Abstract: The objective of this work was to evaluate the effect of tea polysaccharides (TPS, from Wuyuan green tea) on intestinal health and immune regulation in mice. Healthy C57/BL6 mice were randomly divided into four groups, and they were administrated by gavage with different concentrations of tea polysaccharides. After adaptive feeding for one week, the animals in these groups were given high, mediumand low doses of TPS and normal saline as blank control for 21 days, respectively. At the end of the experimental period, the mice were sacrificed, and spleen and thymus were harvested and weighted to calculate immune organ indexes. Peritoneal macrophages were used to examine phagocytosis activity by using neutral red phagocytosis assay. Short chain fatty acids (SCFAs) in colonic contents were analyzed by gas chromatography (GC) and ammonia by the indophenol blue colorimetric method. Meanwhile, the pH and water content of colonic contents were also measured. Results showed that immune organ indexes were increased significantly after TPS administration. The phagocytosis of peritoneal macrophages was improved in a dose-dependent manner. Some SCFAs (acetic acid, propionic acid and butyric acid) were increased while no difference in isobutyrate, pentanoic acid and delphinic acid was detected. A significant decline in the ammonia content and pH of colonic contents of mice was observed, while water content increased. Therefore, TPS can regulate immune function and promote intestinal health in mice.

Key words: tea polysaccharides, immune regulation, intestinal health