New acylated saponins from Polygala myrtifolia

The ten new acylated presenegenin (=(2β,3β,4α )-2,3,27-trihydroxyolean-12-ene-23,28-dioic acid) glycosides 1-10 have been isolated by successive MPLC from the roots of Polygala myrtifolia L. as five inseparable mixtures of the trans- and cis-4-methoxycinnamoyl derivatives, i.e., myrtifoliosides A₁/A₂ (1/2), B₁/B₂ (3/4), C₁/C₂ (5/6), D₁/D₂ (7/8), and E₁/E₂ (9/10). Their structures were elucidated mainly by extensive spectroscopic experiments, including 2D NMR techniques, as 3-O-(β-D-glucopyranosyl)presenegenin 28-{O-β-D-galactopyranosyl-(1 → 3)-O-β-D-xylopyranosyl-(1 → 4)-O-β-D-apio-β -D-furanosyl-(1 → 3)]-O-α-L-rhamnopyranosyl-(1 → 2)-O-[α-L-arabinopyranosyl-(1 → 3)]-4-O-(trans-4-methoxycinnamoyl)-β-D-fucopyranosyl] ester (1) and its cis-isomer 2, 3-O-β-D-glucopyranosyl)presenegenin 28-{O-β -D-galactopyranosyl-(1 → 3)-O-β-D-xylopyranosyl-(1 → 4)-O-[D-apio-β-D-furanosyl-(1 → 3)]-α-L-rhamnopyranosyl-(1 → 2)-4-O-(trans-4-methoxycinnamoyl)-β-D-fucopyranosyl} ester (3) and its cis-isomer 4, 3-O-β-D-glucopyranosyl)presenegenin 28-{O-β -D-galactopyranosyl-(1 → 3)-O-β-D-xylopyranosyl-(1 → 4)-O-α-L-rhamnopyranosyl-(1 → 2)-4-O-(trans-4-methoxycinnamoyl)-β-D-fucopyranosyl} ester (5) and its cis-isomer 6, 3-O-β-D-glucopyranosyl)presenegenin 28-{O-D-apio-β -D-furanosyl-(1 → 3)-O-[β-D-xylopyranosyl-(1 → 4)]-O-α-L-rhamnopyranosyl-(1 → 2)-4-O-(trans-4-methoxycinnamoyl)-β-D-fucopyranosyl} ester (7) and its cis-isomer 8, and 3-O-(β-D-glucopyranosyl)presenegenin 28-{O-α -L-arabinopyranosyl-(1 → 3)-O-[β-D-xylopyranosyl-(1 → 4)]-O-α-L-rhamnopyranosyl-(1 → 2)-4-O-(trans-4methoxycinnamoyl)-β-D-fucopyranosyl} ester (9) and its cis-isomer 10.