Study On The Extraction And Purification Of Polysaccharides From Radix Isatidis, And Its Antioxidant Enhancement Activity In Vitro

In the present study, an effective negative pressure cavitation-microwave assisted extraction was designed to extract polysaccharide from Radix isatidis (RIPs), and the process for enrichment and purification by macroporous absorption resin was optimized. Moreover, the preliminary characterization of RIPs were performed and the antioxidant activity of RIPs were evaluated. Our study provided theoretical guidance and data support for the full development of RIPs.1. The optimum parameters of the Negative pressure cavitation-microwave assisted extraction (NMAE) process for the RIPs extraction were as follows:Liquid/solid ratio: 13 mL/gNegative pressure: -0.06 MpaMicrowave power: 500 WExtraction temperatures: 85℃Extraction time: 25 min Under these optimum extraction conditions, the extraction yields of RIPs reached 16.75%, the content of polysaccharide reached 67.83%. Compared with the tradition hot water extraction (HWE), the extraction yield was increased 4.82%, the content of polysaccharide was increased 25.34%, extraction temperature was decreased 39.5℃, extraction time was saved 200 min.2. The optimum parameters of ADS-11 macroporous resins for the RIPs purification were as follows:Type of resin: ADS-11Flow rate: 1 BV/hMaterial feeding ratio: 2:1Under the optimum conditions, the content of polysaccharides were reached 89.88%, the recovery yield of polysaccharides reached 86.74%. Compared with activated carbon method, sevag method, and H2O2 peroxide method, the content and recovery yield of RIPs were significantly increased by this method. Combined with the NMAE method, the recovery yield of RIPs was 109.8 mg/g.3. The preliminary characterization of RIPs were performed by FT-IR, and the monosaccharide compositions of RIPs were measured by GC-MS as follows:D-Lyxf (1.51%), D-Arap (13.11%), D-Fucf (6.61%), D-Fucp (6.94%), D-Galp (3.41%), GlcA (2.92%), D-Manp (39.30%), D-Talp (4.00%) and D-Glcp (22.20%). This result demonstrated that the RIPs were mainly composed of D-Manp, D-Glcp and D-Arap.4. DPPH scavenging activity test, ABTS radical scavenging activity test and reducing power test were applied to evaluate the antioxidant enhancement activity of RIPs. The results showed that the RIPs could be regard as an antioxidant enhancer to increase the antioxidant activity of chlorogenic acid.In conclusion, by the conjunction of negative pressure cavitation-microwave assisted extraction and macroporous resin purification technology, the extraction yield and content of RIPs were improved significantly. Moreover, the processes of extraction and purification were simplified, the inputs of resource and investment were reduced. This method have achieved the goal of the high efficient preparation of RIPs. This technology could provide materials for the utilizations of RIPs in the fields of drugs, foods, health products, functional products and cosmetics et al. And, this technology could also provide a new process for the industrial production of RIPs. Meanwhile, the preliminary characterization and monosaccharide composition analysis of RIPs was performed, which provided data support for the depth study of RIPs. In addition, this investigation demonstrated the antioxidant enhancement activity of RIPs, provided new scientific evidence and reference for the rational and efficient utilizations of RIPs resource.