Synthesis of neosaponins carrying oligosaccharides from natural products

The natural oligosaccharide moieties, alpha-L-rhamnopyranosyl-(1 --> 2)-bet a-D-galactopyranosyl-(1 --> 2)-beta-D-glucuronopyranose (fabatriose) and al pha-L-arabinofuranosyl-(1 --> 4)-[beta-D-glucopyranosyl-(1 --> 3)]-alpha-L- rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranose (mimosatetraose), were respe ctively cleaved from soyasaponin I and julibrosides, and were linked to app ropriate aglycones to give neosaponins. The cytotoxicity and hepatoprotecti ve activity of the obtained neosaponins were assayed. The transglycosidatio n method developed here could be applied to synthesize novel bioactive glyc osides.