Preventive effect of grape seed extract against high-fructose diet-induced insulin resistance and oxidative stress in rats

The purpose of the present study was to investigate the preventive effect of grape seed extract (GSE) on insulin resistance and oxidative stress in rats fed a high-fructose diet. After 8 weeks of the experiment, the fasting plasma glucose, insulin concentrations, and the homeostasis model assessment of basal insulin resistance (HOMA-IR) of rats fed a high-fructose diet supplemented with 1% GSE were significantly lower than that of a high-fructose diet group. In the oral glucose tolerance test, rats fed a high-fructose diet supplemented with 1% GSE had a significantly reduced plasma glucose and insulin concentrations after 15 min of glucose loading, indicating that GSE improved glucose intolerance. In addition, fed rats fed a high-fructose diet supplemented with 1% GSE markedly increased activity of hepatic superoxide dismutase, catalase, and suppressed lipid peroxidation when compared to rats fed a high-fructose diet. However, rats fed a high-fructose diet supplemented with GSE were not found to have a significant change in the activity of hepatic glutathione peroxidase. In conclusion, intake of GSE may be a feasible therapeutic strategy for prevention of a high-fructose diet-induced insulin resistance and oxidative stress. (C) 2010 Elsevier Ltd. All rights reserved.