Study On Extraction, Purification, Physico-chemical Characteristics And Antioxidant Activity Of Tremella Fuciformis Polysaccharide

This research took dry sample of the Fujian Gutian Tremella fuciformis as test material to isolate and purify three kinds of uniform Tremella fuciformis polysaccharide which named as TF-PA, TF-PB and TF-PC, with the method of ultrasound-water extraction, ethanol precipitating, Sevage-HCl deproteinizing, water dialysis, DEAE-cellulose column and further purified through Sephadex G-200 column chromatography fractionating. And then its physicochemical properties and antioxidant activity were measured. The main findings are as follows:1. Response surface methodology was used to optimize the extraction parameters of water extraction of Tremella fuciformis polysaccharide. According to the mathematical models, the optimum conditions were extraction time 3.8h, extraction temperature 92℃ and solid-liquid ratio 1:43.2. According to the single factor experiment, the Sevage law deproteinized optimum conditions were determined as follows:the shaking time of 1.5h, the addition amount of 1/2 for Sevage reagent to sample (v/v), the volume ratio of 4:1 for chloroform to n-butanol, and the deproteinization time of once. Under this condition, supplemented HCl for 24h, the rate of deproteinization can reach 79.82% and the loss rate of polysaccharide was 29.42%.3. TF-PA is pale yellow crystals, TF-PB and TF-PC are loose white floe. All of them are odorless, hygroscopic, soluble in water, poorly soluble in methanol, ethanol, acetone, butanol solvent and most organic solvents. And their high concentration of the aqueous solution was sticky.4. Through infrared spectroscopy analysis found that many characteristic absorption peak of polysaccharide appeared in the three maps of TF-PA, TF-PB and TF-PC. And combined with sulfuric acid-carbazole reaction, identified the TF-PC contained glucuronic acid. The result of HPLC and GC-MS showed as follow:Firstly, the weight-average molecular weight of TF-PA was 5.34×103 Da in phosphate buffer solution (PBS) respectively. And as a neutral heteropolysaccharide, it’s mainly composed of arabinose. xylose, mannose, glucose and galactose with the molar ratio of 1.39:3.81:8.40:24.65:1:Secondly, the TF-PB was an acidic polysaccharide with the weight-average molecular weight of 7.08×105Da in PBS respectively, mainly composed of arabinose, xylose, mannose. glucose, fructose and galactose with the mole ratio of 1.24:1:2.28:6.78:1.58:1.66; Then thirdly, TF-PC was an acidic polysaccharide that composed of arabinose and glucose in a molar ratio of 1.05:1, and its weight-average molecular weight was 1.47×106Da in PBS respectively.5. The antioxidant experiments in vitro showed that all of the three polysaccharides had certain reducing powers and scavenging capacities on DPPH free radical, hydroxyl free radical and superoxide anion free radical, but its effect were lower than the same concentration of Vc solution, with a minimum clearance TF-PA. When the solution of TF-PA, TF-PB and TF-PC are lmg/mL, their reducing power are, in order,0.3227, 0.5312,0.5127, and hydroxyl radical scavenging rates are, in order,41.13%,74.82%, 75.21%, and DPPH radical scavenging rates are, in order,20.30%,32.19%,35.24%, and superoxide anion scavenging rates are, in order,30.06%,40.28%,43.27%.