Toxicology of mushrooms
Mushrooms are saprophytic macrofungi which have characteristic morphological features such as stem, cap and gills. They are also known as toadstool, puffball, stinkhorn and many more common names. They belong to Ascomycota, Basidiomycota and Agaricomycota group of fungi. Mushrooms have been popular food especially in China, Korea, Japan and Europe. They are consumed for their nutrient richness such as all essential minerals, vitamins like thiamine, riboflavin, niacin, pantothenic acid, D2 or ergosterol; source of Se, Na, Zn, Ca, K and P; they are low calorie food with less fat and carbohydrate content. Some important genera of edible mushrooms are: Agaricus bisporus, Amanita cesarea, Laetiporus sulphureus, Coprinus comatus, Volvariella volvacea and Chanterella spp. But some mushrooms are deadly poisonous and it has always been difficult to differentiate between poisonous and edible species. Mushroom scientists and expert collectors are sometimes unable to recognize poisonous species in wild. Mushroom toxins are usually secondary metabolites or some mushrooms turn toxic after absorption of heavy metals and radioactive irradiation (mushrooms have ability to absorb heavy metals and radiation). Actually toxins are secreted by mushrooms for defense, against consumption or premature destruction.
Mushroom poisoning is known as mycotism. Onset of symptoms in less than 6 hours or several days after ingestion is characteristic of mycotism. Toxic mushrooms include: Amanita phalloides, A. muscaria, A. viros, A. pantherina, A. verna, Omphalotus olearius, Verpa bohemia, Cortinarius orellanus, Clitocybe dealbata, Galerina autumnalis, Coprinopsis atramentaria, Chlorophyllum molybdites, Agaricus hondensis, Inocybe erubescens, different species of Entoloma, Gyromitra, Tricholoma, Conocybe, Lepiota, Hypholoma, Paxillus, Lactarius, Gomphus, Helvella, Psilocybe, Elebeloma and Ramaria. Mushroom toxins were used as medicines for treating psychological disorders but they have fatal side effects.
Amanita phalloides mushroom is deadly poisonous, commonly known as death cap and produces amatoxin. This toxin causes diarrohea, violent vomiting, severe abdominal pain, liver necrosis and kidney failure. Cortinarius orellanus produces orellanine nephrotoxin responsible for acute renal failure and gastrointestinal dysfunction. Turnip foot or Red stain or Inocybe erubescens mushroom produces toxin muscarine. It is very potent toxin causing perspiration, salivation, lacrimation, vomiting, abdominal pain, diarrohea, micturition, flushing, hypotension, bradycardia, pupil constriction, blurred vision, muscle spasm, dehydration and many other symptoms after ingestion. Toxin coprin is produced by Coprinopsis atramentaria and typical poisoning symptoms are headache, flushing, trouble breathing, nausea and palpitation. Gyromitra spp. produces gyromitrin which may trigger acidosis, hypoxia, hepato-renal failure, cerebral odema, hypoglycemia, hemolysis, hypovalemia and methaemoglobinaemia. Some mushrooms produce hallucinogenic toxins. Psilocybe semilanceata and P. cubensis produces psilocybin toxin which contain psychedelic chemicals with psychoactive properties. Although they have medicinal value; their toxic effects on humans should not be ignored. Most prominent symptoms are nausea, vomiting, abdominal pain, tachycardia, dilated pupils, diastolic hypertension, drowsiness, rhabdomyolysis, arrhythmias and myocardial infarction. Their hallucinating effects include restless over activity, lack of coordination, uncommunicative staring, tactile sensation, distorted body image, visual hallucinations, aggressiveness, inability to judge distances and heights. Amanita muscaria also produces psychoactive ibotenic acid and muscimol toxins. Both of them are hepatotoxic. Edible fungi like Agaricus bisporus can be toxic if consumed raw. It contains agaritine toxin which is carcinogenic, asthmatic allergen. Toxin is lost by heat during cooking. Other important mushrooms and their toxins are Amanita smithii (orellanine), Paxillus involutus toxin stimulates immune system to destroy its own erythrocytes, Boletus satanas (bolestine) and toxins of Tricholoma equestre and Pleurocybella porrigens cause acute brain disorder, renal toxicity and rhabdomyolysis.
Don't worry, enjoy your nutritious mushroom preparations but do not forget their toxicity while experimenting in wild and during your nature trails.
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