Structure-function Relationship Study Of Algine-derived Saccharides On H₂O₂-induced Cytotoxicity

Alginates are a family of linear polysaccharides composed ofβ-D-mannuronic acid (ManA) andα-L-guluronic acid(GulA) linked by 1-4 bonds. There are two main fragments: poly-mannuronate, poly-guluronate. The polysaccharides, oligosaccharides and the derivative of alginates have various activities, such as anti-tumor, anti-virus, anti-oxidative, immune modulation.. In view of alginate complicated compositions, the different configurations of glycosidic bonds and the various polymerization degrees, we prepared the alginate series oligosaccharides and detected the protection of the oxidative damage on the neural cells to investigate its structure-function relationship. Furthermore, we hope our research could laid a solid foundation for drug oriented design and the similar medicine production.So we prepared four alginate series oligosaccharides and detected the protection of the oxidative damage on the neural cells to investigate the structure-function relationship. Furthermore, we hope our research could laid a solid foundation for drug oriented designs and the similar medicine productions.1. Alginate polysaccharides, sulfated derivatives preparation.Using alginate derived poly-mannuronic acid, of which optical isomer poly-guluronic acid as the raw material, we semi-synthesized M-SO4 and G-SO4 by anhydrous reaction with chlorosulfuric acid, and thus detected the sulfated radical by infrared spectrum. And we chose nephelometry to detect the content of the sulphur element of the sulfated polysaccharide.2.Comparing different alginate and derivatives on the function of anti-oxidative and neuron cells protection.We chose the cell PC12 oxidative damaged by hydrogen peroxide as the model, and detected the activity of cell by MTT after the polysaccharides affecting for 24 hours, and at last evaluated the protection activity by calculation the survival rates of cells. The research showed that the activity of poly-M was the best one of the four polysaccharides among poly-M, poly-G, M-SO4 and G-SO4.3. Preparation the Alginate derivative oligosaccharides and recognition of the smallest active fragment.We chose the Poly-M as the future research object, degraded it to the oligosaccharides with the degrees of polymerization of one to eight by the method of acidic hydrolysis and confirmed their structures and purities by ESI-MS.After screening these oligomannuronic acid, we found the smallest active fragment was tetrasaccharide.