Toxic Plants - 2 Flashcards
Describe the mechanism of action of anthraquinones
- purgative
- coffee weed causes skeletal and cardiac muscle degeneration
- urine may be coffee colored due to myoglobinuria
- horses usually die from liver failure
Describe the mechanism of action of calcinogenic glycoside
- hypercalcemia
- calcification of the elastic tissues of the arteries, tendons, and ligaments
- increased density of bones causing lameness
Describe the mechanism of action of carboxyatractyloside
- hepatotoxicity
- excessive salivation
- renal damage and hypoglycemia
Describe the mechanism of action of cardiac glycosides
cardiotoxic by inhibiting Na/K ATPase
Describe the mechanism of action of coumarin glycosides
- form dicoumarol in spoiled plants
- hemorrhage due to antagonism of vitamin K by inhibiting vitamin K epoxide reductase resulting in deficiency of coag factors II, VII, IX, and X
Describe the mechanism of action of cyanogenic glycosides
- inhibition of cytochrome oxidase and inhibition of cellular respiration
- vasoconstriction
- inhibition of glycolysis
- inhibition of citric acid cycle
- irritation of mucus membranes
- chronic: neuronal degeneration and antithyroid
Describe the mechanism of action of cycasin
- causes GI irritation and liver damage
- teratogenic, mutagenic, and carcinogenic
- BMAA is neurotoxic
- unknown toxin causes neuronal degeneration in CNS
What are the clinical signs of cycasin?
- GI and liver disease, or ataxia and CNS
- dogs show GI and liver damage
- sheep show GI signs and weight loss
- cattle show neuronal signs
Describe the mechanism of action of glucosinolate
antithyroid
Describe the mechanism of action of nitropropanol glycoside
inhibits enzymes of the krebs cycle and cellular oxidative phosphorylation
What are the clinical signs of nitropropanol glycoside?
- respiratory and neurological signs in cattle and sheep (cracker heels or roaring)
- horses and rodents show neurologic signs
Describe the mechanism of action of phytoestrogens
bind to estrogen receptors causing infertility
What are the clinical signs of phytoestrogens?
- infertility in females
- decreased libido and feminization in males
Describe the mechanism of action of protoanemonin
- a volatile oil released by hydrolysis of the glycoside
- causes severe irritation of GI mucosa and dermatitis
Describe the mechanism of action of ptaquiloside
- death of the precursor cells in the bone marrow causing aplastic anemia in cattle and sheep
- neoplasm in urinary tract causing enzootic bovine hematuria
- tumors of the upper digestive tract and retinal degeneration in sheep
What are the clinical signs of ptaquiloside toxicosis?
- aplastic anemia: anorexia, and hemorrhage
- enzootic hematuria: blood in urine, anemia, tachycardia, and death
Describe the mechanism of action of steroidal plants
- liver damage and inability to eliminate phylloerythrin
- hepatogenic photosensitization
Describe the mechanism of action of gossypol
- cardiotoxic and secondary liver damage
- reduces male fertility by destroying seminiferous tubules
- protein malnutrition, inhibits enzymes, and interferes with hemglobin synthesis
Describe the mechanism of action of molybdenum
causes signs of copper deficiency
- watery diarrhea, wasting, anemia, depigmentation, demyelination, osteoporosis
Describe the mechanism of action of copper
liver damage, hemolysis, and methemoglobinemia
Describe the mechanism of action of selenium
acute: GI irritation and respiratory signs
chronic: hoof and hair abnormalities
Describe the mechanism of action of nitrate
- GI irritation
- formation of methemoglobin
- resp insufficiency
- abortion
Describe the mechanism of action of dimethyl disulfide
- 5-methyl cysteine sulfoxide is reduced by intestinal flora to dimethyl disulfide
- large amounts cause oxidation of RBCs to form heinz bodies
What are the clinical signs of dimethyl disulfide toxicosis?
anemia, depression, hemoglobinemia, hemoglobinuria, icterus, and cyanosis
Describe the mechanism of action of diterpene esters
- direct irritation of skin and mucus membranes
- activate protein kinase C resulting in cell damage and enzyme disfunction
What are the clinical signs of diterpene ester toxicosis?
- irritation and blistering of the skin and GI mucosa
- salivation, vomiting, and diarrhea
Describe the mechanism of action of grayanotoxins
- bind to sodium channels in nerves, skeletal muscles, cardiac muscles, and CNS
- increase permeability of sodium ions
- irritation of GI mucosa
What are the clinical signs of grayanotoxins?
- salivation, vomiting, colic, diarrhea
- depression, tachycardia, tachypnea, seizures, fever
- death due to aspiration pneumonia
Describe the mechanism of action of lectins
- ricin and abrin are glycoproteins
- inhibit cellular protein synthesis resulting in cell death
What are the clinical signs of lectin toxicosis?
hemorrhagic gastroenteritis
Describe the mechanism of action of meliatoxins
enterotoxic and neurotoxic
What are the clinical signs of meliatoxins?
- GI signs
- CNS and peripheral neuronal signs
- death from respiratory failure
Describe the mechanism of action of propyl disulfide
- disulfides produce oxygen free radicals which damage RBC membranes
- also cause denaturation of hemoglobin resulting in heinz bodies
What are the clinical signs of propyl disulfide toxicosis?
anorexia, tachycardia, ataxia, tachypnea, dyspnea, icterus, anion odor, and abortion
Describe the mechanism of action of tetradymol
- induction of microsomal enzymes
- liver damage that decreases elimination of phylloerythrin
What are the clinical signs of tetradymol toxicosis?
- anorexia, depression, incoordination, dyspnea, icterus, and head pressing
- skin swelling, erythema, necrosis, and sloughing
Describe the mechanism of action of thiaminase
destroys thiamine in the diet and produces signs of deficiency in monogastric animals
- neurotoxic
Describe the mechanism of action of triterpenoid saponins
direct irritation of GI mucosa
What are the clinical signs of triterpenoid saponin toxicosis?
salivation, anorexia, vomiting, diarrhea, colic, and hypothermia
Describe the mechanism of action of resins or resinoids
irritation of the nervous or muscle tissue
