MOLECULAR WEIGHT, CHAIN CONFORMATION AND ANTIOXIDANT ACTIVITIES OF SULFATED beta-D-GALACTAN DERIVATIVES FROM DENDROBIUM NOBILE LINDL

摘要

In this study, a series of sulfated polysaccharide fractions (Ps1, Ps2, Ps3, Ps4, Ps5, and Ps6) were derived from one water-soluble beta-D-galactan of Dendrobium nobile by chlorosulfonic acid-pyridine method and their molecular weights, chain conformation, and antioxidant activities of the six derivatives were investigated. Congo red complex formation and viscosity experiments indicated the presence of a low organized conformation in beta-D-galactan and a relatively high-ordered conformation in its sulfated derivatives. In vitro activity experiments showed that antioxidant potentials were significantly enhanced in all sulfated derivatives and Ps2 exhibited the highest antioxidant activities. These results revealed that the different molecular weights and conformation between beta-D galactan and its sulfated derivatives influenced their antioxidant activities and the extended chain conformation of sulfated beta-D-galactan derivatives was beneficial to enhance the antioxidant activities. It was suggested that Ps2 might be used as a potential antioxidant in the food and pharmaceutical industry.