HPLC-Q-TOF MS法研究3种银杏双黄酮成分的质谱裂解途径

本研究采用高效液相色谱-串联四极杆飞行时间质谱(HPLC-Q-TOF MS)在负离子模式下分析3种银杏双黄酮(7-去甲基银杏双黄酮、金松双黄酮、异银杏双黄酮)的质谱裂解途径。结果表明,3种化合物具有相似的裂解途径,均易丢失CH 3OH和CO 2,且该类成分在Ⅰ—C环和Ⅱ—C环发生多种Retro-Diels-Alder(RDA)裂解,可进一步失去取代基,得到相应的特征碎片离子。该结论可为银杏双黄酮类的结构鉴定提供依据。

Mass Spectrometric Fragmentation Pathways of Three Ginkgo Biloba Flavonoids Using HPLC-Q-TOF MS

Ginkgo biloba is one of the best explored herbal drugs which could be widely used in the treatment of cognitive decline and Alzheimer’s diseases.Ginkgo biflavones is a kind of Ginkgo biloba flavone and only existed in the its leaves.As the complex structure of the Ginkgo biflavones,the further analysis and summary of this kinds of constituents were few reported.In this experiment,mass spectrometric fragmentation pathways of three Ginkgo biflavones(Bilobetin,Sciadopitysin,Isoginkgetin)were studied.Three standard Ginkgo biloba flavonoids were prepared into a mixture of 20 mg/L for injection.High performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry(HPLC-Q-TOF MS)was used to collect data from samples with different collision energy at negative ion mode.With the optimizing study of the collision energy,50 eV was selected for the further study as it could provide more abundant fragmentation information.Based on the high resolution mass spectrum data,the fragmentation pathways of the three Ginkgo biloba flavonoids were summarized.As the structural characteristics of bisflavones,the neutral loss of CH 3OH and CO 2 were easily observed.The major fragmentation pathway was Retro-Diels-Alder(RDA)reaction which could occurs onⅠ—C andⅡ—C rings in three types,and the substituents could be further lost to obtain the corresponding characteristic fragment ions.The analysis of fragmentation pathway can provide a basis for the structural identification of Ginkgo biloba flavonoids.Moreover,it provides a rapid method to characterize the flavonoids in traditional Chinese medicine(TCM)by HPLC-Q-TOF MS which also can be used in searching for new constituents and their metabolites in vivo.