Bioactive metabolites from the sponge Suberea sp.

Two new brominated compounds, subereaphenol K (2) and 2-(3,5-dibromo-1-ethoxy-4-oxocyclohexa-2,5-dien-1-yl)acetamide (3), together with subereaphenol B (methyl 2-(2,4-dibromo-3,6-dihydroxyphenyl)acetate; 1) with a revised structure, and five dibromotyrosine-derived metabolites, 4-8, were isolated from the sponge Suberea sp. and characterized by 1D- and 2D-NMR spectroscopic and HR-MS spectrometric data. Compounds 1, 2, 6, and 8 exhibited various weak or moderate bioactivities, including antimicrobial and cytotoxic activities. Furthermore, compounds 1 and 2 inhibited human recombinant phosphodiesterase 4 (PDE4) with IC₅₀ values of 2 μM, whereas compounds 6 and 8 were less active.