Mushroom poisoning has become a serious food safety issue in China. Poisoning incidents caused by species of Inocybaceae have been continuously reported from tropical to temperate regions of China in recent years. Many species of Inocybaceae contain muscarine, which stimulates the parasympathetic nervous system; some also contain psilocybin, resulting in hallucinations, and a few even contain amatoxins. In this study, two new species of the I. aeruginascens group, Inocybe tumericolor and I. subaeruginascens, are described based on combined morphological evidence and multilocus phylogenetic analyses (ITS, LSU, and rpb2). Subsequently, a targeted multi-toxin analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed on these two new species together with the north-temperate species I. asterospora, quantifying 12 toxins, including muscarine, two isoxazole derivatives, three tryptamine alkaloids, three amatoxins, and three phallotoxins. Mixed profiles of muscarine, psilocybin, and psilocin were uncovered, whereas the other nine toxins were below the detection limits in all tested samples. Inocybe tumericolor contained psilocybin (1692.2-2758.7 mg/kg) and psilocin (77.8-134.8 mg/kg) but no muscarine; I. asterospora contained muscarine (79.6-1182.6 mg/kg) and psilocybin (107.1-765.2 mg/kg) but no psilocin; whereas I. subaeruginascens contained all three: muscarine (480.8-752.6 mg/kg), psilocybin (1023.0-2731.2 mg/kg), and psilocin (71.7-148.4 mg/kg). Detailed morphological characters and phylogenetic analyses of the two new species are also provided. These results may enrich knowledge of the diversity of Inocybe species and their toxins and provide scientific evidence for elucidating toxin evolution and facilitating the early diagnosis and treatment of mushroom poisoning. The presence or absence of preformed psilocin may affect the onset of hallucinogenic symptoms, underscoring the need for species-level identification in poisoning management.

Inocybe is a cosmopolitan genus of ectomycorrhizal fungi within the family Inocybaceae. Members of this genus are recognized as a group of toxic mushrooms linked to poisoning incidents worldwide. Clarifying this species diversity and toxin profiles within this genus is critical for both taxonomy and public health. In this study, we describe two newly identified species, I. bicystidiata sp. nov. and I. microcarpa sp. nov., based on phylogenetic analysis and morphological evidence. Phylogenetically, the two new species belong to I. sect. Leptocybe. Inocybe bicystidiata is characterized by nodulose basidiospores with saddle-shaped projections and the coexistence of thick-walled pleurocystidia and thin-walled paracystidia on the lamellar side. Inocybe microcarpa is characterized by very small basidiomata, spinose basidiospores with forked projections, absence of pleurocystidia, and thin-walled cheilocystidia. Ecologically, both of these new species occur in tropical rainforests dominated by Parashorea chinensis, which is considered as their presumed host. In addition, new geographic data are reported for three previously documented species of I. sect. Leptocybe, I. acutata, I. juji, and I. peppa, based on newly obtained specimens. Comprehensive ultra-performance liquid chromatography-mass spectrometry (UPLC-MS)/MS toxin screening revealed no detectable levels of muscarine, psilocybin, psilocin, bufotenine, or baeocystin in 10 examined species of sect. Leptocybe. This contrasts with the known toxin-producing Inocybe lineages, suggesting a divergent secondary metabolism in this clade.

l-(+)-Muscarine (1)-producing mushrooms pose a severe threat to human health as ingestion can result in circulatory collapse or even death. However, their metabolic profile is surprisingly poorly understood, including knowledge of poison release and potentially toxic congeners. In the mycelium of the 1-producing fool's funnel mushroom Clitocybe rivulosa, we identified 4'-phosphomuscarine (2) as the major natural product. Its structure was elucidated by high-resolution mass spectrometry, nuclear magnetic resonance spectroscopy and by comparison with a synthesized reference. We also detected this previously overlooked phosphorylated compound in the fiber cap mushrooms Pseudosperma spectrale and Inocybe nitidiuscula. Studies on the activation of the muscarinic acetylcholine receptor M3 indicate only weak affinity of 2 to this target. Furthermore, we present biological evidence that muscaridine (3), a quaternary amine congener related to and co-occurring with 1, does not activate the muscarinic acetylcholine receptor M3 on human embryonic kidney cells. Our work provides important insight into the metabolic profile and the pharmacology of some of the most poisonous mushrooms. As the harmless 2 can liberate the potentially fatal 1 by unspecific enzymatic ester cleavage, these results are highly relevant for emergency medicine to estimate the true toxicity of these mushrooms.

We report an uncommon case of cholinergic poisoning following an ingestion of wild mushrooms. Two middle-aged patients presented to the emergency unit with acute gastrointestinal symptoms including epigastric pain, vomiting and diarrhea, followed by miosis, palpitations and diaphoresis which were compatible with a cholinergic toxidrome. The patients volunteered a history of taking two tablespoons of cooked wild mushrooms collected in a country park. Mildly elevated liver transaminase was noted in one female patient. Mushroom specimens were sent to a mycologist for identification using morphological analysis. Muscarine, a cholinergic toxin found in mushrooms such as Inocybe and Clitocybe species, was subsequently extracted from and identified in the urine specimens of both patients, using a liquid-chromatography tandem mass spectrometry method. In this report, the variable clinical presentation of cholinergic mushroom poisoning is discussed. Key issues in the management of these cases were presented. In addition to conventional mushroom identification methods, this report also highlights the use of toxicology tests on different biological and non-biological specimens for diagnosis, prognosis and surveillance purposes.

