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Structure‐fragmentation relationship and rapid dereplication of Buxus steroidal alkaloids by electrospray ionization‐quadrupole time‐of‐flight mass spectrometry
Author(s) -
Musharraf Syed Ghulam,
Goher Madiha,
Shahnaz Salma,
Choudhary M. Iqbal
Publication year - 2012
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.6441
Subject(s) - chemistry , tandem mass spectrometry , fragmentation (computing) , electrospray ionization , mass spectrometry , chromatography , electrospray , quadrupole time of flight , computer science , operating system
RATIONALE Tandem mass spectrometric studies of natural products revealed the identification of key fragments which can be helpful for their rapid dereplication in plant extracts utilizing a liquid chromatography/tandem mass spectrometry (LC/MS/MS) approach, particularly for the thermally labile compounds. The knowledge of the collision‐induced dissociation (CID) fragmentation pattern of the molecule is essentially required prior to the analysis by LC/MS/MS. METHODS The fragmentation patterns of eleven Buxus steroidal alkaloids were studied by using a positive ion electrospray ionization quadrupole time‐of‐flight mass spectrometry (ESI‐QqTOF‐MS/MS) hybrid instrument. Chromatographic separation of a Buxus papillosa extract was achieved using a capillary HPLC system coupled with the mass instrument. RESULTS ESI‐QqTOF‐MS (positive ion mode) showed the presence of several characteristic fragments which can be used to rapidly identify various classes of Buxus steroidal alkaloids. The presence of a cyclopropane ring in the cycloartenol skeleton and the hydroxyl group at C‐10 was found to effect on the fragmentation pattern and afford characteristic peaks. This study distinguishes between different types of Buxus steroidal alkaloids based on logical fragmentation pathways. This strategy was successfully applied in LC/ESI‐QqTOF‐MS/MS analysis of Buxus papillosa extract to investigate and characterize Buxus steroidal alkaloids and 14 compounds were identified as steroidal alkaloids. CONCLUSIONS The knowledge of the fragmentation pattern was used for the rapid identification of this bioactive group of biosynthetically unique steroidal alkaloids in complex plant extracts of Buxus species, especially in the absence of any reference material, by combining key fragments, exact mass measurements and relative abundances of diagnostic fragment ions. Copyright © 2012 John Wiley & Sons, Ltd.