Dose-Dependent Levels of Epigallocatechin-3-Gallate in Human Colon Cancer Cells and Mouse Plasma and Tissues

Abstract

ABSTRACT:Epigallocatechin-3-gallate (EGCG; molecular formula: C 22 H 18 0 11 ) is the most abundant catechin in green tea (Camellia sinensis Theaceae). Both EGCG and green tea have been shown to have cancer-preventive activity in a number of animal models, and numerous mechanisms have been proposed based on studies with human cell lines. EGCG has been shown to undergo extensive biotransformation to yield methylated and glucuronidated metabolites in mice, rats, and humans. In the present study, we determined the concentration-dependent uptake of EGCG by HT-29 human colon cancer cells (

Epigallocatechin-3-gallate (EGCG) activates AMPK through the inhibition of glutamate dehydrogenase in muscle and pancreatic ß-cells: A potential beneficial effect in the pre-diabetic state?

“…EGCG stock solution (4 mM, Sigma-Aldrich) was prepared in 1 mM ascorbic acid and stored at −20 • C. Since EGCG is unstable and its concentration decreases rapidly in cell culture medium, with a half-life of about 30 min (Sang et al, 2005), 0.5 mM ascorbic acid was added freshly in all media and buffers used for treatment of islets, INS-1E cells, and myotubes (Lambert et al, 2006).…”

Regulation of Nrf2- and AP-1-mediated gene expression by epigallocatechin-3-gallate and sulforaphane in prostate of Nrf2-knockout or C57BL/6J mice and PC-3 AP-1 human prostate cancer cells

“…Since a desirable objective of using combinatorial approaches is to reduce the dose of the administered agents thereby reducing toxic side-effects, our dose selection of 25 μmol/L of SFN for the current study was guided by its proximity to the observed C max and its suboptimal effectiveness in eliciting transcriptional effects as compared to higher doses of SFN. Besides, in most studies, the concentrations needed to observe the activities of EGCG typically range from 1 to 100 μmol/L; these are, in reality, concentrations that exceed those found in rodent and human plasma by 10-to 100-fold [50,51] . However, the uptake of EGCG in HT-29 cells has also been shown to be concentration-dependent in the range of 20-600 μmol/L [50] .…”

“…Besides, in most studies, the concentrations needed to observe the activities of EGCG typically range from 1 to 100 μmol/L; these are, in reality, concentrations that exceed those found in rodent and human plasma by 10-to 100-fold [50,51] . However, the uptake of EGCG in HT-29 cells has also been shown to be concentration-dependent in the range of 20-600 μmol/L [50] .…”

“…In addition, we have also previously reported [33] that EGCG inhibited HT-29 cell growth with an IC 50 of approximately 100 μmol/L. Accordingly, we elected to test two doses of EGCG (20 and 100 μmol/L) in the current study in combination with the 25 μmol/L dose of SFN.…”

Effect of Green Tea Extract-Enriched Diets on Insulin and Leptin Levels, Oxidative Stress Parameters and Antioxidant Enzymes Activities in Obese Mice

“…Oral administration of GTE in our study was chosen as it represents the most common way of catechins intake. However, oral administration of catechins is characterized by low systemic bioavailability due to their poor absorption but high intestinal exposure [Lambert et al, 2003[Lambert et al, , 2006. Thus, except plasma, erythrocytes and liver, also small intestine was studied to obtain more complex information about the impact of the green tea extract in obese mice.…”