| interactions between smoking and other exposures associated with lung cancer risk in women: diet and physical activity. | the objective of the study is to estimate the differences in the impact of diet and physical exercise on lung cancer risk in female nonsmokers vs. smokers, and reveal interactions, if any. in a hospital based case-control study, data collected by in-person interviews from 569 female lung cancer cases and 2120 controls were analyzed using unconditional logistic regression stratifying by appropriate factors. protective effects were observed for intake of milk/dairy products (or=0.57, 95%ci 0.35-0. ... | 2007 | 17203897 |
| bioactive saponins and glycosides. xxv. acylated oleanane-type triterpene saponins from the seeds of tea plant (camellia sinensis). | seven new acylated oleanane-type triterpene oligoglycosides, theasaponins a(4) (1), a(5) (2), c(1) (3), e(8) (4), e(9) (5), g(1) (6), and h(1) (7), were isolated from the seeds of japanese tea plant (camellia sinensis). the structures of 1-7 were elucidated on the basis of chemical and physicochemical evidence. | 2007 | 17202702 |
| protective effect of black tea polyphenols against 7,12-dimethylbenz[a]anthracene-induced genotoxicity and oxidative stress during hamster buccal pouch carcinogenesis. | abstract this study was designed to evaluate the protective effect of black tea polyphenols (polyphenon b) against genotoxicity and oxidative stress during 7,12-dimethylbenz[a]anthracene (dmba)-induced hamster buccal pouch (hbp) carcinogenesis. since the bone marrow reflects hematopoietic stress caused by tumor cells, we used the frequency of micronuclei, the extent of lipid peroxidation, and the status of antioxidants in the bone marrow plasma as intermediate biomarkers of oxidative stress. all ... | 2007 | 20020977 |
| age-related variations in flavonoid intake and sources in the australian population. | to estimate flavonoid intake in the australian population. | 2006 | 17125569 |
| black tea polyphenols protect against 7,12-dimethylbenz[a]anthracene-induced hamster buccal pouch carcinogenesis. | dietary chemoprevention has emerged as a cost-effective approach for cancer control. we evaluated the chemopreventive effects of black tea polyphenols (polyphenon-b) administration during the preinitiation phase of 7,12-dimethylbenz[a]anthracene (dmba)-induced hamster buccal pouch (hbp) carcinogenesis. the expression of proliferating cell nuclear antigen (pcna) in the buccal pouch and the concentration of lipid peroxides, protein carbonyl, and the antioxidant status in the buccal pouch, liver an ... | 2006 | 17120615 |
| inhibition of folic acid uptake by catechins and tea extracts in caco-2 cells. | in this present study it was aimed to determine whether the catechins contained in green tea and the whole extracts of camellia sinensis (theaceae) inhibit the uptake of folic acid by caco-2 cell monolayers. our results indicate that (-)-epigallocatechin 3-gallate (egcg) and (-)-epicatechin 3-gallate (ecg) inhibit cellular folic acid uptake with ic50 values of 34.8 micromol/l and 30.8 micromol/l, respectively. furthermore, green and black tea extracts were also found to inhibit folic acid uptake ... | 2007 | 17117344 |
| potential health benefits of green tea (camellia sinensis): a narrative review. | | 2013 | 17113495 |
| trapping reactions of reactive carbonyl species with tea polyphenols in simulated physiological conditions. | the carbonyl stress that leads to the formation of advanced glycation end products (ages) in diabetes mellitus has drawn much attention recently. reactive alpha-dicarbonyl compounds, such as glyoxal (go) and methylglyoxal (mgo), have been shown to be a high potential glycation agent in vitro and in vivo. in this study, epicatechins in green tea and theaflavins in black tea were found to be able to reduce the concentration of mgo in physiological phosphate buffer conditions. modified mgo derivati ... | 2006 | 17103374 |
| molecular targets of tea polyphenols in the cardiovascular system. | tea-derived polyphenols have attracted considerable attention in the prevention of cancer and cardiovascular diseases. in comparison to tumour cells, the elucidation of their molecular targets in cardiovascular relevant cells is still at the beginning. although promising experimental and clinical data demonstrate protective effects for the cardiovascular system, little information is actually available on how these beneficial effects of tea polyphenols are mediated at the cellular level. by affe ... | 2007 | 17020753 |
| mechanisms of cancer prevention by green and black tea polyphenols. | drinking green tea is associated with decreased frequency of cancer development. this review outlines the wide range of mechanisms by which epigallocatechin gallate (ecgc) and other green and black tea polyphenols inhibit cancer cell survival. egcg suppressed androgen receptor expression and signalling via several growth factor receptors. cell cycle arrest or apoptosis involved caspase activation and altered bcl-2 family member expression. egcg inhibited telomerase activity and led to telomere f ... | 2006 | 17017850 |
