A systematic investigation of the fragmentation pattern of two furanoheliangolide C‐8 stereoisomers using electrospray ionization mass spectrometry

Sartori, Lucas Rossi; Vessecchi, Ricardo; Humpf, Hans‐Ulrich; Costa, Fernando B. Da; Lopes, Norberto Peporine

doi:10.1002/rcm.6839

Cited by 18 publications

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“…Calculation of PA values of compounds 7 and 8 suggest that protonation occurs on the carbonyl group. This is also backed up by evidence from other combined mass spectrometry and computational studies of the ketones and butenolides . Protonation on the α,β‐carbonyl leads to multiple losses of water, as suggested by Scheme .…”

Section: Resultsmentioning

confidence: 78%

“…This is also backed up by evidence from other combined mass spectrometry and computational studies of the ketones and butenolides. [29][30][31][32][33] Protonation on the α,β-carbonyl leads to multiple losses of water, [33,34] as suggested by Scheme 3. There are possible water losses from the protonated precursor ions to form the stable ions at m/z 285 and 301, respectively, for compounds 7 and 8.…”

Section: Esi-ms/ms Profile Of [M + H] + Molecules and Computational Smentioning

confidence: 99%

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Electrospray ionization tandem mass spectrometry analysis of isopimarane diterpenes from Velloziaceae

Pinto

Vessecchi

Silva³

et al. 2015

Rapid Comm Mass Spectrometry

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2 RATIONALE: The study of natural products by electrospray ionization tandem mass spectrometry (ESI-MS/MS) is an important strategy for the characterization of the major fragmentation reactions which can then help to determine the composition of complex mixtures. Application of ESI-MS/MS to a series of isopimarane diterpenes from Velloziaceae allowed the rationalization of their fragmentation mechanisms. METHODS:Velloziaceae diterpenes were isolated by silica gel column chromatography and investigated by ESI-MS/MS analysis. The fragmentation studies were performed on a quadrupoletime-of-flight instrument using N2 as the collision gas. To help rationalize the fragmentation pathways observed, the geometry and sites of reactivity of the diterpenes were obtained by theoretical calculations using the B3LYP/6-31 + G(d,p) model. Fragmentation mechanisms were proposed on the basis of the calculated protonation sites and product ions energies using density functional theory (DFT) methods. RESULTS:The presence of hydroxyl and carbonyl groups on the terpene core influences the protonation site observed. One compound showed a radical cation as the base peak. MS/MS spectra exhibit water elimination as the major fragmentation pathway (via two ways), either when protonation takes place on the oxygen atom, or through elimination after activation from hydrogen migration. After the elimination of water, the formation of an endocyclic double bond induces a sequential retro-Diels-Alder (RDA) reaction as the major fragmentation step. CONCLUSIONS:A thorough rational analysis of the fragmentation mechanisms of protonated Velloziaceae diterpenes was used to propose the dissociation mechanisms in ESI-MS/MS. The presence of esters in the side chain also influenced the intensity or occurrence of the observed protonated or cationized molecules in ESI-MS. These results will aid the identification of analogues in sample extracts in future metabolomics studies.Keywords: fragmentation mechanism, Velloziaceae, natural products, terpene 3 IntroductionThe Velloziaceae family comprises about 270 species which are distributed mainly in South America and Africa. These plants are found growing in inhospitable environments -sandy and/or rocky soils, with high solar irradiation and low amounts of water. A typical biome is found above 1000 m altitude -known as rupestrian fields 1 . Despite this apparent weakness, many Velloziaceae species present a striking feature of being desiccation tolerant resurrection plants, such as species of the Vellozia genus and the African Xerophyta and Talbotia The structural characterization of the isopimarane diterpenes presented in this paper was performed by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy and compared with previously published data. Although NMR is a most efficient method for the complete structural elucidation of natural products, 6 , 7 a relatively large amount of pure sample is required. This involves timeconsuming and costly isolation procedures or the use of expensive and complex (LC)/NMR ...

