Polyhalogenated Indoles from the Red Alga <i>Rhodophyllis membranacea</i>: The First Isolation of Bromo-Chloro-Iodo Secondary Metabolites

An unusual tetrahalogenated indole with the exceptionally rare inclusion of the three halogens bromine, chlorine, and iodine was found using mass spectrometry within a fraction of a semipurified extract obtained from the red alga <i>Rhodophyllis membranacea.</i> We report herein the isolation and structure elucidation, using a combination of NMR spectroscopy and mass spectrometry, of 11 new tetrahalogenated indoles (<b>1</b>–<b>11</b>), including four bromochloroiodoindoles (<b>5</b>–<b>7</b>, <b>10</b>). Several were evaluated for cytotoxic and antifungal activities against the HL-60 promyelocytic cell line and <i>Saccharomyces cerevisiae</i>, respectively