Determination of ibotenic acid and muscimol, the Amanita mushroom toxins, in human serum by liquid chromatography–tandem mass spectrometry

Mushroom Poisoning

BACKGROUND

Poisonous mushrooms are eaten by mushroom hunters out of ignorance, after misidentification as edible mushrooms, or as a psychoactive drug. Mushroom poisoning commonly leads to consultation with a poison information center and to hospitalization.

METHODS

This review is based on pertinent publications about the syndromes, toxins, and diagnostic modalities that are presented here, which were retrieved by a selective search in PubMed. It is additionally based on the authors' longstanding experience in the diagnosis and treatment of mushroom intoxication, expert consultation in suspected cases, macroscopic identification of wild mushrooms, and analytic techniques.

RESULTS

A distinction is usually drawn between mushroom poisoning with a short latency of less than six hours, presenting with a gastrointestinal syndrome whose course is usually relatively harmless, and cases with a longer latency of six to 24 hours or more, whose course can be life-threatening (e.g., phalloides, gyromitra, orellanus, and rhabdomyolysis syndrome). The DRG diagnosis data for Germany over the period 2000-2018 include a total of 4412 hospitalizations and 22 deaths due to the toxic effects of mushroom consumption. 90% of the fatalities were due to the death cap mushroom (amatoxins). Gastrointestinal syndromes due to mushroom consumption can be caused not only by poisonous mushrooms, but also by the eating of microbially spoiled, raw, or inadequately cooked mushrooms, or by excessively copious or frequent mushroom consumption.

CONCLUSION

There are few analytic techniques available other than the qualitative demonstration of amatoxins. Thus, the diagnosis is generally made on the basis of the clinical manifestations and their latency, along with meticulous history-taking, assisted by a mushroom expert, about the type(s) of mushroom that were consumed and the manner of their preparation.

Human Poisoning from Poisonous Higher Fungi: Focus on Analytical Toxicology and Case Reports in Forensic Toxicology

Several families of higher fungi contain mycotoxins that cause serious or even fatal poisoning when consumed by humans. The aim of this review is to inventory, from an analytical point of view, poisoning cases linked with certain significantly toxic mycotoxins: orellanine, α- and β-amanitin, muscarine, ibotenic acid and muscimol, and gyromitrin. Clinicians are calling for the cases to be documented by toxicological analysis. This document is therefore a review of poisoning cases involving these mycotoxins reported in the literature and carries out an inventory of the analytical techniques available for their identification and quantification. It seems indeed that these poisonings are only rarely documented by toxicological analysis, due mainly to a lack of analytical methods in biological matrices. There are many reasons for this issue: the numerous varieties of mushroom involved, mycotoxins with different chemical structures, a lack of knowledge about distribution and metabolism. To sum up, we are faced with (i) obstacles to the documentation and interpretation of fatal (or non-fatal) poisoning cases and (ii) a real need for analytical methods of identifying and quantifying these mycotoxins (and their metabolites) in biological matrices.

Direct Analysis of Psilocin and Muscimol in Urine Samples Using Single Drop Microextraction Technique In-Line with Capillary Electrophoresis

The fully automated system of single drop microextraction coupled with capillary electrophoresis (SDME-CE) was developed for in-line preconcentration and determination of muscimol (MUS) and psilocin (PSC) from urine samples. Those two analytes are characteristic active metabolites of Amanita and Psilocybe mushrooms, evoking visual and auditory hallucinations. Study analytes were selectively extracted from the donor phase (urine samples, pH 4) into the organic phase (a drop of octanol layer), and re-extracted to the acidic acceptor (background electrolyte, BGE), consisting of 25 mM phosphate buffer (pH 3). The optimized conditions for the extraction procedure of a 200 µL urine sample allowed us to obtain more than a 170-fold enrichment effect. The calibration curves were linear in the range of 0.05–50 mg L⁻¹, with the correlation coefficients from 0.9911 to 0.9992. The limit of detections was determined by spiking blank urine samples with appropriate standards, i.e., 0.004 mg L⁻¹ for PSC and 0.016 mg L⁻¹ for MUS, respectively. The limits of quantification varied from 0.014 mg L⁻¹ for PSC and 0.045 mg L⁻¹ for MUS. The developed method practically eliminated the sample clean-up step, which was limited only to simple dilution (1:1, v/v) and pH adjustment.

Development and application of a forensic toxicological library for identification of 56 natural toxic substances by liquid chromatography–quadrupole time-of-flight mass spectrometry

Purpose

The present study aims to develop a forensic toxicological library to identify 56 natural toxic substances by liquid chromatography–quadrupole time-of-flight tandem mass spectrometry (LC–QTOF-MS/MS).

Methods

For setting up the library of product ion spectra, individual substances (31 plant toxins, 7 mushroom toxins, 5 marine toxins, 5 frog venoms, 4 mycotoxins, and 4 substances derived from plants) were analyzed by LC–QTOF-MS/MS with positive and negative ionization. The product ion spectra were acquired at the collision energies (CEs) of 20, 35, and 50 eV in single enhanced product ion mode and then in collision energy spread mode in which the CE ramp range was set to 35 ± 15 eV.

Results

To test the performance of the library, human blood plasma samples were spiked with a mixture of lycorine and domoic acid, extracted by acetonitrile deproteinization and analyzed by LC–QTOF-MS/MS. Identification by our library search could be achieved for these toxins at the purity scores of 79.1 and 67.2, respectively. The method was also applied to postmortem blood from a death case with an aconite intake, and showed that four toxins in an aconite could be identified in the blood sample at the purity scores of 54.6–60.3.

Conclusions

This library will be more effective for the screening of natural toxic substances in routine forensic toxicological analysis. To our knowledge, there are no reports dealing with development of library for natural toxic substances by LC–QTOF-MS/MS.

Multivariate optimization of the hollow fibre liquid phase microextraction of muscimol in human urine samples

A liquid phase microextraction based on hollow fibre followed by liquid chromatographic determination was developed for the extraction and quantitation of the hallucinogenic muscimol from urine samples. Method applicability on polar hallucinogens was also tested on two alkaloids, a psychedelic hallucinogen, tryptamine and a polar amino acid, tryptophan which exists in its charged state in the entire pH range. A multivariate design of experiments was used in which a half fractional factorial approach was applied to screen six factors (donor phase pH, acceptor phase HCl concentration, carrier composition, stirring rate, extraction time and salt content) for their extent of vitality in carrier mediated liquid microextractions. Four factors were deemed essential for the effective extraction of each analyte. The vital factors were further optimized for the extraction of single-spiked analyte solutions using a central composite design. When the simultaneous extraction of analytes was performed under universal factor conditions biased towards maximizing the enrichment of muscimol, a good composite desirability value of 0.687 was obtained. The method was finally applied on spiked urine samples with acceptable enrichments of 4.1, 19.7 and 24.1 obtained for muscimol, tryptophan and tryptamine respectively. Matrix-based calibration curves were used to address matrix effects. The r(2) values of the matrix-based linear regression prediction models ranged from 0.9933 to 0.9986. The linearity of the regression line of the matrix-based calibration curves for each analyte was directly linked to the analyte enrichment repeatability which ranged from an RSD value of 8.3-13.1%. Limits of detection for the developed method were 5.12, 3.10 and 0.21ngmL(-1) for muscimol, tryptophan and tryptamine respectively. The developed method has proven to offer a viable alternative for the quantitation of muscimol in human urine samples.