Study On Extraction, Purification, Antioxidant Properties Of Flavonoids Fom Winter Jujube

Jujubeis a special and abundant resource in our country because of planting on a large scale. Fresh jujube that is a sweet, delicious, and nutrition fruit contains a variety of bioactive substances, such as flavonoids, saponins, polysaccharide, cAMP and cellulose. jujube is taken as nourish blood and antioxidant effect and so on, and has great potential of development and application.In this paper, the jujube was selected as raw material, the flavonoids were extracted by ethanol, or jujube was fermented for the powder preparation. Then, the flavonoids, jujube power, and fermented power were respectively used to scavenge free radicals in vitro, and to apply as oxidative stress model induced by H2O2, and to study antioxidant of flavonoids, jujube powder, fermented jujube powder by the model of mice hyperlipidemia in vitro and vivo. The aim is to provide theoretical foundation and scientific basis for the extraction of the active substance, and jujube health food development and application. The results were as fellows:1. The crude flavonoids in Jujube extracted by60%ethanol extraction. The FW-1was obtained after preliminary separation by the macro-pore resin, and further separated by silica gel column, and fractionation FW-2was obtained. Flavonoids content in FW-1and FW-2were respectively detected by NaNO2-A1(NO3)3colorimetry method. Flavonoids was67.6%in FW-1and was92.7%in FW-2, respectively. FW-2was detected by LC-MS, the result showed that FW-2was a mixture of flavonoids, and mainly composed of biflavone, and its molecular weight was790, and the special structure needs further study.2. By means of fermentation,1%yeast powder was added to fresh jujube pulp. Fermentation process was determined, and then the ferment jujube powder was obtained. Total sugar content in the fermented jujube powder was reduced by14.02%, and protein content increased by77.4%when compared with jujube powder.3. Antioxidant capacity in vitro of FW-1, FW-2,jujube powder and fermented jujube powder were evaluated by five methods, namely, total antioxidant capacity (FRAP method), reducing measurement, clearing DPPH free radical ability, ability to remove hydroxyl radicals, and superoxide anion. The total antioxidant capacity, reducing capacity of FW-1, FW-2were higher than those of the same mass concentration of Vc. The removing DPPH free radical ability of FW-1, FW-2was similar to Vc. FW-1and FW-2can effectively remove hydroxyl free radicals, capacity is slightly lower than that of the same concentration of Vc. The effect of removing super anion was not obvious at the same as Vc. Jujube powder and fermented jujube powder also showed good antioxidant ability, and was poorer when compared with the same concentrations of Vc.4. The antioxidant properties of FW-1, FW-2, jujube powder, and fermented jujube powder were respectively evaluated by Oxidative stress cells model in HepG2after cells was induced by H2O2. The better oxidative stress cells model is treated by10mmol/L H2O2. FW-1, FW-2at0.5mg/mL and lmg/mL can effectively reduce the ROS level in cells induced by H2O2, and increase the survival rate of cells, and reduce cell oxidative damage, and decrease intracellular and extracellular MDA levels. Jujube powder, fermented jujube powder at lmg/mL and2mg/mL can effectively reduce the ROS level, and increase the survival rate of cells and reduce cell oxidative damage, and decrease intracellular and extracellular MDA levels.(5) Effects of FW-1, jujube powder and fermented jujube powder on high-fat model mice were studied. Two dosage groups of FW-1(150mg/kg. d and300mg/kg. d) were orally administrated for6weeks. The results showed that the FW-1model can effectively reduce the high fat blood lipid level of mice, and decreased serum TC, TG, LDL-C content, and improve the level of serum HLD-C. In liver and kidney tissue from mice, MDA content were reduced, and GSH-PX, SOD activity significantly increased. At the same time, no statistical difference was compared with normal control group. Fermented jujube powder and jujube powder, after administrated at dosage of1g/kg.d for6weeks, the results showed that the high fat blood lipid level of mice, serum TC, TG, LDL-C content were respectively reduced, and improved the level of serum HLD-C. In liver and kidney tissue, MDA content reduced, and SOD activity increased, but the effect was lower than that of FW-1.