[The purification and characterization of polysaccharides isolated from Ginkgo biloba and their in vitro antioxidant activities].

Objective: To isolate and identify the polysaccharides of Ginkgo biloba and determine their antioxidant activities in vitro.

Methods: Used hot extraction and alcohol precipitation to get the crude polysaccharides, removed protein with Sevag method, further purify by column chromatography packed with DEAE-52 and DEAE-Sepharose Fast Flow. The homogeneity and molecular weights were evaluated, configuration and monosaccharide composition were measured by IR and high performance ion chromatography analysis, the scavenging activities of GBPB-S on hydroxyl radical and DPPH were measured.

Results: The molecular weights of GBPB-W and GBPB-S were 26 300 and 19 100, and both of them were composed of rhamnose, arabinose, galactose, glucose and mannose with the ratios of (3.48: 8.47:3.73: 1.76: 1) and (5.34: 5.37: 5.27: 1:1.68). GBPB-S had certain scavenging effect on hydroxyl radical and DPPH.

Conclusion: The polysaccharide isolated from Ginkgo biloba has a direct antioxidant activities in vitro.