Chemical Identification of the Amanita Toxin in Mushrooms

Amanita phalloides Mushroom Poisonings — Northern California, December 2016

“…Amatoxins, consisting of alpha, beta, and gamma amanitin, account for >90% of deaths related to mushroom poisoning worldwide ( 1 ). A. phalloides contains the alpha variety of amanitin, a cyclic octapeptide thought to be the primary agent of toxicity in humans ( 2 ).…”

“…Once ingested, amatoxin is readily absorbed from the gastrointestinal tract into the portal circulation where it is taken up by hepatocytes, binding to DNA-dependent RNA polymerase (II) and halting intracellular protein synthesis, ultimately resulting in cell death ( 3 ). A lethal dose can be as low as 0.1 mg/kg, and a single mushroom can contain up to 15 mg ( 1 ). The clinical course of amatoxin poisoning is described in three phases: delayed gastroenteritis with significant body fluid volume loss (after a postingestion latency of 6–24 hours), symptomatic recovery (24–36 hours after ingestion), and fulminant hepatic and multiorgan failure (typically 3–5 days after the ingestion) ( 4 ).…”

“…Amanita phalloides , colloquially known as the “death cap,” belongs to the Phalloideae section of the Amanita family of mushrooms and is responsible for most deaths following ingestion of foraged mushrooms worldwide ( 1 ). On November 28, 2016, members of the Bay Area Mycological Society notified personnel at the California Poison Control System (CPCS) of an unusually large A. phalloides bloom in the greater San Francisco Bay Area, coincident with the abundant rainfall and recent warm weather.…”

The use of fungi as food and in food processing, II

“…35 In 1910 Murrill 133 estimated that the annual deaths from mushroom poisoning in the U. S. at 50 or more, and several years later Fischer 68 quoted this figure but expressed the belief that not even 10% of the cases of mushroom poisoning find their way into the medical literature. Dreisbach ss stated that over 100 fatalities occur each year (presumably in the U. S.) from eating poisonous mushrooms, and Block et al 23 estimated that there were 50 fatalities annually in the U. S., a figure inadvertently also cited by Emmons 61 Gyromitra esculenta Amanita phalloides 7 11 In the light of the above statements it might seem especially foolhardy for anyone to recommend that any person eat any wild mushrooms of any type at any time. However, this would represent a very narrow and unrealistic point of view, since the known facts at this time most certainly do not bear out the concept that the majority of fleshy fungi are poisonous.…”

“…Therefore, the amatoxins are primarily involved in the poisoning of man, and the amatoxin contents of various species of Amanita have been determined (Block et al, 23 ' 24 Benedict et.al., 15 Tyler etal., 181 Wieland 197 ).…”