Wild mushroom (macrofungi) picking has become a popular activity in Israel in recent years. Besides the estimated 135 edible species, the mycobiota of Israel includes also around 65 poisonous and potentially dangerous species. We conducted a long-term retrospective study to monitor the frequency, severity, seasonal character, species composition, and geographic distribution of mushroom exposure and poisoning in Israel. Using data collected by the Israel Poison Information Center in Rambam Health Care Campus, Haifa, during the years 2010-2021, we report that only 4% of cases of exposures due to biological agents were caused by mushrooms. Males were significantly (P < 0.004) more affected than females. Most cases involved either above 18 years of age (41%) or below the age of 6 years (39%). Most of the children under 6 years of age did not develop signs or symptoms of toxicity. During 2017-2021, 128 cases (82.5%) involved the consumption of raw mushrooms, mostly by children under 6 years of age. The most common season of mushroom exposure was rainy winters (P < 0.05). Mushrooms collected from irrigated lawns in the summer also posed a risk. Ingestion of Chlorophyllum molybdites was the leading mushroom ingestion in summer and that of Inocybe species in winter. Our study contributes to improved awareness of mushroom exposure and poisoning patterns among the Israeli population.

Pseudosperma species are widely distributed worldwide. Many of them cause poisoning incidents every year, and the toxin responsible for poisoning is muscarine, which could stimulate the parasympathetic nervous system. This study established a method using multiwalled carbon nanotube purification and liquid chromatography-tandem mass spectrometry for the targeted screening of mushroom toxins (muscarine, isoxazole derivatives, tryptamine alkaloids, three amatoxins and three phallotoxins) from Pseudosperma umbrinellum, a common poisonous mushroom distributed in north and northwestern China. Surprisingly, in addition to muscarine, phalloidin was also detected in P. umbrinellum, and the contents were 3022.2 ± 604.4 to 4002.3 ± 804.6 mg/kg (k = 2; p = 95%) muscarine and 5.9 ± 1.2 to 9.3 ± 1.8 mg/kg (k = 2; p = 95%) phalloidin.

Some species of Inocybe s. str. caused neurotoxic poisoning after consumption around the world. However, there are a large number of species in this genus that have not been studied for their toxicity or toxin content. In this study, we report two new toxic yellow Inocybe s. str. species from China based on morphological characteristics, phylogenetic analyses and toxin detection. Among the two species, Inocybesquarrosolutea is reported as a newly recorded species of China. We also describe a new species, I.squarrosofulva, which is morphologically similar to I.squarrosolutea. The new species is characterized by its ochraceous squarrose pileus, distinctly annulate cortina on the stipe, nodulose basidiospores and thick-walled pleurocystidia. Muscarine in the fruitbodies was detected by UPLC-MS/MS, the content in I.squarrosolutea and I.squarrosofulva were 136.4 ± 25.4 to 1683.0 ± 313 mg/kg dry weight and 31.2 ± 5.8 to 101.8 ± 18.9 mg/kg dry weight, respectively.

Mushroom poisoning has always been a threat to human health. There are a large number of reports about ingestion of poisonous mushrooms every year around the world. It attracts the attention of researchers, especially in the aspects of toxin composition, toxic mechanism and toxin application in poisonous mushroom. Inocybe is a large genus of mushrooms and contains toxic substances including muscarine, psilocybin, psilocin, aeruginascin, lectins and baeocystin. In order to prevent and remedy mushroom poisoning, it is significant to clarify the toxic effects and mechanisms of these bioactive substances. In this review article, we summarize the chemistry, most known toxic effects and mechanisms of major toxic substances in Inocybe mushrooms, especially muscarine, psilocybin and psilocin. Their available toxicity data (different species, different administration routes) published formerly are also summarized. In addition, the treatment and medical application of these toxic substances in Inocybe mushrooms are also discussed. We hope that this review will help understanding of the chemistry and toxicology of Inocybe mushrooms as well as the potential clinical application of its bioactive substances to benefit human beings.

