A new flavonol triglycoside and other flavonol glycosides from astragalus armatus willd. (Fabaceae)

From the aerial parts of Astragalus armatus, a new acylated flavonol triglycoside, isorhamnetin-3-O-(5‴-p-hydroxybenzoyl)-β-apiofuranosyl-(l→2)[α-rhamnopyranosyl-(l→6)]-β-galactopyranoside (1) which we named astrarmatuside, has been isolated and structurally elucidated together with seven known flavonol glycosides: Tamarixetin-3-0-α-apiofuranosyl-(l→2)[α-rhamnopyranosyl-(l→6)]-β-galactopyranoside (2) (millettiaspecoside D), isorhamnetin-3-0-β-apiofuranosyl-(l→2)[α-rhamnopyranosyl-(l →6)]-β-galacto-pyranoside (3), kaempferol-3-0-α-rhamnopyranosyl-(l→2)[α-rhamnopyranosyl-(l→6)]-β-glucopyranoside (4), kaempferol-3-0-α-rhamnopyranosyl-(l→2)[α-rhamnopyranosyl-(l→6)]-β-galactopyranoside (mauritianin) (5), isorhamnetin-3-0-α-rhamnopyranosyl-(l→2)[α-rhamnopyranosyl-(l→6)]-j6-galactopyranoside (6), kaempferol-3-0-α-rhamnopyranosyl-(l→6)]-β-glucopyranoside (nikotiflorin) (7) and isorhamnetin-3-O-α-rhamnopyranosyl-(1→6)]-β-glucopyranoside (narcissin) (8). The structures of the isolated compounds were established by means of 2D NMR experiments, HPLC-DADMS, HR-MS and UV spectral analyses. Pivotal role in the structure elucidation and in particular in the determination of sugar sequence, played HSQC-TOCSY and ROESY experiments whereas those of the known compounds (2-8) were established by spectral comparison with those published in the literature. © 2014 ACG Publications. All rights reserved.