Anti-inflammatory dihydroxanthones from a Diaporthe species

In a search for anti-inflammatory compounds from fungi inhibiting the promoter activity of the small che-mokine CXCL10 (Interferon-inducible protein 10, IP-10) as a pro-inflammatory marker gene, the new dihydroxanthone methyl (1R, 2R)-1,2,8-trihydroxy-6-(hydroxymethyl)-9-oxo-2,9-dihydro-1H-xanthene-1-carboxylate (2) and the previ-ously described dihydroxanthone AGI-B4 (1) were isolated from fermentations of a Diaporthe species. The structures of the compounds were elucidated by a combination of one-and two-dimensional NMR spectroscopy, mass spectrometry, and calculations using density functional theory (DFT). Com-pounds 1 and 2 inhibited the LPS/IFN gamma induced CXCL10 promoter activity in transiently transfected human Mono-Mac6 cells in a dose-dependent manner with IC50 values of 4.1 mu M (+/- 0.2 mu M) and 1.0 mu M (+/- 0.06 mu M) respectively. More-over, compounds 1 and 2 reduced mRNA levels and synthesis of pro-inflammatory mediators such as cytokines and che-mokines in LPS/IFN gamma stimulated MonoMac6 cells by inter-fering with the Stat1 and NF kappa B pathway.

Automated summary

Two new compounds were isolated from a fungus and found to inhibit the activity of the pro-inflammatory marker gene CXCL10. These compounds also interfered with multiple signaling pathways and reduced the synthesis of inflammatory mediators.