Hydrothermal extraction, structural characterization, and inhibition HeLa cells proliferation of functional polysaccharides from Chinese tea Zhongcha 108

Five subfractions of functional polysaccharides were extracted by hydrothermal technology from Chinese tea Zhongcha 108, followed by purification using DEAE-52 column chromatography. Their structural characteristics were investigated by sugar analysis, GPC, FT-IR, AFM, methylation analysis, and 2D HSQC NMR spectrum. The results showed that the tea functional polysaccharides 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 α-d-Glcp and 1,2,4-linked α-l-Rhap with side chains of 1- and 1,6-linked α-d-Galp substituted at C-2 of α-l-Rhap. Furthermore, anti-cancer activities of the polysaccharides were evaluated by inhibition assays of HeLa cells proliferation. Interestingly, it was found that the acidic polysaccharide showed markedly increased effect while neutral polysaccharides F0.1-F0.3 exhibited markedly inhibitory effects on the proliferation of HeLa cells, the highest inhibition rate can reach up to 10.43% treated by F0.3 at 400 μg/ml for 48 h.