Phenolic Constituents of Licorice. III. Structures of Glicoricone and Licofuranone, and Inhibitory Effects of Licorice Constituents of Monoamine Oxidase

Abstract

Two new phenolic compounds, glicoricone (3) and licofuranone (4), were isolated from a species of licorice brought from the northwestern region of China, and their structures were assigned.Among the twelve licorice constituents examined for the inhibition of monoamine oxidase (MAO), six compounds, 3, 4, genistein (6), licopyranocoumarin (7), licocoumarone (14) and glycyrrhisoflavone (15), inhibited the enzyme with the IC₅₀ (concentration required for 50% inhibition of the enzyme activity) values of 6.0×10^-5-1.4×10<-4> M. Glycyrrhizin (1) also inhibited MAO with the IC₅₀ value of 1.6×10<-4>M.