A case of human poisoning by grayanotoxins following honey ingestion: elucidation of the toxin profile by mass spectrometry

High-resolution mass spectrometry (HRMS) was applied for the detection of grayanotoxins (GrTx) in a contaminated honey sample. This sample was provided by a hospital due to a suspicion of intoxication after a patient had shown the typical symptoms of GrTx poisoning. Subsequent analysis proved the contamination with high amounts of GrTx and other toxins belonging to grayanane-type diterpenoids. This group of natural toxins is synthesised by the plant family Ericaceae and comprises more than 60 individual toxins, but only one compound is available as a reference standard. We applied a screening approach that easily confirms the presence or absence of GrTx without access to standards. By searching for predictable mass spectrometric fragment ions, including typical in-source fragments arising from collision-induced dissociation during electrospray ionisation, the complete toxin profile was screened and allowed the mass spectrometric identification of 15 individual GrTx. The potential of this approach is especially demonstrated by the fact that at least two of these toxins have not been previously described in the literature. A semi-quantitative estimation indicated a total toxin concentration of 358 mg kg⁻¹. An investigation of 49 honeys from the German retail market did not reveal the presence of GrTx.

本研究采用高分辨质谱法（High-resolution mass spectrometry, HRMS）对某受污染蜂蜜样品中的木藜芦毒素（grayanotoxins, GrTx）开展检测。该样品由医疗机构提供，因一名患者出现木藜芦毒素中毒的典型症状后疑似中毒送检。后续分析证实，样品中污染有高含量的木藜芦毒素及其他属于木藜芦烷型二萜类的天然毒素。这类天然毒素由杜鹃花科（Ericaceae）植物合成，目前已报道超过60种单体毒素，但仅有1种化合物可获得参考标准品。本研究建立了一种无需依赖参考标准品即可便捷确认木藜芦毒素存在与否的筛查方法：通过检索可预测的质谱碎片离子（包括电喷雾电离过程中碰撞诱导解离产生的典型源内碎片），对完整毒素谱图进行筛查，最终实现了15种单体木藜芦毒素的质谱鉴定。其中至少2种毒素此前未被文献报道，这充分体现了该方法的应用潜力。半定量估算结果显示，该受污染样品的总毒素浓度为358 mg·kg⁻¹。对德国零售市场的49份蜂蜜样品开展的调查未检出木藜芦毒素。