Tea Polysaccharide And Anti - Oxidation Effect Of Calcium Binding And Level Structure

Tea polysaccharide (TPS) is one of major chemical compositions of tea. In recent ten years, it has been proved that TPS has many biological properties, such as depressing blood-glucose, blood lipid and blood-pressure, anticoagulation, antithrombus, combating inflammation, and enhancing immunological function. In this paper, TPS was isolated from coarse tea, a calcium- polysaccharide complex (Ca-TPS) was prepared, and effect of TPS and Ca-TPS on superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), superoxide anion and hydroxyl radical were studied. The results show that the effect tendency of TPS and Ca-TPS on the antioxidant enzymes is uniform. In a scoop of limited concentration, the activities of antioxidant enzymes were enhanced with the increase of the concentration of TPS and Ca-TPS, and the enzyme activities would decrease if the concentrations of TPS and Ca-TPS were too high. Respectively, TPS could increase the activities of SOD, POD, and CAT by 42%, 25% and 533%, and Ca- TPS could increase by 39%, 88%, 3 39%. The results also show that TPS and Ca-TPS have scavenging effects on free radicals. The effect trend is similar. TPS and Ca- TPS could significantly scavenge superoxide anion (0.7) and hydroxyl radical (OH), while the capacity of scavenging decreased in higher concentration. The highest inhibition percentage of TPS and Ca-TPS on Q respectively were 77% and 83%, and the strongest inhibiton effects of TPS and Ca-TPS on OH were 84% and 98%, respectively. The experimental results proved that TPS had antioxidant activity, which would not be influenced whether TPS bound calcium or not. The antioxidant effects of TPS and Ca-TPS may be by two ways. One is indirect effect by applying to antioxidant enzymes, another is direct effect by scavenging free radicals. The primary structure of TPS2 and Ca-TPS2 were analysed. When TPS and Ca-TPS were treated with dilute alkali, the absorption at 240 nm didn's increase. When sodium borohydride was added into the above reaction system, alanine and a -amtno-n-butyric acid did not increase, too. It is suggested that the polysaccharide chain is linked to peptide chain in TPS and Ca-TPS through N-glycosidic linkage. The structure of TPS2 was determined by periodate oxidation. The polysaccharide chain may be composed of 1→2,1→3,1→4,1→6 linked glycosyl group, in which the oxidable mode may be 1→2,1→4,1→6 linkage.