Theadibenzotropolone A, a new type pigment from enzymatic oxidation of (-)-epicatechin and (-)-epigallocatechin gallate and characterized from black tea using LC/MS/MS

Shengmin Sang, Shiying Tian, Xiaofeng Meng, Ruth E. Stark, Robert T. Rosen, Chung S. Yang, Chi Tang Ho

Research output: Contribution to journalArticlepeer-review

48 Scopus citations

Abstract

Theaflavins and thearubigins are major pigments of black tea. In the course of studies on the oxidation mechanism of tea polyphenols, a new type of tea pigment, theadibenzotropolone A, together with theaflavin 3-gallate were formed by the reaction of (-)-epicatechin (EC) and (-)-epigallocatechin gallate (EGCG) with horseradish peroxidase in the presence of H2O2. The structure of theadibenzotropolone A was elucidated on the basis of MS and 2D NMR spectroscopic analyses. The observation that galloyl ester groups of theaflavins can be oxidized to form dibenzotropolone skeletons strongly implied that this type of oxidation as an important pathway to extend the molecular size of thearubigins. The existence of this compound in black tea was characterized by LC/ESI-MS/MS. Theadibenzotropolone A is the first theaflavin type trimer of catechins in black tea.

Original languageEnglish (US)
Pages (from-to)7129-7133
Number of pages5
JournalTetrahedron Letters
Volume43
Issue number40
DOIs
StatePublished - Sep 30 2002

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

Keywords

  • Black tea
  • Enzyme oxidation
  • HO
  • Peroxidase
  • Theadibenzotropolone A

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