Phenolic constituents of licorice. II. Structures of licopyranocoumarin, licoarylcoumarin and glisoflavone, and inhibitory effects of licorice phenolics on xanthine oxidase.
Five phenolics isolated from licorice inhibited the cytopathic activity of a human immmunodeficiency virus. One of these a coumarin derivative named licopyranocoumarin, isolated from Xi-bei licorice, had structure 5, based on the chemical and spectroscopic evidence.
Phenolic constituents of licorice. II. Structures of licopyranocoumarin, licoarylcoumarin and glisoflavone, and inhibitory effects of licorice phenolics on xanthine oxidase.
An anti-HIV (human immunodeficiency virus) phenolic constituent, licopyranocoumarin (4), and two other new phenolics named licoarylcoumarin (5) and glisoflavone (6) were isolated from Si-pei licorice (a commercial licorice; root and stolon of Glycyrrhiza sp. from the north-western region of China) using droplet countercurrent chromatography and centrifugal partition chromatography, and their structures were assigned based on chemical and spectroscopic data. Kaempferol 3-O-methyl ether (7) and licocoumarone (8) were also isolated from the licorice. The inhibitory effects of ten licorice phenolics on xanthine oxidase were examined. Licohalcone B (1), glycyrrhisoflavone (2), 8 and licochalcone A (19) showed 50% inhibition at the concentration of 1.3-5.6×10<-5>M.