Orozco Timothy J, Wang Janice F, Keen Carl L
Department of Nutrition, University of California, Davis, CA 95616, USA.
J Nutr Biochem. 2003 Feb;14(2):104-10. doi: 10.1016/s0955-2863(02)00273-5.
Cocoa can contain a high concentration of flavanols and procyanidins which have been reported to have strong antioxidative activity. In the present study, male Sprague-Dawley rats were fed diets containing 0, 0.5, 1, or 2% cocoa rich in flavanols for two weeks. Blood, liver, heart and testes were collected and analyzed for markers of oxidative damage. Plasma epicatechin concentrations, 8-hydroxy-2'-deoxyguanosine (8OH2'dG), and oxidized and reduced glutathione were quantitated by HPLC with electrochemical detection. Plasma F(2)-isoprostanes were measured using an enzyme immunoassay. Plasma epicatechin concentrations increased in a dose-dependant fashion according to the amount of cocoa in the diet (128 nM-790 nM). Cocoa supplementation was associated with lower than normal concentrations of 8OH2'dG in the testes (0.590 + 0.40 vs. 0.328 + 0.29; p < 0.05). Liver and heart 8OH2'dG levels were unaffected by dietary treatment. In erythrocytes, the glutathione pool was significantly less oxidized in the cocoa fed group compared to controls (p < 0.05). In liver and testes, no differences in superoxide dismutase activities were detected. Concentrations of plasma F(2)-isoprostanes and thiobarbituric acid reactive substances were similar in all groups. These results support the concept that a diet rich in flavanols and procyanidins can improve oxidant defense and reduce tissue markers for oxidative stress, although these effects can be tissue specific.
可可中含有高浓度的黄烷醇和原花青素，据报道它们具有很强的抗氧化活性。在本研究中，雄性斯普拉格 - 道利大鼠被喂食含有0%、0.5%、1%或2%富含黄烷醇可可的饮食，持续两周。采集血液、肝脏、心脏和睾丸，并分析氧化损伤标志物。通过高效液相色谱 - 电化学检测法定量血浆表儿茶素浓度、8 - 羟基 - 2'-脱氧鸟苷（8OH2'dG）以及氧化型和还原型谷胱甘肽。使用酶免疫测定法测量血浆F(2)-异前列腺素。血浆表儿茶素浓度根据饮食中可可的含量呈剂量依赖性增加（128 nM - 790 nM）。补充可可与睾丸中8OH2'dG浓度低于正常水平有关（0.590 + 0.40 vs. 0.328 + 0.29；p < 0.05）。肝脏和心脏的8OH2'dG水平不受饮食处理的影响。在红细胞中，与对照组相比，喂食可可的组中谷胱甘肽池的氧化程度明显较低（p < 0.05）。在肝脏和睾丸中，未检测到超氧化物歧化酶活性的差异。所有组中血浆F(2)-异前列腺素和硫代巴比妥酸反应性物质的浓度相似。这些结果支持了这样一种观点，即富含黄烷醇和原花青素的饮食可以改善抗氧化防御并降低氧化应激的组织标志物，尽管这些作用可能具有组织特异性。
