title: Characteristic fragmentation behavior of some glucuronide-type triterpenoid saponins using electrospray ionization tandem mass spectrometry.
abstract: The fragmentation behavior of some glucuronide-type triterpenoid saponins from Symplocos chinensis, and their analogues escin Ia and Ib, were investigated by positive ion electrospray ionization tandem mass spectrometry using a quadrupole linear ion trap mass spectrometer. The fragmentation patterns of these saponins significantly changed in accordance with structural variations in the glucuronyl residue of the oligosaccharide chain. It was found that the carboxyl group and hydroxyl group at the C-3' position of the glucuronyl residue were the key sites for determining the fragmentation behavior of these compounds. When the carboxyl group was esterified, only the C(2alpha) ion, and no B(2alpha) ion, and cationized aglycone were observed. When the hydroxyl group at C-3' was acylated, the inherent cross-ring cleavage was hindered. However, glycosidic cleavages always occurred, regardless of the crucial structural variations. The results of the present studies can benefit the determination of trace triterpenoid saponins of this type in crude plant extracts, and also provide background information to aid the structural investigations of similar glycoconjugates.
authors.affiliation: Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.forename: Zeper
authors.initials: Z
authors.lastname: Abliz
authors.forename: Guangmiao
authors.initials: G
authors.lastname: Fu
authors.forename: Meijun
authors.initials: M
authors.lastname: Tang
authors.forename: Shishan
authors.initials: S
authors.lastname: Yu
mesh_terms: D004928:Escin / Q000737:chemistry*; D020719:Glucuronides / Q000737:chemistry*; D019684:Magnoliopsida / Q000737:chemistry; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014315:Triterpenes / Q000737:chemistry*
chemical_list: D020719:Glucuronides; D010936:Plant Extracts; D014315:Triterpenes; C409970:escin Ib; D004928:Escin; C115101:escin Ia