Ultrasonic-assisted extraction, antimicrobial and antioxidant activities of Cyclocarya paliurus (Batal.) Iljinskaja polysaccharides

► Ultrasonic technology was used for polysaccharides extraction from C. paliurus. ► C. paliurus polysaccharide showed good antioxidant properties in vitro assays. ► C. paliurus polysaccharide demonstrated potent antimicrobial activity in vitro. ► C. paliurus polysaccharide can be explored as a novel natural antioxidant. Recently, renewed interest has grown in the use of ultrasonic-assisted extraction as an alternative approach to the traditional extraction methods. In this study, this novel extraction method was used to isolate polysaccharides from Cyclocarya paliurus (Batal.) Iljinskaja, and response surface methodology (RSM) was employed to optimize the extraction conditions. The optimal conditions for the extraction of polysaccharides were determined to be the ratio of liquid to solid of 8, extraction time of 59min and extraction temperature of 58°C. Under these optimal conditions, the yield of polysaccharides obtained was 4.91±0.11%, which was well matched with the value predicted by the model. In vitro antioxidant assays showed that the polysaccharides exhibited strong DPPH radicals (92.09% at 0.25mg/ml) and self-oxidation of 1,2,3-phentriol (37.22% at 1mg/ml) scavenging activities, moderate hydroxyl radicals (43.18% at 1mg/ml) scavenging activity and lipid peroxidation inhibitory effect (31.66% at 1mg/ml). In addition, the polysaccharides showed moderate antimicrobial activity.