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Filip Cuyckens,a Abdelaaty A.
Shahat,a Hilde Van den Heuvel,a Khaled A. Abdel-Shafeek,b Moustafa M. El-Messiry,b Medhat M. Seif-El Nasr,b
Luc Pieters,a Arnold J. Vlietincka and Magda Claeysa*
aUniversity of Antwerp (UA), Department of Pharmaceutical
Sciences, Universiteitsplein 1, B-2610 Antwerp, Belgium. E-mail: claeys@uia.ua.ac.be
bDepartment of Pharmaceutical Sciences, National Research Centre,
12311 Dokki, Cairo, Egypt |
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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. |
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Keywords:
Carrichtera annua, Cruciferae (Brassicaceae), acylated flavonol glycosides, liquid chromatography,
mass spectrometry, electrospray ionization, collision-induced dissociation |
