SAPONIN AND SAPOGENOL .49. ON THE CONSTITUENTS OF THE ROOTS OF GLYCYRRHIZA-INFLATA BATALIN FROM XINJIANG, CHINA - CHARACTERIZATION OF 2 SWEET OLEANANE-TYPE TRITERPENE OLIGOGLYCOSIDES, APIOGLYCYRRHIZIN AND ARABOGLYCYRRHIZIN

Two sweet oleanane-type triterpene oligoglycosides named apioglycyrrhi zin and araboglycyrrhizin were isolated from the air-dried roots of Gl ycyrrhiza inflata BATALIN, collected in Xinjiang province (Shinkyo-Kan zo in Japanese), together with glycyrrhizin (3), licorice-saponins A3 (8), G2 (10), and H2 (11) and known flavonoid glycosides. On the basis of chemical and physicochemical evidence, the structures of apioglycy rrhizin and araboglycyrrhizin have been determined to be expressed as osyl(1-->2)-beta-D-glucuronopyranosyl]glycyrrhetic acid (1) and osyl(1 -->2)-beta-D-glucuronopyranosyl]glycyrrhetic acid (2), respectively. D uring the course of these studies, it has been found that the hydroxyl groups in the oligosaccharide moiety of the glucuronide saponins may be partially methylated by prolonged treatment with diazomethane in me thanol. The sweetness of the saponins hitherto isolated from various G lycyrrhizae Radix has been examined and a structure-sweetness relation ship, as compared with glycyrrhizin, has been found.