Hydrothermal degradation of seaweed polysaccharide: Characterization and biological activities

Fucoidan is a marine sulfated polysaccharide that possesses various biological activities. To enhance the functional properties of fucoidan, it was depolymerized using a green technique viz. subcritical water treatment (SCW) to produce a low molecular weight fucoidan. In this study, response surface methodology (RSM) was used to study the influence of different influences for instance temperature, pressure, liquid to solid ratio, and agitation speed to depolymerize fucoidan. RSM was used to focus on the antioxidant activity and chemical composition of SCW-treated fucoidan. Further, resulting SCW-treated fucoidan was investigated by UV-Vis, FT-IR, Thermal gravimetric analysis (TGA), DSC, Elemental analysis, and ESI-MS. Moreover, the optimized SCW-treated fucoidan was checked for cytotoxicity, antimicrobial, antidiabetic, and anticoagulant activity compared with the untreated fucoidan. The obtained values displayed that SCW treatment breakdowns polymer chain and so it produces low molecular weight fucoidan. Biological activities were improved as the molecular weight was reduced.