ABSTRACT
OBJECTIVE This study aimed to optimize polysaccharides extraction from Urena lobata L.and investigate its antioxidant activity.METHODS The mathematical model was established by re-sponse surface method (RSM) based on the results of single factor experiments, using polysaccha-rides extraction rate as response value,and using the ratio of water to material,cellulase concentra-tion,extraction temperature and time as experimental factors,which was used to screen optimum poly-saccharide extraction conditions from Urena lobata L.. Antioxidant activity of polysaccharides was stud-ied by DPPH and ·OH free radical elimination method. RESULTS The optimum conditions obtained by RSM were as follows:the cellulase level was 10.8 g·L-1,extraction time duration was 72 min,the ra-tio of water to feedstock was 7 mL·g-1,extraction temperature was 43℃,the pH value was 5.0.Under the optimal conditions, there was a difference of less than 5％ between predicted extraction rate 13.37％ and experimental extraction rate 13.32％. The polysaccharide yield was most significantly af-fected by cellulase concentration,followed by extraction time,water to material ratio and extraction tem-perature.IC50of DPPH and·OH were 1.082 g·L-1and 3.202 mg·L-1,respectively.Antioxidant activity of sample polysaccharides was weaker than those of vitamin C. CONCLUSION The polysaccharide extraction process from Urena lobata L. by cellulase enzymolysis approach was obtained, which was convenient and feasible,and extracted polysaccharides had good free radical scavenging activity.