Bromopyrrole Alkaloids of the Sponge <i>Agelas oroides</i> Collected Near the Israeli Mediterranean Coastline

Abstract

Chemical investigation of the Mediterranean Sea sponge, <i>Agelas oroides</i>, collected off the Tel Aviv coast, yielded eight new bromopyrrole metabolites, agesamine C (<b>1</b>), dioroidamide A (<b>2</b>), slagenin D (<b>3</b>), (-)-monobromoagelaspongin (<b>4</b>), (-)-11-deoxymonobromoagelaspongin (<b>5</b>), (-)-11-<i>O</i>-methylmonobromoagelaspongin (<b>6</b>), <i>E</i>-dispacamide (<b>7</b>), and pyrrolosine (<b>8</b>), along with 18 known bromopyrrole alkaloids and a known bromotyrosine derivative. The structures of the new metabolites were elucidated by analysis of the spectroscopic and spectrometric data, including 1D and 2D NMR, ECD, and high-resolution mass spectrometry. The sponge extract exhibited antimicrobial activity against pathogenic and environmental bacteria, and quorum sensing inhibitory activity (QSI) against <i>Chromobacterium violaceum</i>. QSI guided separation of the extract established oroidin, benzosceptrin C, and 4,5-dibromopyrrole-2-carboxamide as the active components. The latter compounds were tested for inhibition of growth and biofilm formation in <i>Pseudomonas aeruginosa</i> PAO1. The most active and available compound, oroidin, was assayed for inhibition of growth and biofilm formation in bacteria that were isolated from the sponge and its environment.