title: Identification of xanthones from Swertia punicea using high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry.
abstract: BACKGROUND
  Swertia punicea Hemsl. (Gentianaceae) are used mainly for the treatment of acute bilious hepatitis, cholecystitis, fever, intoxification and jaundice in China, as a traditional Chinese folk medicine. Xanthones as the main chemical components of Swertia punicea have many possible pharmacological properties, such as hepatoprotective and anti-HIV. In order to obtain an overall picture of the xanthones of Swertia punicea, high-performance liquid chromatography diode-array detection/tandem mass spectrometry (HPLC/DAD-ESI-MS(n)) was applied to the structural characterization of xanthones in ethyl acetate and acetone extracts.
  
  
  METHODS
  The ESI-MS fragmentation behaviors of xanthones were investigated based on the 17 reference xanthones and then applied to the structural characterization of xanthones in ethyl acetate and acetone extracts of Swertia punicea by HPLC/DAD-ESI-MS(n).
  
  
  RESULTS
  The fragmentation rules of aglycone, C-glycosides, O-glycosides, and polyxanthones with different linkages were summarized. The observed fragmentation pathways were used successfully for the analysis of the xanthone constituents of Swertia punicea, and a total of 34 xanthones were identified, among which 16 compounds were new and one compound was reported from this species for the first time.
  
  
  CONCLUSIONS
  The described methods were very valuable for the identification of xanthones, especially of the trace compounds, and therefore could be utilized for sensitive and rapid qualitative analysis of xanthones in Swertia punicea.
authors.affiliation: School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Xin-Gang
authors.initials: XG
authors.lastname: Du
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Qing-Ying
authors.initials: QY
authors.lastname: Zhang
authors.forename: Jun
authors.initials: J
authors.lastname: Cheng
authors.forename: Bharathi
authors.initials: B
authors.lastname: Avula
authors.forename: Ikhlas A
authors.initials: IA
authors.lastname: Khan
authors.forename: De-An
authors.initials: DA
authors.lastname: Guo
mesh_terms: D000085:Acetates / Q000737:chemistry; D000096:Acetone / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification; D008958:Models, Molecular; D010936:Plant Extracts / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D029967:Swertia / Q000737:chemistry*; D053719:Tandem Mass Spectrometry / Q000379:methods; D044004:Xanthones / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D000085:Acetates; D006027:Glycosides; D010936:Plant Extracts; D044004:Xanthones; D000096:Acetone; C007650:ethyl acetate