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（high-resolution mass spectrometry, HRMS）对一份受污染蜂蜜样品中的灰花毒素（grayanotoxins, GrTx）开展检测。该样品由某医疗机构提供，此前一名患者出现灰花毒素中毒的典型症状，医院怀疑其发生中毒事件。后续分析证实，该样品中含有高浓度的灰花毒素及其他属于灰烷型二萜类的毒素。这类天然毒素由杜鹃花科（Ericaceae）植物合成，目前包含超过60种单体毒素，但仅有一种可获得对照品。本研究建立的筛查方法无需对照品即可快速确认样品中是否含有灰花毒素：通过搜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，完成了完整毒素谱的筛查，并通过质谱鉴定出15种单体灰花毒素。该方法的应用潜力尤为突出，其中至少两种毒素此前未见文献报道。半定量估算结果显示，样品中总毒素浓度为358 mg·kg⁻¹。对德国零售市场采集的49份蜂蜜样品开展的调查未检出灰花毒素。