Mudge Elizabeth M, Robertson Alison, Leynse Alexander K, McCarron Pearse, Miles Christopher O
Biotoxin Metrology, National Research Council Canada, 1411 Oxford Street, Halifax, NS, B3H 3Z1, Canada.
Department of Marine Sciences, University of South Alabama, 5871 University Drive North, Mobile, AL 36688, United States; Marine Ecotoxicology, Dauphin Island Sea Lab, Dauphin Island, Dauphin Island, AL 36528, United States.
J Chromatogr B Analyt Technol Biomed Life Sci. 2022 Jan 1;1188:123014. doi: 10.1016/j.jchromb.2021.123014. Epub 2021 Nov 2.
Gambierdiscus spp. are epi-benthic dinoflagellates that have been associated with ciguatera poisoning. These microalgae can have complex secondary metabolite profiles including ciguatoxins, maitotoxins, and gambierones, with varying compositions and toxicities across species and strains. Given this chemical diversity there is a need to develop selective and sensitive methods for secondary metabolite profiling. In this study, we used a cultured Caribbean strain of Gambierdiscus silvae to develop sample preparation and analysis strategies for characterizing vic-diol containing secondary metabolites. A pooled cellular extract was first screened by liquid chromatography-high-resolution mass spectrometry (LC-HRMS) for ciguatoxin-related compounds, which resulted in the confirmation of gambierone (1) and a novel isomer of 44-methylgambierone (3). Treatment of the extract with periodate confirmed that the gambierones each contained one reactive vic-diol, which was exploited for the development of a selective extraction procedure using m-aminophenylboronic acid gel and the non-aqueous binding solvent chloroform. Using this non-traditional boronate affinity procedure, LC-HRMS also revealed the presence of additional sulfated polycyclic ethers in the gambierone-containing vic-diol fraction, while pigments and other contaminants were removed. The developed tools could be applied to screen collections of Gambierdiscus and other benthic algae to provide additional chemical characterization of gambierone-related compounds. The selective extraction procedure may also prove useful as a step in the isolation of these sulfated polyethers for structural, toxicological and biotransformation studies.
冈比甲藻属是与雪卡毒素中毒有关的表栖甲藻。这些微藻具有复杂的次生代谢产物谱，包括雪卡毒素、刺尾鱼毒素和冈比毒素，不同物种和菌株的组成和毒性各不相同。鉴于这种化学多样性，需要开发选择性和灵敏的次生代谢产物分析方法。在本研究中，我们使用了一株培养的加勒比海冈比甲藻菌株来开发用于表征含邻二醇次生代谢产物的样品制备和分析策略。首先通过液相色谱-高分辨率质谱（LC-HRMS）对混合细胞提取物进行雪卡毒素相关化合物筛选，结果确认了冈比毒素（1）和44-甲基冈比毒素的一种新型异构体（3）。用过碘酸盐处理提取物证实，每种冈比毒素都含有一个反应性邻二醇，利用这一特性开发了一种使用间氨基苯硼酸凝胶和非水结合溶剂氯仿的选择性提取程序。使用这种非传统的硼酸酯亲和程序，LC-HRMS还揭示了含冈比毒素的邻二醇部分中存在其他硫酸化多环醚，同时去除了色素和其他污染物。所开发的工具可用于筛选冈比甲藻和其他底栖藻类的样本，以提供与冈比毒素相关化合物的更多化学特征。这种选择性提取程序也可能作为分离这些硫酸化多环醚用于结构、毒理学和生物转化研究的一个步骤而被证明是有用的。
