Phytotoxicity of parthenin, a sesquiterpene lactone, was evaluated against four weedy species (Amaranthus viridis, Cassia occidentalis, Echinochloa crus-galli, and Phalaris minor) through a series of experiments conducted under laboratory or greenhouse conditions to assess its herbicidal potential.
Eleven sesquiterpene lactone derivatives of parthenin (1), obtained from wild feverfew, Parthenium hysterophorus, were prepared by chemical and photochemical transformations. The compounds tested were a pyrazoline adduct (2) of parthenin, its cyclopropyl (3) and propenyl (4) derivatives,