Free radical scavenging activity of the novel anti-ulcer agent rebamipide studied by electron spin resonance

Arzneimittelforschung. 1993 Mar;43(3):363-6.


The anti-free radical action of rebamipide (2-(4-chlorobenzoylamino)-3-[2(1H)-quinolinon-4-yl] propionic acid, CAS 11911-87-6), a novel anti-ulcer agent, was investigated by electron spin resonance spectroscopy. A spin trapping method using 5,5-dimethyl-1-pyrroline-N-oxide showed that rebamipide dose-dependently decreased both the intensity of the hydroxyl radical spin adduct signal generated by the Fenton reaction and the intensity of the superoxide spin adduct generated from opsonized zymosan-stimulated neutrophils. A kinetic study showed that the second order rate constant for the reaction between rebamipide and hydroxyl radicals at pH 7.8 was 2.24 x 10(10) mol l-1 s-1. These results indicate in vitro antioxidant properties of rebamipide which is active as hydroxyl radical scavenger and inhibitor of superoxide production in neutrophils.

MeSH terms

  • Alanine / analogs & derivatives*
  • Alanine / pharmacology
  • Anti-Ulcer Agents / pharmacology*
  • Bepridil / analogs & derivatives
  • Biphenyl Compounds
  • Cyclic N-Oxides
  • Electron Spin Resonance Spectroscopy
  • Free Radical Scavengers*
  • Humans
  • In Vitro Techniques
  • Neutrophils / drug effects
  • Neutrophils / metabolism
  • Picrates*
  • Quinolones / pharmacology*
  • Superoxides / metabolism
  • Zymosan / pharmacology


  • Anti-Ulcer Agents
  • Biphenyl Compounds
  • Cyclic N-Oxides
  • Free Radical Scavengers
  • Picrates
  • Quinolones
  • Superoxides
  • 5,5-dimethyl-1-pyrroline-1-oxide
  • Bepridil
  • Zymosan
  • 1,1-diphenyl-2-picrylhydrazyl
  • rebamipide
  • Alanine