The Coprinus syndrome

The non-fatal Coprinus syndrome (also called Antabuse syndrome) refers to intoxications elicited when alcoholic beverages are consumed with or, usually, sometime after eating fungi that by themselves are harmless. The sensitivity to alcohol can last for up to 5 days. Typically, a few to 30 minutes after drinking the alcohol, a person feels hot, starts to sweat and face, neck and chest intensively redden.

Concentrations of 5 mg/dl alcohol in the blood will initiate first symptoms. With 50-100 mg/dl, symptoms are marked. Above, symptoms of the Coprinus syndrome intermingle with those of pure alcohol poisoning. In severe cases of the Coprinus syndrome, flushing of the skin spreads to other parts of the body. Moreover, there is a metallic taste in the mouth and a tingling sensation in arms and legs, the pulse rate quickens and breathing speeds up, the cardiac rhythm can be disturbed, the blood pressure fall and collapse. Other possible symptoms are throbbing headache, shaking of the limbs, feelings of tightness, anxiety and dizziness. Individuals occasionally experience nausea and vomiting but rarely colic and diarrhea. Symptoms will continue as long as there is alcohol in the system. With elimination of the alcohol, the patient recovers completely.

However, with fresh alcohol consumption the symptoms return. Unless an affected person has a heart condition or high blood pressure, treatment is mostly unnecessary, as the symptoms normally disappear in the course of a few hours without any after-effects (Hatfield and Schaumberg 1978, Bresinsky and Besl 1990, Michelot 1992, Benjamin 1995). In animals, when administered with alcohol, hypotensions and hyperventilation in rabbits, prolongation of the sleep cycle in mice, swelling with increased tear production in rats and, in a cow, the same symptoms that the antabus-alcohol reaction produces in humans were reported (Benjamin 1995, Clémençon 1962).

The Coprinus syndrome is analogous to the responses caused by Antabuse® (from Greek anti = against, and Latin abusus = misuse) [disulfiram, tetraethylthiuramdisulfide, bis(diethylthiocarbamyl)disulfide] that produces

4. Biologically active metabolites and medicinal properties of coprinoid mushrooms

hypersensitivity to alcohol and is therefore applied in treatment of alcoholism since almost 60 years (Fuller and Gordis 2004). Disulfiram interferes with the metabolizing of acetaldehyde formed in the oxidation of ethanol by blocking enzymatic activities of the mitochondrial NAD⁺-dependent, low-Km aldehyde dehydrogenases (ALDH) through irreversible binding to the enzyme. In consequence, there is a transient increase of acetaldehyde in the blood being responsible for the unpleasant bodily reactions (Pettersson and Tottmar 1982, Johannson et al. 1991). Early reports on presence of disulfiram in C. atramentaria (Simandl and Franc 1957) were not confirmed (Hatfield and Schaumberg 1975). Hatfield and Schaumberg (1975) and Lindberg et al. (1977) were able to isolate the atypical (“non-protein”) amino acid coprine (N⁵ -[1-hydroxycyclopropyl]-L-glutamine, Figure 1A) from fruiting bodies of C. atramentaria.

After administration of coprine to mice via a polyethylene stomach tube and intraperitoneally administration of alcohol, acetaldehyde was detected in blood (Hatfield and Schaumberg 1975). After feeding rats with coprine and alcohol, lachrymation and gradual swelling of the animals´ faces occurred (Lindberg et al. 1977). The results suggested that the water-soluble substance in combination with alcohol is the origin of the Coprinus syndrome. Moreover, as the isolated fungal compound, synthetically produced coprine was active in rats at minimal doses of 10 mg/kg body weight (Lindberg et al. 1977, Tottmar and Lindberg 1977). In vivo, coprine is active both against mitochondrial low-Km ALDH from brain and liver of rats but, as disulfiram, not against any high-Km ALDHs (Pettersson and Tottmar 1982). However, coprine is only a pretoxin (Figure 1B) that in vitro shows no inhibitory activity towards low-Km rat-liver ALDH unlike the hydrolytic coprine product 1-aminocyclo-propanol (ACP) (Tottmar and Lindberg 1977). ACP is also active in vivo against mitochondrial low-Km ALDH, probably by irreversible binding to the enzyme (Marchner and Tottmar 1978). Coprine is more potent than disulfiram in increasing the acetaldehyde/ethanol ratio in the blood and decreasing ALDH-activity in the brain and it does not act as disulfiram against dopamine β-hydrolase (Carlsson et al. 1978, Nilsson et al. 1987, Nilsson and Tottmar 1989). Initial ideas of using the more specific and potent coprine like disulfiram in defeat of alcoholism had however to be abandoned when it became clear that the compound is potentially mutagenic and carcinogenic and exerts gonadotoxic properties (Michelot 1992). Coprine and benzcoprine were both positive in Ames tests suggesting they may have alkylating properties (Jönsson et al. 1979). Daily oral administration of coprine and the derivative benzcoprine [N-(1-ethoxycyclopropyl) benzamide] to male

4. Biologically active metabolites and medicinal properties of coprinoid mushrooms

rats and dogs at doses above the level minimally needed for ALDH inactivation in rats (Tottmar and Lindberg 1977) lead to testicular injuries and blocking of

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Figure 1 Molecular structure of the atypical amino acid coprine, which formally may be regarded as a condensation product of glutamine and cyclopropanone (A). Structure of 1-Aminocyclopropanol, the metabolite formed after hydrolysis of coprine (B). Alcohol metabolization in combination with coprine action (C). In the body, alcohol is normally oxidized to acetic acid through the actions of the enzymes alcohol dehydrogenase and aldehyde dehydrogenase. 1-Aminocyclopropanol inhibits the aldehyde dehydrogenase. As a consequence, the acetaldehyde accumulates in the body producing all described symptoms (modified after Clémençon 1962, Bresinsky 1990 and Benjamin 1995).

spermatogenesis. Effective doses in rats were 200 mg/kg/day feed for up to 14 days whilst 20 mg/kg/day was ineffective and effective doses in dogs were 25 and 75 mg/kg/day feed for up to 28 days whilst 7.5 mg/kg/day was ineffective (Jönsson et al.

