Pyrrolizidine Alkaloids from Heliotropium lasiocarpum and Insecticidal Activity of Their Extracts

Abstract

The new pyrrolizidine alkaloid helasine (1) and known heliotrine (2), lasiocarpine N-oxide (3), trachelanthamine (4), and echinatine (5) were isolated from the plant Heliotropium lasiocarpum. Alkaloids 4 and 5 were observed for the first time in H. lasiocarpum. The absolute configurations of isolated alkaloids 2–4 were established by X-ray crystal structure analyses. The insecticidal activity of the CHCl₃, n-BuOH, and H₂O parts of the H. lasiocarpum extract against Callosobruchus maculates and Sitophilus oryzae was examined. The CHCl₃ extract at a dose of 10 mg/L had the highest activity.