11 Cylindrospermopsin : オーストラリア産藍藻が生産する含グアニジン肝臓毒(口頭発表の部)

概要

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Human hepatoenteritis caused by toxic cyanobacterial blooms in domestic water supplies that have become eutrophic is a growing concern. In 1979 an outbreak of hepatoenteritis on Palm Island in Australia was traced to a cyanobacterium, Cylindrospermopsis raciborskii, which had never been implicated before in poisonings. We describe the isolation and structure determination of an unusual alkaloid, cylindrospermopsin, that is responsible for the hepatotoxicity of this alga. Cylindrospermopsin (1), LD_<50>=0.5mg/kg in mice by intraperitoneal injection, was obtained as white microcrystals from aqueous extract of the alga. The molecular formula, C_<15>H_<21>N_5O_7S, of 1 was determined by HRFABMS. The UV spectrum (λ_<max> 262nm) and ^<13>C NMR (δ 154.8, 168.2, 99.6, 158.1) were consistent with 1 being a substituted uracil. By means of 2D NMR spectroscopy such as HMBC partial structure (Figure 3) was deduced. Consideration of NOEs, proton-proton coupling constants, and the deuterium-induced chemical shift experiments (^13C NMR) led us to structure 1. This structure was confirmed by a C, C-COSY spectrum of 80+% ^<13>C-enriched toxin and N, C-COSY of 80+%^ <13>C, 90+% ^<15>N-enriched toxin, produced by the alga grown on ^<13>C-bicarbonate and ^<13>C-bicarbonate and^<15>N-nitrate, respectively.
天然有機化合物討論会の論文
1992-09-10