Abstract
In this study, ultrasonic-assisted enzymatic extraction (UAEE) method was used to obtain the small molecule dandelion polysaccharides. Based on single-factor experiments, the process of extraction the extraction conditions were further optimized by response surface method (RSM) combined with the Box-Behnken design (BBD). The results showed that in combination with enzymes, with a ratio of 1:32 (g/ml), an enzymolysis temperature 55 °C, an ultrasonic temperature 75℃ and the ultrasonic time 55 min. The maximum extraction yield of crude polysaccharides was 3.127 %.After purification by DEAE-cellulose chromatography and Sephadex G-75 gel filtration, a novel polysaccharide (DANP-Ⅱ) was extracted and the results of high performance liquid chromatography (HPLC) indicated its average molecular weight was 3.373 kDa. Gas chromatography (GC) analysis showed that DANP-Ⅱ was mainly contained by glucose and little of glucuronic acid, mannose, galactose, and arabinose. In vitro antioxidant experiments have demonstrated that DANP-Ⅱ can alleviate H2O2-induced cellular damage, reduce apoptosis rates, and exhibit robust antioxidant activity. Hence, DANP-Ⅱ can be utilized as a natural antioxidant to enhance protection against oxidative stress, providing theoretical guidance for the utilization of low-molecular-weight dandelion polysaccharides.