Purification,Composition Analysis and Its Antioxidant Activity of Polyphenols from Red-Flesh Apple of Xinjiang

The red-flesh apple of Xinjiang(Malus niedzwetzkyana Dieck)was used as raw materials in this paper,the red-flesh apple polyphenols was purified through macroporous adsorptive resin method based on the polyphenols extraction with ultrasonic-assisted methodology,and the composition of purified polyphenols from red-flesh apple of Xinjiang was analyzed with HPLC. Using V_C as a control,the antioxidant capacity of polyphenols from red-flesh apple in Xinjiang was examined by an antioxidant test in vitro. The results showed that the NKA-Ⅱ resin behavior of static adsorption and desorption on the polyphenols purification was best in five macroporous resins for red-flesh apple polyphenol,and its absorption and desorption equilibrium time was 6 and 10 h respectively. The optimal process parameters of dynamic adsorption and desorption for apple polyphenols purification were as follows: The concentration of polyphenols and the sampling rate were 0.8 mg/mL and 4.0 BV/h respectively,and the elution concentration and sampling volume were 75% ethanol and 3.5 BV respectively. In this optimal condition,the purity of red-flesh apple polyphenols was increased from 35% to 84%. 10 kinds of phenolic compounds were identified in purified polyphenols by HPLC,which were protocatechuic acid,epigallocatechin,quercitrin,catechinic,procyanidin B₂,chlorogenic acid,4-hydroxybenzoic acid,hyperoside,rutin and quercetin. Among them,the contents of chlorogenic acid was the highest with 123.15 μg/mL,followed by quercitrin and proanthocyanidin B₂ with 25.28 and 21.96 μg/mL.The results of antioxidant test in vitro showed that the different concentrations of polyphenols from red-flesh apple of Xinjiang had significant free radical-scavenging effect on the DPPH free radical,hydroxyl radicals,superoxide anion,while the clearances ratio were 93.99%(0.1 mg/mL),99%(0.8 mg/mL),and 98%(0.4 mg/mL),respectively. The polyphenols from red-flesh apple of Xinjiang also had obvious protective effect for the lipid peroxidation. This experimental results laid the foundation for further study on the anticancer activity of red-flesh apple polyphenols.