title: Direct stereochemical assignment of hexose and pentose residues in flavonoid O-glycosides by fast atom bombardment and electrospray ionization mass spectrometry.
abstract: Mass spectrometric methods have been developed which allow the direct stereochemical assignment of terminal monosaccharide residues in flavonoid O-glycosides without the need for chemical hydrolysis. Standards containing a glucose, galactose, mannose, xylose, arabinose or apiose residue were examined because these monosaccharides are by far the most commonly encountered in flavonoid glycosides. Following acetylation, the major peracetylated sugar related fragments, generated by fast atom bombardment (FAB) or electrospray ionization (ESI), were selected for collisional activation employing a broad range of collision energies. Both FAB and ESI proved to be useful as ionization techniques. Stereoselective fragmentation was achieved and allowed us clearly to differentiate and characterize isomeric monosaccharide residues. The method developed was successfully applied to an unknown flavonoid containing a terminal pentose and hexose residue which was isolated from Farsetia aegyptia.
authors.affiliation: Department of Pharmaceutical Sciences, University of Antwerp (UIA), 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: Luc
authors.initials: L
authors.lastname: Pieters
authors.forename: Magda
authors.initials: M
authors.lastname: Claeys
mesh_terms: D005419:Flavonoids / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry*; D006601:Hexoses / Q000032:analysis* / Q000737:chemistry*; D008968:Molecular Conformation; D015394:Molecular Structure; D008970:Molecular Weight; D010429:Pentoses / Q000032:analysis* / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D016339:Spectrometry, Mass, Fast Atom Bombardment
chemical_list: D005419:Flavonoids; D006027:Glycosides; D006601:Hexoses; D010429:Pentoses; D010936:Plant Extracts