Distribution and action of polyphenols isolated from vaccinium spp.

氧化应激是由促氧化剂的产生和细胞防御机制（包括谷胱甘肽（GSH）代谢）破坏之间的不平衡造成的。氧化应激导致脂质、蛋白质和DNA受损，是许多疾病的最终共同途径。众所周知，摄入水果和蔬菜可以预防许多慢性疾病。这种保护的可能机制是减少氧化应激，因为水果和蔬菜含有大量抗氧化多酚，可以直接中和活性氧。我们最近的研究表明，给经历氧化应激的动物喂食富含多酚的野生蓝莓提取物会增加肝脏和大脑中GSH:GSSH的比例。谷胱甘肽是最重要的抗氧化剂，在大多数细胞中含量相对较高。因此，植物多酚似乎通过增强这些内部抗氧化防御而对动物发挥有益作用。这是如何发生的尚不清楚。此外，我们知道，多酚一旦被摄入体内，会在我们体内产生各种代谢物。我们怀疑是这些代谢物而不是原始的多酚类物质预防了慢性疾病。总之，提出的研究应该增加我们对水果和蔬菜中多酚在预防慢性疾病中的作用的理解。

Oxidative stress results from an imbalance between the creation of pro-oxidants and their destruction by cellular defense mechanisms, including glutathione (GSH) metabolism.  Oxidative stress leads to damage to lipids, proteins and DNA, and is a final common pathway in many forms of disease.  Fruit and vegetable intake is known to be protective against many chronic diseases.  A possible mechanism for this protection is a reduction in oxidative stress since fruits and vegetables contain a large proportion of antioxidant polyphenols that directly neutralize reactive oxygen species.  We have recently shown that feeding polyphenol-rich extracts of wild blueberries to animals experiencing oxidative stress produces an increase in the GSH:GSSH ratio in liver and brain. Glutathione is the most important antioxidant, found in relatively high concentrations in most cells.  Thus, plant polyphenols appear to exert their beneficial effects on animals, by enhancing these internal antioxidant defenses.  How this occurs is not known.  Further, we know that polyphenols produce various metabolites in our bodies once ingested.  We suspect that it is these metabolites and not the original polyphenols that protect against chronic disease.  Together, the studies proposed should increase our understanding of the role of polyphenols from fruit and vegetables in the prevention of chronic disease.