stimulated cells. TBBE also reduced NOX4 over-expression and improved endothelium-dependent relaxation in the aorta of PA-treated rats. In HFD mice, oral administration of TBBE reduced blood free fatty acid, but had no effect on blood glucose, epididymal fat coefficient, liver coefficient or body mass. TBBE also prevented NOX4 activity in the aorta endothelium, confirming the beneficial effect of TBBE on endothelial function in vivo under lipid-challenged conditions. Lipid disorder significantly induced oxidative stress in endothelial cells. However, TBBE ameliorated endothelial dysfunction through NOX4/ROS signal pathway.

Key words: D-chiro-inositol-enriched tartary buckwheat bran extract, palmitic acid, high fat, NADPH oxidase 4, endothelial dysfunction