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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Electrospray ionization tandem mass spectrometry of labdane-type acid diterpenes

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Aguiar, Gabriela P. [1] ; Crevelin, Eduardo J. [2] ; Dias, Herbert J. [2] ; Ambrosio, Sergio R. [1] ; Bastos, Jairo K. [3] ; Heleno, Vladimir C. G. [1] ; Vessecchi, Ricardo [2] ; Crotti, Antonio E. M. [2]
Total Authors: 8
[1] Univ Franca, Nucleo Pesquisas Ciencias Exatas & Tecnol, Franca - Brazil
[2] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Quim, Ribeirao Preto, SP - Brazil
[3] Univ Sao Paulo, Sch Pharmaceut Sci Ribeirao Preto, Ribeirao Preto - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Journal of Mass Spectrometry; v. 53, n. 11, p. 1086-1096, NOV 2018.
Web of Science Citations: 1

Copaifera (Leguminoseae) species produce a commercially interesting oleoresin that displays several biological activities, including antimicrobial and anti-inflammatory properties. Labdane-type diterpenes are the main chemical constituents of these oleoresins, and copalic acid is the only compound that has been detected in all Copaifera oleoresins. In this study, we investigate some aspects of the gas-phase fragmentation reactions involved in the formation of the product ions from the deprotonated compounds (-)-ent-copalic acid (1), (-)-ent-3 beta-hydroxy-copalic acid (2), (-)-ent-3 beta-acetoxy-copalic acid (3), and (-)-ent-agathic acid (4) by electrospray ionization tandem mass spectrometry (ESI-MS/MS) and multiple stage mass spectrometry (MSn). Our results reveal that the product ion with m/z 99 is common to all the analyzed compounds, whereas the product ion with m/z 217 is diagnostic for compounds 2 and 3. Moreover, only compound 4 undergoes CO2 (44 u) and acetic acid (60 u) elimination from the precursor ion. Thermochemical data obtained by computational chemistry at the B3LYP/6-31G(d) level of theory support the proposed ion structures. These data helped us to identify these compounds in a crude commercial Copaifera langsdorffii oleoresin by selective multiple reaction monitoring (MRM). Finally, a precursor ion scan (PIS) strategy aided screening of labdane-type acid diterpenes other than 1 to 4 in the same Copaifera oleoresin sample and led us to propose the structures of 8,17-dihydro-ent-agathic acid (5) and 3-keto-ent-copalic acid (6), which have not been previously reported in Copaifera oleoresins. (AU)

FAPESP's process: 13/20094-0 - Evaluation of the anti-parasitary and insecticidal activities of benzofuran derivatives, and study of their gas-phase fragmentation reactions using tandem mass spectrometry
Grantee:Antônio Eduardo Miller Crotti
Support type: Regular Research Grants
FAPESP's process: 11/13630-7 - Chemical and pharmacological validation of extracts and active compounds of Copaifera species
Grantee:Jairo Kenupp Bastos
Support type: Research Projects - Thematic Grants
FAPESP's process: 14/23604-1 - Computational chemistry: a tool to studies of mass spectrometry, reactivity and fragmentation/reaction mechanisms of organic compounds
Grantee:Ricardo Vessecchi Lourenço
Support type: Regular Research Grants
FAPESP's process: 12/22832-5 - Fragmentation studies on labdane-type diterpenes isolated from Copaifera langsdorffii oleoresin using tandem mass spectrometry
Grantee:Gabriela de Paula Aguiar
Support type: Scholarships in Brazil - Master