title: Identification of in-vivo and in-vitro metabolites of palmatine by liquid chromatography-tandem mass spectrometry.
abstract: OBJECTIVE
  Despite its important therapeutic value, the metabolism of palmatine is not yet clear. Our objective was to investigate its in-vivo and in-vitro metabolism.
  
  
  METHODS
  Liquid chromatography-tandem electrospray ionization mass spectrometry (LC-ESI/MSn) was employed in this work. In-vivo samples, including faeces, urine and plasma of rats, were collected after oral administration of palmatine (20 mg/kg) to rats. In-vitro samples were prepared by incubating palmatine with intestinal flora and liver microsome of rats, respectively. All the samples were purified via a C18 solid-phase extraction procedure, then chromatographically separated by a reverse-phase C18 column with methanol-formic acid aqueous solution (pH 3.5, 70:30 v/v) as mobile phase, and detected by an on-line MSn detector. The structure of each metabolite was elucidated by comparing its molecular weight, retention time and full-scan MSn spectra with those of the parent drug.
  
  
  RESULTS
  The results revealed that 12 metabolites were present in rat faeces, 13 metabolites in rat urine, 7 metabolites in rat plasma, 10 metabolites in rat intestinal flora and 9 metabolites in rat liver microsomes. Except for six of the metabolites in rat urine, the other in-vivo and in-vitro metabolites were reported for the first time.
  
  
  CONCLUSIONS
  Seven new metabolites of palmatine (tri-hydroxyl palmatine, di-demethoxyl palmatine, tri-demethyl palmatine, mono-demethoxyl dehydrogen palmatine, di-demethoxyl dehydrogen palmatine, mono-demethyl dehydrogen palmatine, tri-demethyl dehydrogen palmatine) were reported in this work.
authors.affiliation: Hubei Province Key Laboratory of Biotechnology of Chinese Traditional Medicine, Hubei University, Wuhan, China.
authors.forename: Qian C
authors.initials: QC
authors.lastname: Yang
authors.forename: Wen H
authors.initials: WH
authors.lastname: Wu
authors.forename: Feng M
authors.initials: FM
authors.lastname: Han
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000818:Animals; D001600:Berberine Alkaloids / Q000032:analysis* / Q000097:blood / Q000652:urine; D002853:Chromatography, Liquid; D005243:Feces / Q000737:chemistry; D005260:Female; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry
chemical_list: D001600:Berberine Alkaloids; C005413:palmatine