| the effects of tea on psychophysiological stress responsivity and post-stress recovery: a randomised double-blind trial. | tea has anecdotally been associated with stress relief, but this has seldom been tested scientifically. | 2007 | 17013636 |
| assessment of the polyphenolic composition of the organic extracts of mauritian black teas: a potential contributor to their antioxidant functions. | there is increasing interest in the emerging view that tea improves the antioxidant status in vivo and thereby helps to lower risk of certain types of cancer, coronary heart disease and stroke and its component biofactors could provide prophylactic potential for these diseases. the polyphenolic composition and the antioxidant properties of organic extracts (acetone/methanol) of mauritian commercial black teas were evaluated. hplc data of the individual compounds revealed remarkably high levels ( ... | 2006 | 17012766 |
| the effects of chronic tea intake on platelet activation and inflammation: a double-blind placebo controlled trial. | tea drinking appears to protect against the development of coronary heart disease (chd), but the mediating pathways are uncertain. we studied the effects of 6 weeks of black tea or placebo on platelet activation, c-reactive protein (crp), total antioxidant status, and soluble (s) p-selectin in a randomized double-blind trial. | 2007 | 17010979 |
| enhancement of erythrocyte antioxidants by green and black tea polyphenols during 7,12-dimethylbenz[a]anthracene-induced hamster buccal pouch carcinogenesis. | we evaluated the comparative chemopreventive efficacy of green tea polyphenols (polyphenon-e) and black tea polyphenols (polyphenon-b) on 7,12-dimethylbenz[a]anthracene (dmba)-induced hamster buccal pouch (hbp) carcinogenesis. lipid peroxidation, reduced and oxidized glutathione (gsh and gssg, respectively), and the gsh-dependent enzymes glutathione peroxidase and glutathione s-transferase in the erythrocytes were used as biomarkers of chemoprevention. enhanced lipid peroxidation in erythrocytes ... | 2006 | 17004901 |
| high-throughput analysis of catechins and theaflavins by high performance liquid chromatography with diode array detection. | increased interest in potential health-protective activities of flavonoid-rich tea has created the need to take advantage of hplc column and system advances in order to optimize methodologies for flavonoid analysis. two new rp-c18 methods for hplc-dad analysis of tea flavonoids were developed to facilitate separation of catechins within 5 min and separation of catechins and theaflavins within 10 min total analysis time. calibration results indicate that these methods have on-column limits of det ... | 2006 | 16919286 |
| adsorption of chlorhexidine and black tea onto in vitro salivary pellicles, as studied by ellipsometry. | the adsorption from 0.2% (w/w) chlorhexidine and black tea solutions onto an in vitro pellicle from whole unstimulated saliva on hydroxyapatite discs was studied by ellipsometry. it was found that chlorhexidine adsorbed to the pellicle and caused a modification of the pellicle properties, leading to a subsequent increase in adsorption of salivary and black tea components. there was a distinct order-of-addition effect, whereby chlorhexidine followed by black tea gave an overall greater adsorption ... | 2006 | 16911105 |
| [damage to and protection of sperm dna]. | the damage to sperm dna is one of the most important causes of male infertility. some sperm with damaged dna may escape from the sperm surveillance mechanism and transmit the damage to the offspring. so research on the damage to sperm dna has become one of the hot spots in reproductive medicine. the factors that would damage sperm dna include oxidative stress, microelements, reproductive toxic substances, radioactive rays, and so on, while the body depends on the compressed sperm dna and anti-ox ... | 2006 | 16894946 |
| epigallocatechin-3-gallate (egcg): chemical and biomedical perspectives. | the compound (-)-epigallocatechin-3-gallate (egcg) is the major catechin found in green tea [camellia sinensis l. ktze. (theaceae)]. this polyphenolic compound and several related catechins are believed to be responsible for the health benefits associated with the consumption of green tea. the potential health benefits ascribed to green tea and egcg include antioxidant effects, cancer chemoprevention, improving cardiovascular health, enhancing weight loss, protecting the skin from the damage cau ... | 2006 | 16876833 |
| black tea--helpful or harmful? a review of the evidence. | to consider whether consumption of black tea has a positive or negative impact on health. | 2007 | 16855537 |
| effect of liming and seasonal variation on lead concentration of tea plant (camellia sinensis (l.) o. kuntze). | tea is a widely consumed beverage. however, recent studies revealed that there were an increasing number of cases of tea products exceeding the former maximum permissible concentration (mpc) in china for pb (2 mg kg(-1)). tea pb contamination is an issue affecting trade and consumer confidence. root uptake of pb could contribute significantly to pb accumulation in tea leaves due to the strong acidity of many tea garden soils. we conducted pot and field experiments to evaluate the effect of limin ... | 2007 | 16844190 |
