Structural elucidation of three antioxidative polysaccharides from Tricholoma lobayense

Tricholoma lobayense is a nutritious mushroom with great health benefits. Three polysaccharides with purity higher than 99% were successfully extracted from Tricholoma lobayense . The molecular weights of TLH-1, TLH-2 and TLH-3 were determined to be 8.43   ×   10 5 ，5.36   ×   10 5 and 4.53   ×   10 3   Da, respectively. The backbones of TLH-1 and TLH-2 were mainly composed of 1,4-linked α- d -glucopyranosyl. However, polysaccharide TLH-3 was found to be a highly branched glucogalactan, which is made up of 1,3-linked α- d -glucopyranosyl branched at C-6 and 1,3-linked β - d -galactopyranosyl. In vitro antioxidant activity assays revealed that TLH-3 exhibited highest antioxidant activities among the polysaccharides from Tricholoma lobayense , which were comparable to those of ascorbic acid. The results suggested that the outstanding antioxidant activities of TLH-3 might depend on its low molecular weight, high branch degree, versatile linkage types and complex conformation. These characteristics make TLH-3 an attractive natural antioxidant for food and pharmaceutical applications.