Paraconiothins A–J: Sesquiterpenoids from the Endophytic Fungus Paraconiothyrium brasiliense ECN258

Paraconiothins A–J (1–10), 10 new sesquiterpenoids, as well as five known sesquiterpenoids, were isolated from the cultures of the endophytic fungus Paraconiothyrium brasiliense ECN-258. The structures of the sesquiterpenoids were elucidated by extensive spectroscopic analysis. Furthermore, the absolute structures of 7 and 8 were determined by comparing their experimental and computed electronic circular dichroism data. Paraconiothins A–G (1–7) were eremophilane sesquiterpenoids, while paraconiothins H–J (8–10) had new or rare carbon frameworks that are possibly biosynthesized by a pathway involving the rearrangement of eremophilane sesquiterpenoids. Paraconiothins C (3) and I (9) exhibited an inhibitory effect on the liver X receptor α at a concentration of 50 μM.