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.  LD 50 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 LD 50 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  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

5 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

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  Don’t 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 Common Poisonous Plants and Mushrooms of North America. Timber Press, Oregon.  S Foster and JA Duke Peterson Field Guides Eastern/Central Medicinal Plants.Houghton Mifflin Company, Boston.  A Krochmal and C Krochmal 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.