toxic plants

Secondary compounds

Chemicals not essential for plant survival, used for defense or communication.

Why are toxins from the same classes of secondary compounds as plant medicines

they both evolved as defense or communication methods to deter herbivores and attract pollinators.

What are some plant families well-known for producing toxins

• Fabaceae (legume family)

  • Includes locoweeds (Astragalus), wild peas, and beans

• Solanaceae (nightshade family)

  • Includes deadly nightshade, tobacco, and tomatoes

• Apiaceae (carrot family)

  • Includes poison hemlock

• Ranunculaceae (buttercup family)

  • Includes monkshood (Aconitum)

• Rosaceae (rose family)

  • Includes wild cherries and almonds

• Euphorbiaceae (poinsettia family)

  • Includes castor bean, manchineel

Alkaloids

A class of secondary compounds that can cause various effects, including toxicity.
includes swanisonine. coniine. acotine, nicotine, atropine, and scopolamine

Swainsonine

An alkaloid from the Fabaceae family that causes appetite loss.

Coniine

An alkaloid from poison hemlock that causes respiratory paralysis by blocking acetylcholine receptors.

Aconitine

An alkaloid from monkshood that disrupts sodium channels leading to paralysis or death.

nicotine, atropine, and scopolamine

alkaloids that are neuroactive compounds that vary from stimulant to hallucinogen

Glycosides

Compounds that can be toxic and affect physiological functions such as heart function or release cyanide.
includes digitoxin, amygdalin, and coumarin glycosides

Digitoxin

a glycoside that effects heart function

amygdalin

a cyanogenic glycoside that releases cyanide

coumarin glycosides

used as antocoagulants

Ricin

A phytotoxin from castor bean that inactivates ribosomes and stops protein synthesis.

abrin

a phytotoxin that has a similar action to ricin

Urushiols

Allergenic compounds found in poison ivy and related plants that can cause contact dermatitis. Unusual because it causes delayed allergic reactions

Thiaminase

an enzyme that breaks down thiamine (vitamin B1) and is found in certain toxic plants such as the fish poison plant.

Raphides

Calcium oxalate crystals that cause mechanical injury, resulting in burning and swelling when ingested. Unusual because it causes mechanical damage

ODAP

A neurotoxic amino acid from grass pea that causes lathyrism, characterized by leg paralysis.

The dose makes the poison

A phrase by Paracelsus indicating that the harmful effects of a substance depend on the amount taken.

Chris McCandless

Died in part due to the consumption of plants containing toxic compounds, including those with alkaloids.

Allergens

Substances that cause allergic reactions, often resulting in contact dermatitis.

Phytotoxins

Toxic compounds produced by plants that cause physiological disturbances.