Structures of enzymatic oxidation products of epigallocatechin
Structures of enzymatic oxidation products of epigallocatechin
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DOI：
10.1016/j.tet.2013.07.045
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发表时间：
2013-10-21
期刊：
影响因子：
2.1
通讯作者：
Tanaka, Takashi
中科院分区：
文献类型：
--
作者：
Matsuo, Yosuke;Hayashi, Toshimi;Tanaka, Takashi
为了解未表征的红茶多酚的结构，对表没食子儿茶素的氧化产物进行了研究。酶促氧化和随后加热反应混合物得到四种新的氧化产物（6和9-11）沿着有茶氨酸C（4）和E（5）、脱氢茶氨酸E（12）、表茶黄素、羟基茶黄素和去没食子酰乌龙茶氨酸。新化合物的结构经化学和光谱测定。Isotheasinensin E（6）是5的C-2差向异构体，化合物9和10是12的氧化产物。另一个新化合物11是一种黄色色素，推测是原茶黄素的降解产物。结果揭示了红茶生产过程中发生的新氧化机制。(c)2013爱思唯尔有限公司版权所有。
To understand the structures of uncharacterized black tea polyphenols, the oxidation products of (-)-epigallocatechin were investigated. Enzymatic oxidation and subsequent heating of the reaction mixture afforded four new oxidation products (6, and 9-11) along with theasinensins C (4) and E (5), dehydrotheasinensin E (12), epitheaflagallin, hydroxytheaflavin, and desgalloyl oolongtheanin. The structures of the new compounds were determined chemically and spectroscopically. Isotheasinensin E (6) is a C-2 epimer of 5, and compounds 9 and 10 are oxidation products of 12. Another new compound, 11, is a yellow pigment and presumed to be a degradation product of proepitheaflagallin. The results disclosed new oxidation mechanisms that occur during black tea production. (c) 2013 Elsevier Ltd. All rights reserved.