Chlorinated Azaphilone Pigments with Antimicrobial and Cytotoxic Activities Isolated from the Deep Sea Derived Fungus Chaetomium sp. NA-S01-R1

Abstract

Four novel compounds, chaephilone C (<b>1</b>), chaetoviridides A-C (<b>2</b>-<b>4</b>), were obtained from the culture of a deep sea derived fungus <i>Chaetomium</i> sp. NA-S01-R1, together with four known compounds-chaetoviridin A (<b>5</b>), chaetoviridine E (<b>6</b>), chaetomugilin D (<b>7</b>) and cochliodone A (<b>8</b>). Their structures, including absolute configurations, were assigned based on NMR, MS and time-dependent density functional theory (TD-DFT) ECD calculations. A plausible biogenetic pathway for compounds <b>1</b>-<b>3</b> was proposed. Compounds <b>2</b> and <b>3</b> exhibited antibacterial activities against <i>Vibrio rotiferianus</i> and <i>Vibrio vulnificus</i>. Compounds <b>1</b>, <b>3</b> and <b>4</b> displayed similar anti-methicillin resistant <i>Staphylococcus aureus</i> (anti-MRSA) activities in comparison to chloramphenicol. Compound <b>2</b> showed the most potent cytotoxic activities towards the Hep G2 cell and compounds <b>1</b> and <b>3</b> demonstrated relatively stronger cytotoxic activities than the other compounds against the HeLa cell.