Caracterizaciónparcial yactividadbiológicadeSargassumlapazeanum(Fucales, Phaeophyceae)

Background. The Baja California peninsula contains a wide variety of habitats and climatic conditions and is thus home to an enormous wealth of marine algae. Algae belonging to the Sargassum genus are often dominant in communities of the Gulf of California due to their high biomass. Goals. This study aimed to evaluate the potential of Sargassum lapazeanum as a source of compounds with antioxidant, antibacterial, or anticoagulant activity in addition to its proximal composition and alginate content. Methods. An ethanolic extract (EE) was obtained from dried algae to evaluate antibacterial activity by means of the disc agar diffusion method and antioxidant activity by the stable free radical method (DPPH). The crude fucoidan (CF) obtained was fractionated by different chromatographic techniques, and its anticoagulant activity was evaluated by prothrombin time (PT) and activated partial thromboplastin time (APTT) assays. A structural characterization was also conducted. In addition, the proximal composition and alginate content and quality were determined. Results. The EE and its different fractions showed selective activity against bacteria of the Vibrio genus, such as V. harveyi and V. parahaemolyticus, in addition to free radical scavenging activity. The lowest half maximal effective concentration (EC₅₀ = 39.96 μg mL^-1) was obtained from fraction F6. Crude fucoidan and its fractions showed anticoagulant activity, with values comparable to those observed for heparin at concentrations of 10 μg mL^-1. The sodium alginate yield was 22.8%, with low viscosity and high gel strength. Conclusions. Sargassum lapazeanum has high potential to be a source of compounds with antioxidant, antibacterial, and anticoagulant activity.