Optimization And Antiox Idant Activities Of Exopolysaccharide And Intracellular Zinc Polysaccharides By Grifola Frondosa

Grifola frondosa also named maitake, belongs to Basidiomycotina, Hymenomycetes, Aphyllophorales, Polyporaceae, Grigola. The G. frondosa polysaccharides have the functions of antioxidant, anti-aging, antitumour, enhance immunity, antivirus, antibacterial, etc. Zinc is one of the important trace elements in human body, which consists in more than300enzymes, and important for growth and intelligence.In this paper, the Zinc concentration condition in the liquid medium was decided, and the extraction conditions of G frondosa exopolysaccharide (GEPS) and intrecellular Zn-polysaccharide (GIZPS) in submerged culture were optimized on the basis of Plackett-Burman (PB) design and response surface methodology (RSM). The components of GEPS and their in vitro antioxidant were evaluated. The in vitro and in vivo antioxidant activities of GEPS、GIPS and GIZPS were evaluated. The monosaccharide composition and their molar ratio were decided.(1) The concentration of Zinc in liquid mediumBy comparing biomass and Zinc rich rate of mycelia in different Zinc concentration, the best Zinc concentration was50μg/mL. At this concentration, the biomass of mycelia was1.78g/L and Zinc rich rate was35.2%.(2) Optimization of GEPS extraction and GIZPS extractionThrough PB and RSM experiments, the results showed that the best extract conditions of GEPS were:concentration multiple3, ethanol multiple2.01, precipitation temperature-3.15℃. At this condition, the expected production was0.81g/L. In view of the operating convenience, the optimal extraction parameters were determined to be:concentration multiple3, ethanol multiple2, precipitation temperature-4℃, the actual value was0.797g/L.The results of PB and RSM showed that the best extract conditions of GIZPS were: pH7.69, extract temperature94.74℃, extract time2.43with extraction ratio of6.70%. In view of the operating convenience, the optimal extraction parameters were determined to be:pH8, extract temperature95℃, extract time3. Under this condition, the extraction ratio of GIZPS was6.32%.(3) Separation、purification and antioxidant activities of GEPS in vitroThrough DEAE-Cellulose column, GEPS could get two components:GEPS-1and GEPS-2. At the concentration of500mg/L, the scavenging effects of GEPS on hydroxyl radicals was54.89%and the reducing power was0.56; at the does of1000mg/L, the scavenging effects on DPPH radicals was35.70%. At the does of1000mg/L, the scavenging effects of GEPS-1on hydroxyl radicals was40%and the reducing power was0.40; at the does of1800mg/L, the scavenging effects on DPPH radicals was25.44%. GEPS-2had very strong antioxidant activities.At the concentration of15mg/L, the scavenging effects on hydroxyl radicals was68.82%; at the does of110mg/L, the scavenging effects on DPPH radicals was47.08%; at35mg/L, the reducing power was0.56.(5) Antioxidant activities of GIPS and GIZPS in vitroAt the does of400mg/L, the scavenging effects of GIZPS on hydroxyl radicals and DPPH radicals were89.89%and57.73%, the scavenging effects of GIPS on hydroxyl radicals and DPPH radicals were44.19%and28.40%. At the concentration of1000mg/L, the reducing power of GIZPS was0.385, GIPS was0.59.(6) Anti-aging activities of GEPS、GIPS and GIZPS in vivoThrough the model of senile mice, GEPS、GIPS and GIZPS showed their anti-aging activities. As the results, GEPS、GIPS and GIZPS increased the content of T-AOC in liver, the content of SOD in blood and decreased the content of MDA in kidney.(7) The monosaccharide composition and molar ratio of GEPS、GIPS and GIZPSThe results of GC showed that GEPS mainly contained rhamnose, arabinose, mannose and glucose, and their molar ratio was1:0.14:0.488:17.49. GIPS mainly contained rhamnose and mannose with the molar ratio of6.88:1. GIZPS mainly contained rhamnose and glucose with the molar ratio of3.62:1.