Cytotoxic and antibacterial depsidones from the endophytic fungus <i>Chaetomium brasiliense</i> isolated from Thai rice

Abstract

Four new depsidones, mollicellins V-Y (<b>1</b>-<b>4</b>), together with eight known depsidones (<b>5</b>-<b>12</b>) were isolated from the endophytic fungus, <i>Chaetomium brasiliense,</i> detached from stems of Thai rice. Their structures were determined by extensive spectroscopic methods. Mollicellins X, H, and F (<b>3</b>, <b>8</b> and <b>10</b>) showed potent cytotoxicity against the human oral epidermoid carcinoma (KB) cell line, and mollicellin F (<b>10</b>) also showed a potent cytotoxicity against the human hepatocellular carcinoma (HepG2) cell line. Besides, mollicellin B (<b>11</b>) exhibited cytotoxicity against the colorectal adenocarcinoma (HT-29) cell line. Moreover, most of the isolated depsidones displayed potent antibacterial activity against Gram-positive bacteria, <i>Bacillus cereus</i> and <i>Bacillus subtilis</i>, and several of them showed moderate activity against Methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) and clinical isolates of <i>S. aureus.</i> In addition, a few of them also showed moderate activity against a Gram-negative bacteria <i>Pseudomonas aeruginosa.</i>