A Novel Sodium Alginate Extracted from A Marine Brown Seaweed: Production, Characterization, and Biological Activities

In the context of marine biodiversity valorization, this study presents the extraction, characterization, and biological activities of sodium alginate from the Tunisian brown seaweed Cystoseira compressa (CCSA). The extracted alginate (yield: 21.65%) features a structure rich in homopolymeric blocks (GG: 53%, MM:40%, M/G <1), providing strong gel-forming properties. Structural and rheological analyses revealed pseudoplastic behavior, temperature-sensitive viscosity, and thixotropic characteristics. CCSA forms a rigid gel at 4.94 mM CaCl₂ in a 2% solution. Biologically, CCSA showed moderate antioxidant activity (IC₅₀ ≈ 560 µg/mL) and significant antinociceptive effects comparable to high-dose paracetamol. These results open promising perspectives for food, pharmaceutical, and biomedical applications, notably through the formulation of complexes with other natural biopolymers.