Physicochemical Properties and Antioxidant Activity of Water-Alkali Continuous Extraction of Crude Polysaccharides from Leccinellum crocipodium (Letellier.) Watliag

With Leccinellum crocipodium (Letellier.) Watliag as raw material, the water-extracted crude polysaccharide (LPS) was extracted from the fruiting body of Leccinellum crocipodium (Letellier.) Watliag by water-extraction and alcohol-precipitation method, and the alkaline-extracted crude polysaccharide (LPJ) was extracted from the fungus residue by alkaline-extraction and alcohol-precipitation method. The physical and chemical properties and antioxidant activity of two crude polysaccharides were studied. The results showed that the yields of water-extracted crude polysaccharide LPS and alkaline-extracted crude polysaccharide LPJ were 18.44%±1.30% and 5.50%±0.69%, respectively. LPS was spongy and light brown;LPJ was fluffy and yellowish brown. The polysaccharide content, uronic acid content, sulfate content, and total phenols content of LPS were all higher than LPJ (P<0.05). The antioxidant activity of LPS and LPJ increased gradually with increasing concentration. When the concentration of LPS and LPJ was 4 mg/mL, the scavenging rate of DPPH radicals (87.55%±0.51%, 54.31%±2.72%), the scavenging rate of hydroxyl radicals (54.53%±1.61%, 46.50%±0.64%), the scavenging rate of ABTS cationic radicals (81.56%±4.43%, 68.79%±1.23%), and reducing power absorbance values (1.41±0.02, 1.16±0.01) all reached the maximum, when the concentration was 3 mg/mL, the scavenging rate of superoxide anion radicals (89.16%±2.42%, 85.94%±2.98%) reached the maximum. It showed that LPS and LPJ had better antioxidant ability, and LPS was better than LPJ.