Plant toxicity

Question 1

Plants most likely to cause serious poisoning in humans:

Answer 1

1. Oleander - Nerium oleander 2. Jimson weed - Datura stramonium 3. Jequirty pea - Abrus precatorius 4. Water hemlock - Cicuta maculata 5. Poison Hemlock - Conium maculatum 6. Monkshood - Aconitum napellus

Question 2

Oleander, especially the yellow Peruvian variety

Answer 2

• Cardiac glycosides oleandrin and digitoxigenin: Highest in seeds, stem, and roots. • Exam alert! Plant cardiac glycosides inhibits Na-K ATP-ase; raises intracellular Na and Ca concentrations; severe poisoning may cause hyperkalemia. • May react with digoxin immunoassay lab test but levels do not correlate with toxicity and cannot be used to guide treatment. o Treatment: Digibind Fab fragments can be used; dose is based on patient response.

Question 3

Jimson Weed (Datura stramonium)

Answer 3

• Seeds contain the most toxin. Single fruit equals ~6 mg of atropine. • Anticholinergic poisoning: Dry flushed skin, tachycardia, decreased bowel motility, urinary retention, hallucinations, agitation, seizures, and coma. • Onset 30 minutes; duration 48 hours or longer. • Treatment: Benzodiazepines for sedation. • Physostigmine for severe toxicity not responding to benzodiazepines. “Go low, go slow.” Start with a low dose (2 mg) given slowly by IV infusion to avoid bradycardia and heart block. o Physostigmine has very short half-life compared to anticholinergic alkaloids, so repeat dosing or continuous miniscule infusion might be needed.

Question 4

Toxalbumin group:

Answer 4

Jequirity Pea, Castor Bean • Toxalbumins inhibit cellular protein synthesis and induce cellular injury in various organs. • Jequirty peas (Abrus precatorius) are used to make jewelry. Contains the toxin, abrin. • Castor bean (Ricinis communis) contains the toxin, ricin. The intact bean is surrounded by a hard shell. Even chewed beans rarely result in significant morbidity. o Other plants: Black locust tree (toxin, robin); tropical Florida Sandbox tree (toxin, hurin). • Rapid onset of vomiting, diarrhea, abdominal pain, and delayed multisystem organ failure especially if the exposure is parenteral. • Inhalation of purified toxalbumin (perhaps as a terror event) can lead to rapid airway inflammation/difficulty breathing, myalgia, circulatory failure, death in 36-48 hours.

Question 5

Water Hemlock

Answer 5

cicutoxin - potent, noncompetitive GABA antagonist. Very toxic! o Nausea, vomiting, diarrhea initially; then CNS excitation: Tremors, seizures, coma. o Plants grow in wet areas, grow up to 6-8 feet tall; with branching, tuberous root stalk like a dahlia. The lower part of the stem is chambered; hollow stems may be purplish. Has divided leaves and clusters (umbels) of white flowers. o All parts contain toxin; roots are the most toxic.

Question 6

Poison Hemlock

Answer 6

coniine, a nicotine-like alkaloid, in all plant parts but mainly seeds. o Plants grow up to 8-10 feet tall along the dry side of roads and in pastures; has fernlike foliage, mottled purple spots along stems and umbelled flowers that look like wild carrot or Queen Anne’s lace. Has one main solid taproot and stem. o Symptoms similar to nicotine: Stimulation then fatigue of nicotinic receptors in autonomic ganglia, CNS, and skeletal muscle. Nausea, vomiting, hyper then hypotension, bradycardia, muscle weakness, respiratory depression.

Question 7

Monkshood, Wolfsbane

Answer 7

Aconitum species • Toxin in the root; used in herbal preparations for pain and as an arrow poison. • Aconitine: Causes various neurotoxic and cardiotoxic effects. • Mechanism: Interferes with sodium channel function to induce a chronic depolarization state, at first making it easier to fire cells and to release acetylcholine from nerve terminals. Eventually it paralyzes the nerve. • Mix of GI, neurologic, and cardiovascular effects: GI upset, paresthesia, sweating, muscle cramping then weakness, hypotension, bradycardia or tachycardia, ventricular arrhythmias including Torsades, and death by respiratory paralysis or cardiac arrest.

