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Ameliorative Effects of Proanthocyanidin on Oxidative Stress and Inflammation in Streptozotocin-Induced Diabetic Rats

Lee, Y.A., Kim, Y.J., Cho, E.J., Yokozawa, T.
Journal of agricultural and food chemistry 2007 v.55 no.23 pp. 9395-9400
persimmons, peels, antioxidants, antioxidant activity, proanthocyanidins, anti-inflammatory activity, oxidative stress, inflammation, lipid peroxidation, kidneys, blood serum, reactive oxygen species, protective effect, streptozotocin, diabetes, rats
Recent evidence strongly suggests that oxidative stress due to redox imbalance is causally associated with inflammatory processes and various diseases including diabetes. We examined the effects of proanthocyanidin from persimmon peel, using both oligomers and polymers, against oxidative stress with elucidation of the underlying mechanisms in streptozotocin-induced diabetic rats. The elevation of lipid peroxidation in the kidney and serum under the diabetic condition was decreased by the administration of proanthocyanidin. The suppression of reactive oxygen species generation and elevation of the reduced glutathione/oxidized glutathione ratio were observed in the groups administered proanthocyanidin. These results support the protective role of proanthocyanidin from oxidative stress induced by diabetes. Moreover, proanthocyanidin, especially its oligomeric form, affected the inflammatory process with regulation of related protein expression, inducible nitric oxide synthase, cyclooxygenase-2, and upstream regulators, nuclear factor κB, and inhibitor-binding protein κB-α. Proanthocyanidin ameliorated the diabetic condition by decreases of serum glucose, glycosylated protein, serum urea nitrogen, urinary protein, and renal advanced glycation endproducts. In particular, oligomeric proanthocyanidin exerted a stronger protective activity than the polymeric form. This suggests that the polymerization of proanthocyanidin has an effect on its protective effect against diabetes. The present study supports the beneficial effect of proanthocyanidin against diabetes and oxidative stress-related inflammatory processes.