Structures of enzymatic oxidation products of epigallocatechin

TETRAHEDRON

卷:69

Article

Matsuo, Yosuke¹  Hayashi, Toshimi¹  Saito, Yoshinori¹  Kouno, Isao¹  Tanaka, Takashi¹ 

[1] Nagasaki Univ, Grad Sch Biomed Sci, Nagasaki 8528521, Japan

关键词: Epigallocatechin;    Oxidation;    Theasinensins;    Thearubigins;    Black tea;   

DOI  :  10.1016/j.tet.2013.07.045

来源: Elsevier

【 摘 要 】

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.

【 授权许可】

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