Extraction, Purification, Antioxidant Activity And Stability Of Acanthopanax Sessiliflorus Polyphenols

Acanthopanax sessiliflorus belongs to Araliaceae which is generally distributed in North China.As a traditional Chinese medicine,Acanthopanax sessiliflorus can regulate nervous system, enhance immune function, also has activities such as analgesia and antipyretic, reinforcing function of liver and kidney, making bones and muscles strong, antifatigue, antitumour, scavenging free radicals and so on.Recent studies have shown that polyphenols have a strong antioxidant capacity,which contains flavonoids, phenolic acids, anthocyanins and other types of antioxidants.Recently,the study is increasing on how to extract and purify natural polyphenols from plants and add them to foods.Extracting polyphenols from Acanthopanax sessiliflorus are now mainly concentrated on flavonoids.extraction.activity and stabilization are lessly reported. In this paper. extraction. purification,antioxidant activity and stability of polyphenols were studied.The results are in the following:1. The optimal extraction conditions of polyphenol from Acanthopanax sessiliflorus fruit is as follows:extraction temperature is 62.85 ℃, ethanol concentration is 10.21%, the ratio of liquid to solid is 39.92:1(mL/g), the theoretical value of polyphenol extraction rate is 167.995mg/g under this optimized condition. From the view of practical application. the extraction conditions were modified to 63 ℃,10%and 40:1 under which repeated experiments showed an average yield of polyphenol extraction is (167.930±2.371) mg/g and the extracted polyphenols include,flavonoids is(40.570±0.896)mg/g, phenolic acid is(78.269±1.042)mg/g, and anthocyanins is(6.985±0.558)mg/g.2. HPD700 macroporous resins exhibited the excellent characteristics for polyphenol purification of Acanthopanax sessiliflorus fruit.The optimum conditions of adsorption are as follows:the concentration of polyphenols is 1.5 mg/mL, the pH of sample is 3.5, loading volume is 6BV; the adsorption speed is 0.5 mL · min-1.The optimum conditions of desorption are the 50%ethanol volume of 1.5BV, pH of 4.0 and the desorption speed of 1.OmL · min-1.3. Identified by HPLC, Acanthopanax sessiliflorus polyphenols consist of protocatechuic acid, chlorogenic acid,caffieic acid,hyperoside and quercetin. Further studied by HPLC-MS, Acanthopanax sessiliflorus polyphenols consist of protocatechuic acid,chlorogenic acid,hyperoside and two coffee acyl quinic acid.4. According to the comparative analysis of the value of total antioxidant capacity in Acanthopanax sessiliflorus,blueberry,apple polyphenol extracts, clearing DPPH free radicals IC50 are:Hanfu apple (38.0±0.95) mg/mL,blueberry (21.5±0.73) mg/mL, Acanthopanax sessiliflorus (11.0±0.71)mg/mL,which is from big to small.The polyphenols of Acanthopanax sessiliflorus have the strongest activity. IC50 of clearing hydroxyl free radicals are Hanfu apple (3.88±0.55) mg/mL,blueberry (0.447±0.044) mg/mL, Acanthopanax sessiliflorus (0.231±0.021) mg/mL,so Acanthopanax sessiliflorus polyphenols have the strongest activity.The total antioxidant capacity in the clearing ABTS+free radicals experiments shows that:Acanthopanax sessiliflorus (265.45±1.41) umol/g,blueberry (206.07±1.63) umol/g,and Hanfu apple (8.83±0.92) umol/g.No matter capacity of clearing DPPH free radicals and clearing hydroxyl free radicals,or capacity of scavenging ABTS+free radicals,it is clear that Acanthopanax sessiliflorus’polyphenols has strong antioxidant activity.5.Analysing and comparing the stability of the polyphenol extracts from Acanthopanax sessiliflorus,bluebrry and Hanfu apple:different temperatures,light, pH,additives, metal ions on polyphenols, flavonoids,phenolic acids, anthocyanins content and the effect of polyphenol extracts on clearing DPPH free radicals. The result shows that light, high-temperature,neutral or alkaline environment, Al3+or Fe3+ infulence the stability of polyphenols,the distribution of the total polyphenolic content decreasing in 5h, DPPH clearance rate is also decreasing.On the whole,the content of polyphenols is high in Acanthopanax sessiliflorum,and it also has strong activity.