II. Poisonous Plants w Acute vs. chronic toxicity w a) internal poisons w b) allergens w c) cell modifiers: mutagens, teratogens and lectins

a. Internal Poisons w Alkaloids w Glycosides w Oxalates w Resins

Alkaloids w N-containing heterogenous group of medicinal, toxic, and psychoactive compounds w Found in high concentrations in the Apocynaceae, Berberidaceae, Fabaceae, Papaveracea, Ranunculaceae, Rubiaceae, and Solanaceae w Not found in the Lamiaceae, Rosaceae, and the Gymnosperms

Glycosides w combination of sugar(s) or glycone and another compound (aglycone) w glucose is the most common sugar w toxicity is associated with aglycone moiety

Cynogenic glycosides w Hydrolized to HCN and sugar w Amygdalin is found in seeds of apples, pears, apricot, bitter almonds, wild and domestic cherries, peaches and plums. w HCN blocks the action of cytochrome oxidase in respiration causing cellular asphyxiation

Anthraquinone glycosides w Hydrolysis of anthraquinones w Found in aloe and rhubarb

Cardioactive glycosides w Aglycones are steroidal w Act on the heart (paralysis) w Found in Digitalis (foxglove) and Antirrhinum (snapdragon)

Saponin glycosides w Aglycone forms a steroid or triterpene that form colloidal dispersions in water w Irritates mucous membranes and destroys blood cells. w Found in yams, ginseng, licorice, beech, poke, alfalfa, and english ivy

Coumarin glycosides w Aglycone is a benzopyranone w Causes internal bleeding and dermatitis w Not common w Found in Artemesia species (sagebrush)

Oxalates w organic acid that forms in crystals in vacuole w Reach dangerous levels in oxalis, rhubarb, dock and purslane

Resins w Amorphous products of complex nature. w Insoluble in water and do not contain N w Mixture of oils, gums and sugars w Found in water hemlock, milkweed, rhododendron and azaleas

Allergens w Pollen can cause: w Anaphylatic shock w Allergenic rhinitis (hayfever) w Asthma w Dermatitis w Photodermatitis

Mutagens can cause: w Replacement of nucleotide in DNA w Loss of addition of nucleotide causing more serious mutagenesis w Nondisjunction of chromosomes (extra chromosomes) w Polyploidy (extra set of chromosomes)

Teratogens w Effects on somatic cells of growing embryos usually resulting in malformed organs

Lectins w Can be highly toxic w Proteins with carbohydrate chains attached w Some examples are ricin (castor bean), curcin and abrin (rosary pea) w ricin inhibits protein synthesis by inactivating ribosomes w Some lectins can stimulate cell proliferation

Tannins w bitter tasting polyphenols that bind and precipitate proteins