Ciguatoxins(CTXs)是引起Ciguatera鱼类中毒(CFP)的主要毒素,是以其特征性的多环醚结构而著称的重要化合物。在以前的报告中,我们通过在使用LC-MS的雪卡毒素-3C(CTX3C)的质谱(MS)/MS光谱中假设三个电荷位点,鉴定了通过均裂片段产生的产物离子的结构。本研究旨在阐明雪卡毒素-3C同源物的均裂片段。我们在天然存在的雪卡毒素-3C同源物的MS/MS光谱中分配了产物离子的详细结构,51-羟基环瓜毒素-3C(51-羟基CTX3C),使用具有大气压化学电离(APCI)源的液相色谱/四极杆飞行时间质谱。在C51上引入羟基取代基可诱导不同的片段化途径,包括涉及消除51-OH和形成烯醇醚的M环的新型裂解机制。因此,新的裂解模式在m/z979(C55H79O15)产生产物离子,439(C24H39O7),149(C10H13O),135(C9H11O),和115(C6H11O2)。此外,在m/z509(C28H45O8)处观察到特征产物离子,491(C28H43O7),481(C26H41O8),463(C26H39O7),439(C24H39O7),421(C24H37O6),171(C9H15O3),153(C9H13O2),141(C8H13O2),和123(C8H11O)。
Ciguatoxins (CTXs) stand as the primary toxins causing ciguatera fish poisoning (CFP) and are essential compounds distinguished by their characteristic polycyclic ether structure. In a previous report, we identified the structures of product ions generated via homolytic fragmentation by assuming three charge sites in the mass spectrometry (MS)/MS spectrum of ciguatoxin-3C (CTX3C) using LC-MS. This study aims to elucidate the homolytic fragmentation of a ciguatoxin-3C congener. We assigned detailed structures of the product ions in the MS/MS spectrum of a naturally occurring ciguatoxin-3C congener, 51-hydroxyciguatoxin-3C (51-hydoxyCTX3C), employing liquid chromatography/quadrupole time-of-flight mass spectrometry with an atmospheric pressure chemical ionization (APCI) source. The introduction of a hydroxy substituent on C51 induced different fragmentation pathways, including a novel cleavage mechanism of the M ring involving the elimination of 51-OH and the formation of enol ether. Consequently, new cleavage patterns generated product ions at m/z 979 (C55H79O15), 439 (C24H39O7), 149 (C10H13O), 135 (C9H11O), and 115 (C6H11O2). Additionally, characteristic product ions were observed at m/z 509 (C28H45O8), 491 (C28H43O7), 481 (C26H41O8), 463 (C26H39O7), 439 (C24H39O7), 421 (C24H37O6), 171 (C9H15O3), 153 (C9H13O2), 141 (C8H13O2), and 123 (C8H11O).