New anti-inflammatory guaianes from the Atlantic hydrotherm-derived fungus Graphostroma sp. MCCC 3A00421.

Nine new guaianes (graphostromanes A-I, 1-9) were isolated from the deep-sea-derived fungus Graphostroma sp. MCCC 3A00421, along with four known ones (10-13). The relative configurations were established mainly by detailed analysis of the NMR and HRESIMS data, while the absolute configurations were assigned using the X-ray crystallography and modified Mosher's method. All isolates were evaluated for their inhibitory effects against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 macrophages. Graphostromanes F (6) showed remarkable inhibitory effect with an IC50 value of 14.2 μM, which was even stronger than that of aminoguanidine, a positive control with an IC50 value of 23.4 μM.