Protective effect of red grape seeds proanthocyanidins against induction of diabetes by alloxan in rats

It has been documented that impaired homeostasis in diabetes mellitus is associated with increased production of reactive oxygen species and depletion of the antioxidant defense systems. Natural grape seed proanthocyanidins (GSP) are potent free radical scavengers and hence provide significant protection against oxidative stress. Accordingly, the present study focused on investigating the possible protective role of GSP against free radical-mediated damage in pancreatic tissues of alloxan-induced diabetes in rats. The results revealed that oral administration of 50 and 100 mg kg(-1) (body weight) of GSP for 72 h significantly increased pancreatic glutathione (GSH) levels and inhibited the increase in lipid peroxidation caused by alloxan (p < 0.001). On the other hand, a significant reduction in pancreatic total nitrate/nitrite content (p < 0.001) was observed. Furthermore, GSP caused significant decline in the hyperglycemia induced by alloxan (p < 0.001). Such antihyperglycemic effect of GSP was accompanied by a significant increase in serum insulin levels in diabetic rats following 72 h of administration (p < 0.001). In conclusion, the study suggests that GSP are effective in ameliorating the damage to pancreatic tissue in experimental diabetes mellitus. Such effect may be related to their potent antioxidant properties as evidenced by the increase in pancreatic GSH and reduction of lipid peroxidation as well as total nitrate/nitrite levels. (c) 2005 Elsevier Ltd. All rights reserved.