ChemInform Abstract: Ceratinamides A and B: New Antifouling Dibromotyrosine Derivatives from the Marine Sponge Pseudoceratina purpurea

Ceratinamides A and B ( 1 and 2 ), new bromotyrosine derivatives, have been isolated from the marine sponge Pseudoceratina purpurea , along with the known psammaplysins A ( 3 ) and E ( 4 ), ceratinamine ( 5 ), moloka'iamine ( 6 ), pseudoceratidine ( 7 ), and 4,5-dibromopyrrole-2-carbamide ( 8 ). Their structures were elucidated on the basis of spectral data. Compounds 1–7 inhibited larval settlement and metamorphosis of the barnacle Balanus amphitrite with ED 50 values of 0.10–8.0 μg/mL, while compounds 3 and 8 induced larval metamorphosis of the ascidian Halocynthia roretzi at concentrations of 1.2 and 25 μg/mL, respectively. Compounds 5 and 6 also showed cytotoxicity against P388 murine leukemia cells with IC 50 values of 3.4 and 2.1 μg/mL, respectively; 7 was antibacterial against Flavobacterium marinotypicum .