title: Rapid structural characterization of isomeric benzo[c]phenanthridine alkaloids from the roots of Zanthoxylum nitidium by liquid chromatography combined with electrospray ionization tandem mass spectrometry.
abstract: The fragmentation mechanism of six alkaloids, namely: dihydronitidine, dihydrochelerythrine, 8-acetonyldihydronitidine, 8-acetonyldrochelerythrine, nitidine and 1,3-bis(8-dihydronitidinyl)acetone, was investigated by electrospray ionization multi-stage tandem mass spectrometry (ESI-MSn). Tandem mass spectrometry experiments indicated that different substitution sites of the methoxyl groups at C-9 and C-10 or at C-10 and C-11 determined the different abundances of the MS2 fragmentation ions using the same collision energy. According to the different abundances of MS2 product ions, positional isomeric benzo[c]phenanthridine alkaloids can be differentiated. Moreover, ten constituents in the crude alkaloidol extract from the roots of Zanthoxylum nitidium were rapidly identified by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC/MSn), through comparing the retention times and ESI-MSn spectra with the authentic standards. This work demonstrates that not only the characteristic fragments but also the characteristic abundances of the fragment ions can be used for detailed structural characterization.
authors.affiliation: Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China.
authors.forename: Min
authors.initials: M
authors.lastname: Cai
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Wang
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.forename: Xun
authors.initials: X
authors.lastname: Liao
authors.forename: Lisheng
authors.initials: L
authors.lastname: Ding
mesh_terms: D000470:Alkaloids / Q000032:analysis / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004365:Drugs, Chinese Herbal / Q000032:analysis / Q000737:chemistry; D015394:Molecular Structure; D010617:Phenanthridines / Q000032:analysis / Q000737:chemistry*; D018517:Plant Roots / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013237:Stereoisomerism; D032106:Zanthoxylum / Q000737:chemistry*
chemical_list: D000470:Alkaloids; D004365:Drugs, Chinese Herbal; D010617:Phenanthridines