3-O-beta-D-glucopyranosiduronic acid-3 beta, 16 alpha-dihydroxy-olean-12-en-28-oic acid-28-O-beta-D-xylopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1--> 4)-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranoside