Sesquiterpene Lactones form the Roots of Ixeris sonchifolia

Three known sesquiterpene lactones were isolated from the n-BuOH traction of the roots of Ixeris sonchifolia. Their structures were identified as macrocliniside A (1), glucozaluzanin C (2), and ixerin H (3), by spectral analyses. Compounds 1 and 2 are guaiane-type, while compound 3 is a germacrane-type sesquiterpene lactone. Compounds 1-3 are first isolated from I. sonchifolia.