Vegetable flavonoids and cardiovascular disease.
Vegetable flavonoids and cardiovascular disease.
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DOI：
10.6133/apjcn.2008.17.s1.70
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发表时间：
2008
影响因子：
1.3
通讯作者：
J. Terao;Y. Kawai;K. Murota
中科院分区：
文献类型：
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作者：
J. Terao;Y. Kawai;K. Murota
研究表明，膳食黄酮有助于预防动脉粥样硬化和心血管疾病。抗氧化活性应被视为其在血管系统中影响健康的潜在机制，因为动脉粥样硬化与氧化事件密切相关，如氧化LDL在巨噬细胞中的积累。蔬菜中含有多种黄酮类化合物，如黄酮醇、黄酮和花青素。本研究以洋葱中的主要黄酮类化合物槲皮素（3，3 '，4'，5，7-五羟基黄酮）为研究对象，从生物利用度和靶向转运两个方面考察其抗动脉粥样硬化作用。虽然槲皮素在洋葱中以葡萄糖苷形式存在，但在肠道吸收过程中，它被代谢成几种葡萄糖醛酸苷和/或硫酸酯结合物，有或没有甲基化。我们发现，这些代谢物在人体血流中循环主要定位在血浆白蛋白部分，但不是LDL部分。洋葱消费未能提高抗氧化活性的血浆馏分对LDL氧化，表明槲皮素代谢产物结合到白蛋白的水平是不足以发挥体内的抗氧化作用。相反，我们发现，槲皮素代谢产物积累在主动脉组织中，并发挥其抗氧化活性，当家兔喂饲槲皮素葡萄糖苷和高胆固醇饮食。此外，槲皮素代谢产物只在人动脉粥样硬化主动脉中检测到。这意味着，槲皮素代谢物被纳入动脉粥样硬化区域，并作为补充抗氧化剂，当氧化应激加载在血管系统。血浆白蛋白可能是槲皮素代谢产物转运至血管靶点的载体。
Studies have suggested that dietary flavonoids are helpful in the prevention of atherosclerosis and cardiovascular disease. Antioxidant activity should be noted as underlying mechanism of their health impact in the vascular system, as atherosclerosis is closely related to oxidative events such as oxidized LDL accumulation in the macrophages. Vegetables contain a variety of flavonoids, such as flavonols, flavones and anthocyanidins. We focused on quercetin (3,3',4',5,7- pentahydroxyflavone), a major flavonoid in onion, and its anti-atherosclerotic effect was examined from the aspect of the bioavailability and translocation to the target site. Although quercetin exists as its glucoside form in onion, it is metabolized into several glucuronides and/or sulfate conjugates with or without methylation during its intestinal absorption. We found that these metabolites circulating in the human blood stream were mostly localized in plasma albumin fraction, but not LDL fraction. Onion consumption failed to enhance the antioxidant activity of plasma fraction against LDL oxidation, indicating that the level of quercetin metabolites bound to albumin is insufficient to exert the antioxidative effect in vivo. In contrast, we discovered that quercetin metabolites accumulate in the aorta tissue and exerted their antioxidant activity, when rabbits were fed with quercetin glucoside and high cholesterol diet. Furthermore, quercetin metabolites were detected in human atherosclerotic aorta exclusively. These imply that quercetin metabolites are incorporated into the atherosclerotic region and act as complementary antioxidants, when oxidative stress is loaded in the vascular system. It is likely that plasma albumin is a carrier for translocation of quercetin metabolites to vascular target.