In this study, a water-soluble novel polysaccharide called TPS was successfully prepared and isolated from Liubao tea. The optimal extraction conditions resulted in a yield of 10.70% for the crude TPS. The purified TPS exhibited unique physicochemical properties and structural characteristics. It was identified as an acidic polysaccharide with trace binding proteins, with a →4)-α-D-Galp-(1→) residue. The purified TPS had a dense and uneven appearance, potential crystallisation characteristics, and structural stability. Importantly, it demonstrated the ability to inhibit glucose transport in Caco-2 cells by down-regulating the expression of sodium/glucose cotransporter 1 (SGLT1) and glucose transporter 2 (GLUT2), leading to a hypoglycemic effect. These findings highlight the potential of TPS from Liubao tea as a functional food or additive with hypoglycaemic properties.
Dai, L., Hu, W.W., Xia, L., Xia, M., and Yang, Q. (2016).Transmissible gastroenteritis virus infection enhances SGLT1 and GLUT2 expression to increase glucose uptake. Plos One, 11(11): e0165585.
Gorboulev, V., Schürmann, A., Vallon, V., Kipp, H., Jaschke, A., Klessen, D., Friedrich, A., Scherneck, S., Rieg, T., Cunard, R., Veyhl-Wichmann, M., Srinivasan, A., Balen, D., Breljak, D., Rexhepaj, R., Parker, H.E., Gribble, F.M., Reimann, F., Lang, F., Wiese, S., Sabolic, I., Sendtner, M., and Koepsell, H. (2012). Na(+)-D-glucose cotransporter SGLT1 is pivotal for intestinal glucose absorption and glucose-dependent incretin secretion. Diabetes, 61(1): 187–196.
Jones, R.B., Alderete, T.L., Kim, J.S., Millstein, J., Gilliland, F.D., and Goran, M.I. (2019). High intake of dietary fructose in overweight/obese teenagers associated with depletion of Eubacterium and Streptococcus in gut microbiome. Gut Microbes, 10(6): 712–719.
Kellett, G.L. and Brot-Laroche, E. (2005). Apical GLUT2: a major pathway of intestinal sugar absorption. Diabetes, 54(10): 3056–3062.
Lee, Y.E., Yoo, S.H., Chung, J.O., Park, M.Y., Hong, Y.D., Park, S.H., Park, T.S., and Shim, S.M. (2020). Hypoglycemic effect of soluble polysaccharide and catechins from green tea on inhibiting intestinal transport of glucose. Journal of the Science of Food and Agriculture, 100(10): 3979–3986.
Li, J., Wang, D., Xing, X., Cheng, T.-J.R., Liang, P.-H., Bulone, V., Park, J.H., and Hsieh, Y.S.Y. (2019). Structural analysis and biological activity of cell wall polysaccharides extracted from Panax ginseng marc. International Journal of Biological Macromolecules, 135: 29–37.
Liu, S., Ai, Z., Meng, Y., Chen, Y., and Ni, D. (2021). Comparative studies on the physicochemical profile and potential hypoglycemic activity of different tea extracts: effect on sucrase-isomaltase activity and glucose transport in Caco-2 cells. Food Research International, 148: 110604.
Oh, J.H., Lee, C.Y., Kim, J.E., Kim, W.H., Seo, J.W., Lim, T.G., Lee, S.Y., Chung, J.O., Hong, Y.D., Kim, W.G., Yoo, S.J., Shin, K.S., and Shim, S.M. (2021). Effect of characterized green tea extraction methods and formulations on enzymatic starch hydrolysis and intestinal glucose transport. Journal of Agricural and Food Chemistry, 69(50): 15208–15217.
Qin, H., Huang, L., Teng, J., Wei, B., Xia, N., and Ye, Y. (2021). Purification, characterization, and bioactivity of Liupao tea polysaccharides before and after fermentation. Food Chemistry, 353: 129419.
