Koanolides E and F from the hexanic extract of Koanophyllon gibbosum

Koanolides E and F (1–2), two new germacrane-type sesquiterpene lactones, have been isolated from the hexanic extract of the aerial parts (leaves) of Koanophyllon gibbosum (Asteraceae), along with three other known compounds. The chemical structures of the isolates were elucidated using spectroscopic and spectrometric techniques, and by comparison with previously reported data.