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.