Study On Separation And Purification And Antioxidant Activity Of Polysaccharides Of Gastrodia Elata

Gastrodia elata Blume (Gastrodia El Bl.), as traditional Chinese medicine, has sedative,hypnotic, nootropic, anti-aging and antioxidant activity. Polysaccharides are naturalmacromolecule compound, participate in and maintain a variety of physiological functions oforganism. The objective of this paper is to lay a foundation for further utilization andexploitation of Gastrodia elata Blume polysaccharide.Taking rhizoma gastrodiae as the research object, the extraction, isolation, purificationand antioxidant activity of rhizoma gastrodiae polysaccharides are studied. The results are asfollows:1. Based on single factor test, water extraction process was optimized through theresponse surface optimization method. The influence of different factors for the extractionyield was that liquid ratio was bigger than extraction time which was bigger than extractiontemperature. We established the best polysaccharide extraction process parameters asfollowed: liquid ratio was51(mL/g), the extraction temperature was78℃, the extraction timewas65min. The yield of theoretical value was6.23%under the condition.2. Gastrodia elata crude polysaccharide was treated with deproteinization anddecolorization, after the dialysis, DE-52and gel G-100purification, we got PRG1~PRG5five rhizoma gastrodiae polysaccharides with uniform molecular weight:19251Da(9mg)、3920Da(118mg)、32646Da(11mg)、24786Da(21mg) and17142Da(32mg). Infraredspectrum scanning results showed that the polysaccharide PRG1~PRG5had characteristicabsorption, glycosidic bonds are alpha configurations; Uv scanning results showed thatrhizoma gastrodiae polysaccharides PRG1and PRG5do not contain nucleic acids andproteins, PRG2~PRG4contain trace proteins. Gastrodia elata polysaccharide PRG1~PRG5specific rotation were50.133,73.592,75.117,62.811and131.491°. Monosaccharide analysisresults showed that the PRG1composed of fructose and glucose, the molar ratio of fructoseand glucose is1:10.682; PRG2consists of glucose; PRG3composed of fructose and glucose,the molar ratio of fructose and glucose is1:1.542; PRG5composed of glucose; Gastrodiaelata polysaccharide PRG1~PRG4are white powder, while PRG5is light yellow powder. 3. Gastrodia elata polysaccharide PRG1~PRG5had certain ability of scavenging onDPPH and hydroxyl free radical, while the DPPH scavenging ability was well. PRG1~PRG5scavenging DPPH free radical IC50values were4.52、3.94、7.01、5.67and4.78mg/mL. In acertain range, PRG1~PRG5showed good a dose-effect relationship with the increasing ofconcentration.In summary: by response surface method, we established the optimum extractionconditions of polysaccharides of Gastrodia elata. The homogeneous polysaccharides ofGastrodia elata have been separated and purified. Our work provides certain basis for thestructure analysis and structure-activity relationship research.