1979). Transferring these data to humans, a daily consumption of 3-6 kg C. atramentaria mushrooms by a 70 kg human male could lead to sterility (Benjamin 1995). The 1-aminocyclopropane-1-carboxylic acid a component of C. comatus affects on reproductivity of male mice of the SHN line (Nagasawa et al. 1995).

Coprinoid mushrooms shown to cause the Coprinus syndrome include C. atramentaria, Coprinopsis insignis, C. africana, and C. variegata. Furthermore, Coprinopsis

4. Biologically active metabolites and medicinal properties of coprinoid mushrooms

acuminata and Coprinopsis romagnesiana as close relatives of C. atramentaria (Figure 2) are suspected to have the same property (Bresinsky and Besl 1990, Matthies and Laatsch 1992, Benjamin 1995). In contrast, C. comatus and Coprinellus micaceus (Hatfield and Schaumberg 1978) do not give rise to alcohol-inflicted indispositions. It appears that within the coprinoid mushrooms all troublemakers come from the genus Coprinopsis, and, within of the genus, reactive species are widely spread (Figure 2).

Amongst species causing the Coprinus syndrome, coprine has been found in C. insignis and C. variegata (Hatfield and Schaumberg 1978). In C. atramentaria, coprine amounts of 130-360 mg/kg mushroom fresh weight were determined (Lindberg et al. 1977, Laatsch 1990, Matthies and Laatsch 1992). Furthermore, Matthies and Laatsch (1992) report coprine values as high as 300-400 mg/kg in Coprinopsis picacea, a species that probably will not be eaten by its disagreeable smell (Laatsch and Matthies 1992) and probably therefore is not known to cause the Coprinus syndrome. Hatfield and Schaumberg (1978) could not detect the substance in C. comatus and C. micaceus whilst Laatsch (1990) and Matthies and Laatsch (1992) claim from chromatography analysis presence of coprine also in C. comatus (supported by NMR-spectroscopy), C. disseminatus, and C. micaceus at varying low levels (between 10 and 34 mg/kg fresh weight) as well as in Coprinopsis lagopus and Parasola plicatilis. Such levels would be too small to give any problems for well-being. In Coprinellus xanthotrix and Parasola auricoma, no coprine was detected (Matthies and Laatsch 1992). Some case descriptions suggest consumption of Clitocybe clavipes, Boletus luridus, Verpa bohemia, Tricholoma flavovirens, Pholiota squarrosa or Morchella angusticeps in combination with alcohol may also lead to awkward effects (Laatsch 1990, Michelot 1992, Benjamin 1995). Coprine was not found in B. luridus, C. clavipes and V. bohemia by Hatfield and Schaumberg (1978) whilst Matthies and Laatsch (1992) detected in chromatography an amino acid with coprine-like migration properties in B. luridus and C. claviceps. Further work discarded occurrence of coprine in B. luridus but gave evidence for its presence in the related and easily mistakable species Boletus torosus (Kiwitt and Laatsch 1994). In the other species, alcohol-related symptoms are thought to be of different origin (Laatsch 1990, Matthies and Laatsch 1992) or, in case of P.

squarrosa, they probably would equally have happened in absence of alcohol (Benjamin 1995). In conclusion, the available data in the literature on occurrence of coprine within mushrooms indicate a prevalence of the substance within the genus of Coprinopsis.

Reports on coprine in taxonomically unrelated homobasidiomycetes (including the three

4. Biologically active metabolites and medicinal properties of coprinoid mushrooms

other new genera of coprinoid mushrooms) are few and mostly little or not substantiated by appropriate documentation of supporting experiments and resulting data.

ParasolaCoprinusCoprinellusCoprinopsis

copr, surf, illud, antibact, hemag surf

copr, surf, antibact, antifung, antitum, antiprot, hypoglyc

copr, surf, illud, antibact, hemag surf

copr, surf, antibact, antifung, antitum, antiprot, hypoglyc

Figure 2 Phylogenetic relationships of Coprinopsis species causing Coprinus syndrome and/or producing coprine as well as other biological properties. Tree based on nucleotoid sequences of the region of the 25S large subunit ribosomal RNA gene. Codes indicate NCBI GenBank accession numbers. Bootstrap values (500 replications) above 50 are shown at tree branchings. The scale bar defines the number of nucleotide substitutions per site. The abbreviations in front of the species names indicate biological compounds reported in the literature: Copr= coprine; surf= surface proteins, illud= illudins; antibact= antibacterial; hemag=

hemagglutinating; antifung= antifungal; antitum= antitumor; antiprot= antiprotozoal; hypoglyc=

hypoglycemic. Known examples for these different types of effects are discussed in the text.

4. Biologically active metabolites and medicinal properties of coprinoid mushrooms