Antimicrobial and cytotoxic effects of marine sponge extracts Agelas clathrodes, Desmapsamma anchorata and Verongula rigida from a Caribbean Island.

Although marine sponges are known for their antimicrobial, antifungal and cytotoxic activity, very few studies have been carried out on endemic species of Martinique. Martinique is part of the Agoa Sanctuary, a marine protected area that includes the exclusive economic zones (EEZ) of the French Caribbean islands, making it an abundant source of marine species. To highlight the potential of this area for the discovery of marine biomolecules with antipathogenic and antitumor activities, we tested the aqueous and ethanolic extracts of sponge species Agelas clathrodes, Desmapsamma anchorata and Verongula rigida. Five bacterial strains: Bacillus cereus (CIP 78.3), Escherichia coli (CIP 54.127), Pseudomonas aeruginosa (CIP A22), Staphylococcus aureus (CIP 67.8) and Staphylococcus saprophyticus (CIP 76125) were evaluated, as well as four tumor cell lines: breast cancer (MDA-MB231), glioblastoma (RES259) and leukemia (MOLM14 and HL-60). Antimicrobial activity was evaluated using the disc diffusion technique by determining the minimum inhibitory and minimum bactericidal concentrations. Tumor cytotoxic activity was determined in vitro by defining the minimum concentration of extracts that would inhibit cell growth. Ethanolic extracts of Agelas clathrodes were bactericidal for Staphylococcus aureus and Staphylococcus saprophyticus strains, as well as strongly cytotoxic (IC50 < 20 µg/mL) on all cancer cell lines. Verongula rigida also showed strong cytotoxic activity on cell lines but no antimicrobial activity. These results are innovative for this species on these bacterial lines, highlighting the potential of sponge extracts from this area as bioactive compounds sources.

Antimicrobial Diterpene Alkaloids from an Agelas citrina Sponge Collected in the Yucatán Peninsula.

Three new diterpene alkaloids, (+)-8-epiagelasine T (1), (+)-10-epiagelasine B (2), and (+)-12-hydroxyagelasidine C (3), along with three known compounds, (+)-ent-agelasine F (4), (+)-agelasine B (5), and (+)-agelasidine C (6), were isolated from the sponge Agelas citrina, collected on the coasts of the Yucatán Peninsula (Mexico). Their chemical structures were elucidated by 1D and 2D NMR spectroscopy, HRESIMS techniques, and a comparison with literature data. Although the synthesis of (+)-ent-agelasine F (4) has been previously reported, this is the first time that it was isolated as a natural product. The evaluation of the antimicrobial activity against the Gram-positive pathogens Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus faecalis showed that all of them were active, with (+)-10-epiagelasine B (2) being the most active compound with an MIC in the range of 1-8 µg/mL. On the other hand, the Gram-negative pathogenes Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae were also evaluated, and only (+)-agelasine B (5) showed a moderate antibacterial activity with a MIC value of 16 µg/mL.

In Vitro and In Vivo Assessment of the Efficacy of Bromoageliferin, an Alkaloid Isolated from the Sponge Agelas dilatata, against Pseudomonas aeruginosa.

The pyrrole-imidazoles, a group of alkaloids commonly found in marine sponges belonging to the genus Agelas, display a wide range of biological activities. Herein, we report the first chemical study of the secondary metabolites of the sponge A. dilatata 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 (1), bromoageliferin (2), dibromoageliferin (3), sceptrin (4), nakamuric acid (5), 4-bromo-1H-pyrrole-2-carboxylic acid (6), 4,5-dibromopyrrole-2-carboxylic acid (7) and 3,7-dimethylisoguanine (8). 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 Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii. Bromoageliferin (2) displayed significant activity against P. aeruginosa. Comparison of the antibacterial activity of ageliferins 1-3 (of similar structure) against P. aeruginosa revealed some relationship between structure and activity. Furthermore, in in vitro assays, 2 inhibited growth and biofilm production in clinical strains of P. aeruginosa. Moreover, 2 increased the survival time in an in vivo Galleria mellonella model of infection. The findings confirm bromoageliferin (2) as a potential lead for designing new antibacterial drugs.

New records of the genus Agelas Duchassaing & Michelotti, 1864 (Porifera, Agelasida) off the Amazon River mouth, Brazil, Southwestern Atlantic / Novos registros do gênero Agelas Duchassaing & Michelotti, 1864 (Porifera, Agelasida) ao largo da desembocadura do Rio Amazonas, Brasil, Atlântico Sudoeste

This work provides new information on agelasid sponges found on the continental shelf off northern Brazil. Agelas sceptrum (Lamarck, 1815) and Agelas wiedenmayeri Alcolado, 1984 have their first record for the Brazilian coast. Agelas dispar Duchassaing & Michelotti, 1864 and Agelas schmidti Wilson, 1902, previously recorded from Brazil, are cited for the first time off the mouth of the Amazon River.

Este trabalho fornece novas informações sobre esponjas agelasidas encontradas na costa norte da plataforma continental brasileira. Agelas sceptrum (Lamarck, 1815) e Agelas wiedenmayeri Alcolado, 1984 têm seu primeiro registro para a costa brasileira. Agelas dispar Duchassaing & Michelotti, 1864 e Agelas schmidti Wilson, 1902, registradas anteriormente na costa brasileira, são citadas pela primeira vez ao largo da desembocadura do Rio Amazonas.