绿茶多酚和桑色素对低密度脂蛋白氧化修饰的抑制作用(英文)

Inhibitory effect of green tea polyphenol and morin on the oxidative modification of low density lipoprotein

许多研究报告表明,低密度脂蛋白(LDL)可经多种途径被氧化修饰成ο-LDL,巨噬细胞对ο-LDL的降解速率较LDL快3～10倍,动脉粥样硬化损伤部位的泡沫细胞是由巨噬细胞聚集了大量的胆固醇而形成的,LDL的氧化修饰以及由此导致的巨噬细胞吞噬的增加,对泡沫细胞的形成起到重要作用,本项研究采用紫外线照射和Cu^(2+)-PBS系统分别对LDL进行氧化修饰并且观察了绿茶多酚(10μg·ml^(-1))和黄酮类化合物桑色素(8.5μg·ml^(-1))对这一化学过程的抑制作用,其结果表明,两者均对LDL的氧化修饰具有显著抑制作用,主要实验证据为,它们可使琼脂糖电泳迁移率,硫代巴比妥酸反应物和激发光为360 nm,发射光为420 nm时的荧光强度等的增加量抑制50％左右并使小鼠腹腔巨噬细胞降解o-LDL的速率抑制70％,绿茶多酚和桑色素分别存在于绿茶和蔬菜中,因此它们防止LDL的氧化修饰对于动脉粥样硬化的预防和治疗具有一定的临床意义。

Many studies have shown that low density lipoprotein (LDL) can be oxidatively modified in various ways and the rate of degradation of these oxidized LDL by macrophages can be 3 to 10 times faster than that of native LDL. This process may be important in the formation of cholesterol-laden foam cells derived from macrophages in atherosclerotic lesions. In this study, China green tea polyphenol (CGTP, 10 μg·ml-1) and morin (8.5 μg ·ml-1), one kind of flavonoids, were used as the inhibitors of LDL oxidative modification caused by ultraviolet ray (uv) irradiation and CuSO4. The agarose gel electrophoresis mobility, the level of thiobarbituric acid reactive substance and the fluorescence emission spectra at 360nm excitation as well as the degradation rate by mouse peritoneal macrophages were observed. The results show that both CGTP and morin are the potent inhibitors of the oxidative modification of LDL. These findings afford the possibility that both CGTP and morin may protect LDL from oxidation, prevent and alleviate the atherosclerotic development and may therefore be the effective natural anti-atherosclerotic components.