Mechanism of anti-inflammatory action of liquorice extract and glycyrrhizin

Nat Prod Res. 2007 Dec;21(14):1234-41. doi: 10.1080/14786410701371280.

Abstract

The antiradical activity, protective effect against lipid peroxidation of liposomal membrane, and inhibitory effect on whole blood reactive oxygen species (ROS) liberation of Glycyrrhiza glabra crude extract and glycyrrhizin, its major compound, were assessed. The liquorice extract showed significant activity in all the three assay systems used in a dose dependent manner. It displayed remarkable reactivity with free stable 1,1'-diphenyl-2-picrylhydrazyl (DPPH) radical, inhibitory efficacy in peroxidatively damaged unilamellar dioleoyl phosphatidylcholine (DOPC) liposomes, and inhibition of ROS chemiluminescence, generated by whole blood, induced by both receptor-bypassing stimuli (PMA) and receptor operating stimuli (Opz) in the ranking order of stimuli PMA> Opz. These activities may be attributed to phenolic antioxidants involving isoflavan derivatives, coumarins and chalcones. Nonetheless, triterpene saponin glycyrrhizin exhibited no efficacy in the system of DPPH reaction and peroxidation of liposomal membrane, and negligible inhibition of chemiluminescence generated by inflammatory cells. These results indicate that the mechanism of anti-inflammatory effect of glycyrrhizin most probably does not involve ROS and this major constituent is not responsible for the inhibition effects of liquorice extract on neutrophil functions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Inflammatory Agents / pharmacology*
  • Biphenyl Compounds / chemistry
  • Biphenyl Compounds / metabolism
  • Flavonoids / chemistry
  • Free Radicals / chemistry
  • Free Radicals / metabolism
  • Glycyrrhiza / chemistry*
  • Glycyrrhizic Acid / chemistry
  • Glycyrrhizic Acid / pharmacology*
  • Hydrazines / chemistry
  • Hydrazines / metabolism
  • Lipid Peroxidation / drug effects
  • Luminescence
  • Molecular Structure
  • Oxidation-Reduction / drug effects
  • Phenols / chemistry
  • Picrates
  • Plant Extracts / chemistry
  • Plant Extracts / pharmacology*
  • Polyphenols
  • Reactive Oxygen Species / chemistry
  • Reactive Oxygen Species / metabolism

Substances

  • Anti-Inflammatory Agents
  • Biphenyl Compounds
  • Flavonoids
  • Free Radicals
  • Hydrazines
  • Phenols
  • Picrates
  • Plant Extracts
  • Polyphenols
  • Reactive Oxygen Species
  • Glycyrrhizic Acid
  • 1,1-diphenyl-2-picrylhydrazyl