Raction,Structural Characterization,and Inhibition Hela Cells Proliferation Of Functional Polysaccharides

Tea polysaccharides are a kind of complex polysaccharides with certain physiological activities.Studies have shown that tea polysaccharides can lower blood sugar and cholesterol levels,regulate immunity,increase antioxidant capacity and anti-fatigue ability.In this study,tea polysaccharides were extracted from the old leaves of tea tree for the first time using hydrothermal method.The extraction conditions of this method were studied.In addition,the preliminary structure analysis and in vitro anti-cancer research of purified tea polysaccharides provide a theoretical basis for the structural studies and functional applications of tea polysaccharides.The main contents and results are listed as follows:1.The hydrothermal method was used to extract the tea polysaccharides from Longjing-changye leaves.Process optimization of extraction time,extraction temperature and material-liquid ratio through single-factor test and orthogonal test.The results showed that the optimum extraction conditions were 90 min extraction time at 120°C with 1:25 g/mL of solid-liquid ratio.Under this condition,the yield of tea polysaccharide was 110.23 mg/g.2.Five fractions of functional polysaccharides were extracted by hydrothermal technology from Chinese tea Zhongcha 108,followed by purification using DEAE-52column chromatography.The results showed that after being eluted by DEAE-52 cellulose column,five components of tea polysaccharides F₀,F_0.1,F_0.2,F_0.3 and F_0.4 were obtained.Their structural characteristics were investigated by sugar analysis,GPC,FT-IR,AFM,methylation analysis and 2D HSQC NMR spectrum.The results showed that the functional polysaccharides from Chinese tea Zhongcha 108 were mainly consisted of acidic polysaccharide rich in glucuronic acid and neutral polysaccharides composition of rhamnose,galactose,and glucose.They had a backbone of 1,4-linked?-D-Glcp and 1,2,4-linked?-L-Rhap with side chains of 1-and 1,6-linked?-D-Galp at C-2 of?-L-Rhap.And the possible structure above 10 residues of F_0.3 consists of the sequence was given.3.Furthermore,anti-cancer activities of the polysaccharides were evaluated by inhibition assays of HeLa cells proliferation.It was found that the acidic polysaccharide F₀showed markedly increased effect while neutral polysaccharides F_0.1-F_0.3 exhibited markedly inhibitory effects on the proliferation of HeLa cells,the highest inhibition rate can reach up to10.43%treated by F_0.3 at 400 g/ml for 48 h.