GLYCOSIDES Flashcards
Anthraquinones plants
- cascara sagrada
- buckthorn
- coffeeweed/senna
- aloe
Anthraquinones MOA
-purgatives
-coffeeweed: also has unknown prinicple that causes skeletal and cardiac muscle degeneration and coffee colored urine d/t myoglobinuria (which may cause kidney damage)
(horses die from liver failure and not muscle degeneration)
Calcinogenic glycosides plants
-day-blooming Jessamine (flowers live 1-2 days)
Calcinogenic glycosides MOA
- hypercalcemia (VitD analogue)
- calcification of elastic tissues of arteries, tendons, and ligaments, as well as generalized increased density of bones causing lameness
- looks like VitD poisoning
Carboxyatractyloside (sulfated glycosides) plants
cocklebur
Sulfated glycoside MOA
- hepatotoxicity (liver is primary target)
- excessive salivation (mechanical injury to mouth)
- may be renal damage and hypoglycemia
Cardiac glycosides plants
-foxglove (Digitalis purpurea) • oleander* (most common) • yellow oleander, Lucky nut, Be‐still tree • Periwinkle • squill • lily‐of‐the‐valley • milkweed -butterfly weed -plumeria -christmas kallanchoe
Cardiac glycosides MOA
-IDENTICAL TO DIGITALIS
*clinically important!
-cardiotoxic by inhibiting Na/K ATPase pump –> increases intracellular Na and Ca –> arrhythmias
-also GIT signs!
(Pimobendan increases sensitivity to Ca, but Digitalis increases Ca)
Coumarin glycosides plants
sweet clover (Melilotus)
Coumarin MOA
-forms dicoumerol in spoiled plants
-hemorrhage d/t antagonism of vitamin K by inhibiting vitamin K reductase, resulting in deficiency of coagulation factors 1972
(like warfarin)
*cattle!
Cyanogenic glycosides plants
• wild cherries (Prunus spp.)
• Sorghum/johnsongrass/sudan
• Elderberry
-hydrangea
Cyanogenic glycosides MOA
- Release HCN on hydrolysis in damaged/stressed plants (plants that are frosted or stunted)
- HCN is metabolized in the liver to thiocyanates
Cyanogenic: ACUTE vs CHRONIC
- Acute poisoning:
- Inhibition of cytochrome oxidase and inhibition of cellular respiration
- Vasoconstriction
- Inhibition of glycolysis, citric acid cycle
- Irritation of the mucous membranes
*Chronic:
neuronal degeneration, antithyroid effect
Cycasin plants (2 families)
• Cycad family
– Sago palm
– Japanese cycad
• Zamiaceae
– Cardboard palm
– Coontie (Zamia pumila)
Cycasin plant MOA
• Cycad palms have three toxins:
1) Cycasin is a glycoside that causes GI irritation and liver damage and it is also teratogenic, mutagenic and carcinogenic
2) β‐methylamino‐L‐alanine (BMAA) is a neurotoxic amino acid
3) Unknown toxin that may cause axonal degeneration in the CNS
Cycasin CS
- Signs depend on the amount and duration of exposure
- may show GI and liver disease syndrome OR ataxia and CNS syndrome
- Dogs show GI and liver damage signs including vomiting with or without blood, anorexia, diarrhea, depression, and sometimes seizures
- Sheep show mainly GI signs and weight loss
- Cattle show neuronal signs (ZAMIA STAGGERS) including ataxia, weakness, and weight loss
Glycosinate (thiocyanate glycosides = SCN) plants
- rape seed, kale, broccoli, cabbage, brussels sprouts, turnip, and cauliflower
- soybean
- flax (also can cause cyanide)
Glycosinate MOA
- antithyroid (inferferes w/ iodine transport to thyroid gland)
- -> goiterogenic
- REPEATED exposure to plants = CHRONIC
Nitropropanol glycoside - plants
-milkvetch (legume family)
Nitropropanol MOA
-lack of energy (inhibits enzymes of Krebs cycle and oxidative phosphorylation) –> peripheral neuronal degeneration –> locomotor degeneration
Nitropropanol CS
- Cattle and sheep: respiratory and neurological signs
- horses and rodents: neuro signs
Phytoestrogens plants
- white clover
- subterranean clover
- alfalfa
Phytoestrogen MOA
plant has estrogens –> binds to estrogen receptors –> infertility in females and males
Phytoestrogen CS
- infertility in females
- decreased libido and feminization in males
Protoanemonin - plants
buttercup family (Anemone, Helleborus/Christmas rose, Clematis, Lenten rose)
Protoanemonin MOA
- protoanemonin is a VOLATILE OIL released by hydrolysis of the glycoside
- causes severe irritation of GI mucosa and dermatitis (GIT AND SKIN)
Ptaquiloside - plants
bracken fern
Ptaquiloside MOA
- death in precursor cells in bone marrow, causing aplastic anemia in sheep and cattle
- neoplasm in urinary tract –> enzootic bovine hematuria
- tumors of upper digestive tract and retinal degeneration in sheep (bright blindness)
Ptaquiloside CS
- aplastic anemia in cattle: acute onset, anorexia, hemorrhage
- enzootic hematuria: blood in urine, anemia, tachycardia, death
Steroidal saponins - plants
-agave lechugilla
nolina, panicum
Steroidal saponins MOA
-liver damage –> hepatogenic photosensitization –> can’t eliminate phylloerythrin (photodynamic metabolite of chlorophyll)
Steroidal saponins CS
-signs of photosensitization and liver damage
