title: Rapid Identification of unstable acyl glucoside flavonoids of Oxytropis racemosa Turcz by high-performance liquid chromatography-diode array detection-electrospray ionisation/multi-stage mass spectrometry.
abstract: BACKGROUND
  Oxytropis racemosa Turcz is an important minority medicine that is used mainly to improve children's indigestion, especially in inner Mongolia and Tibet. Previous studies indicated that the characteristic constituents of this plant are acylated flavonoids.
  
  
  OBJECTIVE
  Rapidly identify the characteristic chemical constituents of O. racemosa by high-performance liquid chromatography-diode array detection-electrospray ionisation/multi-stage mass spectrometry (HPLC-DAD-ESI/MS(n) ) and suggest a useful method to control the quality of this medicinal plant.
  
  
  METHODS
  In the HPLC fingerprint, 32 flavonoids were tentatively identified by a detailed analysis of their mass spectra, UV spectra and retention times. Furthermore, 13 flavonoids were confirmed by comparison with previously isolated compounds obtained from O. racemosa.
  
  
  RESULTS
  In total, 32 flavonoids, including 13 flavonoids with 3-hydroxy-3-methylglutaric acid (HMG) moieties and four flavonoids with 3-malonyl moieties, were identified in the extract of O. racemosa. Among the compounds identified, 10 were characterised as new compounds for their particular acylated sugar moieties.
  
  
  CONCLUSIONS
  The method described is effective for obtaining a comprehensive phytochemical profile of plants containing unstable acylated flavonoids. The method is also useful for constructing the chromatographic fingerprint of the minority medicine -O. racemosa Turcz for quality control.
authors.affiliation: State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, P. R. China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Song
authors.forename: Xiu-Ping
authors.initials: XP
authors.lastname: Zheng
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Liu
authors.forename: Rui-Fang
authors.initials: RF
authors.lastname: Du
authors.forename: Zi-Ming
authors.initials: ZM
authors.lastname: Feng
authors.forename: Pei-Cheng
authors.initials: PC
authors.lastname: Zhang
authors.forename: Li-Fu
authors.initials: LF
authors.lastname: Bi
mesh_terms: D002681:China; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005419:Flavonoids / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D005960:Glucosides / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D015394:Molecular Structure; D033021:Oxytropis / Q000737:chemistry*; D010946:Plants, Medicinal / Q000737:chemistry; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005419:Flavonoids; D005960:Glucosides