Green Tea and Cancer Prevention
Department of Chemical Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854-8020, USA. Nutrition and Cancer
(Impact Factor: 2.32).
10/2010; 62(7):931-7. DOI: 10.1080/01635581.2010.509536
Extracts of green tea and green tea polyphenols have exhibited inhibitory effects against the formation and development of tumors at different organ sites in animals. These include animal models for skin, lung, oral cavity, esophagus, stomach, intestine, colon, liver, pancreas, bladder, mammary gland, and prostate cancers. In addition to suppressing cell proliferation, promoting apoptosis, and modulating signaling transduction, green tea polyphenols, especially (-)-epigallocatechin-3-gallate, also inhibit cell invasion, angiogenesis, and metastasis. This article reviews data on the cancer preventive activities of green tea polyphenols, possible mechanisms involved, and the relationship between green tea consumption and human cancer risk.
Available from: Mohd Fadzelly Abu Bakar
- "Basically, tea can be found in many different forms depending on the method of preparation and level of fermentation such as green (unfermented), oolong (semi-fermented) and black (fermented) tea. Numerous scientific and detailed researches on tea have revealed the health promoting properties including prevention of chronic diseases such as cancer and cardiovascular disorder (Oak et al., 2005; Yang and Wang, 2010). Occurrence of chronic diseases were recognized to be associated with the oxidative stress, where the reactive oxygen species (ROS) and reactive nitrogen species (RNS) including free radicals were continuously produced in human cells and led to oxidative damage to cell components (Bagchi and Puri, 1998; Valavanidis et al., 2013). "
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ABSTRACT: Clinacanthus nutans (Burm. F.) Lindau or locally known in Sabah, Malaysia as ‘Sabah Snake Grass’ has been ethnobotanically used to treat various diseases in Asian countries. This study was conducted to determine the total phenolics content (TPC), flavonoids content (TFC) and antioxidant activity of herbal teas developed from C. nutans leaves with different drying techniques (microwave-oven dried and freeze dried) and infusion time (1, 2, 5, 10, 15 and 20 min). Ferric reducing/antioxidant power (FRAP) assay, 2,2’-azino-bis(3-ethylbenzothiazoline- 6-sulphonic acid (ABTS) and 2, 2-diphenyl-1-pycryl-hydrazyl (DPPH) free radical scavenging assays were used to investigate the antioxidant capacity. The highest TPC of herbal tea was observed in 20 min infusion of unfermented microwave-oven dried leaves (177.80 ± 19.10 mg TAE/L), while the highest TFC was observed in 10 min infusion of fermented microwave-oven dried leaves (22.13 ± 1.53 mg CE/L). Short infusion times from 5 min to 15 min were able to extract high amount of phenolics compounds. Unfermented tea contained higher TPC content (P < 0.05) as compared to fermented tea, while, TFC showed no significant difference between both types. Freeze dried infusion shows no significant difference (P > 0.05) as compared to microwave-oven dried for TPC, TFC and antioxidant capacity. Moderate and low correlation was observed between TPC and FRAP values (r = 0.507) and between TFC and ABTS values (r = 0.256). Preparation of C. nutans herbal tea as potential natural antioxidant source can be used as a basic reference for future research on the dietary intake of these herbal teas
Available from: Beatrice Feragalli
- "The phytochemical profile of tea depends on the extent of oxidation (fermentation in the tea lingo) of its catechin constituents, and most studies have focused on green tea that maintains the original polyphenolic profile of the leaves and is the source of sinecatechins, a registered drug for the topical management of genital warts . Cancer prevention  , weight loss  , and diabetes     are some of the other hot areas of clinical investigation where green tea catechins have proved potentially useful both as a stand-alone agent and in combination with lifestyle and pharmacological intervention strategies. "
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ABSTRACT: The beneficial effects of Greenselect Phytosome, a proprietary lecithin formulation of a caffeine-free green tea catechin extract, were evaluated in a controlled registry study on 50 asymptomatic subjects borderline for metabolic syndrome factors and with increased plasma oxidative stress. After 24 weeks of intervention, improvement in weight, blood lipid profile, and blood pressure positioned 68% of subjects in the treatment arm out of the metabolic syndrome profile, while 80% of the subjects in the control group still remained in their initial borderline disease signature. Compared to the control (lifestyle and dietary changes alone), Greenselect Phytosome was especially effective for weight/waist changes. These results highlight the relevance of addressing multiple factors involved in the development of metabolic syndrome with a pleiotropic agent capable of improving the beneficial effects of lifestyle and dietary changes and foster the attainment of a globally improved health profile.
Available from: PubMed Central
- "Consumption of green tea has been associated with improved prognosis of patients with breast cancer , and regular green tea consumption prior to breast cancer diagnosis is associated with decreased subsequent risk of recurrence . Polyphenols make up approximately 40% of the dry weight of green tea leaves, and include epigallocatechin-3 gallate (EGCG), a compound with significant anti-cancer qualities . As current treatment modalities for IBC are inadequate, here we tested for the first time the effects of EGCG on the distinct growth and dissemination properties of IBC cells in culture and on tumor growth in an orthotopic mouse model. "
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ABSTRACT: Inflammatory Breast Cancer (IBC) is a highly aggressive form of cancer characterized by high rates of proliferation, lymphangiogenesis and metastasis, and an overall poor survival. As regular green tea consumption has been associated with improved prognosis of breast cancer patients, including decreased risk of recurrence, here the effects of the green tea polyphenol epigallocatechin-3-gallate (EGCG) were tested on two IBC lines: SUM-149 and SUM-190. EGCG decreased expression of genes that promote proliferation, migration, invasion, and survival. Consistently, growth, invasive properties, and survival of IBC cells were reduced by EGCG treatment. EGCG also reduced lymphangiogenesis-promoting genes, in particular VEGF-D. Conditioned media from EGCG-treated IBC cells displayed decreased VEGF-D secretion and reduced ability to promote lymphangiogenesis in vitro as measured by hTERT-HDLEC lymphatic endothelial cell migration and tube formation. Tumorsphere formation by SUM-149 cells was robustly inhibited by EGCG, suggesting effects on self-renewal ability. Stem-like SUM-149 cells with high aldehyde dehydrogenase (ALDH) activity, previously implicated in poor patient prognosis, were isolated. EGCG treatment reduced growth and induced apoptosis of the stem-like SUM-149 cells in culture. In an orthotopic mouse model, EGCG decreased growth of pre-existing tumors derived from ALDH-positive stem-like SUM-149 cells and their expression of VEGF-D, which correlated with a significant decrease in peritumoral lymphatic vessel density. Thus, EGCG inhibits the overall aggressive IBC phenotype. Reduction of the stem-like cell compartment by EGCG may explain the decreased risk of breast cancer recurrence among green tea drinkers. Recent clinical trials demonstrate the efficacy of green tea polyphenol extracts in treatment of prostate cancer and lymphocytic leukemia with low toxicity. Given the poor prognosis of IBC patients, our findings suggest further exploration of EGCG or green tea in combinatorial treatments against active IBC disease or in maintenance regimens to avoid recurrence is warranted.
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