Agrocybone, a novel bis-sesquiterpene with a spirodienone structure from basidiomycete Agrocybe salicacola

The isolation, structure elucidation, and relative stereochemistry assignment of a novel illudane–illudane bis-sesquiterpene, agrocybone (1), from the basidiomycete Agrocybe salicacola, were reported. Agrocybone represents a structure with eight rings (including two spiro rings) and seven stereogenic carbon atoms. Agrocybone was found to exhibit weak antiviral activity against respiratory syncytial virus (RSV) with IC50 value of 100 μM.