Analysis of Polyphenolic Content,Antioxidant Capacity and α-amylase Inhibitory Activity of Five Fruits

To explore the nutritional value and in vitro activity of fruit grown in the cold region. The total phenolic content and total anthocyanin content of five fruits(kiwiberry,black chokeberry,sour cherry,white currant and cranberry in the cold region)were determined,the antioxidant capacity and α-amylase inhibitory activity were compared,and their correlationship was analyzed. The results showed that there were significant differences in total phenolic content and total anthocyanin content in different fruits(P<0.05). The total phenolic content of five fruits ranged from 13.21 to 66.43 mg GAE/100 g,and the content of black chokeberry was the highest,following by white currant. The total anthocyanin content of five fruits ranged from 0.15 to 66.45 mg C3G/100 g,and the content of black chokeberry was also the highest while sour cherry was the second. In addition,their antioxidant capacity was also different. The antioxidant capacity of the white currant was the strongest,which was determined by DPPH,ABTS,ORAC and FRAP assays. The high-throughput turbidity method showed that different fruits had different inhibitory activities against α-amylase. The white currant had the strongest inhibitory activity against α-amylase,and IC₅₀value was 0.122 mg/mL,which was higher than that of acarbose(0.16 mg/mL). The AE value of white currant against α-amylase was 2034.18 mmol AE/g,which was equivalent to the acarbose(1550 mmol AE/g),and it was 42 to 127 times higher than that of the other three fruits(except for the black chokeberry with no inhibition). Correlationship analysis showed that there was a significant correlationship between total phenolic content,total anthocyanin content and antioxidant capacity of five fruits(P<0.01),and no significant correlation between TPC,TAC and α-amylase inhibitory activity.