Chemical investigation of the MeOH extract of the sponge Acanthostrongylophora ingens afforded the new manzamine derivative ircinal E (1), in addition to six known metabolites (2-7). The structure of the new compound was unequivocally elucidated using one- and two-dimensional NMR spectroscopy, as well as high-resolution mass spectrometry. Compounds 1-6 exhibited strong to moderate cytotoxicity against the murine lymphoma L5178Y cell line with IC50 values ranging from 2.8 to 21.7 µM.