Protection of Diabetic mellitus by Food Components

近年来，氧化应激与糖尿病之间的关系备受关注。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，高葡萄糖水平引起蛋白质的糖基化和活性氧（ROS）的产生，这些ROS诱导膜多不饱和脂肪酸的氧化分解，伴随着脂质氢过氧化物和二次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晚期糖基化终产物（AGEs），命名为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氧化应激的免疫化学评价方法，利用脂质过氧化物修饰蛋白、羧甲基氨酸和8-羟基脱氧鸟苷（8-OH-dG）作为表位，应用多克隆和单克隆抗体。通过详细检查发现，链脲霉素诱导的糖尿病大鼠尿液中检测到大量的脂质氢过氧化物和8-OH-dG，并伴有谷胱甘肽相关酶的变化。在自然发生的人II型糖尿病（DM）模型OLETF排出的尿液中也检测到脂质氢过氧化物和8-OH-dG。我们还发现柠檬黄酮对STZ诱导的糖尿病大鼠模型具有较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.