ABSTRACT
AIM To optimize the subcritical aqueous extraction for polysaccharides from the leaves of Punica granatum L.and to evaluate the in vitro antioxidant activity.METHODS With reaction pressure,solid-liquid ratio,extraction time and extraction temperature as influencing factors,yield of polysaccharides as an evalution index,the extraction was optimized by Box-Behnken method on the basis of single factor test.Then the scavenging effects of polysaccharides on hydroxyl free radical,superoxide anion and DPPH free radical were detected.RESULTS The optimal conditions were determined to be 5 MPa for reaction pressure,1 ∶ 27 for solid-liquid ratio,11 min for extraction time,and 155 ℃ for extraction temperature,the yield of polysaccharides was 1.809％.There was a dose-effect relationship between scavenging rate and polysaccharides' concentration.0.1 mg/mL Polysaccharides displayed the strongest scavenging effects on hydroxyl free radical,superoxide anion and DPPH free radical with the clearance rates of 57.36％,70.51％ and 58.02％,respectively.CONCLUSION This stable and reliable method can be used for the subcritical aqueous extraction for polysaccharides from P.granatum leaves with obvious in vitro antioxidant activity.
ABSTRACT
AIM To optimize the subcritical aqueous extraction for polysaccharides from the leaves of Punica granatum L.and to evaluate the in vitro antioxidant activity.METHODS With reaction pressure,solid-liquid ratio,extraction time and extraction temperature as influencing factors,yield of polysaccharides as an evalution index,the extraction was optimized by Box-Behnken method on the basis of single factor test.Then the scavenging effects of polysaccharides on hydroxyl free radical,superoxide anion and DPPH free radical were detected.RESULTS The optimal conditions were determined to be 5 MPa for reaction pressure,1 ∶ 27 for solid-liquid ratio,11 min for extraction time,and 155 ℃ for extraction temperature,the yield of polysaccharides was 1.809％.There was a dose-effect relationship between scavenging rate and polysaccharides' concentration.0.1 mg/mL Polysaccharides displayed the strongest scavenging effects on hydroxyl free radical,superoxide anion and DPPH free radical with the clearance rates of 57.36％,70.51％ and 58.02％,respectively.CONCLUSION This stable and reliable method can be used for the subcritical aqueous extraction for polysaccharides from P.granatum leaves with obvious in vitro antioxidant activity.