Orellanine - How normal-looking mushrooms can be way poisonous

Orellanine is a nephrotoxic (nephros is Greek for kidney, you do the math) dipyridine possessing positively charged nitrogen atoms that is produced by several species of mushrooms belonging to the genus Cortinarius. Members of this genus are gilled mushrooms that grow in association with plants (i.e. are mycorrhizal) and have their gills protectively covered by a cottony cortina (veil or curtain, not to be confused with the Google Image-hogging vehicle of the same name) that spans between their pileus (cap) and stipe (stem) when they are but wee little shroomies. Known producers of the toxin include C. rubellus (deadly webcap), C. orellanus (fool's webcap), and a bunch more. Some of these are found in Europe, others in North America (most commonly in the fall), meaning that no one in the Western world is safe. These poisonous species are occasionally confused with edible or psychedelic mushrooms, resulting in sweet, sweet natural selection.

It has been estimated that the consumption of only 100 grams (about 3.5 ounces) of fresh C. orellanus is necessary to utterly destroy ones' kidney! Orellanine kills people by accumulating in the renal tubules of their kidneys and somehow selectively damaging this part of the organs to the point that they stop working (acute renal failure), an event that usually takes two to three weeks after the onset of symptoms to occur (okay, make that delayed acute renal failure). Unusually, the onset of symptoms (initially and unfortunately flu-like in nature) is typically delayed up to 3 to 4 days after mushroom consumption in severe cases, and up to three weeks in milder cases. If they don't die outright, about one-third to half of all those poisoned by orellanine develop chronic renal failure and may require dialysis or kidney transplant.

Like aflatoxins, which are mycotoxins produced by Aspergillus moulds that rank among the most carcinogenic chemicals known to man, orellanine is fluorescent, making it a blast at glow-in-the-dark mini putt. Similarly-structured substances include the herbicides paraquat and diquat, which are both toxic to humans. Paraquat is particularly nasty, accumulating in and causing progressive destruction of the lungs in a manner similar to how orellanine savages the kidneys.

- Berger KJ, Guss DA. Mycotoxins revisited: Part II. J Emerg Med. 2005 Feb;28(2):175-83. Review.
- Nilsson UA, Nyström J, Buvall L, Ebefors K, Björnson-Granqvist A, Holmdahl J, Haraldsson B. The fungal nephrotoxin orellanine simultaneously increases oxidative stress and down-regulates cellular defenses. Free Radic Biol Med. 2008 Apr 15;44(8):1562-9. Epub 2008 Jan 31.

3 chemically inspired comments:

A'Llyn said...

Now see, that's just underhanded.

If I eat something and promptly fall ill and die, my fellows will know not to eat that thing. But if I eat something and don't fall ill and die for weeks, heck, my entire social group could be chowing down in the meantime, thinking everything was fine!

Underhanded, but so very clever. More evidence that mushrooms, while delectable, cannot be trusted.

milkshake said...

Not so: One only has to be very conservative when hunting for wild mushrooms.

These were the things I lerned as a little kid from my grandparents and parents: Pick only those mushrooms of which you are absolutely certain you know. Dont be greedy - forgo even delicius kinds that are easy to mistake with the poisonous kinds. Be extra viginalnt with white leafy mushrooms and light-green leafy ones - those can be mistaken with deadcap amanitas ("angel of death"). If you are a novice you must stick only with boletes spongy mushroom and bright orange chanterrrels, etc - there are actually unpleasant bolete kinds too (with striking red sponge under the cap so you may recognise them easily) but those will not kill you should you make the error of eating them.

Avoid moldy mushrooms, cut out the parts with maggot holes, throw away those that are heavily infested (common sense!). Clean and cut the mushroom as soon as you bring them home. Dont put fresh mushroom in air-proof cotainers like a plastic bag, they sweat, heat up and spoil promptly and spoiled mushrooms can make you sick. Never eat mushrooms raw. If you have an excess, you may freeze your mushrooms cooked (with butter and salt), or pickle them, or dry them - but raw one will spoil within days even in the freezer.

Also older people should not eat massive quantities of mushrooms (like several pounds that you get when lucky in the hight of the picking seasons) because mushrooms digest realtively slowly. Also mushrooms are best in the medley - different kinds of mushroom combined will deliciously with meat and vegies, enhancing the savory taste of other foods but on their own they are not very mutritious or awesome as when you combine them with other foodstuff.

C.D. Clements said...

I saw on Discovery Channel yesterday that Grocery Store mushrooms are grown on horse crap and wet straw.

The black stuff which comes on your mushrooms is apparently not entirely plain old dirt.