title: Tandem mass spectrometric fragmentation behavior of lignans, flavonoids and triterpenoids in Streblus asper.
abstract: BACKGROUND
  An unambiguous identification of compounds can be achieved by comparison of known fragmentation patterns. While the literature about fragmentation mechanisms of lignans, flavonoids and triterpenoids is few. So the present study analyses the fragmentation mechanisms of these compounds isolated from Streblus asper.
  
  
  METHODS
  Electrospray ionization ion trap mass spectrometry (ESI-ITMS) and atmospheric pressure chemical ionization ion trap mass spectrometry (APCI-ITMS) were used to obtain the MS(n) spectra of the compounds. By analyzing the differences between the ions, the fragmentation mechanisms of these compounds were explored.
  
  
  RESULTS
  Of the 29 compounds detected, 17, 7, and 5 were lignans, flavonoids and triterpenoids, respectively. The majority of lignans were found to give [M - H](-) ions of sufficient abundance for MS(n) analyses. The flavonoids were prone to the loss of CO and H2O. The triterpenoids always lost one formic acid molecule and two hydrogens, or one H2O from [M - H](-) to form the most abundant product ion in the MS(n) spectrum.
  
  
  CONCLUSIONS
  ESI/APCI-ITMS were demonstrated to be fast, effective and practical tools to characterize the structures of flavonoids, triterpenoids and lignans. Results of the present study can help identify the analogous constituents by analyzing their MS(n) spectra.
authors.affiliation: Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), School of Environment and Resource of Guangxi Normal University, Guilin, 541004, P.R. China; Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Ministry of Education of China), Guilin, 541004, P.R. China.
authors.forename: Chen
authors.initials: C
authors.lastname: Li
authors.forename: Cuiping
authors.initials: C
authors.lastname: Huang
authors.forename: Tailiang
authors.initials: T
authors.lastname: Lu
authors.forename: Liangdeng
authors.initials: L
authors.lastname: Wu
authors.forename: Shengping
authors.initials: S
authors.lastname: Deng
authors.forename: Ruiyun
authors.initials: R
authors.lastname: Yang
authors.forename: Jun
authors.initials: J
authors.lastname: Li
mesh_terms: D005419:Flavonoids / Q000032:analysis / Q000737:chemistry*; D017705:Lignans / Q000032:analysis / Q000737:chemistry*; D000432:Methanol; D029586:Moraceae / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014315:Triterpenes / Q000032:analysis / Q000737:chemistry*
chemical_list: D005419:Flavonoids; D017705:Lignans; D010936:Plant Extracts; D014315:Triterpenes; D000432:Methanol