Poisonous Plants

1
Poisonous Plants

• Dr. Jennifer Frick-Ruppert
• ACEE Executive Director
• Associate Professor of Ecology and Environmental
  Studies

2
Poisonous and Medicinal

• Just a matter of degree!
• Nicotine is a great example
• Cigarettes are smoked because the nicotine is a
  stimulant it is also addictive
• Nicotine is extremely toxic on par with cyanide,
  heroin, atropine.
• LD50 is less than 5 mg per kg of body weight.
  Average lethal dose is 7 drops of pure nicotine.
• Nicotine content of cigarettes is regulated to a
  maximum of 1 mg per cigarette.
• Average human is 155 lbs or 70 kg therefore the
  LD50 for a 70 kg human is about 350 mg or 350
  cigarettes.

3
Some Types of Plant Poisons

• Alkaloids
• Derived from amino acids basic (alkali)
• Most affect the nervous system because they mimic
  or block the action of nerve transmitters
• Glycosides
• Sugar-based with attached subgroup it is the
  subgroup that determines toxicity
• Cyanogenic glycosides release cyanide
  Glucosinolates occur in mustard family Cardiac
  glycosides act on heart
• Oxalic acid
• Crystalline structure is irritating like glass
  shards
• Rhubarb (Rheum rhabarbarum), Beets (Beta
  vulgaris), Sorrels (Oxalis spp., Rumex spp.),
  Purslane (Portulaca oleracea) also Arum family
• Phenols
• Acidic compounds
• Toxicodendron/Rhus species Poison Ivy, Oak, and
  Sumac

4
Edible plants and toxins

• Potato!
• Solanum tuberosum Nightshade Family
• Solanine, a bitter alkaloid
• Present in green parts of leaves, sprouts and
  tubers ancestral forms even dark tubers
• Dont eat green potatoes!
• Taro, Elephants Ears
• Colocasia esculenta Arum Family
• Staple food of the Pacific Islands
• Contain oxalic acid crystals
• Prepared by washing and pounding to make poi

5
Passage through Food Chain

• Milk sickness
• Cattle eat White Snakeroot (Eupatorium rugosum)
• Milk from these cows sicken people
• Common disease in eastern states Lincolns
  mother, my neighbors!
• Several compounds including glycosides and a
  complex alcohol (tremetol)
• Turtles and poisonous mushrooms
• Turtles unaffected humans that eat the turtles
  can be sickened

6
Fungal Pathogens on Food

• Ergot poisoning
• Fungus (Claviceps spp.) growing on Rye or Wheat
  or other grasses humans eat the flour
• Ascomycete fungus makes a hard black elongated
  structure
• Grain containing more than 0.3 ergot is
  prohibited from sale
• Over 40 alkaloids present related to lysergic
  acid
• Symptoms include irritable digestive tract, loss
  of balance, convulsions, drowsiness
• Witch-hunts of Salem and other towns
• Aflatoxins/Mycotoxins
• Contaminants of grain or other foods
• Penicillium, Aspergillus, Monascus commonly
• Confusion between plant toxicity and mold toxicity

7
Foxglove

• Digitalis purpurea Figwort Family
• Native to England and Europe naturalized in USA
  planted in gardens
• Contains a cardiac glycoside
• Used to treat dropsy massive fluid retention
  caused by poor heart function
• Now used in controlled dosages to correct heart
  beat irregularities, improve circulation, relieve
  fluid buildup, help kidney function

8
Mayapple

• Podophyllum peltatum Barberry Family
• Natives used as emetic and worm expellent also
  for syphilis
• Strongly irritating to skin and poisonous
• Contains lignans with anti-cancer and anti-viral
  properties
• Used today to treat venereal warts and testicular
  cancer

9
Buckeye

• Aesculus spp. Horse Chestnut Family
• Main toxin is a saponin glycoside (aesculin)
• All parts of plant toxic
• Natives used ground leaves to kill fish

10
Cherries, Peaches, Plums,

• Prunus spp. Rose Family
• Leaves, bark, and seeds (but not fruits) are
  toxic
• Contain a cyanogenic glycoside (amygdalin)
  resulting in cyanide poisoning if ingested
• Almonds are the seeds of a species of Prunus that
  produces low levels of toxin

11
Poison Ivy, Oak, Sumac

• Toxicodendron or Rhus spp. Cashew Family
• Variable growth form climbing or bushy
• Leaflets in 3 on compound leaves alternate
  leaves
• Contains an oleoresin (urushiol) in sap pollen
  or smoke also irritating
• Poison Sumac has alternate, pinnately compound
  leaves
• Dont confuse with Virginia Creeper
• 5-parted leaves

12
Dolls-Eyes or Baneberry

• Actaea pachypoda and A. rubra Buttercup Family
• All parts toxic, especially berries and roots
• Undetermined toxin, probably a glycoside
• Used by natives as emetic

13
Bloodroot

• Sanguinaria canadensis Poppy Family
• Contains several alkaloids including
  sanguinarine very toxic
• Used to induce glaucoma in laboratory animals

14
False Hellebore

• Veratrum parviflorum and others Lily Family
• Contain several alkaloids including veratridine
• Can be mistaken for other plants, including
  edible Ramps
• Used to treat high blood pressure

15
Poison Hemlock

• Conium maculatum and Cicuta spp. Umbel Family
• NOT the Hemlock tree (Tsuga canadensis)
• Resembles wild carrot, but has smooth leaves
• Used to poison Socrates
• European weed, now naturalized USA
• Contains toxic alkaloids related to nicotine

16
Pokeweed

• Phytolacca americana Pokeweed Family
• Several toxic compounds, mostly saponins, but
  recently a mitogen that damages blood cells
• Young stalks commonly eaten after boiling in
  several waters
• No longer recommended

17
References

• NJ Turner and AF Szczawinski. 1991. Common
  Poisonous Plants and Mushrooms of North America.
  Timber Press, Oregon.
• S Foster and JA Duke. 1990. Peterson Field Guides
  Eastern/Central Medicinal Plants.Houghton Mifflin
  Company, Boston.
• A Krochmal and C Krochmal. 1984. A Field Guide to
  Medicinal Plants. Random House, NY.
• Most of the photos in this presentation were from
  these references or from various internet sites.
  Do not distribute them.