Donghaecyclinones A-C: New Cytotoxic Rearranged Angucyclinones from a Volcanic Island-Derived Marine sp.

Chemical profiling of the 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 (-). The structures of - 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 (-) displayed cytotoxicity against diverse human cancer cell lines (IC: 6.7-9.6 μM for ).