Isolation and Purification of Polysaccharides

Total Polyporus umbellatus polysaccharide was purchased from Hui Zhou Xian Cao Plant Health Care SCI & THE Co., Ltd. (Huizhou, China, batch number 150780681), and the polysaccharide content determined by the phenol-sulfuric acid method was 73.5%. The polysaccharides were deproteinized using Sevag reagent (1-butanol/chloroform, v/v = 1:4), and the supernatant was lyophilized to obtain the deproteinized polysaccharides. The deproteinized polysaccharides were dissolved in deionized water, after which the solution was applied to a DEAE-52 cellulose column (3 × 35 cm) and eluted with deionized water at a flow rate of 1 mL/min. Test tubes were collected using an automated step-by-step fraction collector, after which the total carbohydrate content of each tube was measured based on the absorbance at 490 nm using the phenol-sulfuric acid colorimetric method. The main fraction containing carbohydrates from the elution step was then concentrated and lyophilized. The collected fraction was further applied to a Sephadex G-100 gel-filtration column (2.9 × 50 cm), after which it was eluted with deionized water at a flow rate of 1.0 mL/min. The neutral carbohydrate was eluted as a single fraction according to the elution profile and lyophilized as a white powder.