It is demonstrated that the combination of positive ion chemical ionization and negative ion chemical ionization GC-MS analyses of herb and root extracts of EUPATORIUM CANNABINUM L. offers a rapid, tentative structure elucidation of pyrrolizidine alkaloids (PAs). Compounds identified in aerial parts
The evolution of pathways within plant secondary metabolism has been studied by using the pyrrolizidine alkaloids (PAs) as a model system. PAs are constitutively produced by plants as a defense against herbivores. The occurrence of PAs is restricted to certain unrelated families within the