Fragmentation study of clerodane diterpenes from Casearia species by tandem mass spectrometry (quadrupole time-of-flight and ion trap)

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Danuello, Amanda ; de Castro, Rogerio Cardoso ; Pilon, Alan Cesar ; Pires Bueno, Paula Carolina ; Pivatto, Marcos ; Vieira Junior, Gerardo Magela ; Carvalho, Flavio Alexandre ; Oda, Fernando Bombarda ; Perez, Consuelo Javiera ; Lopes, Norberto Peporine ; Dos Santos, Andre Gonzaga ; Ifa, Demian Rocha ; Cavalheiro, Alberto Jose

• Document type: Journal article
• Source: RAPID COMMUNICATIONS IN MASS SPECTROMETRY; v. 34, p. 7-pg., 2020-05-20.

Abstract

Rationale Clerodane-type diterpenes from Casearia species show important pharmacological activites such as antitumor, antimicrobial and anti-inflamatory. There are several mass spectrometry (MS)-based methods for identification of diterpenes; however, there is still a lack of MS procedures capable of providing characteristic fragmentation pathways for a rapid and unambiguous elucidation of casearin-like compounds. Methods Casearin-like compounds were investigated by electrospray ionization tandem mass spectrometry (ESI-MS/MS). The fragmentation studies were carried out by tandem mass spectrometry in space (quadrupole time-of-flight (QTOF)) using different collision energies and also by tandem mass spectrometry in time (QIT) by selective isolation of product ions. Results Casearin-like compounds presented a predominance of sodium- and potassium-cationized precursor ions. Both QIT and QTOF techniques provided sequential neutral losses of esters related to the R-1 to R-5 substituents linked to the nucleus of the clerodane diterpenes. The fragmentation pathway is initiated with a cleavage of the ester moieties R-2 followed by the elimination of the ester groups R-3, both losing neutral carboxylic acids. Using QIT, it was also possible to observe the cleavage of the ester groups R-1 or R-5 by MS4 experiments. Conclusions Through a rational analysis of the fragmentation mechanisms of Casearia diterpenes it was possible to suggest an annotation strategy based on the sequential cleavages of the ester groups related to the R-2, R-3 and R-5 substituents. These results will assist studies of the dereplication and metabolomics involving casearin-like compounds present in complex extracts of Casearia species. (AU)

• FAPESP's process: 14/50926-0 - INCT 2014: biodiversity and natural products
• Grantee: Vanderlan da Silva Bolzani
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 16/13292-8 - Analysis of nitrogen content in antropic influenced areas in Amazon and Atlantic Forest using a metabolomic tools
• Grantee: Alan Cesar Pilon
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/07600-3 - CIBFar - Center for Innovation in Biodiversity and Drug Discovery
• Grantee: Glaucius Oliva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 11/21440-3 - Infra-specific chemical variability and dynamics of phenolic and diterpenic secondary metabolites in Casearia sylvestris Sw (Salicaceae) from different Brazilian ecosystems: metabolomics and proteomics correlation
• Grantee: Paula Carolina Pires Bueno
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 17/19702-6 - Integrated omics approaches for the evaluation of the micromolecular phenotypic dynamics of Glycine max (soja) genetically modified for water stress tolerance
• Grantee: Paula Carolina Pires Bueno
• Support Opportunities: Scholarships in Brazil - Post-Doctoral