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(+)‐Silybin, a pharmacologically active constituent of Silybum marianum : fragmentation studies by atmospheric pressure chemical ionization quadrupole time‐of‐flight tandem mass spectrometry
Author(s) -
Kéki Sándor,
Tóth Katalin,
Zsuga Miklós,
Ferenczi Renáta,
Antus Sándor
Publication year - 2007
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.3081
Subject(s) - chemistry , fragmentation (computing) , flavanone , tandem mass spectrometry , mass spectrometry , collision induced dissociation , atmospheric pressure chemical ionization , ion , chemical ionization , analytical chemistry (journal) , ionization , chromatography , organic chemistry , flavonoid , computer science , antioxidant , operating system
The fragmentation behavior of (+)‐silybin ( 1 ) and (+)‐deuterosilybin ( 2 ), as well as of their flavanone‐3‐ol‐type building blocks, such as 3,5,7‐trihydroxy‐2‐phenyl‐4‐chromanone ( 3 ) and 2‐(1,4‐benzodioxolanyl)‐3,5,7‐trihydroxy‐4‐chromanone ( 4 ), were investigated by atmospheric pressure chemical ionization quadropole time‐of‐flight tandem mass spectrometry in the positive ion mode (APCI(+)‐QqTOF MS/MS). The product ion spectra of the protonated molecules of 1 revealed a rather complicated fragmentation pattern with product ions originating from consecutive and competitive loss of small molecules such as H 2 O, CO, CH 2 O, CH 3 OH and 2‐methoxyphenol, along with the A + ‐ and B + ‐type ions arising from the cleavage of the C‐ring of the flavanone‐3‐ol moiety. The elucidation of the fragmentation behavior of 1 was facilitated by acquiring information on the fragmentation characteristics of the flavanone‐3‐ol moieties and 2 . The capability of the accurate mass measurement on the quadrupole time‐of‐flight mass spectrometer allowed us to determine the elemental composition of each major product ion. Second‐generation product ion spectra obtained by combination of in‐source collision induced dissociation (CID) with selective CID (pseudo‐MS 3 ) was also helpful in elaborating the fragmentation pathways and mechanism. Based on the experimental results, a fragmentation mechanism as well as fragmentation pathways for 1 and its flavanone‐3‐ol building blocks ( 3 , 4 ) are proposed and discussed. Copyright © 2007 John Wiley & Sons, Ltd.