| isotheasaponins b1-b3 from camellia sinensis var. sinensis tea leaves. | three saponins, isotheasaponins b1-b3, were isolated from the leaves of the tea plant camellia sinensis var. sinensis, and their structures were determined to be theasapogenol b [beta-d-galactopyranosyl(1-->2)][beta-d-xylopyranosyl(1-->2)-alpha-l-arabinopyranosyl(1-->3)]-beta-d-gulcopyranosiduronic acid with two acyl groups by spectroscopic analysis. | 2006 | 16808937 |
| hepatotoxicity due to extracts of chinese green tea (camellia sinensis): a growing concern. | | 2006 | 16793166 |
| characterization of epoxydecenal isomers as potent odorants in black tea (dimbula) infusion. | in a black tea (dimbula) infusion, the potent "sweet and/or juicy" odorants were identified as the cis- and trans-4,5-epoxy-(e)-2-decenals by comparison of their gas chromatography retention indices, mass spectra, and odor quality to those of the actual synthetic compounds. of the two odorants, cis-4,5-epoxy-(e)-2-decenal has been identified for the first time in the black tea. on the basis of the aroma extract dilution analysis on the flavor distillate obtained using the solvent-assisted flavor ... | 2006 | 16787030 |
| nutritional risk factors for the development of chronic obstructive pulmonary disease (copd) in male smokers. | the aim of this study was to investigate whether nutritional risk factors, especially black tea consumptions, are inversely associated with the development of chronic obstructive pulmonary disease (copd) in male smokers. | 2006 | 16782241 |
| acute effect of black and green tea on aortic stiffness and wave reflections. | while most studies have shown an inverse relation between tea consumption and cardiovascular risk, other studies have shown opposite results. aortic stiffness and wave reflections are markers of cardiovascular disease and prognosticators of cardiovascular risk. | 2006 | 16766780 |
| copper (ii) ion selective liquid membrane electrode based on new schiff base carrier. | cu2+ selective pvc membrane electrode based on new schiff base 2, 2'-[1,9 nonanediyl bis (nitriloethylidyne)]-bis-(1-naphthol) as a selective carrier was constructed. the electrode exhibited a linear potential response within the activity range of 1.0 x 10(-6) - 5.0 x 10(-3) moll(-1) with a nernstian slope of 29 +/- 1 mv decade(-1) of cu2+ activity and a limit of detection 8.0 x 10(-7) mol l(-1). the response time of the electrode was fast, 10 s, and stable potentials were obtained within the ph ... | 2016 | 16734023 |
| metabolite profiling and characterization of somaclonal variants in tea (camellia spp.) for identifying productive and quality accession. | a study has been undertaken to characterize 15 field grown somaclonal variants derived from cotyledonary tissues of upasi-10 using morphological, physiological and biochemical characters. although variants were derived from upasi-10, a very few variants possessed unique "chinery" characters while others exhibited "assam" characters. however, no variant showed identical morphological characters aligning with the parent. somaclonal variants showed distinct variation in terms of photosynthetic carb ... | 2006 | 16714038 |
| selected diet and lifestyle factors are associated with estrogen metabolites in a multiracial/ethnic population of women. | diet and lifestyle factors, body size, and smoking behavior may influence estrogen metabolism, but the nature of these relations may vary according to race/ethnic groups. we evaluated the association of lifestyle factors with estrogen metabolites 2-hydroxyestrone (2-ohe1) and 16alpha-hydroxyestrone (16alpha-ohe1) in a racially diverse population. with a cross-sectional study design, urine samples from 1881 african-american, caucasian, chinese, japanese, and hispanic women, aged 42-52 y, from the ... | 2006 | 16702326 |
| modulation of aromatase activity by diet polyphenolic compounds. | estrogens are involved in physiological actions related to reproduction, body fat distribution, and maintenance of bone mass and are also related to the pathogenesis of estrogen-dependent cancers. the aim of this work was to study the effect of polyphenols on estrogen synthesis. the effect of polyphenols and polyphenolic-rich beverages on aromatase activity was tested in jar cells (a choriocarcinoma cell line) through the tritiated water release assay. some of the tested polyphenols inhibited es ... | 2006 | 19127721 |
| the effect of green tea in oxidative stress. | green tea, an infusion prepared with the leaves of camellia sinensis is particularly rich in flavonoids, which are strong antioxidants. tea drinking, by providing antioxidants, may become valuable in several oxidative stress conditions. our aim was to evaluate the effect of green tea drinking on some factors reflecting the development of oxidative stress in plasma and in erythrocytes. | 2006 | 16698148 |
| black tea extract and its major polyphenolic pigment may ameliorate the gastrointestinal disorder in irritable bowel syndrome. | | 2006 | 16678978 |