Wild mushroom foraging involves a high risk of unintentional consumption of poisonous mushrooms which is a serious health concern. This problem arises due to the close morphological resemblances of toxic mushrooms with edible ones. The genus Inocybe comprises both edible and poisonous species and it is therefore important to differentiate them. Knowledge about their chemical nature will unambiguously determine their edibility and aid in an effective treatment in case of poisonings. In the present study, the presence of volatile toxic metabolites was verified in Inocybe virosa by gas chromatography. Methyl palmitate, phenol, 3,5-bis (1,1-dimethyl ethyl) and phytol were the identified compounds with suspected toxicity. The presence of the toxin muscarine was confirmed by liquid chromatography. The in vitro study showed that there was negligible effect of the digestion process on muscarine content or its toxicity. Therefore, the role of muscarine in the toxicity of Inocybe virosa was studied using a bioassay wherein metameters such as hypersalivation, immobility, excessive defecation, heart rate and micturition were measured. Administration of muscarine resulted in an earlier onset of symptoms and the extract showed a slightly stronger muscarinic effect in comparison to an equivalent dose of muscarine estimated in it. Further, the biological fate of muscarine was studied by pharmacokinetics and gamma scintigraphy in New Zealand white rabbits. Significant amount of the toxin was rapidly and effectively concentrated in the thorax and head region. This study closely explains the early muscarinic response such as miosis and salivation in mice. By the end of 24 h, a relatively major proportion of muscarine administered was accumulated in the liver which stands as an explanation to the hepatotoxicity of Inocybe virosa. This is one of the rare studies that has attempted to understand the toxic potential of muscarine which has previously been explored extensively for its pharmaceutical applications.

Mushroom poisoning is a serious food safety issue in China. However, there is insufficient information on many poisoning incidents, including mushroom species and their clinical manifestations, diagnosis, treatments and toxins. Detailed epidemiological investigation was conducted after the occurrence of a mushroom poisoning incident resulting in typical muscarinic syndrome in Ningxia, China. The suspected mushroom species was identified based on morphological and phylogenetic analyses. Muscarine was detected using ultrahigh-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). On September 2, 2019, two patients exhibited typical muscarinic syndrome after consuming wild mushrooms. The clinical manifestations included chills, sweating, salivation and diarrhoea; the incubation period was approximately 2 h. Treatments, including anti-inflammatory, detoxification and nutritional support, were remedial. Full recovery ensued within 24 h. The specimen was identified as Inocybe serotina, and its muscarine content was 324.0 ± 62.4 mg/kg (k = 2, p = 95%). Two patients were poisoned via stimulation of their parasympathetic nervous system due to mistaken consumption of muscarine-containing I. serotina. They fully recovered with supportive treatments. To our knowledge, this is the first case report of I. serotina poisoning worldwide and is the first record of this species in China. Further, a method for muscarine detection was established using UPLC-MS/MS.

We describe here a paradigmatic case of mushroom poisoning mimicking a stroke. A 64-year old male was referred to the emergency department (ED) for a car accident. He was found diaphoretic, hypotensive, bradycardic, and slightly confused at presentation. No signs of trauma were observed on physical examination. The patient had weakness of the right limbs and bilateral severe myosis. The lab tests were normal, except for leukocytosis, mild hyperglycemia, mild hyperazotemia and moderate hypokalemia. The clinical picture, with the exception of miosis, was thereby suggestive for a stroke, which was also considered the cause of the car accident. The patients' wife, who was brought later to the ED, reported that the husband had suffered a stroke 4 years earlier, with residual right hemiparesis. She also referred that the patient showed signs of diaphoresis and confusion, and the car was intentionally driven into the ditch. Among other details, she referred that the husband ate mushrooms that she had personally collected 2 hours before taking the drive. Two mg of atropine, intravenous rehydration and potassium were hence administered in the suspicion of a cholinergic toxydrome, and complete clinical remission was rapidly obtained. Among the mixture of mushrooms eaten by the patient, a mycologist identified Armillaria Mellea (an edible mushroom) and notably Inocybe Fastigiata, a toxic muscarine-containing mushroom, easily confounded with Armillaria. After observation and oral rehydration, the patient was discharged.

Picking mushrooms, especially in summer and autumn, is still very popular in Poland. Despite raising awareness of poisonous mushrooms in the Polish society, year after year hospitals treat many patients diagnosed with poisoning with the most common toxic species of mushroom found in our country. Furthermore, growing interest in hallucinogenic mushrooms among young people has become a serious medical problem of our time. Websites make it incredibly easy for people to obtain information on the morphology and appearance of mushrooms with psychoactive properties, which leads inexperienced pickers to misidentification, resulting frequently in a fatal outcome. The article explores the subject of poisoning with the most common mushrooms with neurotropic effects, these are: Amanita muscaria, Amanita pantherina, Inocybe rubescens, Clitocybe dealbata, Clitocybe rivulosa and Psilocybe semilanceata. Toxins found in these species show symptoms that affect the central nervous system, parasympathetic system as well as the gastro-intestinal system. The effects of poisoning in the mushroom species mentioned above are mild in general, liver and kidney damage occur rarely, but the symptoms depend on both the dosage of the consumed toxins and individual susceptibility. In most cases the treatment is of symptomatic nature. There is no specific treatment. Medical procedures mainly involve induced gastrolavage--stomach pumping (providing that the patient is conscious), prescription of active carbon as well as replacement of lost body fluids and electrolytes. If the muscarinic symptoms prevail it is generally advised to dose atropine. Patients showing the signs of hyperactivity receive tranquilizers or narcoleptics to eliminate psychotic symptoms.