Identification of Flavone Glucuronide Isomers by Metal Complexation and Tandem Mass Spectrometry: Regioselectivity of Uridine 5鈥?Diphosphate鈥揋lucuronosyltransferase Isozymes in the Biotransformation o
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- 作者：Scott A. Robotham ; Jennifer S. Brodbelt
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2013
- 出版时间：February 20, 2013
- 年：2013
- 卷：61
- 期：7
- 页码：1457-1463
- 全文大小：269K
- 年卷期：v.61,no.7(February 20, 2013)
- ISSN：1520-5118
文摘
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鈥搇igand solution after separation of the glucuronide products generated upon incubation of each flavone with an array of uridine 5鈥?diphosphate (UDP)鈥揼lucuronosyltransferase (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.