Extraction, Purification, Biological Activities Of Polysaccharides From The Fruiting Bodies Of Zizyphus Jujuba Cv. Yuanlingdazao

The polysaccharides extracted from the fruiting bodies of jujube have various potential biological activities that could be applied to food or medicine, such as antioxidant, antitumor antiviral, anticomplementary and immunological properties. The jujube (Zizyphus jujuba Miller), which belongs to the plant family Rhamnaceae, is widely used as food, food additives, flavors and traditional Chinese medicine in Asian countries, especially in China. Z. jujuba cv. Yuanlingdazao is one of eight cultivars, which was commonly planted in China. Z. jujuba cv. Yuanlingdazao is a kind of delicious and nutritious fruit. However, the studies of Z. jujuba cv. Yuanlingdazao have focused on the preservation and processing to enhance quality. There is little information relating to isolation, purification and activity determination of Z. jujuba cv. Yuanlingdazao. In the current work, we extracted polysaccharides from Z. jujuba cv. Yuanlingdazao (YP) and purified polysaccharides by chromatography on a DEAE-52cellulose anion-exchange column and Sephadex G-200gel column. The antioxidant and immunological activities in vitro of YP were also investigated. The main results were as follows:1. The polysaccharides were extracted from the Z.jujuba cv. yuanlingdazao by the method of hot-water and ultrasonic extraction technology. The optimal hot-water extraction conditions were liquid-solid ratio of20:1, extraction temperature of90℃and extraction time of5.3h. Under these conditions, the experimental yield of polysaccharides was5.27±0.03%. The results indicated that the order of the influence of the three factors on the yield of polysaccharides was extraction temperature, the liquid-solid ratio and extraction time. The interaction between ultrasonic power and extraction temperature was not significant. The interaction of every two other factors on the influence of the polysaccharide yield was significant.The optimal ultrasonic extraction conditions were ultrasonic power of360W, extraction time of40min, extraction temperature of55℃and liquid-solid ratio of12:1. Under these conditions, the experimental yield of polysaccharides was4.93±0.03%. The results indicated that the order of the influence of the four factors on the yield of polysaccharides was ultrasonic power, extraction time, extraction temperature and the liquid-solid ratio. The interaction between ultrasonic power and extraction temperature was not significant. The interaction between every two other factors on the influence of the polysaccharide yield was significant.2. The crude polysaccharides were applied to a DEAE-52cellulose anion-exchange column and a Sephadex G-200gel column and then obtained YP1a、YP2、YP3and YP4a. There were no absorption peaks at260nm and280nm, suggesting that the four purified fractions not contain nucleic acid and protein.3. HPGPC analysis revealed that the average molecular weight (Mw) of YPla, YP2, YP3and YP4a were2.02×104Da,8.95×10*Da,2.51×105Da and5.22×105Da. The results of monosaccharides composition were analyzed by GC. YP1a was composed of rhamnose, arabinose, glucose and galactose in a molar ratio of1:3.69:0.78:1.14. YP2was composed of rhamnose, arabinose and galactose in a molar ratio of1:2.49:1.82. YP3was composed of rhamnose, arabinose and galactose in a molar ratio of1:0.88:0.78. YP4a was composed of rhamnose and arabinose in a molar ratio of1:0.81. In comparison, arabinose was the main monosaccharide units for all the polysaccharide fractions.4. The antioxidant properties of crude polysaccharides and four purified polysaccharide fractions were evaluated based on the method of FRAP, DPPH radical scavenging activity, hydroxyl radical scavenging activity and superoxide anion scavenging activity. The results showed that the antioxidant properties of the polysaccharides would increase with the increasing concentration of polysaccharides. The crude polysaccharides had the strongest antioxidant properties. The antioxidant properties of YP2and YP4a were stronger than YP1a and YP3.5. The lymphocyte proliferation was assessed by using the MTT-based colorimetric assay. All the four purified polysaccharides could promote the lymphocyte proliferation depend of the concentration of polysaccharides. The degree of lymphocyte proliferation was different among the four purified polysaccharides. The lymphocyte proliferation of YP2were stronger than YP3and YP4a. YP1a and YP2had synergy with ConA.