Anti-inflammatory Dimeric Benzophenones from an Endophytic Pleosporales Species.

Eight new polyketides, including three dimeric benzophenones, named dipleosporones A-C ( 1 - 3 ), three benzophenones ( 4 - 6 ), one xanthone ( 7 ), and one phenylbenzoate ( 8 ), along with seven known polyketides ( 9 - 15 ) were isolated from the fungus Pleosporales sp. YY-4. The structures of the new compounds were established on the basis of spectroscopic methods, including high-resolution electrospray ionization mass spectrometry and one- and two-dimensional nuclear magnetic resonance. This is the first report of a benzophenone dimer connection via a C bridge from natural sources. An anti-inflammatory assay indicated that the dimeric benzophenones ( 1 - 3 ) inhibited lipopolysaccharide-induced NO production in RAW 264.7 cells, with half-maximal inhibitory concentration (IC 50 ) values ranging from 8.8 to 18.1 μM, being more potent than the positive control, dexamethasone (IC 50 = 22.2 μM).