Study On The Extraction, Purification, Antioxidative Function Of Pomegranate Peel Polyphenols

Pomegranate (Punica grantum L.) blongs to Punica L. of Punicaceae,China is rich in Pomegranate resources and it has been cultured for more than 2000 years in China. According to Compendium of Materia Medica,the granatum is the peel of punicaceae plants. Both fresh and dried granatums are available, Pomegranate is rich in Biological active materials, polyphenols is the most abundant class of bioactive substances in Pomegranate peel. Polyphenols is the secondary metabolites in Plant. Modern scientific researeh has confirmed that polyphenols have varieties of biological activities and have Positive impacts on human health. so it has avariety of effects on Preventing and curing diseases.In this study,Pomegranate peel as the research object,the extraction and analysis, purification technology and antioxidation progerty were studied, The results are as follows:The polyphenols were extracted with three methods from six pomegranate peels and the total polyphenol, total flavonoid and tannin of the extracts were detemined, in order to developping functional food and nutraceutical and optimizing analytical methods. The results were showed as following.①The extraction method did not effected significantly on the extractive yield of total polyphenol and total flavonoid, but of tannin, to which the yields increased gradually with 70% acetone, 70% ethanol and 20% ethanol as extactive solvent respectively.②The compounds'contents of different peels were different high significantly. The mutual effect between extraction method and variety of peel was no significant impact on the extractive yield.③There were significant (P<0.01) linear-correlations among the contents of the three compounds in anyone of the six peels, no matter which extractive method being used.Adsorption and desorption experiments were carried out to screen the suitable macroporous absorbent resin for pomegranate peel polyphenols. The purification techenologise of the crude extracts by macro-porous adsorbing resins were decided through the study esperiments,which included selective esperiments for choseing the best sample concentration ,sample pH and eluting reagents in static adsorption tests,and for choseing the best column, eluent usage amont and flow rates of eluent in dynamic adsorption tests.The results were showed as following.①Results indicate that macroporous resin HZ-818 possesse the strongest absorbend ability and easier desorption property,and its adsorption rate is 38.76 % , desorption rate is 81.57%.②The optimum absorption conditions of macroporous resin HZ-818 are concentration of feeding 2.5 mg/mL , pH 3.0, feeding rate 5 BV/h. And the optimum desorption conditions are eluteethanol concentration 70 % , elution rate 2 BV/h,with the polyphenols mass fraction increasing from 34% to 72.3%. The antioxidation capability and scavenging free radicals of the pomegranate peel polyphenols were studied, with VC been as reference. The results were showed as following.①The pomegranate peel polyphenols had obviously scavenging activity to free radicals ,which were approximately in the increase order of ABTS+>DPPH·>·OH.②The pomegranate peel polyphenols have obviously scavenging activity after purification. In the selected concentration range, the scavenging activity show that: ethyl acetate part>resin purification>water part>VC>crude extract.③The oxidation resistance capability of pomegranate peel polyphenols were approximately in the increase order of VC>ethyl acetate part>resin purification>water part>crude extract., and deoxidization capability of pomegranate polyphenols were ethyl acetate part>resin purification>VC>water part>crude extract.