Optimization of Enzyme−Assisted Aqueous Extraction of Polysaccharide from Acanthopanax senticosus and Comparison of Physicochemical Properties and Bioactivities of Polysaccharides with Different Molecular Weights

To obtain the optimal process for the enzyme−assisted aqueous extraction of polysaccharides from Acanthopanax senticosus, and study the physicochemical properties of polysaccharides of different molecular weights, the extraction of Acanthopanax polysaccharides was optimized using the BBD response surface test. The polysaccharides with different molecular weights were obtained by ethanol−graded precipitation at 40%, 60%, and 80%, which were presented as ASPS40, ASPS60, and ASPS80. The polysaccharides were analyzed by HPGPC, ion chromatography, FT−IR, UV, SEM, TGA, XRD, Congo red, and I2−KI tests. The antioxidant assay was used to evaluate their antioxidant properties in vitro. The findings demonstrated that the recovery rate of Acanthopanax polysaccharide was 10.53 ± 0.682%, which is about 2.5 times greater compared to the conventional method of hot water extraction. Based on FT−IR, TGA, polysaccharides with different molecular weights did not differ in their structure or thermal stability. The XRD suggests that the internal structure of ASPSs is amorphous. Congo red and I2−KI showed that all three polysaccharides had triple helix structures with longer branched chains and more side chains. Furthermore, the antioxidant results showed the antioxidant activity of polysaccharides is not only related to the molecular weight size but also can be related to its composition and structure. These studies developed a green, and scalable method to produce polysaccharides from Acanthopanax senticosus and evaluated the properties of Acanthopanax polysaccharides of different molecular weights.