Which plants cause pyrrolizidine alkaloid toxicosis with hepatic signs? (flowers MOST TOXIC and carcinogenic)

• A. Nettle
• B. Lupine
• C. Pokeweed
• D. Fiddleneck (Amsinckia), Crotalaria, Hound's Tongue (Cynoglossum), Viper's Bugloss (Eichium), Tansy Ragwort + Groundsel (Senecio), Comfrey (Symphytum)

Answer: (D)

Pyrrolizidine alkaloids are activated in the liver to reactive metabolites that damage hepatocytes and biliary tissue, leading to chronic liver injury, fibrosis, and even liver neoplasia. Plants containing these alkaloids include several genera known for hepatic toxicosis, especially ragwort and groundsel in flowers, and others like fiddleneck, crotalaria, hound's tongue, viper's bugloss, and comfrey. Because flowers in this group can have high PA content and PAs are both hepatotoxic and carcinogenic, this set of plants best explains hepatic signs after ingestion. The other plants listed don’t contribute PA-related liver toxicity to the same extent, so they don’t fit as well with pyrrolizidine alkaloid toxicosis.