Orellanine

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Orellanine

General
Systematic name	Orellanine
Other names	Orellanin, 2,2-bipyridine-3,3-4,4-tetrol-1,1-dioxide, 3,3',4,4'-Tetrahydroxy-2,2'-bipyridine-N,N'-dioxide
Molecular formula	C₁₀H₈N₂O₆
Molar mass	252,17 g/mol
CAS number	[37338-80-0]
Hazards
Main hazard	Highly toxic
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Orellanine or Orellanin is a pyridinic, crystalline alkaloid that is found naturally in some lifeforms, specifically certain fungi.

It has been found in at least 34 Cortinariaceae. [1]

1 History
2 Chemistry
3 Toxicity
4 Treatment
5 References
6 See also
7 External links

[edit] History

In Poland during the 1950s there was a small epidemic where over 100 people became ill. What caused the illness remained a mystery until 1952 when Polish physician Dr. S. Grzymała discovered that everyone suffering from the illness, which had now claimed several lives, had eaten the mushroom Cortinarius orellanus.^[1]

In 1955 he isolated a substance from the fungus. After the Latin name of this toadstool, he named it orellanine. Given orally to research animals, he produced the same reaction as in humans. [2]

In 1973 orellanine was discovered in the toadstool Cortinarius rubellus.

[edit] Chemistry

The chemical constitution of orellanine remained unknown until the Polish chemists Antkowiak and Gessner in the last half of the 1970s discovered that it belongs to a group of compounds called bipyridines, a double ring structure where both rings are principally a pyridine ring (a heterocyclic ring with one nitrogen atom). In the most stable form of orellanine, the nitrogen atoms are positively charged.[3]

An interesting feature of orellanine is its ability to bind aluminium ions to organic complexes.[4]

[edit] Toxicity

Bipyridines with positively charged nitrogen atoms were already before the structure of orellanine was elucidated known to be poisonous. The herbicides paraquat and diquat are toxic not only to plants, but also to animals including humans. The main mechanism of bipyridines with charged nitrogen atoms is that they confound important red-ox reactions in organisms, ‘stealing’ one or two electrons and sometimes bypass the electrons into other and often undesirable red-ox reactions. The terminal product can be peroxide or superoxide ions. Specially, the last ion is harmful to the cells. It's likely that orellanine works in the same way, although the process from disturbed red-ox reactions to the serious clinical kidney damage has not been properly resolved.

In humans, a characteristic of poisoning by the nephrotoxin orellanine is the long latency, the first symptoms usually don't appear until 2-3 days after ingestion and can in some cases take as long as 3 weeks. The first symptoms of orellanine poisoning are similar to the common flu (nausea, vomiting, stomach pains, headaches, myalgia, etc), these symptoms are followed by early stages of renal failure (immense thirst, frequent urination, pain on and around the kidneys) and eventually decreased or nonexistent urine output and other symptoms of renal failure occur. If left untreated death will follow.

The lethal dose of orellanine in mice is 12 to 20 mg per kg body weight,^[2]^[3] where it must be noted that this is the dose which leads to death within two weeks. From cases of orellanine-related mushroom poisoning in humans it seems that the lethal dose for humans is considerably lower.

[edit] Treatment

Although there is no known antidote against orellanine poisoning early hospitalisation can sometimes prevent serious injury and usually prevent death. Research is ongoing, like some treatments that make use of anti-oxidant therapy and corticosteroids to help victims recover from their renal failure.^[4]

[edit] References

^ *Spoerke, David G.; Rumack H Rumack, Barry H Rumack (January 1994). Handbook of Mushroom Poisoning: Diagnosis and Treatment. CRC Press. ISBN 0-8493-0194-7.
^ *Prast H, Werner ER, Pfaller W, Moser M. (1988). "Toxic properties of the mushroom Cortinarius orellanus. I. Chemical characterization of the main toxin of Cortinarius orellanus (Fries) and Cortinarius speciosissimus (Kuhn & Romagn) and acute toxicity in mice.". Arch Toxicol. 62.
^ *Holmdahl, J (2001). Mushroom poisoning: Cortinarius speciosissimus nephrotoxicity. Göteborg University.
^ *Rachael G. Kilner et al (1999). "Acute renal failure from intoxication by Cortinarius orellanus: recovery using anti-oxidant therapy and steroids". Oxford Journals Nephrology Dialysis Transplantation 14 (11): 2779-2780. full text