Extraction of Snow Chrysanthemum Polysaccharides

The hot water extraction (HWE) was performed according to a previously reported method with some modifications [31 (link)]. Briefly, the snow chrysanthemum powders (1.0 g) were firstly refluxed with 10 mL of 80% (v/v) ethanol at 80 °C for 2 h to remove most of the small molecules. Subsequently, the snow chrysanthemum polysaccharides (SCPs) were extracted twice with 30 mL of deionized water at 90 °C for 2 h. After centrifugation at 4000× g for 15 min (Heraeus Multifuge X3R Centrifuge, Thermo Fisher scientific, Waltham, MA, USA), the supernatants were combined and concentrated to 1/3 of the origin volume by a rotary evaporator under a vacuum at 60 °C. Furthermore, the supernatants were precipitated with three volumes of 95% ethanol (v/v) overnight at 4 °C. The precipitations were washed with 70% ethanol (v/v) for three times and then dissolved in deionized water. Finally, the crude snow chrysanthemum polysaccharides (SCP-W) were freeze dried and stored at −20 °C for further analysis.