Pyrrolizidine alkaloids in human diet

Area of Science:

• Toxicology
• Natural Products Chemistry
• Human Health Risk Assessment

Background:

• Pyrrolizidine alkaloids (PAs) are prevalent plant-derived toxins implicated in human and animal diseases.
• Metabolic activation of PAs in the liver generates reactive electrophiles that form adducts with cellular macromolecules, potentially initiating toxicity.
• Human exposure occurs via contaminated food or medicinal herbs, posing significant health risks.

Purpose of the Study:

• To review and synthesize the available literature on the health outcomes associated with human exposure to pyrrolizidine alkaloids.
• To assess the carcinogenic potential of PAs in humans based on existing evidence.

Main Methods:

• Literature review of human exposure data and toxicological studies on pyrrolizidine alkaloids.
• Analysis of reported cases of disease and toxicity linked to PA ingestion.
• Evaluation of experimental data on PA carcinogenicity and mutagenicity.

Main Results:

• Pyrrolizidine alkaloids are associated with veno-occlusive disease and childhood cirrhosis in humans.
• PA adducts can persist in tissues, with potential for delayed toxicity.
• While some PAs are mutagenic and carcinogenic in animal models, no clinical association with human cancer has been established.

Conclusions:

• Humans exposed to pyrrolizidine alkaloids face risks of liver diseases such as veno-occlusive disease and childhood cirrhosis.
• Despite evidence of mutagenicity and carcinogenicity in experimental systems, pyrrolizidine alkaloids are not considered carcinogenic to humans.