Mechanism of anti-inflammatory action of glycyrrhizin: Effect on neutrophil functions including reactive oxygen species generation

The effect of glycyrrhizin on inflammatory mediators such as neutrophil functions including reactive oxygen species (ROS) generation was examined. Glycyrrhizin significantly decreased neutrophil-generated O₂^-, H₂O₂ and OH^. in a dose-dependent manner. However, the drug did not reduce any of the ROS generated in a cell-free, xanthine-xanthine oxidase system. The drug did not affect neutrophil chemotaxis or phagocytosis, either. The present study indicates that glycyrrhizin is not an ROS scavenger but exerts an anti-inflammatory action by inhibiting the generation of ROS by neutrophils, the most potent inflammatory mediator at the site of the inflammation.