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Section: Resultsmentioning

confidence: 78%

Section: Esi-ms/ms Profile Of [M + H] + Molecules and Computational Smentioning

confidence: 99%

Electrospray ionization tandem mass spectrometry analysis of isopimarane diterpenes from Velloziaceae

Pinto

Vessecchi

Silva³

et al. 2015

Rapid Comm Mass Spectrometry

Self Cite

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“…The fragmentation pathways of organic compounds are also important for characterization and structural elucidation of substances in metabolomic studies . Computational quantum calculations provide the information required to identify the ionization sites and the stability of each ionic species formed during the fragmentation in MS/MS experiments . Thus, the combination of MS/MS with computational chemistry provides valuable information for understanding gas‐phase fragmentation and to support the characterization of organic compounds in general …”

Section: Introductionmentioning

confidence: 99%

“…[29] Computational quantum calculations provide the information required to identify the ionization sites and the stability of each ionic species formed during the fragmentation in MS/MS experiments. [30][31][32] Thus, the combination of MS/MS with computational chemistry provides valuable information for understanding gas-phase fragmentation and to support the characterization of organic compounds in general. [28,33,34] Due to the remarkable biological activities of piplartine, (1, Fig.…”

Section: Introductionmentioning

confidence: 99%

Gas‐phase fragmentation of protonated piplartine and its fungal metabolites using tandem mass spectrometry and computational chemistry

et al. 2017

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Piplartine, an alkaloid produced by plants in the genus Piper, displays promising anticancer activity. Understanding the gas-phase fragmentation of piplartine by electrospray ionization tandem mass spectrometry can be a useful tool to characterize biotransformed compounds produced by in vitro and in vivo metabolism studies. As part of our efforts to understand natural product fragmentation in electrospray ionization tandem mass spectrometry, the gas-phase fragmentation of piplartine and its two metabolites 3,4-dihydropiplartine and 8,9-dihydropiplartine, produced by the endophytic fungus Penicillium crustosum VR4 biotransformation, were systematically investigated. Proposed fragmentation reactions were supported by ESI-MS/MS data and computational thermochemistry. Cleavage of the C-7 and N-amide bond, followed by the formation of an acylium ion, were characteristic fragmentation reactions of piplartine and its analogs. The production of the acylium ion was followed by three consecutive and competitive reactions that involved methyl and methoxyl radical eliminations and neutral CO elimination, followed by the formation of a four-member ring with a stabilized tertiary carbocation. The absence of a double bond between carbons C-8 and C-9 in 8,9-dihydropiplartine destabilized the acylium ion and resulted in a fragmentation pathway not observed for piplartine and 3,4-dihydropiplartine. These results contribute to the further understanding of alkaloid gas-phase fragmentation and the future identification of piplartine metabolites and analogs using tandem mass spectrometry techniques. Copyright © 2017 John Wiley & Sons, Ltd.

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“…All analyses were supported by computational methods, and it was possible to suggest the kinetic control of the two different 5 fragmentation pathways. A significant difference between the spectra acquired on QqQ and Orbitrap-HCD and the spectra acquired with TOF was clearly demonstrated 182 . These data were important in assisting structure elucidation, but they can also be an error source in the analysis of sesquiterpene lactones by MS 10 for inexperienced researchers in the spectrometry area.…”

Section: The Use Of Fragmentation Spectra (Ms/ms and Ms N ) In Metabomentioning

confidence: 97%

Anotação probabilística de perfis de metabólitos obtidos por cromatografia líquida acoplada a espectrometria de massas

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A systematic investigation of the fragmentation pattern of two furanoheliangolide C‐8 stereoisomers using electrospray ionization mass spectrometry

Cited by 18 publications

References 43 publications

Electrospray ionization tandem mass spectrometry analysis of isopimarane diterpenes from Velloziaceae

Electrospray ionization tandem mass spectrometry analysis of isopimarane diterpenes from Velloziaceae

Gas‐phase fragmentation of protonated piplartine and its fungal metabolites using tandem mass spectrometry and computational chemistry

Anotação probabilística de perfis de metabólitos obtidos por cromatografia líquida acoplada a espectrometria de massas

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