title: Transport mechanisms of flavanone aglycones across Caco-2 cell monolayers and artificial PAMPA membranes.
abstract: OBJECTIVE
  We recently reported that flavanone aglycones (hesperetin, naringenin and eriodictyol) are efficiently absorbed via proton-coupled active transport, in addition to transcellular passive diffusion, in Caco-2 cells. Here, we aimed to evaluate in detail the absorption mechanisms of these flavanones, as well as homoeriodictyol and sakuranetin.
  
  
  METHODS
  We evaluated the absorption mechanisms of the above compounds by means of in vitro studies in Caco-2 cells in parallel with an artificial membrane permeation assay (PAMPA) under pH-gradient and iso-pH conditions.
  
  
  RESULTS
  Comparison of the permeability characteristics of flavanones in Caco-2 cells and in PAMPA under these conditions, as well as a consideration of the physicochemical properties, indicated that hesperetin, naringenin, eriodictyol and homoeriodictyol were efficiently transported by passive diffusion according to the pH-partition hypothesis, except in the case of sakuranetin. However, transport of all flavanones were remarkably temperature-dependent, and was significantly reduced when Caco-2 cells were treated with amino acid-modifying reagents.
  
  
  CONCLUSIONS
  Our data confirm that both passive diffusion and an active transport mechanism contribute to flavanone absorption through human intestinal epithelium.
authors.affiliation: Research Center for Food Safety, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan. ashoko@mail.ecc.u-tokyo.ac.jp
authors.forename: Shoko
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Toshitada
authors.initials: T
authors.lastname: Nagai
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Konishi
authors.forename: Soichi
authors.initials: S
authors.lastname: Tanabe
authors.forename: Kaori
authors.initials: K
authors.lastname: Morimoto
authors.forename: Takuo
authors.initials: T
authors.lastname: Ogihara
mesh_terms: D001693:Biological Transport, Active; D018938:Caco-2 Cells / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000502:physiology*; D044950:Flavanones / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D008962:Models, Theoretical; D010539:Permeability; D004364:Pharmaceutical Preparations
chemical_list: D044950:Flavanones; D008567:Membranes, Artificial; D004364:Pharmaceutical Preparations