Question 8

Oleander

Answer 8

Cardiac glycoside

Question 9

foxglove

Answer 9

Cardiac glycoside

Question 10

lily of the valley

Answer 10

Cardiac glycoside

Question 11

red squill

Answer 11

Cardiac glycoside

Question 12

balloon cotton

Answer 12

Cardiac glycoside

Question 13

dogbane

Answer 13

Cardiac glycoside

Question 14

butterfly weed

Answer 14

(Asclepias) Cardiac glycoside

Question 15

cane toad

Answer 15

(Bufo marinus) Cardiac glycoside

Question 16

False or green hellebore

Answer 16

Veratrum alkaloid

Question 17

Zygadenus venenosus

Answer 17

(death camus) Veratrum alkaloid

Question 18

black snakeroot

Answer 18

Veratrum alkaloid

Question 19

certain azaleas

Answer 19

Grayonotoxin

Question 20

rhododendron

Answer 20

Grayonotoxin

Question 21

mountain laurel

Answer 21

Grayonotoxin

Question 22

honey made from pollen

Answer 22

Grayonotoxin

Question 23

Yew

Answer 23

Contains taxines, which are sodium and calcium channel blockers. -Nausea, vomiting, abdominal pain, bradycardia, conduction delays, hypotension, arrhythmias.

Question 24

Autumn crocus, glory lily

Answer 24

Colchicine • Purified agent is a drug to treat gout by inhibiting cell division and migration of white cells. • Nausea, vomiting, diarrhea, abdominal pain, and more severe toxicity of bone marrow suppression and multi-organ damage.

Question 25

Pokeweed

Answer 25

(Phytolacca toxin, saponine, mitogens) - Root contains the most toxins. • Self-limited headache and gastroenteritis, burning sensation in the mouth, intense vomiting, abdominal cramping, hemorrhagic gastritis, frothy diarrhea. • Cooking does not always render safe to eat. If no symptoms in 6 hours most likely will not have any symptoms (true of most GI irritants.)

Question 26

Philodendron

Answer 26

Insoluble calcium oxalate crystals irritate mouth and throat:

Question 27

dumbcane

Answer 27

Insoluble calcium oxalate crystals irritate mouth and throat:

Question 28

caladium

Answer 28

Insoluble calcium oxalate crystals irritate mouth and throat:

Question 29

elephants ear

Answer 29

Insoluble calcium oxalate crystals irritate mouth and throat:

Question 30

jack-in-the-pulpit

Answer 30

Insoluble calcium oxalate crystals irritate mouth and throat:

Question 31

rhubarb

Answer 31

Heavy in soluble oxalates; increased risk of calcium oxalate kidney stones. o Soluble oxalates are perceived as sour/biting when eaten, but it does not contain the needle-like raphide crystals that can pierce the oral mucosa.

Question 32

Raw or uripe Ackee fruit

Answer 32

Exam alert! Usually affects children who do not yet know to avoid unripe or uncooked fruit. Cooking water also toxic. Imported from Jamaica and found in international grocery stores. o Hypoglycin A causes profound hypoglycemia and intractable vomiting, thus the name of the illness, “Jamaican vomiting sickness.” o Abdominal discomfort begins 2-6 hours after ingestion, followed by sudden onset of vomiting. In severe cases, potentially life-threatening CNS depression. o Hypoglycemia occurs due to inhibition of glucose output by the liver. Microscopically the injury to the liver cells is similar to Reye’s Syndrome. o Treatment: Bedside monitoring of serum glucose; bolus dextrose as needed (D50 adult, D25 older child, D10 young child).

Question 33

Comfrey/Comfrey tea

Answer 33

Induces hepatic veno-occlusive disease that closes down sinusoids and veins in the liver, causing acute portal hypertension.

Question 34

Sassafras

Answer 34

Safrole is a potential liver carcinogen; banned by the FDA from commercial food use. Safrole-free sassafras is still OK to use. Filé, a spice used in Cajun cooking, is made from ground sassafras leaves.

Question 35

Prunus species

Answer 35

(bitter almond, apricot, apple, peach, pear, plum, cherry, etc.) pits and seeds contain amygdalin. o Only bitter almonds and kernels from apricot pits are risky for mild-to-moderate symptoms of acute cyanide toxicity if eaten in reasonably-normal quantities such as 1-2 ounces. o These are typically obtained from the internet or holistic health food/alternative medicine suppliers, not the grocery store.

Question 36

Cassava

Answer 36

Is a tuber that provides the primary carbohydrate source for much of the world’s tropical and semitropical populations. It is our source of tapioca pudding. Once properly prepared and cooked, the cyanogenic glycoside isgone and it is safe. If not properly prepared, it supplies small amounts of cyanide. o Chronic, low-level cyanide exposure is associated with the development of goiter and with tropical ataxic neuropathy, a neurologic disorder that renders a person unsteady and uncoordinated. o Severe sub-acute dietary cyanide poisoning from eating a particular variety, “bitter cassava”, particularly during famines, is associated with outbreaks of an irreversible, debilitating, spastic paralytic disorder called Konzo.

Question 37

Veratrum alkaloids

Answer 37

Severe nausea and vomiting, then bradycardia, heart block, syncope, diaphoresis, weakness, hypotension.

Question 38

Grayanotoxins

Answer 38

Salivation, burning mouth, perioral numbness, nausea, vomiting, dizziness, diaphoresis, significant hypotension and bradycardia.