In Vitro and In Vivo Assessment of the Efficacy of Bromoageliferin, an Alkaloid Isolated from the Sponge , Against

The pyrrole-imidazoles, a group of alkaloids commonly found in marine sponges belonging to the genus , display a wide range of biological activities. Herein, we report the first chemical study of the secondary metabolites of the sponge from the coastal area of the Yucatan Peninsula (Mexico). In this study, we isolated eight known alkaloids from an organic extract of the sponge. We used NMR and MS analysis and comparison with existing databases to characterize the alkaloids: ageliferin (), bromoageliferin (), dibromoageliferin (), sceptrin (), nakamuric acid (), 4-bromo-1H-pyrrole-2-carboxylic acid (), 4,5-dibromopyrrole-2-carboxylic acid () and 3,7-dimethylisoguanine (). We also evaluated, for the first time, the activity of these alkaloids against the most problematic multidrug-resistant (MDR) pathogens, i.e., the Gram-negative bacteria , and . Bromoageliferin () displayed significant activity against . Comparison of the antibacterial activity of ageliferins - (of similar structure) against revealed some relationship between structure and activity. Furthermore, in in vitro assays, inhibited growth and biofilm production in clinical strains of . Moreover, increased the survival time in an in vivo model of infection. The findings confirm bromoageliferin () as a potential lead for designing new antibacterial drugs.