Chrysoxanthones A⁻C, Three New Xanthone⁻Chromanone Heterdimers from Sponge-Associated Penicillium chrysogenum HLS111 Treated with Histone Deacetylase Inhibitor.

By treating with histone-deacetylase inhibitor valproate sodium, three new heterdimeric tetrahydroxanthone⁻chromanone lactones chrysoxanthones A⁻C (1⁻3), along with 17 known compounds were isolated from a sponge-associated Penicillium chrysogenum HLS111. The planar structures of chrysoxanthones A⁻C were elucidated by means of spectroscopic analyses, including MS, 1D, and 2D NMR. Their absolute configurations were established by electronic circular dichroism (ECD) calculations. Chrysoxanthones A⁻C exhibited moderate antibacterial activities against Bacillus subtilis with minimum inhibitory concentration (MIC) values of 5⁻10 μg/mL.