Brown macroalgae as natural marine wealth with multiple antimicrobial activities on human pathogens: A mini-review

The increasing emergence of bacterial resistance poses a serious global threat to both public health and food safety, prompting an urgent need for new antimicrobial agents derived from natural sources. Brown macroalgae have been recognized as a promising reservoir of bioactive compounds with significant antibacterial potential, largely attributed to their rich content of polyphenols, polysaccharides, and pigments. This review systematically analyzed recent studies that investigated the antibacterial activities of brown macroalgae and their derived compounds. Emphasis was placed on identifying the major bioactive components—such as phlorotannins, fucoidans, and fucoxanthin—and evaluating their mechanisms of antibacterial and anti-biofilm action against both Gram-positive and Gram-negative pathogens. Among the examined compounds, phlorotannins from species including Fucus vesiculosus, Desmarestia aculeata, and Ectocarpus siliculosus exhibited strong inhibitory effects on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Fucoidan-rich extracts demonstrated notable disruption of bacterial biofilm formation, while algae-synthesized metallic nanoparticles (AgNPs and CuO-NPs) enhanced antibacterial efficacy through synergistic mechanisms. Collectively, these findings highlight the potent antimicrobial and anti-biofilm activities of brown macroalgae metabolites. Brown macroalgae represent a valuable and renewable source of novel antimicrobial agents with significant potential to address the growing challenge of antibiotic resistance. Further exploration of structure-activity relationships, biosynthetic optimization, and nanoparticle-based delivery systems could pave the way for their application in pharmaceutical, biomedical, and food industries.