Alkaloids

Question 1

Yew

Answer 1

• Contains alkaloid taxine (cardiotoxic effect) and antimitotic agents called taxans.
• Taxine inhibits sodium and calcium channels on myocardium leading to decreased
  contractility.
• The whole plant is toxic except the red aril surrounding the seed.
• Signs of intoxication are: nausea, vomiting, diarrhoea, mydriasis, decrease in blood
  pressure, decrease in temperature, bradycardia and bradypnoe, heart collapse and
  death.
• Most sensitive are horses, which may die within a few minutes after ingestion.
• Treatment is only symptomatic.

Question 2

Horsetail

Answer 2

• Contains alkaloids palustrine and nicotine, and enzyme thiaminase.
• Alkaloids activate nicotinic receptors and lead to excitation, lack of thiamine leads to
  neurological signs.
• Poisonings mainly in cattle, usually after chronic intake.
• Signs of chronic intake: decrease of body weight, decrease of milk yield, diarrhoea,
  paralysis of muscles.
• Treatment: change of the diet and a supplement of vitamin B1 (thiamine)

Question 3

Hemlock

Answer 3

• Contains alkaloid coniine – inhibits nicotinic Ach receptors.
• Coniine irritates GIT, then causes paralysis of motoric centres.
• It is an up-going poisoning – first there is a paralysis of legs, then of a neck, head and
  finally trunk and chest. Death comes due to the paralysis of respiration muscles and it
  is in full consciousness.
• Coniine is a volatile substance, so beware of smelling to it, can cause a mild poisoning
  – headaches, vomiting – even while smelling to it.
• Poisonings are typical in ruminants from hay.
• Treatment is only symptomatic and usually unsuccessful

Question 4

Monkshood

Answer 4

• Contains alkaloid aconitine, which is the most potent plant toxic substance in Europe – the lethal dose is 2 mg of aconitine for the an adult man.
• It is very dangerous as it is absorbed via all routes including intact skin.
• It blocks neuronal transmission especially in nervus vagus, inhibits Na channels on
  synapses and in heart and causes death similar to that in coniine – a respiration
  paralysis in the full consciousness, or heart failure.
• Treatment is only symptomatic, but rarely successful.

Question 5

Ragwort

Answer 5

• Contains pyrrolizidine alkaloids – senecin, senecionin.
• Most common is spring poisoning after chronic or long-term exposure. In spring, the
  alkaloids are bound in a plant to sugars and other chemicals, so they don’t change its taste. Young and inexperienced animals - especially horses - are the main victims. In late summer and autumn, pyrrolizidine alkaloids are released from their bonds and cause a very bitter taste of plants, so there aren’t poisonings in this period of year.
• Pyrrolizidine alkaloids create adducts with DNA leading to hepatotoxicity and consequent hepatopathic encephalopathy.
• Signs: weakness, inappetence, jaundice, increased neuronal irritability, blindness, apathy, ataxia, liver failure.
• Prognosis is always poor, because signs are significant at the time when the damage of liver is too massive. Treatment is only symptomatic.
• In the CZ the poisoning of horses is called Žďár disease of horses.

Question 6

Deadly nightshade, Jimsonweed (thorn apple) and other Solanaceae (Atropa belladonna, Datura stramonium etc.)

Answer 6

• Contain alkaloids atropine
• Potatoes from Solanaceae contain solanine (lecture on food toxins) and tobacco plant
  contains nicotine (stimulation of nicotinic Ach receptors).
• Most poisonings by plants containing atropine.
• Some animals are resistant to atropine, they have an enzyme in blood which
  deactivates it - singing birds, guinea pigs, rabbits.
• Horses are very sensitive to this poisoning.
• Atropine is a parasympatolytic agent (xerostomia, inhibition of peristaltics, mydriasis,
  hallucinations, seizures, hyperthermia).
• Treatment of the poisoning is usually symptomatic, but the antidote is physostigmine.

Question 7

Boxwood

Answer 7

• Contains alkaloids cyclobuxine and buxamine.
• Lethal dose is similar to yew tree, so it is very poisonous.
• Cytotoxic, stimulate apoptosis + inhibit cholinesterases.
• Causes mainly vomiting, diarrhoea, colic, tremors, seizures, exhaustion, pain and
  vocalisation, death.
• Treatment is only symptomatic

Question 8

Sycamore maple tree

Answer 8

• Contains toxic aminoacid hypoglycin A.
• Most of the active substance is found in the seeds (autumn) and seedlings (spring).
• Hypoglycin A inhibits beta oxidation of fatty acids in muscles and leads to so called
  Atypical myopathy (rhabdomyolysis).
• Signs include apathy, colic pains in belly, sweating, reluctance to move, dark urine,
  weakness, recumbency, kidney damage, death. Mortality rate is very high.
• Treatment is only symptomatic but rarely successful.

Question 9

Frogflower and other Ranunculaceae

Answer 9

• Contain lactone called protoanemonin, which is found in all the Ranunculaceae family
• The alkaloid is highly toxic for water organisms, especially for fish and young frogs.
• It affects mainly kidneys, treatment is symptomatic.
• The poison is one of the few which is destroyed by drying – hay is not toxic.