Evaluation of Antioxidant Activity of Polyphenols from Different Varieties Apples in Vitro

Objective:Thirteen varieties apples were chosen to evaluation the difference of polyphenols antioxidant activity by determining total polyphenols and free phenols antioxidant activity. Methods:Apple polyphenols were extracted using organic solvent with steam explosion-ultrasonic assisted. The antioxidant activity of total polyphenols and free phenols were studied with determining scavenging effect of DPPH· free radical,nitrogen oxide radical free radical(NO₂^-·),hydroxyl free radical(·OH)and superoxide anion free radical(O₂^-·),total reduction capacity was determined. Results:The polyphenols content of thirteen varieties apples were between 2.05 mg/g and 5.35 mg/g. Apple polyphenols of all varieties showed a strong scavenging effect of DPPH·,and a weak scavenging effect of NO₂^-·,·OH and O₂^-·,there was difference in total reduction capacity,pivona,nagafu 2,cameo,honggailu and yuhuazaofu showed the strongest antioxidant activity. A total of ten free phenols were determined in the thirteen apple polyphenols,the content of ellagic acid,chlorogenic acid and epicatechin were in a high level,and catechin,caffeic acid and protocatechic acid were in a low level. The antioxidant activities of ten free phenols were determined,and protocatechic acid,epicatechin and chlorogenic acid showed the strongest antioxidant activity. Conclusion:There had relationship between antioxidant activity and free phenols contents of apples polyphenols in different varieties.