Premium
Rapid structural determination of alkaloids in a crude extract of Stemona saxorum by high‐performance liquid chromatography/electrospray ionization coupled with tandem mass spectrometry
Author(s) -
Peng ShuYing,
Shi Ting,
Wang YaZhou,
Lin LiGen,
Yang YiMing,
Jiang HuaLiang,
Ye Yang
Publication year - 2009
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.4299
Subject(s) - chemistry , azepine , electrospray ionization , tandem mass spectrometry , chromatography , mass spectrometry , fragmentation (computing) , electrospray , high performance liquid chromatography , stereochemistry , computer science , operating system
The electrospray ionization (ESI) mass spectrometric behavior of five Stemona alkaloids, stemokerrin, oxystemokerrin, oxystemokerrilactone, oxystemokerrin N ‐oxide and stemokerrin N ‐oxide, was studied using an ESI tandem mass technique (MS n ). These compounds, isolated from Stemona saxorum endemic in Vietnam, represent a class of alkaloids containing a pyrido[1,2‐a]azepine A,B‐ring core with a 1‐hydroxypropyl side chain attached to C‐4. Their fragmentation pathways were elucidated by ESI‐MS n results and the elemental composition of the major product ions was confirmed by accurate mass measurement. In order to rationalize some fragmentation pathways, the relative Gibbs free energies of some product ions were estimated using the B3LYP/6‐31+G(d) method. Based on the ESI‐MS n results of five reference compounds, a reversed‐phase high‐performance liquid chromatography with tandem mass spectrometry (RP‐HPLC/MS n ) method was developed for the characterization of Stemona alkaloids with a pyrido[1,2‐a]azepine A,B‐ring core from the extract of S . saxorum . A total of 41 components were rapidly identified or tentatively characterized, of which 12 compounds were identified as Stemona alkaloids with a pyrido[1,2‐a]azepine A,B‐ring core, including four new compounds. This method is convenient and sensitive, especially for minor components in complex natural product extracts. Copyright © 2009 John Wiley & Sons, Ltd.