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

Autor(es)

da Silva-Junior, E. A. ; Paludo, C. R. ; Gouvea, D. R. ; Kato, M. J. ; Furtado, N. A. J. C. ; Lopes, N. P. ; Vessecchi, R. ; Pupo, M. T.

• Tipo de documento: Artigo Científico
• Fonte: Journal of Mass Spectrometry; v. 52, n. 8, p. 517-525, AUG 2017.
• Citações Web of Science: 3

Resumo

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 (C) 2017 John Wiley \& Sons, Ltd. (AU)

• Processo FAPESP: 11/01404-2 - Estudos de metabolismo in vitro de produtos naturais: biotransformação microbiana da piplartina
• Beneficiário: Eduardo Afonso da Silva Junior
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 09/51812-0 - Desenvolvimento de uma plataforma para o estudo do metabolismo in vivo e in vitro de produtos naturais, uma necessidade para o sistema de ensaios pré-clínicos
• Beneficiário: Norberto Peporine Lopes
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Temático
• Processo FAPESP: 14/23604-1 - Química computacional: uma ferramenta para estudos envolvendo espectrometria de massas, reatividade e mecanismos de reação/fragmentação de compostos orgânicos
• Beneficiário: Ricardo Vessecchi Lourenço
• Modalidade de apoio: Auxílio à Pesquisa - Regular