the Extraction of Flavonoids and Polyphenols from Vaccinium bracteatum Thunb.Leaves and Its Antioxidant Activity

The extraction process of flavonoids and polyphenols from Vaccinium oracteatum Thunb. leaves(VBTL) was optimized with response surface method and the antioxidant activity of the product was studied. The results showed that the optimal extraction conditions of flavonoids and polyphenols were 50% ethanol, liquid / solid ratio of 1∶41, extraction time of 50 min and extraction temperature of 83 ℃. Under these conditions, the yields of flavonoids and polyphenols were 33.4 and 23.5mg / g, respectively. Extracts from VBTL were found to have excellent DPPH· and ·OH scavenging activities with IC50 values of 4.8 and 11.3 μg / mL, respectively. It had stronger scavenging activity than VC had. It is indicated that the extracts have strong antioxidant capacity.