Seasonal differences in foliar content of chlorogenic acid, a phenylpropanoid antioxidant, in Mahonia repens
Seasonal differences in foliar content of chlorogenic acid, a phenylpropanoid antioxidant, in Mahonia repens
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DOI：
10.1046/j.1365-3040.1998.00282.x
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发表时间：
1998-05-01
影响因子：
7.3
通讯作者：
Adams, WW
中科院分区：
文献类型：
--
作者：
Grace, SC;Logan, BA;Adams, WW
评估绿原酸可能的生理功能（CGA，3-O-咖啡酰奎尼酸）在体内，我们表征了纯苯丙素类化合物和叶提取物对两种自由基，超氧阴离子和2，2 '-连氮双（3-乙基苯并噻唑啉-6-磺酸）（ABTS）自由基阳离子，发现CGA是这些自由基的高效清除剂，超过了所有其他测试的苯丙素类以及“经典的”抗氧化剂抗坏血酸的活性。以生长在不同光照环境下的阔叶万年青十大功劳（Mahonia repens）为研究对象，研究了其叶片中CGA含量的季节差异。在冬季，完全暴露在阳光下的植物叶片含有的CGA（74 +/- 10 mmol m（-2））明显高于生长在深阴影条件下的植物叶片（17 +/- 2 mmol m（-2））。阳光驯化，但没有阴影驯化，叶也产生了高水平的花青素在冬季，这表明同时增加了碳流通过苯丙烷和类黄酮途径，以应对强光和季节性低温胁迫。在夏季，高光驯化的叶片含有约2倍的CGA比在冬季，而CGA水平是相似的季节之间的遮荫叶片。与CGA体外测定的强清除能力一致，在两种清除试验中，CGA含量和叶提取物的抗氧化活性之间观察到线性相关性。在这些结果的基础上，我们提出，CGA是一个强大的供氢抗氧化剂，可能在减轻植物氧化胁迫的影响中发挥重要作用。
To assess the possible physiological function of chlorogenic acid (CGA, 3-O-caffeoylquinic acid) in vivo, we characterized the free radical scavenging properties of pure phenylpropanoids and leaf extracts against two free radicals, superoxide and the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical cation, CGA was found to be a highly efficient scavenger of these free radicals, surpassing the activity of all other phenylpropanoids tested, as well as the 'classical' antioxidant ascorbate. Seasonal differences in the leaf content of CGA were examined in field populations of the broadleaf evergreen Mahonia repens growing in different light environments. Leaves of fully sun-exposed plants contained significantly more (74 +/- 10 mmol m(-2)) CGA in winter than leaves from plants growing under deeply shaded conditions (17 +/- 2 mmol m(-2)). Sun-acclimated, but not shade-acclimated, leaves also produced high levels of anthocyanins in winter, suggesting a simultaneous increase in carbon flow through the phenylpropanoid and flavonoid pathways in response to high light and seasonal low temperature stress. In summer, high light-acclimated leaves contained approximate to 2-fold less CGA than in winter, whereas CGA levels were similar between seasons in shaded leaves. Consistent with the strong scavenging capacity of CGA measured in vitro, a linear correlation was observed between CGA content and the antioxidant activity of leaf extracts in both scavenging assays. On the basis of these results, we propose that CGA is a powerful hydrogen-donating antioxidant that may play an important role in mitigating the effects of oxidative stress in plants.