Fused multicyclic polyketides with a two-spiro-carbon skeleton from mangrove-derived endophytic fungusEpicoccum nigrumSCNU-F0002

A pair of uncommon fused multicyclic polyketides with a two- spiro-carbon skeleton, (+/-)-isoepicolactone, (+/-)-1, and one new isobenzofuranone monomer (4), together with four other known biosynthetically related compounds were isolated from the fermentation of an endophytic fungus,Epicoccum nigrumSCNU-F0002, which was isolated from the fresh fruit of the mangrove plantAcanthus ilicifolius L. Comprehensive spectroscopic analysis, X-ray crystallography, together with calculated ECD, were employed to define the structures. The antibacterial and COX-2 inhibitory activities of the compounds (1-6) were evaluated. A possible biogenetic pathway of (+/-)-isoepicolactone was confirmed.