Green Tea Research Today is a free monthly online journal that collates and summarizes the latest research about Green Tea, including details on benefits, antioxidants, weight loss, diet, side effects.

Inhibition of Cyclophoshamide-Induced Mutagenicity by Microsized Powder of Selenium-Enriched Green Tea in Mice.

Xu J, Zhou J, Sheng J, Fang Y, Li F, Sun G, Hu Q

College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, Institute of Supervision and Inspection on Product Quality, Lianyungang Bureau of Quality and Technical Supervision, Lianyungang 222000, and Department of Nutrition and Food Hygiene, School of Public Health, Southeast University, Nanjing 210095, Peopleʼs Republic of China qiuhuihu@njau.edu.cn.

Previously, the antioxidant activity of Se-enriched green tea extracts has been studied in vitro. In the present study, an in vivo micronuclei test was employed to assess the antimutagenic effect of microsized Se-enriched green tea powder (MSTP) in mice bone marrow. Pretreatments of MSTP, micrometer-sized regular tea powder (MRTP), selenite, and MRTP + selenite were given by gavage for 29 consecutive days prior to cyclophoshamide (CP) treatment. Certain key antioxidant enzymes were also investigated to elucidate the mechanism of antimutagenic effect. Results indicated that MSTP and MRTP or selenite alone did not significantly induce micronuclei at either concentration, confirming its nonmutagenicity. In the CP-treated groups, significant suppressions in the micronuclei were recorded following pretreatment with MSTP, MRTP, and selenite administration. The antimutagenic effect of MSTP was evidently observed by significant reduction in the frequencies of micronuclei in bone marrow cells when compared to a positive control group. The administration of MSTP, selenite, and MRTP + selenite also increased the levels of selenium concentration, glutathione peroxidase (GPx), and superoxide dismutase (SOD) enzymes in both blood and liver. However, no pronounced differences in activities of GPx and SOD were found among MSTP, selenite, and MRTP + selenite. The present findings demonstrate that the antimutagenic potential of MSTP could not be solely related to the enhancment of antioxidant enzymes of GPx and SOD.

Published 25 April 2008 in J Agric Food Chem.
Full-text of this article is available online (may require subscription).

Articles on Green Tea published 25 April 2008:

Preparative isolation and purification of theaflavins and catechins by high-speed countercurrent chromatography.   J Chromatogr B Analyt Technol Biomed Life Sci.

High-speed countercurrent chromatography (HSCCC) has been applied for the separation of theaflavins and catechins. The HSCCC run was carried out with a two-phase solvent system composed of hexane-ethyl acetate-methanol-water-acetic acid (1:5:1:5:0.25, v/v) by eluting the lower aqueous phase at 2ml/min at 700rpm. The results indicated that pure theaflavin, theaflavins-3-gallate, theaflavins-3'-gallate and theaflavin-3,3'-digallate could be obtained from crude theaflavins sample and black tea. ... [Abstract] [Full-text]

Articles on Green Tea published 23 April 2008:

Transport of aspalathin, a Rooibos tea flavonoid, across the skin and intestinal epithelium.   Phytother Res, 22(5): 699-704.

Since Rooibos tea contains high levels of flavonoid antioxidants with potential health benefits when taken orally or applied topically, the quantity of the antioxidants crossing the physiological barriers is of scientific, clinical and commercial importance. This study investigated the in vitro transport of aspalathin, a unique flavonoid constituent of Rooibos tea, across intestinal epithelial cells and the human skin. The transport studies were conducted for both pure aspalathin solutions and ... [Abstract] [Full-text]

Effect of green tea and (-)-epigallocatechin gallate on ethanol-induced toxicity in HepG2 cells.   Phytother Res, 22(5): 669-674.

Despite the continuing reports supporting the hepatoprotective effects of green tea against ethanol intoxication, there remain controversies regarding the active compound(s) and molecular mechanism. These issues were addressed in the present study using cultured HepG2 cells exposed to a lethal dose of ethanol. Gamma-glutamyl transferase (GGT) was chosen as a marker of ethanol toxicity because it is widely used in clinics. When the cells were treated with ethanol at various concentrations, there ... [Abstract] [Full-text]

Articles on Green Tea published 22 April 2008:

GCG-Rich Tea Catechins are Effective in Lowering Cholesterol and Triglyceride Concentrations in Hyperlipidemic Rats.   Lipids, 43(5): 419-29.

The (-)-gallocatechin gallate (GCG) concentration in some tea beverages can account for as much as 50% of the total catechins, as a result of sterilization. The present study aims to examine the effects of GCG-rich tea catechins on hyperlipidemic rats and the mechanisms associated with regulating cholesterol metabolism in the liver. By performing heat epimerization of (-)-epigallocatechin gallate (EGCG), we manufactured a mixture of catechins that had a GCG content of approximately 50% (w/w). ... [Abstract] [Full-text]

Epigallocatechin-3-gallate (EGCG) inhibits the migratory behavior of tumor bronchial epithelial cells.   Respir Res, 9(1): 33.

ABSTRACT: BACKGROUND: Many studies associate the main polyphenolic constituent of green tea, (-)-Epigallocatechin-3-gallate (EGCG), with inhibition of cancers, invasion and metastasis. To date, most of these studies have focused on the effect of EGCG on cell proliferation or death. Since cell migration is an important mechanism involved in tumor invasion, the aim of the present work was to target another approach of the therapeutic effect of EGCG, by investigating its effect on the cell ... [Abstract] [Full-text]

Articles on Green Tea published 21 April 2008:

(-)-Epigallocatechin Gallate, A Major Constituent of Green Tea, Poisons Human Type II Topoisomerases.   Chem Res Toxicol, 21(4): 936-43.

(-)-Epigallocatechin gallate (EGCG) is the most abundant and biologically active polyphenol in green tea, and many of the therapeutic benefits of the beverage have been attributed to this compound. High concentrations of EGCG are cytotoxic and trigger genotoxic events in mammalian cells. Although this catechin affects a number of cellular systems, the genotoxic effects of several bioflavonoid-based dietary polyphenols are believed to be mediated, at least in part, by their actions on ... [Abstract] [Full-text]

(-)-Epigallocatechin gallate induces Nrf2-mediated-antioxidant enzyme expression via activation of PI3K and ERK in human mammary epithelial cells.   Arch Biochem Biophys.

The chemopreventive and chemoprotective activities of green tea have been attributed to the polyphenolic ingredient (-)-epigallocatechin-3-gallate (EGCG). Here, we report that treatment of human breast epithelial (MCF10A) cells with EGCG induces the expression of glutamate-cysteine ligase, manganese superoxide dismutase (MnSOD), and heme oxygenase-1 (HO-1). NF-E2-related factor (Nrf2) has been reported to regulate the antioxidant (ARE)-mediated expression of many antioxidant as well as ... [Abstract] [Full-text]

Articles on Green Tea published 17 April 2008:

Reaction Kinetics of Degradation and Epimerization of Epigallocatechin Gallate (EGCG) in Aqueous System over a Wide Temperature Range.   J Agric Food Chem, 56(8): 2694-701.

(-)-Epigallocatechin gallate (EGCG) is the most abundant catechin in green tea, which has been linked with many health benefits. To ensure the conceivable health benefits from thermally processed products, a kinetic study on the stability of (-)-EGCG in aqueous system was carried out using a HPLC-UV system and Matlab programming. Simultaneous degradation and epimerization of (-)-EGCG were characterized during isothermal reactions at low temperatures (25-100 degrees C) combined with previously ... [Abstract] [Full-text]

© 2004-2008 Green Tea Research Today. All Rights Reserved.