| Abstract: | Four new oleanane type saponins, monepalosides G–J (1–4), were isolated from the water-soluble part of the whole plant of Morina nepalensis var. alba Hand-Mazz. On the basis of chemical and spectroscopic evidence, their structures were determined as 3-O-α-L-arabinopyranosyl-(1→3)-α-L-arabinopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside G, 1), 3-O-α-L-arabinopyranosyl-(1→3)-β-D-xylopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside H, 2), 3-O-α-L-arabinopyranosyl-(1→3)-β-D-glucopyranosyl-(1→2)]-α-L-arabinopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside I, 3), 3-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyranosy-(1→3)]-α-L-arabinopyranosyl oleanolic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (monepaloside J, 4), respectively. Two-dimensional NMR spectra, including H–H COSY, HMQC, 2D HMQC–TOCSY, HMBC and ROESY were utilized in the structure elucidation and complete assignments of 1H and 13C NMR spectra. |
