An oxidative coupling product of luteolin with cysteine ester and its enhanced inhibitory activity for xanthine oxidase

Bioorg Med Chem Lett. 2015 Aug 15;25(16):3117-9. doi: 10.1016/j.bmcl.2015.06.016. Epub 2015 Jun 11.

Abstract

Oxidative coupling reactions of several flavonoids with a cysteine ester (a radicalic and nucleophilic biochemical) were carried out and the abilities of the coupling products against xanthine oxidase (XO) were screened. One of the products, derived from luteolin, showed a notable inhibitory effect. A potent XO inhibitory compound was isolated from the complex mixture of the product of the coupling of luteolin and cysteine ethyl ester, and its structure was determined by NMR and MS analysis. The compound has a unique 1,4-thiazine ring unit on the luteolin B-ring and is inhibited XO 4.5 times more strongly than it did luteolin.

Keywords: Cysteine; Flavonoid; Oxidative coupling; Structure determination; Xanthine oxidase inhibition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cysteine / analogs & derivatives*
  • Cysteine / chemistry
  • Enzyme Inhibitors / chemical synthesis
  • Enzyme Inhibitors / chemistry*
  • Luteolin / chemistry*
  • Magnetic Resonance Spectroscopy
  • Mass Spectrometry
  • Molecular Conformation
  • Oxidative Coupling
  • Xanthine Oxidase / antagonists & inhibitors*
  • Xanthine Oxidase / metabolism

Substances

  • Enzyme Inhibitors
  • ethyl cysteine
  • Xanthine Oxidase
  • Cysteine
  • Luteolin