Fragmentation pathway and structural characterization of new glycosylated phenolic derivatives from Eremanthus glomerulatus Less (Asteraceae) by electrospray ionization tandem mass spectrometry

Abstract

Fragmentation pathway and structural characterization of new glycosylated phenolic derivatives from Eremanthus glomerulatus Less (Asteraceae) by electrospray ionization tandem mass spectrometry Dear editor, The genus Eremanthus Less (Asteraceae: Vernonieae) comprises 22 species endemic in the Brazilian "Cerrado," 1,2 which has demonstrated itself as a rich source of new natural products with biological activity as antitumor, antimicrobial, antioxidant, and schistosomicidal. 3-5 Previous phytochemical investigations into E. glomerulatus leaves led to the isolation of sesquiterpene lactones (STL) of furanoheliangolide, germacranolide, and guaianolide moieties; these studies also detected sesquiterpenes, triterpenes, and some flavonoids. 6,7 Glycosylated phenolic derivatives have not been described for Eremanthus genus, and their identification have usually been made by isolation and structural elucidation by nuclear magnetic resonance (NMR) and other techniques. The isolation and characterization of natural secondary metabolites is extremely difficult, once the procedure is time-consuming, labor intensive, and expensive, besides the large amount of solvents, reagents, and equipment needed. These obstacles highlight the need /journal/jms 783 JMS LETTERS 785 Journal of MASS SPECTROMETRY fragmentations of this compound occur in a consecutive way, while in compound 3, because there is no path of fragmentation as the same favoring, the fragmentations occur by competitive routes, thus generating a greater number of product ions. 14 The reporting of these diglycosylated phenolic compounds is also important for chemotaxonomy. This chemical class is unusual in Eremanthus genus, despite the glycosylated phenolic derivatives have already been described for Asteraceae family. 15 Moreover, this chemical class has been described for a wide range of biological activities, which are very interesting for pharmacology studies in the search for new drugs. Shiraga et al 16 described three glycosylated phenolic derivatives with relevant antiulcerogenic activity in rats; also, Duynstee et al 17 suggest that the biological activity would be due to the presence of a rare apiofuranose sugar and the rather electron-rich aryl moiety. Arthur et al 18 described phenylethanoid glycosides (phenolics) as the major responsible for antioxidant activity in crude extracts of Lippia multiflora. Moreover, Granica et al 15 showed novel stilbenoids (glycosylated phenolics) with potential anti-inflammatory activity.It is possible to conclude that our study provides rich information about compounds 3 and 8, which allow their identification in complex samples in future works. Our fragmentation study also leads us to observe that MS n experiments were applied successfully in fragmentation study allowing us to propose a plausible mechanistic pathway for the glycosylated phenolic compounds with the aim of improving MS interpretation knowledge. Besides, this compound class was described for the first time in the genus Eremanthus, which could help in future phyt...

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

“…Alternatively, tandem mass spectrometry (MS/MS)‐based techniques have been successfully used for determination of natural product isomers, such as phenolics, diterpenes and alkaloids 29–31 . Electrospray ionization tandem mass spectrometry (ESI‐MS/MS) using collision‐induced dissociation (CID) is a very valuable tool for the analyses of labile compounds with low vapor pressures and/or highly polar chemical functionalities 32 …”

Antibacterial Activity from Momordica charantia L. Leaves and Flavones Enriched Phase

“…A total of 32 major metabolites were detected in the EE. Of these, 25 compounds were annotated in level 2 and 3 of identification according to MSI [36] based on HRMS and MS/MS data and the literature; most of these compounds have well characterized fragmentation (MS/MS) profiles [37].…”

Detailed 1H and 13C NMR structural assignments of four sesquiterpene lactones isolated from Eremanthus elaeagnus (Asteraceae)

“…[14][15][16] The Eremanthus Less (Asteraceae: Vernonieae) genus is endemic to Brazil, comprises 22 species, and has demonstrated to be a rich source of new NPs with an expressive range of biological activities such as antimicrobial, antitumor, schistosomicidal, and antioxidant. [17][18][19] Among these compounds, 4,5-dihydro-1 0 ,2 0 -epoxyeremantholide-C (1), 4,5-dihydro-2 0 ,3 0 -dihydroxy-15-desoxy goyazensolide…”