Saponins in alfalfa (Medicago sativa L.) root and their structural elucidation

Twenty-four saponins have been identified in alfalfa roots, including 13 me dicagenic acids, 2 zanhic acids, 4 hederagenins, 1 soyasapogenol A, 2 soyas apogenol B's, 1 soyasapogenol E, and 1 bayogenin glycoside. Ten of the iden tified compounds, including 3-O-[beta-D-glucopyranosyl(1-->3)-beta-D-glucop yranosyl]-28-O-beta-D-glucopyranoside medicagenate, 3-O-[alpha-L-rhamnopyra nosyl(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside] medicage nic acid, 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)-be ta-D-glucopyranosyl]-28-beta- D-glucopyranoside medicagenate, 3-O-[beta-D-g lucuronopyranosyl methyl eater]-28-O-[beta-D-xylopyranosyl(1-->4)-alpha-L-r hamnopyranosyl(1-->2)-alpha-L-arabinopyranoside] medicagenate, 3-O-[alpha-L -rhamnopyranosyl(1-->2)-beta-D-galactopyranosyl(1-->2)-beta-D-glucuronopyra nosyl]-21-O-alpha-L-rhamnopyranoside soyasapogenol A, 3-O-[beta-D-glucopyra nosyl(1-->2)-beta-D-glucopyranosyl (1-->2)glucopyranosyl] -28-O-[beta-D-xyl opyranosyl(1-->4)-alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranoside] medicagenate, 3-O-[beta-D-glucopyranosyl( 1-->2)-beta-D-glucopyranosyl(1-- >2)glucopyranosyl]-28-O-[beta-D-xylopyranosyl(1-->4)-)-[beta-D-apiofuranosy l-(1-->3)]-alpha-L-rhamnopyranosyl(1-->2)-alpha-L-arabinopyranoside) medica genate, 3-O-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl(1-->2)-beta -D-glucopyranosyl]-28-O-[beta-D-xylopyranosyl (1-->4)-alpha-L-rhamnopyranos yl(1-->2)-alpha-L-arabinopyranoside] zanhic acid, 3-O-[beta-D-glucopyranosy l(1-->2)-beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl]-28-O-{beta-D-x ylopyranosyl(1-->4)-[beta-D-apiofuranoside-(1-->3)]-alpha-L-rhamnopyranosyl (1-->2)-alpha-L-arabinopyranoside}zanhic acid, and 3-O-[beta-D-galactopyran osyl(1-->2)-beta-D-glucuronopyranosyl]-28-O-beta-D-glucopyranoside bayogeni n, were not reported before, and their structures were established by spect ral (FAB-MS and NMR) techniques. In addition, 3-O-[alpha-L-rhamnopyranosyl( 1-->2)-beta-D-galactopyranosyl(1-->2)-beta-D-glucuronopyranoside] soyasapog enol E was identified in the roots for the first time.