Sesquiterpene lactones. XXXVIII. Constituents of Picris echioides L. and their antifeedant activity.
Reinvestigation of components of the composite plant Picris echioides led to the isolation of pure jacquinelin and 8-deoxylactucin, the chemical structures of which are given. Using the stored products pests Tribolium confusum, Trogoderma granarium and Sitophilus granarius as test insects, the deterrent activities of the 2 compounds and their 1:5 mixture, and of a chloroform extract of the plant, were demonstrated.