Four new oleanane type Saponins from Morina nepalensis var. alba

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

1

H and

13

C NMR spectra.