Molecular Modification Of Fucoidan From Sargassum Fusiforme And Its Antioxidant Activity In Vitro

Fucoidan is one of the most important active ingredients in the polysaccharides of Sargassum fusiformis with its high medicinal development value.The value of fucoidan has been recognized but it has not been developed and applied.Degradation and molecular modification of fucoidan from Sargassum fusiformis helps to improve its biological activity,and lay a foundation for further exploring the structure-activity relationship of fucoidan.Therefore,based on the study of the physical and chemical properties and antioxidant activity of fucoidan extracted from different extraction methods,the multi-index comprehensive weighted scoring method was used to comprehensively analyze and optimize the optimal solution for the extraction of fucoidan from Sargassum.It was extracted by 20 times distilled water and extracted at 85?for 3 times,each time for 1 hour.Subsequently,the molecular modification technology was applied to the study of fucoidan.The degrading modification of SFF revealed that the degradation of H₂O₂ was too strong and the homogeneity of the product was poor.The solid phase acid was used to treat SFF at a relatively low temperature.The degradation is relatively mild,which is conducive to controllable degradation,and the conditions for initial solid acid degradation are initially optimized:the initial concentration of fucoidan is 10 mg/mL,the temperature is 60?,and the concentration of732^#cationic resin is 200 mg/mL,degradation for 3 hours.SD-SFF can be prepared into three different molecular weight fractions of the fusulin fucoidan by ultrafiltration and fractionation.The DMSO-methanol method has high desulfurization efficiency,no significant degradation occurs during the desulfurization reaction and does not affect the homogeneity of the product.The DS-SFF sulfate content obtained was only 1.52%.By studying the in vitro antioxidative activity of SFF and its molecular modification products,the effects of molecular modification on the biological activity of fucoidan were studied.The results showed that moderate degradation could increase the antioxidant activity of fucoidan in vitro,but its antioxidative activity in vitro decreased significantly when the molecular weight was reduced to less than 5 kDa.The free radical scavenging activity of fucoidan produced by the desulfurization modification of the two systems was significantly decreased,indicating that the original structure and composition of fucoidan is more critical to its antioxidant activity.