poisonous plants and fungi Flashcards
what are poisonous plants and fungi?
One which causes a serious departure from normal health when a small quantity of the plant/fungus or certain part of the plant/fungus is eaten by an animal susceptible to its effects.’
How to assess poisonous plant
Accessibility to poisonous plants/fungi is relatively easy. These may be found in the countryside (e.g. fields, woods, and hedges), but many are kept in houses and greenhouses as ornamental plants
Explain why the number of cases of plant poisoning increases during Autumn and summer?
The number of cases increases during late summer and autumn. This is probably because the season/time when the plants produce berries coincides with vacation time.
children require a smaller dose to have a similar toxic effect; greater chance of displaying toxic symptoms. true/false
true
State the 3 groups plants and fungi are classed as poisonous
There are plants, which are undoubtedly toxic, such as ___________, but they have medical application in defined doses.
There are plants that are toxic and have no medicinal potential or this has not been realized yet
e.g. _____________ that contains ___________(a polyyne compound) and _____________ (a peptide) in _________ (death cap). (Yew and taxol!)
There are plants and fungi that are toxic and are abused for their hallucinogenic properties such as _____________ and ____________ species (liberty cap).
There are plants, which are undoubtedly toxic, such as Atropa belladonna, but they have medical application in defined doses.
There are plants that are toxic and have no medicinal potential or this has not been realized yet
e.g. Oenanthe crocata that contains oenanthotoxin (a polyyne compound) and amatoxins (a peptide) in Amanita phalloides (death cap). (Yew and taxol!)
There are plants and fungi that are toxic and are abused for their hallucinogenic properties such as nutmeg and Psilocybe species (liberty cap).
Symptoms of plant ingestion
: nausea, vomiting, diarrhoea and stomach cramps. Blistering of the mouth and other lining may be present. This is dependent on the plant involved (presence of irritants). The above symptoms are non-specific and occur with most cases of poisoning. These are called cases of ingestion.
list the symptoms of plant poisoning
In some cases systemic effects will be forth coming i.e. effects on CNS, muscle, respiration and heart. These are called cases of poisoning.
The symptoms displayed are dependent on what and how much has been consumed.
- was set up in 1963 for advice on all types of poison
National Poisons Information Service (NPIS)
List examples of plant that causes constipation
ragwort and acorns
List some some poisonous plants that causes blood disorders
Mercury and bracken
State the problems of diagnosis with plants/fungi poisoning
It is usually difficult to identify a plant poison from the symptoms displayed. Hence, diagnosis, in order to start treatment on the patient is not possible from this approach.
Furthermore, information is required about the locality of where the person or animal was, and amount and what was consumed.
The problem could stem from something unrelated to plants e.g. _____________
Not all plant poisons cause diarrhoea. A few plants cause constipation e.g. ragwort and acorns. Some cause blood disorders e.g. dog’s mercury and bracken.
Toxic symptoms are not always forth coming immediately e.g. _______, __________ and _________ – it takes a few hours; ______ and ___________ – about two days; bracken and ragwort – ____________
It is usually difficult to identify a plant poison from the symptoms displayed. Hence, diagnosis, in order to start treatment on the patient is not possible from this approach.
Furthermore, information is required about the locality of where the person or animal was, and amount and what was consumed.
The problem could stem from something unrelated to plants e.g. pesticides sprayed on plants.
Not all plant poisons cause diarrhoea. A few plants cause constipation e.g. ragwort and acorns. Some cause blood disorders e.g. dog’s mercury and bracken.
Toxic symptoms are not always forth coming immediately e.g. foxglove, hemlock and yew – it takes a few hours; nitrate and autumn crocus – about two days; bracken and ragwort – weeks to months.
types of toxic principles in plants and fungi
Plant/fungi poisons may be either highly active so that a small dose gives rise to pronounced pharmacological effects, or may be relatively less active but when consumed in large quantities will give rise to pronounced effects.
Toxic principles of plants/fungi may break down spontaneously, change as a result of metabolic enzymes acting on them (perhaps becoming toxic as a result), or remain intact in the body.
Usually the body attempts to make compounds more water- soluble in order to eliminate them from the body.
What are the effects of toxic compounds?
Local effects such as ____________
Systemic effects and these may be _________________
Others effects such as _______and ____________.
The nature of the toxic principles is not known for all the plants/fungi classed as ‘poisonous’.
Most of the toxic principles can be divided into similar classes as for the ____________
Local effects such as blistering especially the lining of the mouth and intestine.
Systemic effects and these may be direct on one or more organs e.g. heart, CNS and lungs.
Others effects such as liver damage or oxalates coupling with calcium and causing hypocalaemia and kidney damage.
The nature of the toxic principles is not known for all the plants/fungi classed as ‘poisonous’.
Most of the toxic principles can be divided into similar classes as for the beneficial natural products
Some fungi accumulate certain types of heavy metals and produce compounds that are not directly toxic .true/false?
Some types of fungi are able to accumulate certain types of heavy metals e.g. _________, ___________, ________, __________. Some fungi produce compounds that are not directly toxic, but only in the presence of ethanol by interfering with the alcohol metabolism (e.g. ___________ (ink caps) of fungi contains a compound _____________).
