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Structures of Epicatechin Gallate Trimer and Tetramer Produced by Enzymatic Oxidation

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タイトル: Structures of Epicatechin Gallate Trimer and Tetramer Produced by Enzymatic Oxidation
著者: Kusano, Rie / Tanaka, Takashi / Matsuo, Yosuke / Kouno, Isao
発行日: 2007年12月
出版者: The Pharmaceutical Society of Japan
引用: Chemical & Pharmaceutical Bulletin v.55(12) p.1768-1772, 2007
抄録: 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.
キーワード: 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
関連リンク : http://dx.doi.org/10.1248/cpb.55.1768
資料タイプ: Journal Article
原稿種類: publisher
出現コレクション:050 学術雑誌論文

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



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