Extraction Of Cordyceps Militaris Polyasccharide And Dihydromyricetin In Bine Tea And Their Interation Eddcets On Functional Properties

Dihydromyricetin（DMY）exists in vine tea,a homologous plant of medicine and food.It is a special flavonoid compound with good physiological health care effects,especially antioxidant activity.But it has low bioavailability due to poor solubility and stability.Cordyceps militaris fruiting body polysaccharide（CMP）has been shown to be a functional food and a potential natural supplement with large molecular weight and complex structure.In this paper,on the basis of extraction,purification and structural identification of DMY and CMP,the effect of their interaction on functional properties was studied.Extracted dihydromyricetin from rattan tea:the extraction temperature was 75℃,the extraction time was 2 h,the material-liquid ratio was 1:30（g/m L）,the ethanol concentration was 75%,to obtain the crude product of dihydromyricetin.Purify the crude dihydromyricetin:30 times volume of acetone refluxed for 30 minutes,adsorbed by 1%activated carbon,crystallized once every 12 h,and repeated 3 times to obtain the purified sample.The yield of purified sample was 13.34%,and the purity was 95.96%.HPLC confirmed that the purified sample was a single component.The structure identification was carried out by UV full-wavelength scanning,FT-IR,NMR,SEM,etc.,which indicated that the purified sample was dihydromyricetin.Extracted the polysaccharides from Cordyceps militaris fruiting bodies:te extraction temperature was 80℃,the extraction time was 4 h,the material-water ratio was 1:30（g/m L）,and the extraction was repeated 3 times.Then separated and purified by ethanol precipitation,protein removal,pigment removal,dialysis to obtain the crude polysaccharides of Cordyceps militaris fruiting bodies.And the crude polysaccharides was purified by Sephadex G-200column chromatography to obtain the pure polysaccharide of the fruiting body of Cordyceps militaris.It was confirmed to be a single component by HPLC with Mw of 3.3×10³k Da.The monosaccharide composition results showed that CMP was composed of D-Man,D-Glc and D-Gal with a molar ratio of 1.00:6.67:0.32.By FT-IR spectroscopy,NMR spectroscopy,periodate oxidation and Smith degradation,and methylation analysis,it was composed of（1→）-D-Glcp,（1→6）-D-Galp,（1→4）-D-Glcp,（1→3）-D-Glcp,（1→4）-β-D-Glcp and（1→3）-D-Manp,and the molar ratio is 1.00:0.63:5.96:1.46:0.66:1.38.The effect of CMP on the solubility and stability of DMY was determined,and its mechanism was explored from solid state and liquid state,and the antioxidant activity was determined.The solubility of DMY in saturated CMP solution increased by 3.23 times compared to that in aqueous solution.The stability was measured by isothermal acceleration method,and the results showed that the half-life of DMY increased from 5.49h to 7.32h after adding CMP.The results of phase solubility studies indicated that DMY and CMP formed AL-type complexes in water at a stoichiometric ratio of 1:1.The FT-IR,SEM and thermogravimetric characterization of the solid-state complexes showed that they may interact through non-covalent bonds such as van der Waals forces,hydrogen bonds,and electrostatic forces.The results of in vitro antioxidant test showed that the inhibition rates of DMY on DPPH·、ABTS^·+、O^2-·and·OH free radicals were 72.47%,99.91%,42.51%and61.23%,respectively,when all the concentration was 0.5 mg/m L;the inhibition rates of CMP were 16.32%,28.76%,28.72%and 28.41%,respectively;the inhibition rates of complexes were 67.24%,99.89%,41.38%and 35.25%,respectively.In general,when the DMY content is greatly reduced,the antioxidant activities of the complexes were mostly still good,even reaching the same effect as DMY.