The flowers of Tanacetum argenteum subsp. argenteum yielded two new ge
rmacranolides, in addition to some known sesquiterpene lactones. The s
tructures were elucidated by spectral methods and chemical transformat
ions. 8 alpha-Angeloyloxycostunolide showed cytotoxic activity and ant
ifeedant activity against neonate larvae of Spodoptera littoralis.