Preparation,Physicochemical Characteristics And Antioxidant Activity Of Polysaccharide From Gynostemma Pentaphyllum

Objective:To obtain the homogeneous polysaccharide from Gynostemma Pentaphyllum, extraction,separation and purification technology will be established and optimized. And itsphysicochemical properties and in vitro antioxidant activity will be studied. This studywill provide important reference value and experimental basis for the development andutilization of Gynostemma Pentaphyllum and polysaccharide which is one of theimportant active components of Gynostemma Pentaphyllum.Methods:1Single factor and response surface optimization method to determine the bestextraction technique. D301G macroporous resin adsorption and DEAE-52ion-exchangecolumn were used to obtain a homogenous polysaccharide.2The physicochemical characteristics of GPP were studied by HPLC, GPC, IR,elemental analysis, PMP derivatization HPLC method, Infrared spectrum analysis, etc.3Antioxidant activity in vitro were also been studied with the HO, ABTS, O2-,DPPH and hydroperoxide scavenging and iron chelatingassay.Results:1Single factor and response surface optimization method to determine the bestextraction technique for crude polysaccharides， which was purified to obtain ahomogenous polysaccharide (named GPP) with D301G macroporous resin adsorptionand DEAE-52ion-exchange column. The neutral sugars and uronic acid content ofGPP was respectively73.1%and23.9%through phenol sulfuric acid and hydroxyldiphenyl method.2The physicochemical characteristics of GPP were studied by HPLC，IR，etc. Noobvious absorption peaks were observed in ultraviolet spectrum at260nm and280nm.The elemental analysis result suggested that GPP did not contain nitrogen. It was showed a single symmetry peak in the plot of HPLC, and the purity was more than98.8%, which implied a homogenous polysaccharide. The molecular weight of GPP was2.52x103kDa with GPC method. It contained glucuronic acid，mannose，galactose,with little of xylose and rhamnose，measured by PMP derivatization HPLC method.Infrared spectrum analysis showed that carbon end group of GPP was alphaconfiguration.3GPP exhibited the effective HO, ABTS scavenging and iron chelating capacities.Conclusion:Results above implied that polysaccharides may one of active components ofGynostemma Pentaphyllum, and the homogeneous polysaccharide from GynostemmaPentaphyllum (GPP) may be used as a potential natural antioxidant.