The Pyrrolizidine Alkaloids (PAs) are a group of chemicals found in a variety of plant species throughout the world. These toxic alkaloids are distributed mainly in Senecio (Compositae), Crotalaria (Legominosae) and Heliotropium (Boraginaceae) species. Plants containing these alkaloids cause significant mammalian morbidity and mortality, especially in humans. Upon ingestion, metabolic activatio...