title: Differentiation of common diastereoisomeric ursane-type triterpenoids by high-performance liquid chromatography/tandem mass spectrometry.
abstract: A rapid and stable method consisting of high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry was established for the identification and differentiation of common diastereoisomeric ursane-type triterpenoids at the C-3 position. Two characteristic fragment ions, [M-H-H(2) O-CO(2)](-) and [M-H-H(2)O-HCOOH](-) , exhibited significant stereochemical effects and were utilized to distinguish 3-OH epimers. Based on reference standards, the abundance of the fragment ion [M-H-H(2)O-HCOOH](-) in 3β-OH compounds in the MS(3) experiment was dramatically higher compared to [M-H-H(2) O-CO(2)](-); however, for 3α-OH compounds, the product ion [M-H-H(2) O-CO(2)](-) was noted to be higher than [M-H-H(2)O-HCOOH](-). Energy-resolved mass spectrometric experiments were carried out to support the differentiation of these diastereoisomeric triterpenoids at the C-3 position. Using this method, a total of nine ursane-type triterpenoids from a plant crude extract, including four pairs of epimers at the C-3 position, were identified and distinguished rapidly. Furthermore, offline Fourier transform ion cyclotron resonance tandem mass spectrometry was also performed to assign accurate elemental compositions.
authors.affiliation: Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Gao
authors.forename: Jianmei
authors.initials: J
authors.lastname: Shi
authors.forename: Xiaomeng
authors.initials: X
authors.lastname: Lu
authors.forename: Cuirong
authors.initials: C
authors.lastname: Sun
authors.forename: Yuanjiang
authors.initials: Y
authors.lastname: Pan
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification; D027824:Rosaceae / Q000737:chemistry; D013237:Stereoisomerism; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification*; D053978:Pentacyclic Triterpenes
chemical_list: D010936:Plant Extracts; D014315:Triterpenes; C000606873:ursane; D053978:Pentacyclic Triterpenes