Toxic metabolite profiling of Inocybe virosa

Abstract

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. 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 resemblance of toxic mushrooms with edible ones. The genus Inocybe also comprises both edible and poisonous species and it is therefore important to differentiate them. The species Inocybe virosa which is the focus of the present study is closely allied to Inocybe cutifracta which is an edible mushroom. The taxonomic classification of a mushroom species under the genus Inocybe, generally raises a suspicion about its edibility. This inevitable caution stems from the literature which abounds in cases of poisonings due to Inocybe mushrooms. Some of the poisonings reported have been associated with Inocybe fastigiata 1,2 , I. tristis 3 , I. anterospora 4 , I. aeruginascens 5 and I. patouillardii 6. Species such as I. asterospora, I. gobeyi, I. napipes, I. repanda, I. radiata, I. rimosa show psychotropic effects and classified as neurotoxic. Most of the I...

Two new Inosperma (Inocybaceae) species with unexpected muscarine contents from tropical China

“…Surprisingly, of the two new species we assayed, both of them have a high content of muscarine that is about 30 to 50 times higher than I. virosum (Sailatha et al 2014;Latha et al 2020). For humans, a lethal dose of muscarine is estimated from 40 mg to 495 mg (Pauli et al 2005).…”

“…2009). Many Inocybaceae species were well known to contain muscarine (Peredy et al 2014;Patocka et al 2021), and various methods have been used to detect this toxin in the past years (Fahrig 1920;Eugster 1957;Brown et al 1962;Robbers 1964;Kosentka et al 2013;Latha et al 2020). Five Inosperma species were reported as muscarine positive, including I. cervicolor (Pers.…”

“…Five Inosperma species were reported as muscarine positive, including I. cervicolor (Pers. (Kosentka et al 2013;Latha et al 2020). In addition, I. carnosibulbosum (C.K.…”

“…Pradeep & Matheny) Matheny & Esteve-Rav., a species described from India, is probably a muscarine positive species due to a recent report of poisonous case (Chandrasekharan et al 2020). Among these muscarine positive species in Inosperma, I. virosum described from India, is more extensively studied in toxin detection, toxicity in vitro using NCM460 colon epithelial cell line, toxic effects in vivo and pharmacokinetics of muscarine (Latha et al 2020). The muscarine content of I. virosum is 270 or 300 mg/kg reported by separate studies (Sailatha et al 2014;Latha et al 2020).…”

“…Muscarine C 9 H 20 NO 2 + , CAS number: 300-54-9, is a toxic alkaloid found in Inocybaceae, Clitocybe and several other mushroom genera (Patocka et al 2021). The ingestion of muscarine-containing mushrooms would cause diaphoresis, salivation, urination, nausea, vomiting, gastrointestinal effects and muscular cramp, and fatal muscarinic syndromes like miosis, bronchoconstriction, and bradycardias in humans (Wilson 1947;Lurie et al 2009;Chandrasekharan et al 2020;Latha et al 2020;Patocka et al 2021), or even death (Pauli et al 2005;Işıloğlu et al 2009;Zosel et al 2015). Many species of Inocybaceae are known to contain muscarine , especially in Inocybe sensu stricto, and Pseudosperma (Kosentka et al 2013;Matheny et al 2020).…”