29741-10-4Relevant articles and documents
Identification of flavone glucuronide isomers by metal complexation and tandem mass spectrometry: Regioselectivity of uridine 5′-diphosphate- glucuronosyltransferase isozymes in the biotransformation of flavones
Robotham, Scott A.,Brodbelt, Jennifer S.
, p. 1457 - 1463 (2013/04/23)
Flavone glucuronide isomers of five flavones (chrysin, apigenin, luteolin, baicalein, and scutellarein) were differentiated by collision-induced dissociation of [Co(II) (flavone-H) (4,7-diphenyl-1,10-phenanthroline) 2]+ complexes. The complexes were generated via postcolumn addition of a metal-ligand solution after separation of the glucuronide products generated upon incubation of each flavone with an array of uridine 5′-diphosphate (UDP)-glucuronosyltransferase (UGT) isozymes. Elucidation of the glucuronide isomers allowed a systematic investigation of the regioselectivity of 12 human UGT isozymes, including 8 UGT1A and 4 UGT2B isozymes. Glucuronidation of the 7-OH position was the preferred site for all the flavones except for luteolin, which possessed adjacent hydroxyl groups on the B ring. For all flavones and UGT isozymes, glucuronidation of the 5-OH position was never observed. As confirmed by the metal complexation/MS/MS strategy, glucuronidation of the 6-OH position only occurred for baicalein and scutellarein when incubated with three of the UGT isozymes.