Some types of fungi are able to accumulate certain types of heavy metals e.g. cadmium, caesium, iron, mercury. Some fungi produce compounds that are not directly toxic, but only in the presence of ethanol by interfering with the alcohol metabolism (e.g. Coprinus spp (ink caps) of fungi contains a compound coprine).
Name the Britain’s most toxic plant used as one time to treat trigeminal neuralgia
_______, a diterpene alkaloid obtained from Aconitum species
common names are ________ and __________
Aconitine, a diterpene alkaloid obtained from Aconitum species
common names are monkshood and wolfbane
Facts about Aconitine
____________- varies with stage of growth. Roots of the plant were previously used to provide _______for various conditions. The roots have been mistaken for ____________ leading to fatalities. As much as ________ is considered to be enough to kill
Alkaloid content varies with stage of growth. Roots of the plant were previously used to provide pain relief for various conditions. The roots have been mistaken for horse radish leading to fatalities. As much as 5 mg is considered to be enough to kill
Mode of action of Aconitine
Aconitine and related structures are complex terpene esters and they are neurotoxins acting on the sodium channels. No antidote available
Symptoms of poisoning with Aconitine
9
! Symptoms of poisoning include burning of the mouth and throat, abdominal pain, intense thirst, headache, slow pulse, paralysis, convulsions, delirium and coma. Treatment would be symptomatic.
Chronic intake of certain amino acid leads to great toxicity. True/false?
True
Where toxic amino acids commonly occur
These types of substances are commonly occurring in the seeds of the ___________________ e.g. consuming large quantities of chick peas during drought season.
These types of substances are commonly occurring in the seeds of the bean family (Fabaceae) e.g. consuming large quantities of chick peas during drought season.
Chick peas contain —-
α-amino-β-oxalylamino propionic acid
Toxic amino acid can cause what type of condition?
It can cause _____________. Condition that develops is called ‘___________’- toxicity of the nerves.
It can cause paralysis of the lower limbs. Condition that develops is called ‘neurolathyrism’- toxicity of the nerves.
Large amount of sweet peas cause
‘osteolathyrism’.
Some species of the genera inocybe and clitocybe produce ——-
Muscarine
Facts about L(+) Muscarine
L (+) Muscarine has structural similarities to the transmitter acetylcholine and thus activates acetylcholine receptors. Unlike acetylcholine, muscarine does not have an ester bond and cannot be hydrolysed by acetylcholinesterase and results in prolonged stimulation.
State the symptoms experienced 15-30mins after consuming fungus that produces muscarine
10
After 15-30 minutes of having consumed the fungus, typical symptoms are heavy breathing, salivation, lachrymation, vomiting, diarrhoea, colic, constriction of the pupils, decreased blood pressure, slow pulse and bronchial asthma; all relating to over stimulation of the acetylcholine receptors.
What can be used to counteract the action of muscarine?
Atropine can be used to counteract this action. Normal dose is adult 1-2 mg IM or IV every ½ to 1 hour until toxicity subside
Other stereoisomers of L (+) Muscarine have been isolated as well, but have reduced potency (600-12000 times less). Therefore these are not toxicologically significant. true/false
False
Toxins from peptides of Amanita phalloides are———
Generally very toxic
The toxins in Amanita species are subdivided into 3 namely;
amatoxins, phallotoxins and virotoxins.
Amatoxins are….
bicyclic octa
Phallotoxins are
Hepta peptides
Virotoxins are
Hepta peptides with a monocyclic structure
Toxicity symptoms caused by Amanita phalloides species
Initially there is the gastrointestinal phase. There is sudden onset of nausea, abdominal pain, colic, vomiting and bloody diarrhoea. Increased electrolyte loss will cause shock and cramps. This lasts for 12-24 hours, followed by a deceptive period of (12-24 hours) of recovery. The first signs of liver damage become apparent at this stage.
The liver will become enlarged and pressure sensitive. There will be jaundice, stomach and intestinal bleeding, followed by hepatic coma and death. If the liver starts to regenerate, then slow recovery is possible.
Facts about Phallotoxins and Virotoxins
Phallotoxins are not easily absorbed through the gut, and have tenth of the toxicity when administered into the blood stream. Virotoxins have similar properties to phallotoxins.
Facts about Amatoxins
The amatoxins (ring shaped made of __________) are stable to boiling and the enzymes in the ___________. They attack the nuclei of __________and stop _________. Fatal amount needed for an adult is __________. The toxic compounds are rapidly excreted in the _____, but then ____________(enterohepatic circulation). Methods are used to stop the reabsorption, but the main excretion of these compounds is through the _________. (RNA ____________ inhibited by α-amanitin leading to protein shortage in cells.)
The amatoxins (ring shaped made of eight amino acids) are stable to boiling and the enzymes in the GI tract. They attack the nuclei of liver cells and stop transcription of DNA. Fatal amount needed for an adult is 5-7 mg. The toxic compounds are rapidly excreted in the bile, but then reabsorbed (enterohepatic circulation). Methods are used to stop the reabsorption, but the main excretion of these compounds is through the kidneys. (RNA polymerase II inhibited by α-amanitin leading to protein shortage in cells.)
