Studies On The Extraction, Isolation And Activity Of Polyphenols In Wild Jujube Peel

In this research, the jujube peel was taken as the research material. The paper optimized the optimum technological parameters of extracting conditions and refined method of polyphenols from the jujube peel, a comparative study on their antioxidant ability and a preliminary study of its chemical composition was made.Three extracting methods which were reflux extraction by ethanol, ultrasonic and microwave irradiation were compared in this paper. According to the orthogonal experimental results, the optimum extracting condition of polyphenols from the jujube peel by reflux was showed as follows: extracting solvent was 70% ethanol, solid-liquid ratio was 1:20, extracting temperature was 70℃, extracting time was 1 h and extracting once. According to the best condition, the content of polyphenols from apple pomace was 35.69g/kg. When extracted by microwave irradiation, the optimum extracting condition was showed as follows: extracting solvent was 70% ethanol, solid-liquid ratio was 1:15, microwave radiation was 200W, extracting time was 7 min. According to the best condition, the content of polyphenols was 32.07g/kg.These extracts were further purified by olvent extraction and macroporous resin. These extracts were divided into three parts by different polar solvents, the polyphenol content of the ethylacetate part was doubled, significantly higher than the other parts; the extraction purified by D4020 macroporous adsorbent resin, the polyphenol content were nearly ten times improved.Then the polyphenol extracts of the jujube peel in vitro antioxidant effects and their impact on SAM mouse antioxidation system were studied in this paper. In vitro antioxidant studies, the various parts of purified extract and crude extracts were included. These extracts had strong antioxidant activity on reducing capacity, FRAP ability, lipid-peroxidation, and scavenging effects on hydroxyl radical, DPPH·and peroxide radical. The ethylacetate part and the extraction purified by D4020 macroporous adsorbent resin with high the polyphenol content had more power antioxidant effects than other four extracts.Compared with the model group, the jujube peel extract showed better antioxidant action, and SOD gene expression was significantly higher than the model control group (p <0.05). Morphological observation showed that the jujube peel extract has a protective effect on the morphological structure of the normal liver, can slow down the speed of reduction of nerve cells and deformation, maintain the normal function of the cerebral cortex, but have nothing better improved on interstitial nephritis.Some preliminary research on chemical composition of the jujube peel extract were made in the research. After a variety of high-performance liquid conditions, one obvious goal peak eventually isolated from extract. The target area increased after macroporous resin purification, which are consistent with the content of polyphenols and antioxidant activity. It can be inferred that the target peak is antioxidant substance or one of substances. For LC-MS analysis, the molecular weight of the target material should be 342 or 341. There are much more methods should be study to determine chemical composition of the jujube peel extract.