title: Absorption properties and mechanism of trolline and veratric acid and their implication to an evaluation of the effective components of the flowers of Trollius chinensis.
abstract: OBJECTIVE
  To study the absorption properties and mechanism of two important components, trolline and veratric acid, from the flowers of Trollius chinensis, in order to better understand the contribution of these two compounds to the effectiveness of these flowers.
  
  
  METHODS
  The human Caco-2 cell monolayer model was employed to study the transport of trolline and veratric acid from apical side (AP) to basal side (BL), and from BL to AP by determining the transport rates as the function of time and concentration and calculating apparent permeability coefficients (Papp).
  
  
  RESULTS
  Trolline and veratric acid were transported across Caco-2 cell monolayer through different mechanisms in a concentration dependent manner. Trolline was transported at a Papp level of 10(-6) cm·s(-1) with a Papp AP→BL/Papp BL→AP ratio of more than 1.8 or less than 0.8, while veratric acid was transported at a Papp level of 10(-5)cm·s(-1) with a Papp AP→BL/Papp BL→AP ratio of close to 1.0.
  
  
  CONCLUSIONS
  Trolline is moderately absorbed through an associative mechanism involving active and passive transport, and veratric acid is well-absorbed mainly through passive diffusion. These factors should be taken into account when chemically assessing the pharmacodynamic material basis of the flowers of T. chinensis.
authors.affiliation: School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100102, China.
authors.forename: Li-Jia
authors.initials: LJ
authors.lastname: Liu
authors.affiliation: School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100102, China.
authors.forename: Xiu-Wen
authors.initials: XW
authors.lastname: Wu
authors.affiliation: School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100102, China. Electronic address: wangrufeng@tsinghua.org.cn.
authors.forename: Ru-Feng
authors.initials: RF
authors.lastname: Wang
authors.affiliation: School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100102, China.
authors.forename: Yu-Shuai
authors.initials: YS
authors.lastname: Peng
authors.affiliation: School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100102, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Otorhinolaryngology, Peking University Third Hospital, Beijing 100191, China. Electronic address: liujunxiusanyuan@sina.com.
authors.forename: Jun-Xiu
authors.initials: JX
authors.lastname: Liu
mesh_terms: D000470:Alkaloids / Q000378:metabolism* / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000378:metabolism / Q000494:pharmacology; D000893:Anti-Inflammatory Agents / Q000378:metabolism / Q000494:pharmacology; D001692:Biological Transport; D018938:Caco-2 Cells; D035264:Flowers / Q000737:chemistry*; D006801:Humans; D007408:Intestinal Absorption; D010936:Plant Extracts / Q000378:metabolism* / Q000494:pharmacology; D029626:Ranunculaceae / Q000737:chemistry*; D014641:Vanillic Acid / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology
chemical_list: D000470:Alkaloids; D000890:Anti-Infective Agents; D000893:Anti-Inflammatory Agents; D010936:Plant Extracts; C574561:trolline; C009333:veratric acid; D014641:Vanillic Acid
keywords: Caco-2 cell monolayer model; Trolline; Trollius chinensis; absorption; veratric acid