Protection of Diabetic mellitus by Food Components

近年来，氧化应激与糖尿病的关系备受关注。高糖水平导致蛋白质糖化，并在多元醇代谢、氧化还原、前列腺素代谢和葡萄糖自氧化过程中产生活性氧物种(ROS)，这些ROS导致膜的氧化破坏，多不饱和脂肪酸被认为伴随着脂质过氧化和次生产物的复杂混合物的形成。我们已经成功地分离出一种新型的高级糖基化终末产物(AGEs)，称为MRX，它是由葡萄糖、精氨酸和半胱氨酸反应产生的。我们还成功地开发了以过氧化脂质修饰蛋白、羧甲基异氨酸和8-羟基脱氧鸟苷(8-OH-DG)为表位的多克隆和单抗用于氧化应激的免疫化学评价方法。通过详细检查发现，在链脲佐菌素诱导的糖尿病大鼠尿液中检测到大量的过氧化脂质和8-OH-dG，并伴有谷胱甘肽相关酶的变化。OLETF的尿液中也检测到过氧化脂质和8-OH-DG，这是自然发生的2型糖尿病(DM)的模型L。我们还发现，柠檬总黄酮对链脲佐菌素诱导的糖尿病大鼠有很强的抗氧化保护作用。

Recently, much attention has been focused on the relationship between the oxidative stress and diabetes. High glucose level causes glycation of proteins and also generation of reactive oxygen species (ROS) during the polyol metabolism, redox, prostagrandins metabolisms and autoxidation of glucose, and these ROS induce oxidative break down of the membrane polyunsaturated fatty acids is known to be acompanied by the formation of a complex mixture of lipidhydroperoxides and secondary products. We have been succeeded in isolationg a novel type of advanced glycation end products (AGEs), named MRX,which has been found to be produced by the reaction of glucose, arginine and cysteine. We have also suceeded in developing immunochemical evaluation methods for oxidative stress by application of polyclonal and monoclonal antibodies using lipidperoxide-modified proteins, carboxymethylisine and 8-hydroxy-deoxyguanosine (8-OH-dG) as an epitope. By detailed examination, it was found that a large quant ity of lipidhydroperoxides and 8-OH-dG was detected in urine excreted streptozotocin-induced diabetic rats, together with the changes of glutathione-related enzymes. lipidhydroperoxides and 8-OH-dG was also detected in urine excreted by OLETF,the mod l of naturally occuring diabetes mellitus (DM) type II of human. We have also found that lemon flavonoids have strong antioxidative protection in diabetic rat model induced by STZ.