Kawakami Yuki, Tsurugasaki Wakako, Yoshida Yu, Igarashi Yasuo, Nakamura Shingo, Osada Kyoichi
Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan.
J Agric Food Chem. 2004 Mar 24;52(6):1764-8. doi: 10.1021/jf0345898.
Male Sprague-Dawley rats, 4 weeks of age, were fed purified diets either with or without 0.2% soy isoflavones rich powder for 5 weeks to elucidate their direct functions such as antioxidative action and regulation of lipid metabolism. Dietary soy isoflavones decreased serum lipid peroxide level in rats. Levels of liver and serum alpha-tocopherol were higher in the rats fed isoflavone than in those fed isoflavones-free diet. Thus, dietary soy isoflavones exhibited mild antioxidative function in this animal experiment. Isoflavone metabolites from diet may act as scavengers of reactive oxygen species. Dietary soy isoflavones lowered hepatic 3-hydroxy-3-methylglutaryl CoA reductase activity, although liver cholesterol level was not modulated. However, the levels of serum cholesterol and triglyceride decreased by consumption of soy isoflavones. Therefore, dietary soy isoflavones may exhibit hypocholesterolemic and hypolipidemic functions. Moreover, dietary soy isoflavones lowered hepatic Delta6 desaturase activity. Reflecting this observation, Delta6 desaturation indices ((18:2(n = 6) + 18:3(n = 6))/20:4(n = 6)) of tissue lipids tended to be lower in rats fed isoflavones than in those fed isoflavones-free diet. This action may contribute to the prevention of inflammatory response by imbalance of eicosanoids. These observations suggest that the positive intake of soy isoflavones may reduce the risk of some cardiovasucular diseases through their radical scavenging function and hypocholesterolemic action.
4周龄的雄性斯普拉格-道利大鼠被喂食含或不含0.2%富含大豆异黄酮粉末的纯化饮食5周，以阐明其抗氧化作用和脂质代谢调节等直接功能。饮食中的大豆异黄酮降低了大鼠血清脂质过氧化物水平。喂食异黄酮的大鼠肝脏和血清α-生育酚水平高于喂食无大豆异黄酮饮食的大鼠。因此，在该动物实验中，饮食中的大豆异黄酮表现出轻度抗氧化功能。饮食中的异黄酮代谢产物可能作为活性氧清除剂。饮食中的大豆异黄酮降低了肝脏3-羟基-3-甲基戊二酰辅酶A还原酶活性，尽管肝脏胆固醇水平未受调节。然而，食用大豆异黄酮后血清胆固醇和甘油三酯水平降低。因此，饮食中的大豆异黄酮可能具有降胆固醇和降血脂功能。此外，饮食中的大豆异黄酮降低了肝脏Δ6去饱和酶活性。反映这一观察结果的是，喂食异黄酮的大鼠组织脂质的Δ6去饱和指数（（18:2（n = 6）+ 18:3（n = 6））/20:4（n = 6））往往低于喂食无大豆异黄酮饮食的大鼠。这种作用可能有助于预防因类二十烷酸失衡引起的炎症反应。这些观察结果表明，积极摄入大豆异黄酮可能通过其自由基清除功能和降胆固醇作用降低某些心血管疾病的风险。
