Fragmentation Study of the C Ring in Flavone and Isoflavone Aglycones by Electrospray Ion Trap Time-of-Flight Mass Spectrometry

采用电喷雾-离子阱-飞行时间串联质谱在负离子模式下分析了4个黄酮苷元和6个异黄酮苷元的质谱数据,并总结了两类化合物C环上的裂解规律.黄酮化合物C环以Rretro-Diels-Alder(RDA)裂解断裂为主,形成A1,3-离子且相对丰度较高;而异黄酮化合物C环断裂以碳0和碳3键的断裂为主,形成B0,3-离子,且相对丰度较高.说明黄酮化合物的交叉共轭体系和异黄酮的非交叉共轭体系对C环的裂解影响较大,而且黄酮化合物的B环和异黄酮化合物的A,B环上取代基的类型和位置对生成碎片离子的稳定性也有影响,导致生成的碎片离子类型及其相对丰度不同,根据其质谱数据(包括碎片离子的质荷比和相对离子丰度)可以推测黄酮类化合物的结构类型和取代状况,为快速鉴定黄酮化合物和异黄酮化合物结构奠定了基础.Our experiment analyzed the mass spectrometric behavior of four flavone and six isoflavone aglycones in negative ion mode using HPLC/ESI-IT-TOF. We summarized the relationship between their structural features and the corresponding characteristic fragmentation behavior. The fragmentation of A(1,3-) was formed by Rretro-Diels-Alder( RDA) reaction on the C ring of flavone aglycones and the relative abundances were higher than other fragmentation types'. Furthermore, isoflavone aglycones appeared specific fragmentations of B(0,3-) which derived from the C ring's breakage with high relative abundances. These results show that the various conjugated systems belong to flavone and isoflavone aglycones influenced the fragmentation behavior of C ring. In addition, the substitution patterns on A and B rings lead to different types of produce ions and the intensity of relative abundances, respectively. Our findings will be helpful in identifying the structures of flavone and isoflavone aglycones rapidly with the method of mass spectrometry.国家重点基础研究发展规划(973计划)http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000262921100011&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701SCI(E)中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)10146-503