Sesquiterpene lactones. XXXVIII. Constituents of Picris echioides L. and their antifeedant activity

Reinvestigation of components of Picris echioides L. led to the isolation of pure jacquinelin (I) and 8-deoxylactucin (II). The insect deterrent activities of compounds I and II, of their 1:5 mixture, as well as of the chloroform extract of Picris echioides were determined.