Senecionine

Senecionine is a toxic pyrrolizidine alkaloid produced by several plant species, most notably within the Senecio genus (ragworts and groundsel) and related genera such as Crotalaria. It occurs in leaves, stems, seeds, and sometimes nectar, and can enter the human and animal food chain through contaminated forage, herbal remedies, or honey derived from PA-containing plants.

Chemistry: As a pyrrolizidine alkaloid, senecionine comprises a pyrrolizidine nucleus esterified with necic acids. It is one of many 1,2-unsaturated PAs; natural product samples commonly contain a mixture of stereoisomers.

Toxicology: Senecionine is hepatotoxic upon ingestion. After oral intake, liver enzymes metabolize it to reactive dehydro pyrrolizidine metabolites that can form adducts with proteins and DNA. This can cause hepatic injury, including veno-occlusive disease, fibrosis, and, with long-term exposure, increased risk of liver cancer in animal studies and suggested associations in humans.

Occurrence and regulation: Because of its toxicity, senecionine-containing plants and products are subject to regulatory controls in many countries. Analytical methods detect pyrrolizidine alkaloids in plant materials, honey, and dietary supplements to assess exposure risk.