Production, preliminary characterization and antitumor activity (SKOV-3 cell lines) in vitro of glycans from green tea

Novel Targeted Anti-Tumor Nanoparticles Developed from Folic Acid-Modified 2-Deoxyglucose

The glucose analog, 2-deoxyglucose (2-DG), specifically inhibits glycolysis of cancer cells and interferes with the growth of cancer cells. However, the excellent water solubility of 2-DG makes it difficult to be concentrated in tumor cells. In this study, a targeted nano-pharmacosome was developed with folic acid-modified 2-DG (FA-2-DG) by using amino ethanol as a cleavable linker. FA-2-DG was able to self-assemble, forming nano-particles with diameters of 10–30 nm. The biological effects were evaluated with cell viability assays and flow cytometry analysis. Compared with a physical mixture of folic acid and 2-DG, FA-2-DG clearly reduced cell viability and resulted in cell cycle arrest. A computational study involving docking simulation suggested that FA-2-DG can dock into the same receptor as folic acid, thus confirming that the structural modification did not affect the targeting performance. The results indicated that the nano-pharmacosome consisting of FA-2-DG can be used for targeting in a nano-drug delivery system.

Tea Polysaccharide Prevents Colitis-Associated Carcinogenesis in Mice by Inhibiting the Proliferation and Invasion of Tumor Cells

The imbalance between cell proliferation and apoptosis can lead to tumor progression, causing oncogenic transformation, abnormal cell proliferation and cell apoptosis suppression. Tea polysaccharide (TPS) is the major bioactive component in green tea, it has showed antioxidant, antitumor and anti-inflammatory bioactivities. In this study, the chemoprophylaxis effects of TPS on colitis-associated colon carcinogenesis, especially the cell apoptosis activation and inhibition effects on cell proliferation and invasion were analyzed. The azoxymethane/dextran sulfate sodium (AOM/DSS) was used to induce the colorectal carcinogenesis in mice. Results showed that the tumor incidence was reduced in TPS-treated AOM/DSS mice compared to AOM/DSS mice. TUNEL staining and Ki-67 immunohistochemistry staining showed that the TPS treatment increased significantly the cell apoptosis and decreased cell proliferation among AOM/DSS mice. Furthermore, TPS reduced the expression levels of the cell cycle protein cyclin D1, matrix metalloproteinase (MMP)-2, and MMP-9. In addition, in vitro studies showed that TPS, suppressed the proliferation and invasion of the mouse colon cancer cells. Overall, our findings demonstrated that TPS could be a potential agent in the treatment and/or prevention of colon tumor, which promoted the apoptosis and suppressed the proliferation and invasion of the mouse colon cancer cells via arresting cell cycle progression.

Selenium-containing polysaccharides from Ziyang green tea ameliorate high-fructose diet induced insulin resistance and hepatic oxidative stress in mice

The present study was designed to evaluate the effects of selenium-containing tea polysaccharides (Se-GTP) from a new variety of selenium-enriched Ziyang green tea against high fructose (HF)-induced insulin resistance and hepatic oxidative stress in mice. Healthy male Kunming mice were fed 20% high fructose water and administered 200, 400 and 800 mg per kg bw Se-GTP for 8 weeks. Mice fed HF in drinking water displayed significant insulin resistance, hepatic steatosis and oxidative stress observed by hyperglycemia and hyperinsulinemia, as well as increases in hepatic non-esterified fatty acid (NEFA) and malonaldehyde (MDA). The administration of Se-GTP at 400 and 800 mg per kg bw significantly improved insulin sensitivity, and reduced liver steatosis and oxidative stress damage, and brought back the antioxidants and hepatic lipids towards near-normal values. In the oral glucose tolerance test, the administration of Se-GTP at 400 and 800 mg per kg bw had reduced plasma glucose concentrations after 30 min of glucose loading in HF-fed mice, suggesting that Se-GTP improved glucose intolerance. Histopathological examination indicated that the impaired pancreatic/hepatic tissues were effectively restored in HF-fed mice following the Se-GTP treatment. This is the first report showing that Se-GTP can ameliorate the high fructose-induced insulin resistance and hepatic oxidative injury.

A review on the structure-function relationship aspect of polysaccharides from tea materials

Tea (Camellia sinensis) has a long history of medicinal use in the world. The chemical components of tea mainly consist of polyphenols (TPP), proteins, polysaccharides (TPS), chlorophyll, alkaloids, and so on. Great advances have been made in chemical and bioactive studies of catechins and TPP from tea in recent decades. However, the TPS from tea materials have received much less consideration than that of TPP. The number of relevant publications on the TPS from tea leaves and flowers has increased rapidly in recent years. This mini-review summarizes the structure-function relationship of TPS from tea leaves and flowers. The application of purified TPS from tea material as functional or nutritional foods was still little. It will help to develop the function foods with tea TPS and better understand the structure-bioactivity relationship of tea TPS.