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Green tea: Potential health benefits

Department of Family Medicine, Maine Medical Center, Portland, Maine 04102, USA.
American family physician (Impact Factor: 1.82). 05/2009; 79(7):591-4.
Source: PubMed

ABSTRACT Green tea has been used widely and in high doses for centuries as a health tonic in many societies. Evidence suggests that green tea is effective for treating genital warts. There is some supportive evidence for the use of green tea in cancer prevention. Drinking green tea is associated with a decrease in all-cause mortality, but not in cancer-related mortality. Small clinical studies have found that green tea may also be helpful in losing and managing weight, and lowering cholesterol. Epidemiologic evidence suggests that green tea may prevent stroke and cardiovascular disease. Green tea appears to be safe, although there have been case reports of hepatotoxicity possibly related to a specific extract in pill or beverage form. Green tea seems to be a low-risk complementary therapy for a number of conditions, but more studies are needed.

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Available from: Craig Schneider, Feb 05, 2014
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    • "Green tea, a polyphenol-rich beverage has drawn much attention due to its health benefits in cardiovascular disease, diabetes, inflammatory diseases, and its prevention and treatment of cancer [21]. Green tea is rich in flavonoids and contains many catechins, including (-)- epigallocatechin-3-gallate (EGCG), which is the most abundant (~60%) catechin in green tea [22]. "
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    ABSTRACT: Aging is associated with impaired learning and memory accompanied by reductions in adult hippocampal neurogenesis and brain expression of neurotrophic factors among other processes. Epigallocatechin-3-gallate (EGCG, a green tea catechin), β-alanine (β-ala, the precursor of carnosine), and exercise have independently been shown to be neuroprotective and to reduce inflammation and oxidative stress in the central nervous system. We hypothesized that EGCG, β-ala supplementation or exercise alone would improve learning and memory and increase neurogenesis in aged mice, and the combined intervention would be better than either treatment alone. Male Balb/cByJ mice (19 mo) were given AIN-93M diet with or without EGCG (182mg/kg/d) and β-ala (417mg/kg/d). Half of the mice were given access to a running wheel (VWR). The first 10 days, animals received 50mg/kg bromodeoxyuridine (BrdU) daily. After 28 days, learning and memory was assessed by Morris water maze (MWM) and contextual fear conditioning (CFC). Brains were collected for immunohistochemical detection of BrdU and quantitative mRNA expression in the hippocampus. VWR increased the number of BrdU cells in the dentate gyrus, increased expression of brain-derived neurotrophic factor, decreased expression of the inflammatory cytokine interleukin-1β, and improved performance in the MWM and CFC tests. The dietary intervention reduced brain oxidative stress as measured by 4-hydroxynonenal in the cerebellum, but had no effect on BrdU labeling or behavioral performance. These results suggest that exercise, but not a diet containing EGCG and β-ala, exhibit pro-cognitive effects in aged mice when given at these doses in this relatively short time frame.
    Behavioural Brain Research 07/2014; 272. DOI:10.1016/j.bbr.2014.05.049 · 3.39 Impact Factor
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    • "). Recently, green tea has attracted attention due to its excellent performances in consumer health and even in weight management (Schneider and Segre 2009). Tea plant (Camellia sinensis (L.) O. Kuntze) is an evergreen perennial whose vegetative buds stop growing and develop dormancy in fall as a defence against chilling stress during winter in temperate regions. "
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    ABSTRACT: Tea plant (Camellia sinensis (L.) O. Kuntze) is an important cash crop. In temperate regions, bud dormancy in winter and budbreak in spring are important biological phenomena for the tea plant life cycle. To understand the molecular mechanism of dormancy maintenance and release in tea plant, the differentially expressed genes in dormant and sprouting axillary buds were investigated in two cultivars (special early-sprouting tea cultivar ‘Camellia sinensis cv. Longjing 43’ (‘LJ’) and late-sprouting tea cultivar ‘C. sinensis cv. Zhenghe Dabaicha’ (‘ZD’)), using suppression subtractive hybridization (SSH) approach. Four high performance complementary DNA (cDNA)-SSH libraries (‘LJ’ sprouting bud library, ‘LJ’ dormant bud library, ‘ZD’ sprouting bud library and ‘ZD’ dormant bud library) were constructed, and 1,736 valid ESTs were obtained, in which 1,242 ESTs were unique to the sprouting bud libraries and 494 ESTs were unique to the dormant bud libraries. Based on sequence matching and gene ontology analysis, 1,287 unigenes consisting of 208 contigs and 1,079 singletons were identified, in which 995 had Blast hits. The putative functions of differentially regulated sequences were involved in most aspects of plant biological processes. The quality and expression patterns of partial ESTs from these four libraries were validated by qRT-PCR. We identified numerous differentially expressed genes mainly involved in stress response, water metabolism, cell division regulation, energy metabolism and hormone regulation from dormant and sprouting bud libraries. This study provides general information on tea plant axillary bud dormancy and release at the transcriptional level and provides some hypotheses for further exploration on the mechanism of bud dormancy and budbreak in tea plant.
    Tree Genetics & Genomes 06/2014; 10(5). DOI:10.1007/s11295-014-0749-6 · 2.44 Impact Factor
    • "They are providing reddish tonality to black tea in contrast with green and white tea. The color of a black tea, however, is not only affected by the TRs, but some other intrinsic compounds like unoxidized polyphenols and TFs are also involved (Das et al., 2009; Schneider and Segre, 2009). Originally, TRs formation (Figure 1) is initiated after conversion of 75% the phenolic flavan-3-ol molecules from catechins. "
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    ABSTRACT: Dietary interventions are among the emerging trends to curtail physiological malfunctioning like cancer, diabetes, cardiac complications, etc. The essence of phytonutrients has developed the concept of nutraceuticals at the junction of diet health linkages. In this context, theaflavin & thearubigins are the oxidized derivatives of black tea catechins during fermentation having nutraceutical potential owing to esterification of hydroxyl ring with digallate esters. Theaflavin may influence activation of transcription factors such as NFnB or AP-1 that ultimately hinder the formation of nitric oxide expression gene. Likewise, black tea contains a unique amino acid theanine acts as neurotransmitter owing to its ability to cross the blood-brain barrier. Moreover, it boasts immunity by enhancing the disease-fighting ability of gamma delta T cells. Theaflavin & thearubigins act as safeguard against oxidative stress thereby effective in the cardiac functioning. The mechanistic approach of these antioxidants is likely to be associated with inhibition of redox sensitive transcription factors & pro-oxidant enzymes such as xanthine oxidase or nitric oxide synthase. However, their involvement in antioxidative enzyme induction as in glutathione-S-transferases is also well documented. They act as curative agent against numerous pathological disorders by disrupting the electron chain thus inhibiting the progression of certain ailments. Black tea polyphenols established themselves as strong antioxidants due to their standard one-electron potential, and their vitality is dependent on the concentration of polyphenols and pH for their inclusive execution. Present review is an attempt to enrich the readers regarding the health promoting aspects of black tea polyphenols. Concomitantly, it needs core attention of researchers for the exploitations of black tea flavanols as an important dietary constituent for the vulnerable segment.
    Critical reviews in food science and nutrition 02/2014; 54(8):1002-11. DOI:10.1080/10408398.2011.623198 · 5.55 Impact Factor
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