Cytotoxic constituents of Achillea clavennae from Montenegro

Guaianolides 1-8, bisabolenes 9-11, flavonols 12-15, sesamin and isofraxidin were isolated from the aerial parts of Achillea clavennae. Compounds 2 (a new compound) and 8 exhibited significant cytotoxic effects to HeLa, K562 and Fem-X human cancer cell lines, whereas 9 was moderately active. The most active was 12, already known as the cytotoxic compound.