Studies on the constituents of Pueraria lobata. IV. Chemical constituents in the flowers and the leaves.

A new triterpenoidal saponin, 3-O-[α-L-rhamnopyanosyl(1→2)-α-L-arabinopyranosyl(1→2)-β-D-glucuronopyranosyl]sophoradio (I), was isolated from the flowers of Pueraria lobata (WILLD.) OHWI (Leguminosae). Its structure was elucidated on the basis of chemical and physicochemical evidence. In addition, a known oligoglycoside kaikasaponin III (II) was isolated from both flowers and leaves of this plant, together with several known aromatic compounds.