title: Acylated flavonol glycosides from the forage legume, Onobrychis viciifolia (sainfoin).
abstract: Ten acylated flavonol glycosides were isolated from aqueous acetone extracts of the aerial parts of the forage legume, Onobrychis viciifolia, and their structures determined using spectroscopic methods. Among these were eight previously unreported examples which comprised either feruloylated or sinapoylated derivatives of 3-O-di- and 3-O-triglycosides of kaempferol (3,5,7,4'-tetrahydroxyflavone) or quercetin (3,5,7,3',4'-pentahydroxyflavone). The diglycosides were acylated at the primary Glc residue of O-α-Rhap(1→6)-β-Glcp (rutinose), whereas the triglycosides were acylated at the terminal Rha residues of the branched trisaccharides, O-α-Rhap(1→2)[α-Rhap(1→6)]-β-Galp or O-α-Rhap(1→2)[α-Rhap(1→6)]-β-Glcp. Identification of the primary 3-O-linked hexose residues as either Gal or Glc was carried out by negative ion electrospray and serial MS, and cryoprobe NMR spectroscopy. Analysis of UV and MS spectra of the acylated flavonol glycosides provided additional diagnostic features relevant to direct characterisation of these compounds in hyphenated analyses. Quantitative analysis of the acylated flavonol glycosides present in different aerial parts of sainfoin revealed that the highest concentrations were in mature leaflets.
authors.affiliation: Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK.
authors.forename: Nigel C
authors.initials: NC
authors.lastname: Veitch
authors.forename: Ionela
authors.initials: I
authors.lastname: Regos
authors.forename: Geoffrey C
authors.initials: GC
authors.lastname: Kite
authors.forename: Dieter
authors.initials: D
authors.lastname: Treutter
mesh_terms: D000215:Acylation; D007887:Fabaceae / Q000737:chemistry*; D044948:Flavonols / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification*; D006027:Glycosides / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D013237:Stereoisomerism; D006113:United Kingdom
chemical_list: D044948:Flavonols; D006027:Glycosides