Cytotoxic Tetrahydroxanthone Dimers from the Mangrove-Associated Fungus Aspergillus versicolor HDN1009

Abstract

Three new tetrahydroxanthone dimers, 5-<i>epi</i>-asperdichrome (<b>1</b>), versixanthones N (<b>2</b>), and O (<b>3</b>), were isolated from the mangrove-derived fungus <i>Aspergillus versicolor</i> HDN1009. Their structures, including the absolute configurations, were elucidated by NMR, HRMS, and circular dichroism (CD) experiments. Among them, compound <b>1</b> was the second example of tetrahydroxanthone dimers, which dimerized by a rare diaryl ether linkage and showed promising antibacterial activities against <i>Vibrio parahemolyticus</i>, <i>Bacillus subtilis</i>, <i>Mycobacterium phlei</i>, and <i>Pseudomonas aeruginosa</i>, with MIC values ranging from 100 μM to 200 μM; whilst compounds <b>2</b> and <b>3</b> exhibited extensive cytotoxicities against five cancer cell lines (HL-60, K562, H1975, MGC803, and HO-8910), with IC₅₀ values ranging from 1.7 μM to 16.1 μM.