Bioprospecting of Marine Organisms: Exploring Antibacterial Activities in Aqueous and Organic Extracts

This study investigated the antibacterial activity of aqueous and organic extracts from 78 marine organisms, including seaweeds and sponges, collected from the coastal zone of Ceará, Brazil. Biological tissue extracts were obtained by maceration using distilled water and 50% acetonitrile. The extracts were tested against Gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) and Gram-negative (Escherichia coli) bacterial strains using the disk diffusion method and measuring inhibition zone diameters. Results showed that 30.7% of the organisms exhibited antibacterial activity, with greater effectiveness in organic extracts. Demonstrated remarkable bioactive potential, particularly the genus Aplysina, Amphimedon compressa, Amphimedon viridis, Mycale sp., and Pseudosuberites sp. Seaweeds showed no activity in aqueous extracts, but some organic extracts were effective against Gram-positive strains, notably Amansia multifida. Most extracts were more effective against Gram-positive bacteria, likely due to their simpler cell wall structure. These findings highlight the biotechnological potential of marine organisms from the Brazilian coast as sources of novel antibacterial molecules, contributing to the search for alternative therapies in response to the growing issue of bacterial resistance.