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Hypermethylation of CpG islands in the promoter regions is an important mechanism to silence the expression of many important genes in cancer. The hypermethylation status is passed to the daughter cells through the methylation of the newly synthesized DNA strand by 5-cytosine DNA methyltransferase (DNMT). We report herein that (-)-epigallocatechin-3-gallate(More)
(-)-Epigallocatechin-3-gallate (EGCG), the principal polyphenol in green tea, has been shown to inhibit the growth of many cancer cell lines and to suppress the phosphorylation of epidermal growth factor receptor (EGFR). We observed similar effects of EGCG in esophageal squamous cell carcinoma KYSE 150 cells and epidermoid squamous cell carcinoma A431(More)
(-)-Epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, has been shown to inhibit tumorigenesis and cancer cell growth in animal models. Nevertheless, the dose-response relationship of the inhibitory activity in vivo has not been systematically characterized. The present studies were conducted to address these issues, as well as the(More)
The present study was designed to investigate the effects of two main constituents of green tea, (-)-epigallocatechin-3-gallate (EGCG) and caffeine, on intestinal tumorigenesis in Apc(min/+) mice, a recognized mouse model for human intestinal cancer, and to elucidate possible mechanisms involved in the inhibitory action of the active constituent. We found(More)
(-)-Epigallocatechin-3-gallate (EGCG), the most abundant and biologically active compound in tea, has been extensively studied for its activities related to disease prevention in animal models and in vitro. However, its stability under different experimental conditions has not been well-characterized. In the present study, the stability of EGCG in animal(More)
Plant polyphenolic compounds are known to be strong antioxidants. Because oxidative stress is believed to contribute to many acute and chronic diseases, these polyphenols have been postulated to have many beneficial health effects, such as the prevention of cancer and cardiovascular diseases. Indeed, some of these beneficial effects have been demonstrated(More)
Syntheses are reported for metabolites M4 (1) and M6 (2) of the green tea polyphenols epicatechin (EC) and epigallocatechin (EGC) and their gallate derivatives. Several methoxy-derivatives of 1 and 2 were also prepared. Compounds 1 and 2 were evaluated for growth inhibitory activity against a panel of immortalized and malignant human cell lines with 1 being(More)
Derivatives based on a benzotropolone skeleton (9-26) have been prepared by the enzymatic coupling (horseradish peroxidase/H2O2) of selected pairs of compounds (1-8), one with a vic-trihydroxyphenyl moiety, and the other with an ortho-dihydroxyphenyl structure. Some of these compounds have been found to inhibit TPA-induced mice ear edema, nitric oxide (NO)(More)
The inhibition of carcinogenesis by tea and tea polyphenols has been demonstrated in different animal models by many investigators. The mechanisms of this inhibitory activity have also been investigated extensively, mostly in cell culture systems, but no clear conclusion can be reached concerning the cancer preventive mechanisms in vivo. In this article, we(More)