In our search for cytotoxic compounds from marine animals we have isolated representatives from various classes of nitrogen-containing compounds, most of which show cytotoxic activity. Structure elucidation of these compounds is discussed. Included among the isolates are new acylated spermidines, polycyclic aromatic alkaloids related to amphimedine and 2-bromoleptoclinidinone, and a representative of a novel sulfur containing 3,5,8-isoquinolinetrione. © 1990 IUPAC