Seven new pyrroloiminoquinone alkaloids, makaluvamines HM [19-24] and damirone C [25], together with the known compounds, makaluvamines C [13], D [14], and G [17], were isolated from the sponge Zyzzya fuliginosa collected at Nahpali Island, Pohnpei, Micronesia. The structures of the new compounds were elucidated by interpretation of spectral data. The chemotaxonomic relationships involving the makaluvamines and related pyrroloiminoquinone alkaloids are discussed.

Pyrroloiminoquinone alkaloids have been isolated from several sponges and from an ascidian. The simplest of these alkaloids are batzellines AC [1—3] and isobatzellines A—D [4—7] from a deep-water Caribbean sponge of the genus Batzella (1, 2) and damirones A [8] and B [9] from a Damiria sp. from Palau (3)· The most complex of these alkaloids are the discorhabdins, exemplified by discorhabdin A [10], which have been reported from a New Zealand collection of Latrunculia sp.(4—6), Prianos míanos from Okinawa (7, 8), and Zyzzya cf. marsailis from Fiji (9). Makaluvamines AG [11-17] are cytotoxic alkaloids from the Fijian Zyzzya cf. marsailis (9) and an Indonesian Histodermlla sp.(10) that are intermediate in complexity and may in fact be intermediatesin the biosynthetic route to the discorhabdins. In addition, a related pyrroloiminoquinone alkaloid, wakayin [18], was isolated from an ascidian of the genus Clavelina from Fiji (11). From the viewpoint of chemotaxonomy, this very complex situation has recently been simplified by the taxonomic reassignments noted below. We now report the isolation and identification of seven new alkaloids, makaluvamines HM [19-24], and damirone C [25], together with the known metabolites makaluvamines C [13], D [14], and G [17], from a Pohnpeian specimen of Zyzzya fuliginosa (order Poecilosclerida)(Carter, 1879)·