[Studies on flavonoid constituents isolated from the leaves of Glycyrrhiza uralensis Fisch].

Four flavonoids were isolated from the alcoholic extract of the leaves of Glycyrrhiza uralensis Fisch. (Leguminosae). On the basis of physicochemical properties and spectroscopic analysis their structures were elucidated as 3,5,7,3',4'-pentahydroxy-5'-isoprenylflavone(I), 3,6,7,3',4'-pentahydroxy-2'-isoprenylflavone(II) and 5,7,3',4'-tetrahydroxy-5'-isoprenyl-flavonone(III) and quercetin-3,3'-dimethylether(IV). Compounds I, II and III are new compounds and named uralenol, neouralenol and uralenin respectively. Compound IV was found in this genus for the first time. Compound III was shown to be the major constituent in the leaves of Glycyrrhiza uralensis Fishch.