Diphenyl Ethers from a Marine-Derived Aspergillus sydowii .

Six new diphenyl ethers ( 1 ⁻ 6 ) along with eleven known analogs were isolated from the ethyl acetate extract of a marine-derived Aspergillus sydowii guided by LC-UV-MS. Their structures were unambiguously characterized by HRESIMS, NMR, as well as chemical derivatization. Compounds 1 and 2 are rare diphenyl ether glycosides containing d-ribose. The absolute configuration of the sugar moieties in compounds 1 ⁻ 3 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 1 , 5 , 6 , and 8 ⁻ 11 were found to exhibit selective cytotoxicity against different cancer cell lines.