Preparation And Characterization Of The Sulfated Polysaccharides From Aralia Chinensis L.root-bark And Study Of Antioxidant Activity

Aralia chinensis L.,which belongs to Aralia,Araliaceae was widely distributed in the most areas of China.It has been used as Chinese herbal medicine as well as an edible food for many years,its buds and leaves rich in sugar,protein,amino acid,vitamin,crude fiber and carotene nutrients,was high-grade edible wild herbs;its root bark and stem bark can be used as medicine,which were effective on analgesia,anti-inflammatory,expel dampness and promote blood circulation.In recent years,through the introduction of various functional groups（such as sulfate,phosphate etc.）to enhance plant polysaccharides activity has become a hot research topic in the field of natural products,including sulfated polysaccharide derivatives because of their excellent physical and chemical properties the biological activity and received special attention.Therefore,chemical modified A,chinensis stem-bark polysaccharides（ACP）was prepared and the structure-activity relationship was studied.The main conclusions are as follows:1.The response surface method to optimize the preparation process and structure characterization of the polysaccharide sulfate（SACP）By chlorosulfonic acid pyridine method（CSA/Py）of Aralia chinensis L.root-bark polysaccharide sulfate（SACP）was synthesized by the response surface（RSM）experiments to determine the optimum reaction conditions were:the ratio of CSA/Py to,the reaction time is 5.23,the reaction temperature is 61.25,the degree of substitution（DSs）is 0.57,conforming to the model through expectations.Infrared spectroscopy,X ray photoelectron spectroscopy（XPS）,sulfuric acid groups have been introduced in the SACP,S exists in the form of S⁶⁺.Size exclusion chromatography with laser light scattering method（SEC-LLS）to determine the average molecular weight（Mw）showed that acidic reaction conditions cause the reduction of Mw.Gas chromatography mass spectrometry（GC-MS）analysis showed that monosaccharide composition of SACP were arabinose,glucose,galactose and mannose.2.A preliminary study on the antioxidant activities of SACP and ACP in vitroThe results of antioxidant activities of SACP and ACP in vitro showed that the scavenging activity of SACP and ACP on DPPH radical,hydroxyl radical,superoxide radical and reducing power increased gradually with the increase of polysaccharides concentration,and free radicals scavenging ability of SACP higher than ACP,indicated that SACP can enhance its antioxidant ability in a certain extent.