Recent Advances in the Structure, Extraction, and Biological Activity of Sargassum fusiforme Polysaccharides

Sargassum fusiforme polysaccharides (SFPs) are acidic polysaccharides that possess significant medicinal and commercial potential. This review aims to summarize recent advances in the structure, extraction methods, and diverse biological activities of SFPs, including their antioxidant, antitumor, immunomodulatory, antiviral, intestinal flora-regulating, and anti-diabetic properties. The key findings reveal the complex composition of polysaccharides, highlighting alginic acid, fucoidan, and laminaran as the primary constituents, and detailing their structural features. At the same time, the characteristics as well as the advantages and disadvantages of hot water extraction, acid extraction, alkali extraction, ultrasonic extraction, microwave extraction, and enzyme extraction were systematically compared. Finally, this review concludes by emphasizing the necessity for further research to elucidate the structure–function relationships of SFPs, optimize their extraction techniques, and provide a theoretical foundation for subsequent studies.