28 微量シガトキシン同族体のMS/MS分析による構造決定(口頭発表の部)

抄録

The ciguatoxins are the causative agents responsible for a peculiar form of fish poisoning termed "ciguatera". Precursor toxins produced by the dinoflagellate Gambierdiscus toxicus undergo structural modification in fish to produce various metabolite toxins including ciguatoxin (CTX), the principal toxin in ciguatera. Because of the extreme difficulty to obtain these congeners in sufficient amounts for NMR studies, we carried out FAB MS/MS experiments to elucidate their structures. A total of 53 toxic fractions were prepared from the flesh and viscera of moray eels Gymnothorax javanicus, the flesh of red snappers Lujanus bohar, the flesh of parrotfish Scarus gibbus, and G. toxicus collected from three different places (Tahiti, Tubuai, and Rangiroa). Many of these samples were mixtures and in amounts less than 10μg. Collision induced ions generated from Na-adduct precursor ions were characteristic for the structural modifications. Supportive data were also obtained by measuring spectra of a 2-sulfobenzoate of a CTX congener. Out of 20 congeners detected by LC/MS, the following 17 congeners were identified: CTX4A, M-seco-CTX4A, 52-epi-54-deoxy-CTX, CTX, 52-epi-CTX, 54-deoxy-50-hydroxy-CTX, 7-oxo-CTX, 7-hydroxy-CTX, 3-hydroxy-7-oxo-CTX, CTX3C, 49-epi-CTX3C, 51-hydroxy-CTX3C, 3-hydroxy-CTX3C, 51-hydroxy-3-oxo-CTX3C, 2,3-dihydroxy-CTX3C, 2,3,51-trihydroxy-CTX3C, and A-seco-51-hydroxy-CTX3C.