Periconianone A, a New 6/6/6 Carbocyclic Sesquiterpenoid from Endophytic Fungus Periconia sp. with Neural Anti-inflammatory Activity

Periconianone A (1), a poly­oxygenated sesqui­terpe­noid with a new 6/6/6 tri­carbo­cyclic skeleton, and periconia­none B (2) were isolated from the endophytic fungus Periconia sp. Their structures and absolute configurations were elucidated by extensive spectroscopic analyses, calculated ECD, and single-crystal X-ray diffraction (Cu Kα). The biosynthesis of the unusual six-membered carbonic ring of 1 was postulated to be formed through intramolecular aldol condensation. Compounds 1 and 2 showed significant neural anti-inflammatory activity.