Mono- and Dimeric Xanthones with Anti-Glioma and Anti-Inflammatory Activities from the Ascidian-Derived Fungus Diaporthe sp. SYSU-MS4722.

Seven new xanthones, diaporthones A-G ( 1 - 7 ), together with 13 known analogues, including five mono- ( 8 - 14 ) and six dimeric xanthones ( 15 - 20 ), were obtained from the ascidian-derived fungus Diaporthe sp. SYSU-MS4722. Their planar structures were established by extensive spectroscopic analyses, including 1D and 2D NMR and high-resolution mass spectrometry (HR-ESIMS). The absolute configurations of 1 - 7 were clearly identified by X-ray crystallographic analysis and calculation of the ECD Spectra. Compounds 15 - 20 showed significant anti-inflammatory activity with IC 50 values between 6.3 and 8.0 μM. In addition, dimeric xanthones ( 15 - 20 ) showed selective cytotoxicity against T98G cell lines with IC 50 values ranging from 19.5 to 78.0 μM.