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Structures of Epicatechin Gallate Trimer and Tetramer Produced by Enzymatic Oxidation

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Title: Structures of Epicatechin Gallate Trimer and Tetramer Produced by Enzymatic Oxidation
Authors: Kusano, Rie / Tanaka, Takashi / Matsuo, Yosuke / Kouno, Isao
Issue Date: Dec-2007
Publisher: The Pharmaceutical Society of Japan
Citation: Chemical & Pharmaceutical Bulletin v.55(12) p.1768-1772, 2007
Abstract: During black tea production, catechins and their galloyl esters are enzymatically oxidized to generate a complex mixture of black tea polyphenols. The role of galloyl ester groups in this process has yet to be determined. Enzymatic oxidation of epicatechin 3-O-gallate (1) yielded two new oxidation products, theaflavate C and bistheaflavate A, along with theaflavate A (2), a known dimer of 1 generated by coupling of the B-ring with the galloyl group. Theaflavate C is a trimer of 1 and possesses two benzotropolone moieties generated by the oxidative coupling of the galloyl groups with the catechol B-rings. Bistheaflavate A was found to be a tetramer produced by intermolecular coupling of two benzotropolone moieties of 2. From the structures of the products, it was deduced that oxidative coupling of galloyl groups resulted in extension of the molecular size of the products in catechin oxidation.
Keywords: epicatechin 3-O-gallate / benzotropolone / oxidation / black tea / polyphenol
URI: http://hdl.handle.net/10069/14908
ISSN: 00092363
DOI: 10.1248/cpb.55.1768
PubMed ID: 18057757
Relational Links: http://dx.doi.org/10.1248/cpb.55.1768
Type: Journal Article
Text Version: publisher
Appears in Collections:Articles in academic journal

Citable URI : http://hdl.handle.net/10069/14908

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