Chemical Interaction between Polyphenols and a Cysteinyl Thiol under Radical Oxidation Conditions
Chemical Interaction between Polyphenols and a Cysteinyl Thiol under Radical Oxidation Conditions
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DOI：
10.1021/jf3008822
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发表时间：
2012-05-23
影响因子：
6.1
通讯作者：
Masuda, Toshiya
中科院分区：
文献类型：
--
作者：
Fujimoto, Aya;Masuda, Toshiya
在自由基氧化条件下，使用模型半胱氨酰硫醇衍生物，N-苯甲酰半胱氨酸甲酯，多酚和硫醇之间的化学相互作用进行了研究。用化学计量的2，2-二苯基-1-苦基肼（DPPH）进行自由基氧化，并且通过HPLC分析测量多酚和硫醇的量的减少。通过LC-MS检查反应中各种多酚和硫醇之间的交叉偶联产物，结果显示多酚和硫醇均减少。LC-MS结果表明，3种酚酸酯（咖啡酸甲酯、二氢咖啡酸甲酯和原儿茶酸甲酯）和6种黄酮类化合物（山奈酚、杨梅素、毛地黄黄酮、桑色素、紫杉叶素和儿茶素）生成了相应的巯基加合物，而3种多酚类化合物（阿魏酸甲酯、芥子酸甲酯和槲皮素）只生成二聚体或简单的氧化产物，没有巯基取代基。分离了结构相关化合物咖啡酸甲酯和二氢咖啡酸甲酯的硫醇加合物，并通过NMR分析确定了它们的化学结构。根据产物的结构讨论了硫醇加成反应的机理。
Chemical interaction between polyphenols and thiols was investigated under radical oxidation conditions using a model cysteinyl thiol derivative, N-benzoylcysteine methyl ester. The radical oxidation was carried out with a stoichiometric amount of 2,2-diphenyl-1-picrylhydrazyl (DPPH), and the decreases in the amounts of polyphenols and the thiol were measured by HPLC analysis. Cross-coupling products between various polyphenols and the thiol were examined by LC-MS in reactions that showed decreases in both the polyphenols and the thiol. The LC-MS results indicated that three phenolic acid esters (methyl caffeate, methyl dihydrocaffeate, and methyl protocatechuate) and six flavonoids (kaempferol, myricetin, luteolin, morin, taxifolin, and catechin) gave corresponding thiol adducts, whereas three polyphenols (methyl ferulate, methyl sinapate, and quercetin) gave only dimers or simple oxidation products without thiol substituents. Thiol adducts of the structurally related compounds methyl caffeate and methyl dihydrocaffeate were isolated, and their chemical structures were determined by NMR analysis. The mechanism for the thiol addition was discussed on the basis of the structures of the products.