On the defense: Sesterterpenoid 1 and its 11‐dehydroxy derivative, which possess a unique C25 skeleton, have been isolated from the glandular trichomes of Leucosceptrum canum. They have potent antifeedant activities and inhibitory effects against pathogenic fungi, which suggest a role of sesterterpenoids in plant defense.

No abstract

Two novel sesterterpenoids, leucosceptroids C (1) and D (2), possessing unusual antipodal cyclopentenones while maintaining the stereochemistry and functionality of the tricyclic cores, were discovered from the leaves of Leucosceptrum canum (Labiatae). Their structures including absolute stereochemistries were determined by comprehensive NMR, MS, and single-crystal X-ray diffraction analyses. The potent antifeedant activity of 1 against the generalist plant-feeding insect Helicoverpa armigera (EC(50) = 0.017 μmol/cm(2)) suggested them to be new defensive sesterterpenoids of L. canum.