Analysis of epipolythiodioxopiperazines in fungus Chaetomium cochliodes using HPLC-ESI-MS/MS/MS.
A series of epipolythiodioxopiperazines in the fungus Chaetomium cochliodes was investigated using reversed-phase liquid chromatography with diode array detection and electrospray quadrupole time-of-flight-type tandem mass spectrometry in the positive ion mode. The fragmentation of protonated molecular ions including low-abundance parent ions, [M+H]+ for five known epipolythiodioxopiperazines, dethiotetra(methylthio)chetomin, chaetocochins A-C, and chetomin, was carried out using low-energy collision-induced electrospray ionization tandem spectrometry. It was found that McLafferty rearrangements occurred in the CID processes and produced a complementary pair of characteristic fragment ions containing piperazine rings (fused and unfused), especially to determine the number of S atoms on each ring. The fragmentation differential between [M+H]+ and [M+Na]+ was uncovered. Complementary fragmentation information obtained from [M+H]+ and [M+Na]+ precursor ions is especially valuable for rapid identification of epipolythiodioxopiperazines. A likely known compound, possibly related to chetoseminudin A, and three new species of epipolythiodioxopiperazines from the fungus C. cochliodes were identified or tentatively characterized based on tandem mass spectra of known ones.
Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People's Republic of China.
Zhi-Jun
ZJ
Wu
Guo-You
GY
Li
Dong-Mei
DM
Fang
Hua-Yi
HY
Qi
Wei-Jian
WJ
Ren
Guo-Lin
GL
Zhang
D002597:Chaetomium / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004220:Disulfides / Q000032:analysis; D006576:Heterocyclic Compounds, 4 or More Rings / Q000032:analysis; D026121:Indole Alkaloids / Q000032:analysis; D013058:Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure; D010879:Piperazines / Q000032:analysis* / Q000737:chemistry*
D004220:Disulfides; D006576:Heterocyclic Compounds, 4 or More Rings; D026121:Indole Alkaloids; D010879:Piperazines; C483272:chetoseminudin A; C001598:chetomin