The chemical reactivity of (-)-epicatechin quinone mainly resides in its Bring

Ming Zhang, Lily Vervoort, Mohamed Moalin, Alex Mommers, Caroline Douny, Gertjan J. M. den Hartog, Guido R. M. M. Haenen*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

15 Citations (Web of Science)

Abstract

As one of the important dietary antioxidants, (-)-epicatechin is a potent reactive oxygen species (ROS) scavenger involved in the redox modulation of the cell. When scavenging ROS, (-)-epicatechin will donate two electrons and become (-)-epicatechin quinone, and thus take over part of the oxidative potential of the ROS. The aim of the study is to determine where this chemical reactivity resides in (-)-epicatechin quinone. When this reactivity is spread out over the entire molecule, i.e. over the AC-ring and B-ring, this will lead to partial epimerization of (-)-epicatechin quinone to (-)-catechin quinone. In our experiments, (-)-epicatechin quinone was generated with tyrosinase. The formation of (-)-epicatechin quinone was confirmed by trapping with GSH, and identification of (-)-epicatechin-GSH adducts. Moreover, (-)-epicatechin quinone could be detected using Q-TOF/MS despite its short half-life. To detect the epimerization, the ability of ascorbate to reduce the unstable flavonoid quinones into the corresponding stable flavonoids was used. The results showed that the reduction of the formed (-)-epicatechin quinone by ascorbate did not result in the formation of an appreciable amount of (-)-catechin. Therefore it can be concluded that the chemical reactivity of (-)-epicatechin quinone mainly resides in its B-ring. This could be corroborated by quantum chemical calculations. Understanding the stabilization of the (-)-epicatechin quinone will help to differentiate between flavonoids and to select the appropriate compound for a specific disorder.
Original languageEnglish
Pages (from-to)31-39
Number of pages9
JournalFree Radical Biology and Medicine
Volume124
DOIs
Publication statusPublished - 20 Aug 2018

Keywords

  • (-)-epicatechin
  • (-)-catechin
  • Antioxidant
  • Quinone
  • Epimerization
  • OXIDATIVE STRESS
  • ENDOTHELIAL-CELLS
  • QUERCETIN
  • ANTIOXIDANTS
  • GLUTATHIONE
  • METABOLITES
  • FLAVONOIDS
  • ASCORBATE
  • CATECHIN
  • PROTECT

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