[Two new isoprenyl flavonoids from the leaves of Glycyrrhiza uralensis Fisch].

In previous papers, we reported flavonoids isolated from the leaves of Glycyrrhiza uralensis on the west of Inner Mongolia. Three of these flavonoids had the isoprenyl on the B ring, one was phenolic glucoside and six were flavonoidic glucosides. In the present paper, we report the isolation and identification of flavonoids from the leaves of this plant. The structures of these compounds have been identified as 5,7,3',4'-tetrahydroxy-3-methoxy-5'- isoprenylflavone(I),5,6,3',4'-tetrahydroxy-3-methoxy-6'-isopren ylfavone(II) and quercetin (III) by chemical method and spectroscopic analyses. I and II are new compounds and named uralenol-3-methylether and uralene, respectively. III was found for the first time in this species.