Grape seed procyanidin extract modulates proliferation and apoptosis of pancreatic beta-cells

► GSPE does not modulate apoptosis and proliferation under basal conditions. ► It enhances the pro-apoptotic effect of high glucose. ► GSPE shows antiproliferative effects under altered conditions. ► Its antiproliferative effects are likely due to the high molecular weight species. ► GSPE modulates pro- and anti-apoptotic markers in cafeteria diet-treated rats.