Dactylomelane Diterpenes from the Sea Hare <i>Aplysia depilans</i>

A chemical investigation of the organic extract of the sea hare <i>Aplysia depilans</i>, collected off Skyros Island, Greece, yielded eight new brominated diterpenes (<b>1</b>–<b>8</b>), featuring the rare dactylomelane skeleton, together with the previously reported luzodiol (<b>9</b>). The structure elucidation and the assignment of the relative configurations of the new natural products were based on extensive NMR spectroscopic and MS spectrometric analyses. Compounds <b>1</b>–<b>9</b> were evaluated for their cytotoxic activities against five human tumor cell lines, but were proven inactive