| Objective: Extract, purify polysaccharides contained in grapevine bleeding sapselected from different area of Xinjiang and compare their content. Analysepolysaccharides structure and determine their antioxidant activity respectively. Method:1.Compare polysaccharide content by using anthrone-sulfuric acid method.2. Preparecrude polysaccharide using alcohol precipitation and by improved Sevage method.3.Purify the obtained crude polysaccharide by DEAE-52and Sephadex G-150columnchromatography.4. Study the physicochemical properties of the polysaccharides, analysethe monosaccharide composition and preliminary structural respectively by GC (gaschromatography) and UV, IR.5. Determine the antioxidant activity of polysaccharides invitro by applying the hydroxyl free radical, oxygen free radicals, DPPH radicals, nitrosoradicals，ABTS radicals. Results:1. Polysaccharides content is highest, up to816μg.mL-1in the Artux Munage grapevine bleeding sap, while it is lowest with18.3μg.mL-1in theTurpan Manaizi grapevine bleeding sap.2. The best condition to determine thepolysaccharide content in grapevine bleeding sap is to eliminate impurities byprecipitation using the20%alcohol, then get crude polysaccharides by80%alcoholprecipitation and remove proteins by using improved Sevage method.3. The crudepolysaccharides obtained from Kashgar and Turpan grapevine bleeding sap are separatedby DEAE-52, purified by SephadexG-150, and then eight relatively pure polysaccharidesare obtained. Their eluting peaks are unimodal and molecular weight varies between1.4×104-1×105.4. According to the physicochemical properties stdies, these purifiedpolysaccharides do not contain nucleic acids, or proteins and they have polysaccharidescharacteristic absorption peaks. From the result obtained by GC analysis, monosaccharidecomposition of GBSK-3polysaccharide is relatively simple and mainly composed ofxylose. GBST-5polysaccharide is composed of rhamnose, mannose, glucose, galactose;Polysaccharides GBSK-2, GBSK-5, GBST-3have similar monosaccharide compositionand they are mainly composed of rhamnose, arabinose, mannose, glucose, galactose; While the polysaccharides GBSK-1, GBST-1, GBST-2have similar monosaccharidecomposition and they are mainly composed of rhamnose, arabinose, xylose, mannose,glucose, galactose.5. All polysaccharides have antioxidant activity and they have highhydroxyl radical scavenging ability, but their scavenging abilities of four other radical arenot so high. Conclusion:1. Grapevine bleeding sap polysaccharide content is not onlydepends on the grapevine origin but also depends on the variety.2. Results show thatgrapevine bleeding sap polysaccharide isolation and purification by DEAE-52celluloseand SephadexG-150is effective; this indicates that this method is suitable for thegrapevine bleeding sap polysaccharide separation and purification.3. Results show thatthere are some difference between polysaccharides from Kashgar and Turpan grapevinebleeding sap in terms of molecular weight, monosaccharide composition and infraredspectrum, which confirms the differences in their biological activity.4. All grapevinebleeding sap polysaccharides have showed their antioxidant activity for all free radicals,especially high hydroxyl radical scavenging ability. |
