Detection of the tremorgenic mycotoxin paxilline and its desoxy analog in ergot of rye and barley: a new class of mycotoxins added to an old problem

A newly developed enzyme immunoassay (EIA) for the detection of the tremorgenic indole-diterpene alkaloid paxilline (PAX) and closely related analogs was used to analyze ergot sclerotia collected from rye and barley fields. The mean EIA standard curve detection limit was 0.47 +/- 0.14 ng/mL; relative cross-reactivity of toxin standard solutions was found for 11-hydroxy-paspaline (terpendole E, 1.1%) but not for lolitrem B or ergot alkaloids. Sclerotia from all fields were positive in the PAX-EIA at concentration levels of 620 +/- 200 and 160 +/- 37 mu g/kg in ergot of rye and 130 +/- 47 mu g/kg in ergot of barley. Confirmatory analyses of sclerotia by liquid chromatography-tandem mass spectrometric detection identified PAX and its analog 13-desoxypaxilline. To the best of our knowledge, this is the first report on the natural occurrence of tremorgenic indole-diterpene alkaloid mycotoxins in ergot sclerotia from rye and barley. Along with details on the analytical methodology developed in this study, particularly PAX-antibody production, the relevance and implications of these findings for food and feed safety are discussed. Presence or absence of elevated levels of tremorgenic mycotoxins, along with the ergot alkaloids, would help in explaining the difference between the two distinct manifestations of historic ergotism, the convulsive and the gangrenous form. Further method development for paxilline and other tremorgenic mycotoxins in cereals used for food and feed is a prerequisite for a comprehensive risk assessment, which seems to be necessary in light of the findings reported here.

一种新开发的用于检测震颤性吲哚二萜生物碱帕西林（PAX）及其密切相关类似物的酶免疫测定法（EIA）被用于分析从黑麦和大麦田中采集的麦角菌核。EIA标准曲线的平均检测限为0.47±0.14纳克/毫升；发现毒素标准溶液对11 - 羟基帕斯帕林（萜品醇E，1.1%）有相对交叉反应，但对洛利特林B或麦角生物碱无交叉反应。所有田地的菌核在PAX - EIA中均呈阳性，黑麦麦角中的浓度水平为620±200和160±37微克/千克，大麦麦角中为130±47微克/千克。通过液相色谱 - 串联质谱检测对菌核进行的确认分析鉴定出了PAX及其类似物13 - 脱氧帕西林。据我们所知，这是首次关于黑麦和大麦麦角菌核中存在震颤性吲哚二萜生物碱霉菌毒素的报道。除了本研究中开发的分析方法的细节，特别是PAX抗体的生产外，还讨论了这些发现对食品和饲料安全的相关性和影响。震颤性霉菌毒素以及麦角生物碱水平的高低，将有助于解释历史上麦角中毒的两种不同表现形式，即惊厥型和坏疽型之间的差异。进一步开发用于食品和饲料的谷物中帕西林和其他震颤性霉菌毒素的检测方法是进行全面风险评估的先决条件，鉴于此处报道的发现，这似乎是必要的。