Characterization and antioxidant activity of two low-molecular-weight polysaccharides purified from the fruiting bodies of Ganoderma lucidum.

Two low-molecular-weight polysaccharides, GLP(L)1 and GLP(L)2, purified from a crude Ganoderma lucidum polysaccharide preparation GLPP were investigated for their physicochemical properties, structure characterization and antioxidant activities. The results indicated that GLP(L)1 was a glucan with an average molecular weight of 5.2kDa, while GLP(L)2 was composed of glucose, galactose and mannose in a ratio of 29:1.8:1.0 with the average molecular weight of 15.4kDa. GLP(L)1 and GLP(L)2 had similar structure characteristic which contained linkages such as -->3)-Glcp-(1-->, -->4)-Glcp-(1-->, -->6)-Glcp-(1-->, -->3,6)-Glcp-(1-->, and -->4,6)-Glcp-(1--> in the percentage ratio of 21.9:20.3:23.7:24.0:3.7 and 23.0:34.6:7.0:14.1:3.0 in the backbone or branches, respectively. Antioxidant results showed that both GLP(L)1 and GLP(L)2 exhibited antioxidant activities while GLP(L)1 was more effective in free radicals scavenging and Fe(2+) chelating. Low-molecular-weight polysaccharide seems to play an important role in the exploration of natural antioxidants in food industry and pharmaceuticals.