A novel ring-expanded product with enhanced tyrosinase inhibitory activity from classical Fe-catalyzed oxidation of rosmarinic acid, a potent antioxidative Lamiaceae polyphenol

Bioorg Med Chem Lett. 2010 Dec 15;20(24):7393-6. doi: 10.1016/j.bmcl.2010.10.040. Epub 2010 Oct 14.

Abstract

The iron-ion catalyzed oxidation of the ethanol solution of rosmarinic acid, a potent antioxidant polyphenol of Lamiaceae (Labiatae) plants, afforded a highly tyrosinase-inhibitory active product. The structure of the active product in the oxidation product mixture was determined using extensive NMR spectroscopy to have a novel oxygen-containing seven-membered ring system. The formation mechanism of the unique ring structure from the catechol part of the rosmarinic acid was proposed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antioxidants / chemistry
  • Catalysis
  • Catechols / chemistry
  • Cinnamates / chemical synthesis
  • Cinnamates / chemistry*
  • Cinnamates / pharmacology
  • Depsides / chemical synthesis
  • Depsides / chemistry*
  • Depsides / pharmacology
  • Enzyme Inhibitors / chemical synthesis
  • Enzyme Inhibitors / chemistry*
  • Enzyme Inhibitors / pharmacology
  • Flavonoids / chemistry
  • Iron / chemistry*
  • Lamiaceae / chemistry*
  • Magnetic Resonance Spectroscopy
  • Molecular Conformation
  • Monophenol Monooxygenase / antagonists & inhibitors*
  • Monophenol Monooxygenase / metabolism
  • Oxidation-Reduction
  • Phenols / chemistry
  • Polyphenols
  • Rosmarinic Acid

Substances

  • Antioxidants
  • Catechols
  • Cinnamates
  • Depsides
  • Enzyme Inhibitors
  • Flavonoids
  • Phenols
  • Polyphenols
  • Iron
  • Monophenol Monooxygenase
  • catechol