Structures of Epicatechin Gallate Trimer and Tetramer Produced by Enzymatic Oxidation

• Kusano Rie

  Graduate School of Biomedical Sciences, Nagasaki University

• Tanaka Takashi

  Graduate School of Biomedical Sciences, Nagasaki University

• Matsuo Yosuke

  Graduate School of Biomedical Sciences, Nagasaki University

• Kouno Isao

  Graduate School of Biomedical Sciences, Nagasaki University

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.

収録刊行物

• ＣＨＥＭＩＣＡＬ　＆　ＰＨＡＲＭＡＣＥＵＴＩＣＡＬ　ＢＵＬＬＥＴＩＮ

  ＣＨＥＭＩＣＡＬ　＆　ＰＨＡＲＭＡＣＥＵＴＩＣＡＬ　ＢＵＬＬＥＴＩＮ 55 (12), 1768-1772, 2007

  公益社団法人 日本薬学会

キーワード

• epicatechin 3-<i>O</i>-gallate
• benzotropolone
• oxidation
• black tea
• polyphenol

詳細情報

• CRID: 1390001204168627840
• NII論文ID: 110006532125
• NII書誌ID: AA10885497
• DOI: 10.1248/cpb.55.1768
• ISSN: 13475223
• ISSN: 00092363
• HANDLE: 10069/14908
• NDL書誌ID: 9274186
• Web Site: https://nagasaki-u.repo.nii.ac.jp/records/21024
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I9274186
• Web Site: http://www.jstage.jst.go.jp/article/cpb/55/12/55_12_1768/_pdf
• 本文言語コード: en
• データソース種別:
  • JaLC
  • IRDB
  • NDL
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可