The IPB has once again been recognized for its exemplary actions in terms of equal opportunity-oriented personnel and organizational policies and has received the TOTAL E-QUALITY certification for the…
The Plant Science Student Conference (PSSC) has been organised by students from the two Leibniz institutes, IPK and IPB, every year for the last 20 years. In this interview, Christina Wäsch (IPK) and…
Moura, P. H. B.; Porzel, A.; Nunes, R. M.; Baratto, L. C.; Wessjohann, L. A.; Martins, R. C. C.; Leal, I. C. R.;Antioxidant capacity and fragmentation features of
C‐glycoside isoflavones by high‐resolution electrospray ionization tandem mass spectrometry using collision‐induced and high‐energy collisional dissociation techniquesJ. Mass Spectrom.56e4793(2021)DOI: 10.1002/jms.4793
The rapid annotation and identification by mass spectrometry techniques
of flavonoids remains a challenge, due to their structural diversity and
the limited availability of reference standards. This study applies a
workflow to characterize two isoflavonoids, the orobol-C-glycosides
analogs, using high-energy collisional dissociation (HCD)- and
collision-induced dissociation (CID)-type fragmentation patterns, and
also to evaluate the antioxidant effects of these compounds by ferric
reducing antioxidant power (FRAP), 2,2′-azino-bis(3-ethylbenzothiazolin
acid) 6-sulfonic acid (ABTS), and 2,2-diphenyl-1-picrylhydrazyl (DPPH)
methods. By the CID-type fragmentation, in positive mode and at all
high-resolution mass spectrometry (HRMS) multiple stage, there were
shown differences in the annotation of the compounds, mainly concerning
some ratios of relative abundance. At CID-MS2 20 eV, the compounds could be efficiently characterized, because they present distinct base peaks [M + H]+ and [M + H–H2O]+ for the orobol-8-C- and orobol-6-C-glycoside, respectively. Similarly, by the HCD-type fragmentation, in HRMS2 stage, differences between orobol analogs in both mode of ionization were observed. However, the HR HCD-MS2 at 80 eV, in positive mode, generated more ions and each isomer presented different base peaks ions, [0,2X]+ for the orobol-8-C-glycoside and [0,3X]+ for the orobol-6-C-glycoside. By the DPPH, the 8-C-derivative
showed a very close value compared with the standard rutin and, in the
ABTS method, a higher radical-scavenging activity. In both methods, the
EC50 of orobol-8-C-glycoside was almost twice better compared with orobol-6-C-glycoside. In FRAP, both C-glycosides showed a good capacity as Fe+3
reducing agents. We could realize that combined MS techniques,
highlighting the positive mode of ionization, can be used to evaluate
the isoflavones analogs being useful to differentiate between the
isomeric flavones; therefore, these data are important to mass
spectrometry dereplication studies become more efficient.