title: Structure revision of hupehensis saponin F and G and characterization of new trace triterpenoid saponins from Anemone hupehensis by tandem electrospray ionization mass spectrometry.
abstract: Electrospray ionization ion-trap tandem mass spectrometry (ESI-MS(n)) was first employed for reinvestigating the structures of hupehensis saponin F and G previously isolated from Anemone hupehensis in our lab. Hupehensis saponin G was determined to contain one more trisaccharide unit (Rha-(1→4)-Glc-(1→6)-Glc-), not a glucose residue, than saponin F based on their molecular weights deduced from their [M+Na](+) ions in ESI-MS spectra. The (2,4)A(4α)-ion at m/z 551.3 formed by retro-Diels-Alder (RDA) rearrangement in positive mode illustrated that the C-28 sugar chains of the two saponins were composed of trisaccharide repeating moieties with (1→4) linkages rather than (1→3) linkages. The interpretation of 2D-NMR spectra of the two compounds also confirmed the results obtained by ESI-MS(n). Moreover, from the water soluble part of A. hupehensis, two novel triterpene saponins were tentatively characterized to contain 4 and 5 (1→4)-linked above trisaccharide repeating moieties at C-28 position according to their ESI-MS(n) behaviors, respectively.
authors.affiliation: Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China.
authors.forename: Fu
authors.initials: F
authors.lastname: Li
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Minghai
authors.initials: M
authors.lastname: Tang
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.forename: Lisheng
authors.initials: L
authors.lastname: Ding
authors.forename: Lijuan
authors.initials: L
authors.lastname: Chen
authors.forename: Mingkui
authors.initials: M
authors.lastname: Wang
mesh_terms: D031883:Anemone / Q000737:chemistry*; D002240:Carbohydrate Sequence; D008969:Molecular Sequence Data; D012503:Saponins / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014315:Triterpenes / Q000737:chemistry*
chemical_list: D012503:Saponins; D014315:Triterpenes