Highly Substituted Phenol Derivatives with Nitric Oxide Inhibitory Activities from the Deep-Sea-Derived Fungus Trichobotrys effuse FS524

Chemical investigation on EtOAc extract of the deep-sea-derived fungus Trichobotrys effuse FS524 resulted in the isolation of six new highly substituted phenol derivatives, trieffusols A–F (1–6), along with ten known relative analogs (7–16). Their structures with absolute configurations were extensively characterized on the basis of spectroscopic data analyses, single-crystal X-ray diffraction experiments, and electronic circular dichroism (ECD) calculations. Structurally, trieffusols A and B shared an unprecedented ploy-substituted 9-phenyl-hexahydroxanthone skeleton with an intriguing 6-6/6/6 tetracyclic fused ring system, which is often encountered as significant moieties in the pharmaceutical drugs but rarely discovered in natural products. In the screening towards their anti-inflammatory activities of 1–6, trieffusols C and D exhibited moderate inhibitory activities against nitric oxide (NO) production in LPS-induced RAW 264.7 macrophages with IC(50) values ranging from 51.9 to 55.9 μM.