Oleanane-type glycosides from the roots of Weigela florida ``rumba'' and evaluation of their antibody recognition

Three triterpene glycosides were isolated from the roots of Weigela florida ``rumba'' (Bunge) A. DC.: two previously undescribed 3-O-beta-D-xylopyranosyl-(1 -> 2)-beta-D-xylopyranosyl-(1 -> 4)]-beta-D-xylopyranosyl-(1 -> 4)-beta-D-xylopyranosyl-(1 -> 3)-alpha-L-rharnnopyranosyl-(1 -> 2)-a-t-arabinopyranosyloleanolic acid (1) and 3-O-beta-D-xylopyranosyl-(1 -> 2)-[beta-D-glucopyranosyl-(1 -> 4)]-O-D-xylopyranosyl-(1 -> 4)-beta-D-xylopyranosyl-(1 -> 3)-alpha-L-rhamnopyr-anosyl-(1 -> 2)-alpha-L-arabinopyranosyloleanolic acid (2), and one isolated for the first time from a natural source 3-O-beta-D-xylopyranosyl-(1 -> 3)-alpha-L-rhamnopyranosyl-(1 -> 2)-alpha-L-arabinopyranosyloleanolic acid (3). Their structures were elucidated mainly by 2D NMR spectroscopic analysis (COSY, TOCSY, NOESY, HSQC, HMBC) and mass spectrometry. Compounds 2 and 3 were further evaluated as antigens in enzyme-linked immunosorbent assay (ELISA) to recognize IgM antibodies in multiple sclerosis (MS) patients' sera.