Isolation And Purification Of A Mycelium Polysaccharide From Auricularia Auricula And Its Biological Activity On Hypolipidemic

Auricularia auricula is valuable edible-medicinal colloid fungi in our country. The polysaccharide is the important active ingredient of Auricularia auricula, its bio-logical activity attracted more and more attention. In order to explore the potential value of functional food materials and drug leads, the submerged fermentation, solid fermentation of Auricularia auricula, extraction of mycelium polysaccharide, isola-tion and purification were studied. The structure of pure polysaccharide and the activ-ity on hypolipidemic were discussesed. The main results are as follows.1. The glucose and peptone were the best carbon and nitrogen source for Auricu-laria auricula submerged fermentation. The orthogonal experiments exhibited that the optimal conditions for obtaining the mycelium biomass is glucose concentration 3%, potato 20%, peptone 0.2%, KH2PO40.1%, MgSO4·7H2O 0.05%, pH=5, liquid volume 120 mL, shake speed 160 r/min, cultivate 10 d. The submerged fermentation mycelia was used as liquid spawn in solid fermentation, which had the characteristics of fast growth and short cycle.2. The orthogonal experiment showed that the optimal fermentation conditions for polysaccharide from solid-state fermentation is begass:bean dregs= 3:2, tem-perature 30℃, fermentation time 28 d.3. Used software Design Expert, the Box-Behnken Design set up water extrac-tion temperature X1, extraction time X2, liquid-to-solid ratio(m/m) X3 and yield of polysaccharide on second order polynomial mathematics model, correlation coeffi-cient R2=0.9630, P< 0.0001 (P=0.0003), regression model significantly, fitting de-gree well; The optimum extraction condition is extraction temperature 90℃, extrac-tion time 90 min, liquid-to-solid ratio 27:1, predictive value of yield is 7.86 mg/g, checking value is 7.74 mg/g, error is 1.53%. It proved that this model is reasonable and reliable, and can be used in the actual forecast.4. The polysaccharide was purified by DEAE Sephadex A-50, and gained three main components of the polysaccharide, named AAP-I, AAP-Ⅱ and AAP-Ⅲ. AAP-Ⅰ was further purified by Sephadex G-200 chromatography, showed that it is a single component polysaccharide. Results of ultraviolet spectrum scanning indicated that AAP-Ⅰ does not contain the nucleic acid and protein, and thin layer chromatog-raphy indicated AAP-Ⅰ may be pure. The chemical structure of AAP-1 was studied by infrared spectrum and nuclear magnetic resonance and the result revealed it is a kind of polysaccharide.5. The hypolipidemic activity of polysaccharide was investigated in the vivo, compared with the high lipid model group, that the polysaccharide AAP-Ⅰ has good activity on hypolipidemic(P<0.05).