Aasen John A B, Hardstaff William, Aune Tore, Quilliam Michael A
Institute for Marine Biosciences, National Research Council of Canada, 1411 Oxford St., Halifax, NS, B3H 3Z1, Canada.
Rapid Commun Mass Spectrom. 2006;20(10):1531-7. doi: 10.1002/rcm.2501.
Cultured mussels sampled in the spring of 2002 and 2003 from Skjer, a location in the Sognefjord, Norway, tested positive in the mouse bioassay for lipophilic toxins. In a previous report, it was established that a number of spirolides, cyclic imine toxins produced by the phytoplankton Alexandrium ostenfeldii, were present in the mussels and were responsible for the observed toxicity. The main toxin proved to be a new compound named 20-methyl spirolide G. In subsequent studies, a delayed onset of spirolide-like symptoms in the mouse bioassay exceeding the usual time limit of 20 min was observed in some samples, with symptoms and death appearing as long as 45-50 min after injection. It is well known that shellfish can extensively metabolize other toxins, such as okadaic acid and the dinophysistoxins, to fatty acid acyl esters and it is also known that a delayed onset of toxic symptoms with such metabolites can occur. Analyses performed with liquid chromatography/tandem mass spectrometry (LC/MS/MS) have revealed a complex mixture of esters of 20-methyl spirolide G in the contaminated mussels. Precursor ion scanning has delineated the range of fatty acid esters involved, while product ion scanning has provided information on structure. Identity was also supported through reaction of 20-methyl spirolide G with palmitic anhydride, which produced a derivative with a retention time and spectrum identical with one putative metabolite, 17-O-palmitoyl-20-methyl spirolide G.
2002年春季和2003年从挪威松恩峡湾的斯基尔采集的养殖贻贝，在小鼠生物测定中对亲脂性毒素检测呈阳性。在之前的一份报告中确定，贻贝中存在多种由浮游植物奥氏亚历山大藻产生的螺环内酯类环状亚胺毒素，这些毒素是观察到的毒性的原因。主要毒素被证明是一种名为20-甲基螺环内酯G的新化合物。在随后的研究中，在一些样本中观察到小鼠生物测定中螺环内酯样症状的延迟发作超过了通常20分钟的时间限制，症状和死亡在注射后长达45 - 50分钟才出现。众所周知，贝类可以将其他毒素，如冈田酸和鳍藻毒素，广泛代谢为脂肪酸酰基酯，并且也知道这些代谢产物会出现毒性症状延迟发作的情况。用液相色谱/串联质谱法（LC/MS/MS）进行的分析揭示了受污染贻贝中20-甲基螺环内酯G酯的复杂混合物。前体离子扫描划定了所涉及的脂肪酸酯的范围，而产物离子扫描提供了结构信息。通过20-甲基螺环内酯G与棕榈酸酐反应也支持了其身份，该反应产生了一种保留时间和光谱与一种推定代谢产物17-O-棕榈酰-20-甲基螺环内酯G相同的衍生物。
