Saponins from European Licorice Roots (Glycyrrhiza glabra)

Abstract

European licorice roots ( Glycyrrhiza glabra), used in the food and beverage industry due to their distinctive sweet and typical licorice flavor, were fractionated, with the triterpenoid saponins isolated and their chemical structures determined by means of ESIMS, ESIMS/MS, HRESIMS, and 1D/2D NMR experiments. Next to the quantitatively predominant saponin glycyrrhizin (11) and some previously known saponins, the structures of 10 monodesmosidic saponins were assigned unequivocally for the first time, namely, 30-hydroxyglycyrrhizin (1), glycyrrhizin-20-methanoate (2), 24-hydroxyglucoglycyrrhizin (3), rhaoglycyrrhizin (4), 11-deoxorhaoglycyrrhizin (5), rhaoglucoglycyrrhizin (6), rhaogalactoglycyrrhizin (7), 11-deoxo-20α-glycyrrhizin (8), 20α-galacturonoylglycyrrhizin (9), and 20α-rhaoglycyrrhizin (10).