Optimization of Polysaccharides Extraction from Lycopus lucidus Turcz. by Response Surface Methodology and Study on Its Antioxidant Activity

OBJECTIVE To optimize the technology parameters of polysaccharides extraction from Lycopus lucidus Turcz. by cellulase and ultrasound, and its antioxidant activity is analyzed. METHODS On the basis of single factor experiment, with liquid to material ratio(A), cellulase dosage(B), ultrasonic power(C) and ultrasonic temperature(D) as independent variables, and the extraction rate(Y) of Lycopus lucidus Turcz. polysaccharides as response value, the extraction process of polysaccharides from Lycopus lucidus Turcz. was optimized by response surface analysis with 4 factors and 4 levels, at the same time, the scavenging capacity of Lycopus lucidus Turcz. polysaccharides to DPPH free radical was also determined. RESULTS The optimum conditions for the extraction were:liquid to material ratio 60 mL·g^-1, cellulase dosage 3.6%, ultrasonic power 300 W, ultrasonic temperature 30℃, ultrasonic time 40 min, under these conditions, the extraction amount of polysaccharides from Lycopus lucidus Turcz. was (378.56±1.346)mg·g^-1, which was close to the predicted value(381.68 mg·g^-1). Lycopus lucidus Turcz. polysaccharides had a certain scavenging effect on DPPH free radical, and gradually increased with the increase of polysaccharides concentration. When the concentration of polysaccharides was 0.420 mg·mL^-1, the scavenging rate was 91.36%. CONCLUSION The parameters of polysaccharides extraction process optimized by response surface method are accurate and reliable, which can be used for the extraction of Lycopus lucidus Turcz. polysaccharides. Lycopus lucidus Turcz. polysaccharides has strong antioxidant capacity in vitro.