TY - JOUR T1 - Bimodal Effect of Glycyrrhizin on Macrophage Nitric Oxide and Prostaglandin E<sub>2</sub> Production JF - In Vivo JO - In Vivo SP - 583 LP - 586 VL - 22 IS - 5 AU - TAKAO KATO AU - NORIO HORIE AU - KEN HASHIMOTO AU - KAZUE SATOH AU - TETSUO SHIMOYAMA AU - TADAYOSHI KANEKO AU - KAORU KUSAMA AU - HIROSHI SAKAGAMI Y1 - 2008/09/01 UR - http://iv.iiarjournals.org/content/22/5/583.abstract N2 - Glycyrrhizin is a major constituent of Kanzo, a popular herbal medicine used in food and cosmetics. Glycyrrhizin alone did not stimulate nitric oxide (NO) or prostaglandin E2 (PGE2) production by RAW 264.7 cells, but modified lipopolysaccharide (LPS)-stimulated NO and PGE2 production in a bimodal fashion: it was stimulatory at lower concentrations, whereas it was inhibitory at higher concentrations. Electron-spin resonance spectroscopy showed that glycyrrhizin slightly scavenged the superoxide anion generated by hypoxanthine-xanthine oxidase reaction, but did not scavenge the DPPH and NO radicals. The present study demonstrates the concentration-dependent action of glycyrrhizin on both PGE2 and NO production by activated macrophages. ER -