Ultrasonic enzymatic extraction of total flavonoids from Saussurea involucrata leaves and its antioxidant capacity analysis

Optimization of ultrasonic enzymatic extraction of total flavonoids from Saussurea involucrata leaves was studied by single factor and response surface experiments. The antioxidant capacity of the total flavonoids extracted from the leaves of S. involucrata was evaluated using the scavenging rate and total reducing power of DPPH·. The results showed that the best technology of total flavonoids from S. involucrata leaves by ultrasonic enzyme method was: adding the crushed leaves of S. involucrata to 30% ethanol solution, with the material liquid ratio 1:60 (g/mL) and the ultrasonic treatment at 50 °C, for 12 min. After adjusting the pH to 4.8, with the enzymatic hydrolysis for 66 min under the condition of cellulase concentration 0.40 mg/mL, the yield of total flavonoids was 6.317% under the technology. The total flavonoids extracted from the leaves of S. involucrata had antioxidant capacity, which was positively correlated with the concentration. DPPH· clearance rate reached 71.09% at 0.6 mg/mL, and the total reduction force closed to V. In conclusion, the extraction of total flavonoids from the S. involucrata leaves by ultrasonic wave enzyme method was feasible and effective, and the extraction rate was high. The total flavonoids extract had better antioxidant capacity.