Antioxidant Activity and Characterization of One New Polysaccharide Obtained from Perigord Truffle (Tuber huidongense)

As a medicinal and edible fungus parasitizing on the trees, Perigord Truffle (Tuber huidongense) is well known for its delicious taste, unique smell, and high medical value for healthcare. One new water-soluble nonstarch polysaccharide (PST-W with the yield of 0.41%) from Perigord Truffle (Tuber huidongense) was purified and identified on structural characteristics for the first time. The characterizations of PST-W were studied on physicochemical properties, main components of monosaccharide(s), and molecular structure. The monosaccharide compositions of PST-W were studied and identified as glucan, only containing D-glucoses with the molecular structure of [→6) α-D-Glcp   α-D-Glcp (1→]n by methylation analysis and NMR. In the determination of total reducing capacity, the reducing abilities of polysaccharide extracts could be listed as vitamin C > PST-W > crude polysaccharides-3 > crude polysaccharides-2 > crude polysaccharides-1. All of PST-W, crude polysaccharides-2, and crude polysaccharides-3 were relatively good scavenger for 1,1-Diphenyl-2-picrylhydrazyl radical 2,2-Diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl radicals with IC50 of 2.81, 4.17, and 3.44 mg/mL, respectively. However, clearing abilities of PST-W and crude polysaccharides were obviously weaker. The activities of total crude extract were the worst, indicating that the impurities might negatively affect the antioxidant activity. Thus, the separation and purification of polysaccharides were significant to increase the antioxidant activity in some degree.