Diphenyl Ethers from a Marine-Derived Aspergillus sydowii

Abstract

Six new diphenyl ethers (<b>1</b>⁻<b>6</b>) along with eleven known analogs were isolated from the ethyl acetate extract of a marine-derived <i>Aspergillus sydowii</i> guided by LC-UV-MS. Their structures were unambiguously characterized by HRESIMS, NMR, as well as chemical derivatization. Compounds <b>1</b> and <b>2</b> are rare diphenyl ether glycosides containing d-ribose. The absolute configuration of the sugar moieties in compounds <b>1</b>⁻<b>3</b> was determined by a LC-MS method. All the compounds were evaluated for their cytotoxicities against eight cancer cell lines, including 4T1, U937, PC3, HL-60, HT-29, A549, NCI-H460, and K562, and compounds <b>1</b>, <b>5</b>, <b>6</b>, and <b>8</b>⁻<b>11</b> were found to exhibit selective cytotoxicity against different cancer cell lines.