Regio- and isoform-specific glucuronidation of psoralidin: evaluation of 3-o-glucuronidation as a functional marker for UGT1A9.
In this study, we aimed to determine the glucuronidation potential of psoralidin in humans and to perform validation on use of psoralidin-3-O-glucuronidation as a functional marker for UGT1A9. Glucuronidation kinetics was determined using human liver microsomes (HLMs), human intestine microsomes (HIM), and expressed UDP-glucuronosyltransferase (UGT) enzymes. The chemical structures of metabolites were determined by liquid chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy analyses. Validation of psoralidin-3-O-glucuronidation as a UGT1A9 marker was performed using combined approaches including reaction phenotyping, chemical inhibition, activity correlation analysis, and determination of relative activity factor (RAF). HLM and UGT1A9 generated two monoglucuronides (9-O-glucuronide and 3-O-glucuronide) from psoralidin, whereas HIM, UGT1A1, UGT1A7, and UGT1A8 generated one only (9-O-glucuronide). Formation of 3-O-glucuronide in HLM was markedly inhibited by the UGT1A9-selective inhibitors magnolol and niflumic acid. Further, psoralidin-3-O-glucuronidation was strongly correlated with propofol-glucuronidation in a group of nine individual HLMs (r = 0.978, p < 0.001). Strong correlation was also observed between psoralidin-3-O-glucuronidation and the UGT1A9 protein levels measured by Western blotting (r = 0.944, p < 0.001). Moreover, UGT1A9 was responsible for 99.6% of psoralidin-3-O-glucuronidation in HLM based on the RAF approach. In conclusion, psoralidin was subjected to efficient glucuronidation, generating one or two monoglucuronides depending on UGT isozymes. Also, psoralidin-3-O-glucuronidation was an excellent in vitro marker for UGT1A9.
Division of Pharmaceutics, College of Pharmacy, Jinan University, Guangzhou, 510632, China.
Hua
H
Sun
Division of Pharmaceutics, College of Pharmacy, Jinan University, Guangzhou, 510632, China.
Zhiguo
Z
Ma
Division of Pharmaceutics, College of Pharmacy, Jinan University, Guangzhou, 510632, China.
Danyi
D
Lu
Division of Pharmaceutics, College of Pharmacy, Jinan University, Guangzhou, 510632, China.
Baojian
B
Wu
D001572:Benzofurans / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism*; D001713:Biphenyl Compounds / Q000378:metabolism; D003374:Coumarins / Q000378:metabolism*; D020719:Glucuronides / Q000378:metabolism*; D014453:Glucuronosyltransferase / Q000378:metabolism*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D007700:Kinetics; D017705:Lignans / Q000378:metabolism; D008862:Microsomes, Liver / Q000378:metabolism; D009544:Niflumic Acid / Q000378:metabolism; D000090264:UDP-Glucuronosyltransferase 1A9
D001572:Benzofurans; D015415:Biomarkers; D001713:Biphenyl Compounds; D003374:Coumarins; D020719:Glucuronides; D007527:Isoenzymes; D017705:Lignans; C000715591:UGT1A9 protein, human; C005498:magnolol; D009544:Niflumic Acid; D014453:Glucuronosyltransferase; D000090264:UDP-Glucuronosyltransferase 1A9; C102768:psoralidin
UGTs; functional marker; glucuronidation; psoralidin; reaction phenotyping