title: ¹H-NMR fingerprinting of Vaccinium vitis-idaea flavonol glycosides.
abstract: BACKGROUND
  The fruits of Vaccinium vitis-idaea L. are a valuable source of biologically active flavonoid derivatives. For studies focused on the purification of its quercetin glycosides (QGs) and related glycosides from plants and for the purpose of biological studies, the availability of numeric datasets from computer-assisted ¹H iterative full spin analysis (HiFSA), that is, ¹H-NMR fingerprinting, can replace and assist the repetitive and tedious two-dimensional NMR identification protocol required for both known and new compounds, respectively.
  
  
  OBJECTIVE
  To fully interpret the complex ¹H-NMR fingerprints of eight QGs obtained from the berries of V. vitis-idaea and provide complete and unambiguous signal assignments.
  
  
  METHODS
  Vaccinium vitis-idaea QGs were purified in a single run by long-bed gel permeation chromatography and identified by comparison with commercially available compounds using LC-MS combining ion-trap and time-of-flight detection and one- or two-dimensional NMR. The HiFSA analysis yielded full sets of ¹H chemical shifts and proton-proton coupling constants, allowing for field-independent spectral simulation.
  
  
  RESULTS
  Signal assignments were achieved for the reference standards and the QGs that dominated in purified fractions. However, even mixtures of two to three QGs could be fitted using the HiFSA approach. In the case of the overlapped sugar resonances, the initial fitting of the ¹H spectra of reference compounds, together with values extracted from the two-dimensional NMR data and literature data, assisted in the process.
  
  
  CONCLUSIONS
  The HiFSA method revealed for the first time the presence of Q-3-O-β-glucopyranoside and Q-3-O-β-glucuronopyranoside in the berries of V. vitis-idaea, and unambiguously confirmed the structures of Q-3-O-[4″-(3-hydroxy-3-methylglutaroyl)]-α-rhamnopyranoside, Q-3-O-α-rhamnopyranoside, Q-3-O-β-galactopyranoside, Q-3-O-α-arabinofuranoside, Q-3-O-β-xylopyranoside and Q-3-O-α-arabinopyranoside.
authors.affiliation: Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, Illinois, 60612-7231, USA; Institute of Public Health and Clinical Nutrition, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland.
authors.forename: Kaisu R
authors.initials: KR
authors.lastname: Riihinen
authors.forename: Velitchka V
authors.initials: VV
authors.lastname: Mihaleva
authors.forename: Tanja
authors.initials: T
authors.lastname: Gödecke
authors.forename: Pasi
authors.initials: P
authors.lastname: Soininen
authors.forename: Reino
authors.initials: R
authors.lastname: Laatikainen
authors.forename: Jacques M
authors.initials: JM
authors.lastname: Vervoort
authors.forename: David C
authors.initials: DC
authors.lastname: Lankin
authors.forename: Guido F
authors.initials: GF
authors.lastname: Pauli
mesh_terms: D002853:Chromatography, Liquid; D044948:Flavonols / Q000032:analysis*; D006027:Glycosides / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D013058:Mass Spectrometry; D011522:Protons; D029801:Vaccinium vitis-idaea / Q000737:chemistry*
chemical_list: D044948:Flavonols; D006027:Glycosides; D011522:Protons
keywords: 1H iterative full spin analysis; 1H-NMR fingerprint; HiFSA; berries; flavonol glycosides; food and dietary supplement analysis