Four New Oleanene Derivatives from the Seeds of Astragalus complanatus

抄録

Four new methyl ester derivatives of oleanene glycosides (3-6) were isolated from the seeds of Astragalus complanatus R. BR. together with two known triterpene glycosides, astragaloside VIII methyl ester (1) and soyasaponin I methyl ester (2) after treatment with diazonethane during separation procedure. The structures of 3-6 were elucidated as 3-O-α-L-rhamnopyranosyl(1→2)-β-D-xylopyranosyl(1→2)-6-O-methy-β-D-glucuronopyranosyl-soyasapogenol B 22-O-β-D-glucopyranosede, 3-O-α-L-rhamnopyranosyl(1→2)-β-D-galactopyranosyl(1→2)-6-O-methyl-β-D-glucuronopyranosyl-soyasapogenol B 22-O-β-D-glucopyranoside, 3-O-α-L-rhamnopyranosyl(1→2)-β-D-xylopyranosyl(1→2)-6-O-methyl-β-D-glucuronopyranosyl 3β, 22β, 24-trihydroxy-11-oxo-olean-12-ene and 3-O-α-L-rhamnopyranosyl (1→2)-β-D-galactopyranosyl(1→2)-6-O-methyl-β-D-glucuronopyranosyl 3β, 22β, 24-trihydroxy-11-oxo-olean-12-ene, respectively.