A Comparative Study On The Characterization And Antioxidant Activity Of Ganoderma Lucidum Polysaccharides Produced By Solid State, Liquid Fermentation

Ganoderma lucidum is a mushroom having been widely used in China as Traditional Chinese Medicine as well as healthy food for thousand years, which could promote longevity and health. The polysaccharides, which are the main active components of G. lucidum, are capable of eliminating free radicals, anti-oxidation, anti-aging and immunoregulation. They are mainly extracted from fermentation broth of liquid fermentation and fruit bodies of solid state fermentation. In this paper, two polysaccharides from G. Lucidum (GLEP from fermentation broth and GSIP from fruiting body) were obtained and the structural characterizations, antioxidant activities of them were investigated, as well as the culture conditions of GLEP. The main results are as follows:The fermentation process of GLEP was optimized through single factor experiments and RSM design tests. Results showed that the optimum media components and culture conditions were as follows:39 g/L glucose,21 g/L yeast extract,3.0 g/L KH2PO4 and 1.0 g/L MgSO4·7H2O, pH 6.0 and incubation size 10%. Under these conditions, the yield of GLEP was 2.65 g/L closed to the predicted values 2.74 g/LGLEP-1 and GSIP-1 were obtained by the means of purification using DEAE-650 ion exchange resin and gel sephadex G-100 successively. The results of UV spectrum showed that there were no protein, nucleic and pigment in GLEP-1 or GSIP-1, and the results of FTIR showed that both GLEP-1 and GSIP-1 were β-pyranose which had the characteristic absorption peaks of polysaccharides. The results of GC-MS showed that both GLEP-1 and GSIP-1 were mainly composed of ribose, rhamnose, arabinose, xylose, mannose, glucose and galactose, while the molecular weight of GLEP-1 and GSIP-1 were 2150Da and 2606Da, respectively.The antioxidant activities of GLEP and GSIP were determined on the basis of DPPH, hydroxyl radical scavenging oxidation experiments, reducing power, and protective effect on yeast cells from UV, H2O2. The results indicated that two polysaccharides exhibited antioxidant activities in a dose-dependent manner. At 5.0 mg/mL, the scavenging rate on DPPH, hydroxyl radical and reducing power of GLEP were 1.25,50.5% and 80.7%, while that of GSIP were 1.46,85.5% and 78.3%, respectively. GLEP and GSIP also showed strong protective effect on yeast cells from UV and H2O2 damage. At 20 mg/mL, the protective effect of GLEP were 57.1% and 49.1%, and that of GSIP were 84.3% and 79.3%, respectively.The results of anti-fatigue experiment indicated that GLEP and GSIP were safe and non-toxic, and their anti-fatigue effect was obvious. The mice swimming exhaustion experiment showed that GLEP and GSIP could significantly prolong the swimming exhaustion time. The results of the biochemical index determination indicated that GLEP and GSIP could significantly enhance the activity of SOD, GSH-Px in mouse blood and reduce the content of MDA. Moreover, they could maintain the level of glycogen in the body and extend exercise endurance of the body. However, they had no significant effect on LD and LDH in mouse body.