Saponin and sapogenol. XL. Structure of sophoraflavoside I, a bisdesmoside of soyasapogenol B, from Sophorae Radix, the root of Sophora flavescens Aiton.

A new bisdesmoside of soyasapogenol B (3), named sophoraflavoside I (2), was isolated together with soyasaponin I (1) from Sophorae Radix (Sophora flavescens AITON, root). By employing a photochemical cleavage method for the glucuronide linkage in 2 and on the bases of chemical reactions and spectral analyses, the structure of sophoraflavoside I has been determined to be 3-O-[α-L-rhamnopyranosyl (1→2)-β-D-galactopyranosyl (1→2)-β-D-glucuronopyranosyl]-22-O-[β-D-glucopyranosyl (1→2)-α-L-arabinopyranosyl] soyasapogenol B (2).