Microcystins (MCs) are hepatotoxic heptapeptides produced by cyanobacteria and are potent inhibitors of protein phosphatases in eukaryotic cells. Algae for dietary supplements are harvested from outdoor environments and can be contaminated with MCs. Monitoring of MCs in these products is necessary but is complicated by their structural diversity (>250 congeners). We used a combination of protein phosphatase inhibition assay (PPIA), ELISA, LC−MS/MS, and nontargeted LC–high-resolution MS (LC–HRMS) with thiol derivatization to characterize the total MCs in 18 algal dietary supplements. LC–MS/MS revealed that some products contained >40 times the maximum acceptable concentration (MAC) of 1 μg/g MCs, but ELISA and PPIA showed up to 50–60 times the MAC. LC–HRMS identified all congeners targeted by LC–MS/MS plus MC-(H4)YR contributing up to 18% of total MCs, along with numerous minor MCs. Recommended dosages of the products greater than the MAC would result in 2.6–75 times the tolerable daily intake, presenting a risk to consumers. This study confirms the need for monitoring these products and presents strategies to fully describe the total MC pool in environmental samples and algal products.

中文翻译：

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通过生物测定，免疫测定和质谱法相结合揭示的藻类膳食补充剂中潜在危险水平的微囊藻毒素。

微囊藻毒素（MCs）是由蓝细菌产生的具有肝毒性的七肽，是真核细胞中蛋白质磷酸酶的有效抑制剂。膳食补充剂的藻类是从室外环境中收获的，并可能被MC污染。对这些产品中的MC进行监测是必要的，但由于其结构多样性（> 250个同类物）而变得复杂。我们结合了蛋白质磷酸酶抑制试验（PPIA），ELISA，LC-MS / MS和非靶向LC-高分辨率MS（LC-HRMS）与硫醇衍生化的组合来表征18种藻类膳食补充剂中的总MC。LC-MS / MS表明，某些产品的最大可接受浓度（MAC）是1μg/ g MC的40倍以上，但ELISA和PPIA却高达MAC的50-60倍。LC-HRMS确定了LC-MS / MS加MC-（H4）YR靶向的所有同类物，占总MC的18％，以及许多次要MC。建议产品的剂量大于MAC，将导致每日可摄入量的2.6-75倍，给消费者带来风险。这项研究证实了监测这些产品的必要性，并提出了充分描述环境样品和藻类产品中总MC池的策略。