Download Plant Identification and Poisonous Plants

Poisonous Plants
Dr. Jennifer Frick-Ruppert
ACEE Executive Director
Associate Professor of Ecology and
Environmental Studies
1
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.
2
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
3
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
 Don’t eat green potatoes!
 Taro, Elephant’s Ears




Colocasia esculenta; Arum Family
Staple food of the Pacific Islands
Contain oxalic acid crystals
Prepared by washing and pounding to make poi
4
Passage through Food
Chain
 Milk sickness
 Cattle eat White Snakeroot (Eupatorium rugosum)
 Milk from these cows sicken people
 Common disease in eastern states; Lincoln’s
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
5
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
6
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
7
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
8
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
9
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
10
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
 Don’t confuse with Virginia Creeper
 5-parted leaves
11
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
12
Bloodroot
 Sanguinaria canadensis; Poppy Family
 Contains several alkaloids including
sanguinarine; very toxic
 Used to induce glaucoma in laboratory
animals
13
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
14
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
15
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
16
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.
17