Donghaecyclinones A–C: New Cytotoxic Rearranged Angucyclinones from a Volcanic Island-Derived Marine <i>Streptomyces</i> sp.

Abstract

Chemical profiling of the Streptomyces sp. strain SUD119, which was isolated from a marine sediment sample collected from a volcanic island in Korea, led to the discovery of three new metabolites: donghaecyclinones A−C (1−3). The structures of 1−3 were found to be rearranged, multicyclic, angucyclinone-class compounds according to nuclear magnetic resonance (NMR) and mass spectrometry (MS) analyses. The configurations of their stereogenic centers were successfully assigned using a combination of quantum mechanics−based computational methods for calculating the NMR shielding tensor (DP4 and CP3) as well as electronic circular dichroism (ECD) along with a modified version of Mosher’s method. Donghaecyclinones A−C (1−3) displayed cytotoxicity against diverse human cancer cell lines (IC50: 6.7−9.6 μM for 3).

Keywords

• molecular modeling
• electronic circular dichroism
• quantum mechanics-based computation
• angucyclinone
• <i>streptomyces</i>
• cytotoxicity