title: Fragmentation of plumeran indole alkaloids from Aspidosperma spruceanum by electrospray ionization tandem mass spectrometry.
abstract: The fragmentation of six plumeran indole alkaloids (PIAs) previously isolated from Aspidosperma spruceanum has been investigated by electrospray ionization tandem mass spectrometry (ESI-MS/MS) in the positive ion mode. The fragmentation pathways have been established on the basis of MS/MS experiments using fragment ions generated in-source and deuterium-labeled alkaloids as precursor ions and on the basis of accurate mass measurements. Our results demonstrated that the fragmentation routes observed for the protonated PIAs are essentially derived from a pericyclic reaction and from the opening of rings D and E, followed by 1,4-hydrogen rearrangements. Product ions resulting from radical eliminations were also observed, contrary to the 'even-electron rule'. Our data reveals that some product ions from protonated PIAs provide crucial information for the characterization of the acyl substituent at N-1, the methoxyl and hydroxyl groups at the aromatic moiety, and give evidence of an ether bridge between C-18 and C-21. The data reported here were used for the dereplication of these compounds in a stem bark methanolic extract of Aspidosperma spruceanum.
authors.affiliation: Núcleo de Pesquisas em Ciências Exatas e Tecnológicas, Universidade de Franca, 14404-600 Franca-SP, Brazil.
authors.forename: Gabriela P
authors.initials: GP
authors.lastname: Aguiar
authors.forename: Kamila A L
authors.initials: KA
authors.lastname: Wakabayashi
authors.forename: Guilherme F
authors.initials: GF
authors.lastname: Luz
authors.forename: Vilma B
authors.initials: VB
authors.lastname: Oliveira
authors.forename: Leda
authors.initials: L
authors.lastname: Mathias
authors.forename: Ivo J C
authors.initials: IJ
authors.lastname: Vieira
authors.forename: Raimundo
authors.initials: R
authors.lastname: Braz-Filho
authors.forename: Antonio E M
authors.initials: AE
authors.lastname: Crotti
mesh_terms: D030009:Aspidosperma / Q000737:chemistry*; D026121:Indole Alkaloids / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D015394:Molecular Structure; D024301:Plant Bark / Q000737:chemistry; D011522:Protons; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D026121:Indole Alkaloids; D011522:Protons