Amatoxins

Poisoning and sometimes death from eating (unidentified) mushrooms is well known. In particular, Amanita sp. are particularly dangerous, with much emphasis on the death cap fungus , Amanita phalloides.24 The best known toxins are the amatoxins and phallotoxins, which are complex, bicyclic peptides. An unusual feature relates to sulfur a tryptophan (or substituted tryptophan) unit is linked to a cysteine sulfur at the carbon atom next to the NH group of the pyrrole ring, forming the unit, -CH2-S-C(NH)=C, e.g. in... 

Amatoxins are a family of cyclic peptides, with oc-amanitin and 3-amanitin (Figure 3.1) accounting for >90% of the total amatoxins. In A. virosa, mushrooms collected in Virginia a-amanitin found to be completely replaced by amaninamide (Figure 3.1). The peptides are not destroyed by cooking and... 

Figure 3.1 Structures of the main amatoxins a-amanitin, (3-amanitin, and amaninamide.

As with amatoxin poisoning, attempts to remove the toxin from plasma by extra-corporal purification methods at the time of hospitalization do not seem promising because of the long latent period. However, beside supportive care, hemodialysis is the option during the clinical course. For a recent review on Corinarius spp. poisoning, see Danel et al. (2001). A renal transplantation should not be carried out too early the mean time for a transplant among the cases published so far was 6 to 30 months. 

Fortunately, of the vast number of mushroom species that exists, only a few produce secondary metabolites that cause fatal poisonings. If toxins causing benign symptoms, such as abdominal pain and diarrhea, hallucinations, or alcohol incompatibility, are disregarded, the most significant mushroom toxins are the extremely hazardous compounds of amatoxins, orellanine, and, to a lesser extent, methylhydrazine and its derivatives. Consequently, there is only a... 

Enjalbert, F., Rapior, S., Nougier-Soule, J. Guillon, S., Amouroux, N. and Cabot, C. (2002). Treatment of amatoxin poisoning 20-year retrospective analysis, J. Toxicol. Clin. Toxicol., 40, 715-757. 

Kaneko, H., Tomomasa, T., Inuoe, Y., Kunimoto, F., Fukusato, T., Muraoka, S., Gonmori, K., Matsumoto, T. and Morikawa, A. (2001). Amatoxin poisoning from ingestion of Japanese Galerina mushrooms, J. Toxicol. Clin. Toxicol., 39, 413-416. 

Meunier, B.C., Camus, C.M., Houssin, D.P., Messner, M.J., Gerault, A.M. and Launois, B.G. (1995). Liver transplantation after severe poisoning due to amatoxin-containing Lepiota - report of three cases, J. Toxicol. Clin. Toxicol., 33, 165-171. 

Liver failure and Mushrooms - "Death Amatoxin and phalloidin... 

Delayed-onset mushroom poisoning, usually caused by Amanita phalloides, A virosa, Galerina autumnalis, or G marginata, manifests its first symptoms 6-12 hours after ingestion. Although the initial symptoms usually include nausea and vomiting, the major toxicity involves hepatic and renal cellular injury by amatoxins that inhibit RNA polymerase. Atropine is of no value in this form of mushroom poisoning (see Chapter 58). 

Scheme 6 Structure of the 6 -Hydroxytryptathionine (R)-Sulfoxide Moiety of Amatoxins...

The phallotoxins 106, e.g. phalloidin, and the amatoxins 107, e.g. a-amanitin, produced by Amanita phalloides or death cup, are among the best-known peptide poisons 233). 

The amatoxins are cyclic octapeptides composed only of L-amino acids and containing a sulfoxide group instead of the thioether bridge in phallotoxin. Over 90% of the fatal cases of mushroom poisoning can be traced back to the amatoxins. Wieland et al. 234) have shown that, in addition to the toxins, the death cup contains a low concentration of an antitoxic cyclic decapeptide antamanide 108. 

The amatoxins and phallotoxins are cyclic peptides (peptides are made... 

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