Subscribe to RSS
DOI: 10.1055/s-0030-1264850
Chemotaxonomic study of the Polygalaceae family: saponins from Securidaca welwitschii
From a chemotaxonomic point of view, in a continuation of our study on saponin constituents of the Polygalaceae family [1–3], we have examined the saponin fraction of stem barks of S. welwitschii. Five new presenegenin glycosides 1-5 were isolated by successive MPLC over silica gel, together with one known oligosaccharide multi-ester, 1-4 as two inseparable (E)/(Z)-isomers of a 3,4-dimethoxycinnamoyl derivative (1/2 and 3/4). Their structures were elucidated mainly by 2D-NMR techniques and mass spectrometry as 3-O-(β-D-glucopyranosyl)presenegenin 28-O-{β-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-[ β-D-glucopyranosyl-(1→3)]-4-O-[(E)-3,4-dimethoxycinnamoyl]- β-D-fucopyranosyl} ester (1) and its (Z)-isomer (2), 3-O-(β-D-glucopyranosyl)presenegenin 28-O-{β-D-galactopyranosyl-(1→4)- β-D-xylopyranosyl-(1→4)-3-O-acetyl-α-L-rhamnopyranosyl-(1→2)-[ β-D-glucopyranosyl-(1→3)]-4-O-[(E)-3,4-dimethoxycinnamoyl]- β-D-fucopyranosyl} ester (3) and its (Z)-isomer (4), and 3-O-(β-D-glucopyranosyl)presenegenin 28-O-{β-D-galactopyranosyl-(1→3)- β-D-xylopyranosyl-(1→4)- α -L-rhamnopyranosyl-(1→2)-O-β-D-fucopyranosyl} ester (5).
References: 1. Mitaine-Offer, A. C. et al. (2009) Phytochemistry. 71: 90–94.
2. Mitaine-Offer, A. C. et al. (2002)J. Nat. Prod. 65: 553–557.
3. Haddad, M. et al. (2003)J. Nat. Prod. 66: 372–377.