title: The application of liquid chromatography-electrospray ionization mass spectrometry and collision-induced dissociation in the structural characterization of acylated flavonol O-glycosides from the seeds of Carrichtera annua.
abstract: The flavonoid fraction from the seeds of Carrichtera annua was studied using high-performance liquid chromatography simultaneously coupled to a photodiode array detector (LC/UV-DAD) and a mass spectrometer equipped with an electrospray source (LC/ESI-MS). Collision-induced dissociation (CID) mass spectral data obtained off-line by nanospray (nano-ESI) analysis provided a wealth of complementary structural information, which was consistent with structures established by NMR or led to the proposal of base structures of the flavonol O-glycosides present in the Carrichtera annua seed extract. The flavonoid fraction was found to contain 12 structurally related flavonol O-glycosides. Eleven flavonoids, of which several were new compounds, were acylated with one or more benzoyl, feruloyl or sinapoyl groups. These acyl groups gave rise to characteristic product ions in the [M + H](+) and [M + Na](+) CID spectra as well as to radicalar acid-related product ions at high-energy collisional activation. In addition to the characterization of the acyl substituents, the mass spectral data allowed the identification of the aglycone, the determination of the base structure and the differentiation of several positional isomers.
authors.affiliation: University of Antwerp (UA), Department of Pharmaceutical Sciences, Universiteitsplein 1, B-2610 Antwerp, Belgium.
authors.forename: Filip
authors.initials: F
authors.lastname: Cuyckens
authors.forename: Abdelaaty A
authors.initials: AA
authors.lastname: Shahat
authors.forename: Hilde
authors.initials: H
authors.lastname: Van den Heuvel
authors.forename: Khaled A
authors.initials: KA
authors.lastname: Abdel-Shafeek
authors.forename: Moustafa M
authors.initials: MM
authors.lastname: El-Messiry
authors.forename: Medhat M
authors.initials: MM
authors.lastname: Seif-El Nasr
authors.forename: Luc
authors.initials: L
authors.lastname: Pieters
authors.forename: Arnold J
authors.initials: AJ
authors.lastname: Vlietinck
authors.forename: Magda
authors.initials: M
authors.lastname: Claeys
mesh_terms: D000215:Acylation; D019607:Brassicaceae / Q000737:chemistry*; D002853:Chromatography, Liquid / Q000379:methods*; D005419:Flavonoids / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D012639:Seeds / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D005419:Flavonoids; D006027:Glycosides