Effects of extraction methods on antioxidant and immunomodulatory activities of polysaccharides from superfine powder Gynostemma pentaphyllum Makino.

Superfine grinding (SG) technology has attracted considerable attention in food and medicine researcher fields. Polysaccharides in superfine powder of Gynostemma pentaphyllum Makino (GPP) were extracted using three methods, including hot water extraction (HWE), ultrasound-assisted hot extraction (UAE), and microwave-assisted hot extraction (MAE), and the purified polysaccharides were specially denoted as GPWP, GPUP, and GPMP, respectively. The possible structures of polysaccharides were investigated by FT-IR, HPLC and SEM. In addition, the antioxidative and immunomodulatory activities were evaluated by in vitro radical-scavenging activity assay and immune cell functional evaluation. We observed that the yield of GPUP (20.31%) was relatively higher than that of GPWP (15.34%) and GPMP (16.96%). Among all products, GPWP exhibited the highest antioxidative activities against DPPH, hydroxyl, and superoxide anion radicals. GPWP could also preferably chelate Fe These results indicate that the HWE method is an excellent technique for extracting GPP with high bioactivities that would be suitable for various industrial applications. Graphical Abstract.