title: [Biotransformation by human intestinal flora and absorption-transportation characteristic in a model of Caco-2 cell monolayer of d-corydaline and tetrahydropalmatine].
abstract: OBJECTIVE
  To study the biotransformation by human intestinal flora, and the absorption and transportation characteristic in a model of human colon adenocarcinoma cell lines (Caco-2 cell) monolayer of d-corydaline (CDL) and tetrahydropalmatine (THP).
  
  
  METHODS
  CDL or THP was incubated with crude enzymes of human intestinal flora under the anaerobic environment and 37 degrees C conditions to transform CDL or THP. Caco-2 cell monolayer was used as an intestinal epithelial cell model for determination of the permeability of CDL or THP from apical side (AP side) to basolateral side (BL side) or from BL side to AP side. Transportation parameters and permeability coefficients (P(app)) were then calculated, and P(app) values were compared with the reported values for model compounds, propranolol as a well absorbed drug and atenolol as a poor absorbed drug. The concentration of CDL or THP was measured by HPLC coupled with photodiode array detector.
  
  
  RESULTS
  CDL or THP in the human intestinal flora incubation system did not happen biotransformation. In the Caco-2 cell monolayer model, the P(app) magnitudes of both CDL and THP were 1 x 10(-5) cm x s(-1) in the bi-directional transport, which were identical with propranolol. And their transports were concentration dependent between 0-180 min.
  
  
  CONCLUSIONS
  Both CDL and THP may be stable in the human intestinal flora incubation system, and their absorption and transportation in the human Caco-2 cell monolayer model are mainly via passive diffusion mechanism.
authors.affiliation: Department of Natural Medicines, School of Pharmaceutical Sciences, State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100191, China. liujx0324@sina.com
authors.forename: Yang-Zi
authors.initials: YZ
authors.lastname: Liu
authors.forename: Xin-Bao
authors.initials: XB
authors.lastname: Yang
authors.forename: Xiu-Wei
authors.initials: XW
authors.lastname: Yang
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: Yao
authors.forename: Li
authors.initials: L
authors.lastname: Ran
authors.forename: Shuai
authors.initials: S
authors.lastname: Wu
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.forename: Jian-Xun
authors.initials: JX
authors.lastname: Liu
mesh_terms: D001419:Bacteria / Q000378:metabolism; D001600:Berberine Alkaloids / Q000378:metabolism / Q000493:pharmacokinetics*; D001692:Biological Transport; D001711:Biotransformation; D018938:Caco-2 Cells; D031311:Corydalis / Q000737:chemistry*; D004365:Drugs, Chinese Herbal / Q000378:metabolism / Q000493:pharmacokinetics*; D006801:Humans; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000382:microbiology; D008954:Models, Biological
chemical_list: D001600:Berberine Alkaloids; D004365:Drugs, Chinese Herbal; C452799:corydaline; C014215:tetrahydropalmatine