title: Screening and identification of glyceollins and their metabolites by electrospray ionization tandem mass spectrometry with precursor ion scanning.
abstract: A method has been developed for screening glyceollins and their metabolites based on precursor ion scanning. Under higher-energy collision conditions with the employment of a triple quadrupole mass spectrometer in the negative ion mode, deprotonated glyceollin precursors yield a diagnostic radical product ion at m/z 148. We propose this resonance-stabilized radical anion, formed in violation of the even-electron rule, to be diagnostic of glyceollins and glyceollin metabolites. Liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) established that scanning for precursors of m/z 148 can identify glyceollins and their metabolites from plasma samples originating from rats dosed with glyceollins. Precursor peaks of interest were found at m/z 337, 353, 355, 417, and 433. The peak at m/z 337 corresponds to deprotonated glyceollins, whereas the others represent metabolites of glyceollins. Accurate mass measurement confirmed m/z 417 to be a sulfated metabolite of glyceollins. The peak at m/z 433 is also sulfated, but it contains an additional oxygen, as confirmed by accurate mass measurement. The latter metabolite differs from the former likely by the replacement of a hydrogen with a hydroxyl moiety. The peaks at m/z 353 and 355 are proposed to correspond to hydroxylated metabolites of glyceollins, wherein the latter additionally undergoes a double bond reduction.
authors.affiliation: Department of Chemistry, University of New Orleans, 2000 Lakeshore Drive, New Orleans, Louisiana 70148, United States.
authors.forename: Syeda S
authors.initials: SS
authors.lastname: Quadri
authors.forename: Robert E
authors.initials: RE
authors.lastname: Stratford
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Boué
authors.forename: Richard B
authors.initials: RB
authors.lastname: Cole
mesh_terms: D000818:Animals; D010936:Plant Extracts / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D036343:Pterocarpans / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D012639:Seeds; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D010936:Plant Extracts; D036343:Pterocarpans; C017343:glyceollin