title: Evaluation of the first-pass glucuronidation of selected flavones in gut by Caco-2 monolayer model.
abstract: OBJECTIVE
  Four flavones, namely Apigenin, Baicalein, Chrysin and Luteolin, were selected for study and comparison of their absorption and metabolism in gut using the in vitro Caco-2 monolayer model.
  
  
  METHODS
  Transport of the four flavones in the Caco-2 monolayer model was studied in both Apical-to-Basolateral and Basolateral-to-Apical directions.
  
  
  RESULTS
  All of the selected flavones were able to pass through the Caco-2 cell monolayer with no significant efflux. The permeability coefficients of the four compounds were all greater than 10(-6) cm/sec and those of Apigenin and Baicalein were even greater than 10(-5) cm/sec. Glucuronides of the tested flavones were all formed in the Caco-2 cell monolayer model and a structure-activity relationship has been proposed for this glucuronidation. In addition, Apical-to-Basolateral transport studies were performed in Caco-2 models pre-treated with Chrysin, an UGT inducer. Quantities of the corresponding glucuronides formed were all significantly higher in Chrysin-treated groups than the controls.
  
  
  CONCLUSIONS
  It demonstrated that all selected flavones were substrates of the UGT isoforms that are inducible by Chrysin.
authors.affiliation: Faculty of Medicine, The Chinese University of Hong Kong, School of Pharmacy, Shatin, New Territories, Hong Kong.
authors.forename: Siu Pong
authors.initials: SP
authors.lastname: Ng
authors.forename: Ka Yin
authors.initials: KY
authors.lastname: Wong
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Zhong
authors.initials: Z
authors.lastname: Zuo
authors.forename: Ge
authors.initials: G
authors.lastname: Lin
mesh_terms: D001692:Biological Transport / Q000502:physiology; D018938:Caco-2 Cells; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical / Q000379:methods; D047309:Flavones / Q000737:chemistry / Q000378:metabolism*; D041981:Gastrointestinal Tract / Q000166:cytology / Q000378:metabolism*; D020719:Glucuronides / Q000378:metabolism*; D006801:Humans
chemical_list: D047309:Flavones; D020719:Glucuronides