Qiu, S., Huang, L., Xia, N., Teng, J., Wei, B., Lin, X., and Khan, M.R. (2022). Two polysaccharides from Liupao tea exert beneficial effects in simulated digestion and fermentation model in vitro. Foods, 11(19): 2958.
Shen, S., Xu, Z., Feng, S., Wang, H., Liu, J., Zhou, L., Yuan, M., Huang, Y., and Ding, C. (2018). Structural elucidation and antiaging activity of polysaccharide from Paris polyphylla leaves. International Journal of Biological Macromolecules, 107(Pt B): 1613–1619.
Snoussi, C., Ducroc, R., Hamdaoui, M. H., Dhaouadi, K., Abaidi, H., Cluzeaud, F., Nazaret, C., Le Gall, M., and Bado, A. (2014). Green tea decoction improves glucose tolerance and reduces weight gain of rats fed normal and high-fat diet. Journal of Nutritional Biochemistry, 25(5): 557–564.
Wang, Q., Yang, X., Zhu, C., Liu, G., Sun, Y., and Qian, L. (2022). Advances in the utilization of tea polysaccharides: preparation, physicochemical properties, and health benefits. Polymers, 14(14): 2775.
Williamson, G. (2013). Possible effects of dietary polyphenols on sugar absorption and digestion. Molecular Nutrition & Food Research, 57(1): 48–57.
Wu, Y., Sun, H., Yi, R., Tan, F., and Zhao, X. (2021). Anti-obesity effect of Liupao tea extract by modulating lipid metabolism and oxidative stress in high-fat-diet-induced obese mice. Journal of Food Science, 86(1): 215–227.
Zhu, J., Chen, X., Li, F., Wei, K., Chen, J., Wei, X., and Wang, Y. (2022). Preparation, physicochemical and hypoglycemic properties of natural selenium-enriched coarse tea glycoproteins. Plant Foods for Human Nutrition, 77(2): 258–264.
Zhu, J., Chen, Z., Chen, L., Yu, C., Wang, H., Wei, X., and Wang, Y. (2019). Comparison and structural characterization of polysaccharides from natural and artificial Se-enriched green tea. International Journal of Biological Macromolecules, 130: 388–398.
Zhu, J., Chen, Z., Zhou, H., Yu, C., Han, Z., Shao, S., Hu, X., Wei, X., and Wang, Y. (2020a). Effects of extraction methods on physicochemical properties and hypoglycemic activities of polysaccharides from coarse green tea. Glycoconjugate Journal, 37(2): 241–250.
Zhu, J., Du, M., Wu, M., Yue, P., Yang, X., Wei, X., and Wang, Y. (2020b). Preparation, physicochemical characterization and identification of two novel mixed ACE-inhibiting peptides from two distinct tea alkali-soluble protein. European Food Research and Technology, 246(7): 1483–1494.
Zhu, J., Wu, M., Zhou, H.,Cheng, L., Wei, X., and Wang, Y. (2021a). Liubao brick tea activates the PI3K-Akt signaling pathway to lower blood glucose, metabolic disorders and insulin resistance via altering the intestinal flora. Food Research International, 148: 110594.
Zhu, J., Yu, C., Han, Z., Chen, Z., Wei, X., and Wang, Y. (2020c). Comparative analysis of existence form for selenium and structural characteristics in artificial selenium-enriched and synthetic selenized green tea polysaccharides. International Journal of Biological Macromolecules, 154: 1408–1418.
Zhu, J., Yu, C., Zhou, H., Wei, X., and Wang, Y. (2021b). Comparative evaluation for phytochemical composition and regulation of blood glucose, hepatic oxidative stress and insulin resistance in mice and HepG2 models of four typical Chinese dark teas. Journal of the Science of Food and Agriculture, 101(15): 6563–6577.
Zhu, J., Zhou, H., Zhang, J., Li, F., Wei, K., Wei, X., and Wang, Y. (2021c). Valorization of polysaccharides obtained from dark tea: preparation, physicochemical, antioxidant, and hypoglycemic properties. Foods, 10(10): 2276.