title: Wedelolactone metabolism in rats through regioselective glucuronidation catalyzed by uridine diphosphate-glucuronosyltransferases 1As (UGT1As).
abstract: BACKGROUND
  Wedelolactone (WEL), a medicinal plant-derived coumestan, has been reported to exhibit a diverse range of pharmacological activities. However, the metabolism and disposition of WEL remain unexplored.
  
  
  OBJECTIVE
  The present study aims to investigate the metabolism of WEL in rats and identify the enzymes responsible for forming major WEL metabolites.
  
  
  METHODS
  Plasma, urine, feces, and bile samples were collected before and after 50 mg/kg WEL was orally administered to rats. Metabolites were profiled by ultrahigh performance liquid chromatography/quadrupole time-of-flight mass spectrometry and identified by high-performance liquid chromatography-solid-phase extraction-nuclear magnetic resonance spectroscopy. The in vitro WEL glucuronidation activities of human liver microsomes, human kidney microsomes, human intestine microsomes, and 12 recombinant human uridine diphosphate-glucuronosyltransferase (UGT) isoforms were screened. Molecular docking simulation of the interaction between WEL and UGT1A9 was conducted.
  
  
  RESULTS
  WEL underwent extensive metabolism, and 17 metabolites were identified. The major metabolic pathways observed were glucuronidation and methylation. Glucuronic acid was preferentially introduced into 5-OH, whereas no obvious regioselectivity was observed in the methylation of 11-OH and 12-OH. Multiple UGTs, including UGT1A1, UGT1A3, UGT1A6, UGT1A7, UGT1A8, UGT1A9, and UGT1A10, were involved in forming WEL glucuronides and O-methylated WEL glucuronides.
  
  
  CONCLUSIONS
  The extensive glucuronidation and methylation is responsible for the low oral bioavailability of WEL in rats. UGT1A1 and UGT1A9 were the major enzymes involved in the glucuronidation of WEL and O-methylated WEL. Molecular docking studies revealed that 5-OH was accessible to the catalytic domain of UGT1As; therefore, 5-OH exhibited a high probability of glucuronidation.
authors.affiliation: Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.affiliation: State Key Laboratory of Natural Medicines, Research Department of Pharmacognosy, China Pharmaceutical University, 639 Longmian Road, Nanjing 211198, China.
authors.forename: Xue-juan
authors.initials: XJ
authors.lastname: Huang
authors.affiliation: Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China.
authors.forename: Jian-long
authors.initials: JL
authors.lastname: Peng
authors.affiliation: Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China.
authors.forename: Ming-yue
authors.initials: MY
authors.lastname: Zheng
authors.affiliation: Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China.
authors.forename: Da-fang
authors.initials: DF
authors.lastname: Zhong
authors.affiliation: State Key Laboratory of Natural Medicines, Research Department of Pharmacognosy, China Pharmaceutical University, 639 Longmian Road, Nanjing 211198, China. Electronic address: njchaofeng@126.com.
authors.forename: Chao-feng
authors.initials: CF
authors.lastname: Zhang
authors.affiliation: Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201203, China. Electronic address: xychen@simm.ac.cn.
authors.forename: Xiao-yan
authors.initials: XY
authors.lastname: Chen
mesh_terms: D000818:Animals; D019659:Asteraceae / Q000737:chemistry; D001682:Biological Availability; D003374:Coumarins / Q000378:metabolism / Q000493:pharmacokinetics*; D020723:Glucuronic Acid / Q000378:metabolism; D020719:Glucuronides / Q000378:metabolism*; D014453:Glucuronosyltransferase / Q000378:metabolism*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D013058:Mass Spectrometry; D008745:Methylation; D008861:Microsomes / Q000378:metabolism; D062105:Molecular Docking Simulation; D010936:Plant Extracts / Q000378:metabolism; D020033:Protein Isoforms; D051381:Rats; D000090264:UDP-Glucuronosyltransferase 1A9; D014530:Uridine Diphosphate / Q000378:metabolism*; D000099148:UGT1A1 Enzyme
chemical_list: D003374:Coumarins; D020723:Glucuronic Acid; D020719:Glucuronides; D014453:Glucuronosyltransferase; D010936:Plant Extracts; D020033:Protein Isoforms; D000090264:UDP-Glucuronosyltransferase 1A9; D014530:Uridine Diphosphate; D000099148:UGT1A1 Enzyme; C000715591:UGT1A9 protein, human; C051122:wedelolactone; C505898:coumestan
keywords: Metabolism; Molecular docking; Uridine diphosphate-glucuronosyltransferase (UGT); Wedelolactone