Separation and structural analysis of some saponins from Quillaja saponaria Molina

A fraction of saponins from Quillaja saponaria Molina, QH-B, was fractionated by consecutive separations on three different reverse-phase HPLC systems. Eight compounds were isolated and the structures of these were elucidated mainly by sugar analysis and NMR spectroscopy. The structures consisted of a quillaic acid substituted with two different trisaccharides at C-3, beta-D-Galp-(1 --> 2)-[alpha-L-Rhap-(1 --> 3)1-beta-D-GlcpA and beta-D-Galp-(1 --> 2)-[beta-D-Xylp-(1 --> 3)]-beta-D-Glcp A, and a tetra- or pentasaccharide at C-28, beta-D-Xylp-(1 --> 4)-[beta-D-Glcp-(1 --> 3)]-alpha-L-Rhap-(1 --> 2)-beta-D-Fucp and beta-D-Apif-(1 --> 3)-X-D-Xylp-(1 --> 4)-[beta-D-Glcp -(1 --> 3)]-alpha-L-Rhap-(1 --> 2)-beta-D-Fucp. These compounds were further substituted with an acyl group either at O-3 or O-4 of the fucose residue, which is the sugar linked to C-28 of the quillaic acid. (C) 2000 Elsevier Science Ltd. All rights reserved.