POISONOUS PARTS
Whole plant.3,4
TOXICITY
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Toxic Constituents
Pyrrolizidine alkaloids such as senecionine, seneciphylline and senkirkine.5,6
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Toxic Dose
Long-term consumption of 1 mg pyrrolizidine alkaloids per day can be toxic.7
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Mechanism
Pyrrolizidine alkaloids are converted into highly reactive metabolites after transformation in the liver by the cytochrome P450 system. These metabolites bind to proteins, DNA and RNA, and induce acute and chronic toxicities. Liver is the major organ affected, and veno-occlusive disease (Budd-Chiari syndrome) could occur. As liver metabolism is involved, toxicity is not strictly dose-dependent but shows individual variability.8,9
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Poisoning Features
Pyrrolizidine alkaloid poisoning has acute and chronic effects. Acute: abdominal pain, hepatomegaly, ascites, liver necrosis and even death. Chronic: hepatomegaly, recurrent ascites, hepatic vein occlusion (Budd-Chiari syndrome), cirrhosis, hepatocellular carcinoma, pulmonary hypertension and even death.7,8
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Poisoning Events
There were 2 main sources of pyrrolizidine alkaloid poisoning. The consumption of cereal grains contaminated by the toxic weeds had caused numerous poisoning in many countries. In Afghanistan alone, an estimated 8000 people were affected with more than 1600 deaths. The other source is the use of pyrrolizidine alkaloid-containing herbs for medicinal and dietary purposes, leading to poisoning in all parts of the world.7,8
CLINICAL MANAGEMENT
Supportive treatment. Early diagnosis and avoidance of further exposure to the toxins is important.9
IDENTIFICATION FEATURES
Perennial herbs, with rhizomes. Stems 0.5–5 m long, striate. Petioles 0.5–2 cm long; leaf blades 4.5–8 × 1.5–4.5 cm, base broadly cuneate or truncate. Capitula heterogamous, 2–2.2 cm in diameter, branches and peduncles widely spreading. Central florets tubular, 5–6 mm long. Marginal ligulate florets 7–10, ligule 9–10 × 2 mm, yellow. Cypselae 3 × 0.7–0.8 mm, puberulous, brown; pappus white.10
MEDICINAL USES
Whole plant used in TCM: clear heat and remove toxin, clear the liver and improve vision, drain dampness, kill parasites. Recommended dose: 15–30 g.5,11–13
LABORATORY ANALYSIS
Senecionine, seneciphylline and senkirkine can be detected by GC-MS and LC-MS/MS.6,14
