Enzyme- assisted Extraction of Total Flavonoids from Folium Isatidis and Study on Antioxidant Effects

Enzyme- assisted extraction of total flavonoids from folium Isatidis was studied in this paper. Frist enzymatic hydrolysis by cellulase,and then reflux by ethanol to extract total flavonoids. Ethanol concentration of 70%,solid- liquid ratio of 1: 20 g /mL and reflux time of 2h were fixed. The preferred extraction conditions were determined by single factor experiment and orthogonal experiment. The experiment reveals that: cellulase concentration of 4U /mL,enzymatic hydrolysis pH of 4. 5,enzymatic hydrolysis temperature of 40℃ and enzymatic hydrolysis time of 1. 5 h. The extraction ratio of total flavonoids reached up to 2. 85 % by using spectrophotometry. Antioxidant effects of flavonoids and BHT were measured to remove hydroxyl radicals by comparative experiments. Antioxidant experiments showed that flavonoids from folium Isatidis showed a strong scavenging effect on hydroxyl radicals.