ABSTRACT

Seaweeds contain compounds from different chemical families, including polysaccharides, fatty acids, phenolics, pigments, lectins, alkaloids, terpenoids and halogenated compounds with reported antimicrobial action. Different Chlorophyta, Rhodophyta and Phaeophyta species collected in several coasts around the world were reported showing antibacterial, antifungal, antiprotozoal and/or antiviral activity among other biological properties. The most widely used methods to detect and quantify the antimicrobial (antibacterial and antifungal) activity of algae extracts and/or their purified compounds are the diffusion agar test and micro and macro dilution tests. Their results are discussed although it is difficult to unify results because different concentrations of tested algal extracts and microbial strains are used. In vivo assays are less numerous and their performance depends on target organisms or substrates. The search for active compounds and advances in the formulation of novel materials as nanoparticles can offer effective tools against spoilage microorganisms and especially against antibiotic resistant pathogens.