Aspermeroterpenes A-C: Three Meroterpenoids from the Marine-Derived Fungus GZU-31-1.

Aspermeroterpene A () with an unprecedented and highly congested 5/3/6/6/6/5 hexacyclic skeleton, together with two precursors aspermeroterpenes B () and C (), were isolated from the marine-derived fungus GZU-31-1. Their structures were elucidated by quantum chemical calculations, X-ray diffraction, and spectroscopic methods. The biogenetic pathway for - is proposed. Aspermeroterpenes A-C (-) showed significant inhibitory activities against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 cells compared to positive control.