| comparison of the antioxidant activity of roasted tea with green, oolong, and black teas. | although the antioxidant properties of green, oolong, and black teas have been well studied, antioxidant activity has not been examined in roasted tea. therefore, in the current studies, we investigated the antioxidant activity of roasted tea in comparison with those of green, oolong, and black teas. using water extracts of the various teas, we examined the total phenolic content as well as the antioxidant activities, including the reducing power, the 1,1-diphenyl-2-picrylhydrazyl (dpph) radical ... | 2005 | 16638659 |
| high tea consumption diminishes salivary 17beta-estradiol concentration in polish women. | we hypothesized that among reproductive-age women consuming large quantities of tea, the production of estradiol would be suppressed. it has been shown that catechins and theaflavines, the major constituents of tea, inhibit aromatase, an enzyme which catalyses the conversion of androgens to oestrogens. our study included polish women living in urban (n 61) and rural (n 48) areas. women collected daily saliva samples for one complete menstrual cycle and filled out dietary questionnaires. saliva s ... | 2006 | 16611391 |
| potent inhibitory effects of black tea theaflavins on off-odor formation from citral. | the present study was conducted to investigate the ability of black tea theaflavins to inhibit the off-odor formation from citral under acidic aqueous conditions. acidic buffer solutions (ph 3.0) containing citral (10 mg/l) and an inhibitor (0-5 mg/l) were stored at 40 degrees c for 2 weeks. the formation of possible off-odorants p-cresol and p-methylacetophenone in the citral solutions was monitored by high-performance liquid chromatography. a mixture of the theaflavins showed inhibitory effect ... | 2006 | 16608230 |
| induction of neutral endopeptidase (nep) activity of sk-n-sh cells by natural compounds from green tea. | deposition of amyloid beta-peptide as senile plaques in the brain is one of the neuropathological hallmarks of alzheimer's disease, which is the most prevalent progressive neurodegenerative disease leading to dementia. neutral endopeptidase is one of the major beta-amyloid-degrading enzymes in the brain. to examine the influence of different polyphenols and other natural products from green tea extract (from camellia sinensis, theaceae), we used the neuroblastoma cell line sk-n-sh and studied th ... | 2006 | 16597367 |
| metabolic effects of spices, teas, and caffeine. | consumption of spiced foods or herbal drinks leads to greater thermogenesis and in some cases to greater satiety. in this regard, capsaicin, black pepper, ginger, mixed spices, green tea, black tea and caffeine are relevant examples. these functional ingredients have the potential to produce significant effects on metabolic targets such as satiety, thermogenesis, and fat oxidation. a significant clinical outcome sometimes may appear straightforwardly but also depends too strongly on full complia ... | 2006 | 16580033 |
| preconcentration system for cadmium and lead determination in environmental samples using polyurethane foam/me-btanc. | in this work, polyurethane foam (puf) loaded with 2-(6'-methyl-2'-benzothiazolylazo)chromotropic acid (me-btanc) was packed in a minicolumn and it was used in an on-line preconcentration system for cadmium and lead determination. optimum hydrodynamic and chemical conditions for metal sorption were investigated. the effects of several foreign substances on the adsorption of cadmium and lead were also reported. the enrichment factor obtained was 37 (cd and pb) for 180 s preconcentration time. the ... | 2006 | 16530947 |
| fluoride levels in various black tea commodities: measurement and safety evaluation. | in order to determine the fluoride content of various products of black tea and to make safety evaluations, 37 commodities in the different manufactured forms of tea were assessed by means of ion-selective electrode and spectrophotometric methods. the results showed wide differences in fluoride levels. the fluoride content was found 0.95-1.41 mg/l in black tea sticks, 0.70-2.44 mg/l in black tea granules and 1.15-6.01 mg/l in black tea bags. of the products tested, the fluoride content was great ... | 2006 | 16510229 |
| effects of tea polyphenols on emulsification of olive oil in a small intestine model system. | tea catechins have been shown to reduce plasma cholesterol and suppress hypertriacylglycerolemia by reducing triglyceride absorption. however, the mechanism is not yet clear. one of the possible mechanisms is that tea polyphenols may modify dietary fat emulsification in the gastrointestinal tract. the digestive enzyme (lipase) acts on specific emulsion interface properties (droplet size and surface area). therefore, changes in these properties may modify emulsification and lead to changes in die ... | 2006 | 16506852 |
| 5s rdna gene diversity in tea (camellia sinensis (l.) o. kuntze) and its use for variety identification. | variability in the organization of repeats of 5s rdna is useful for phylogenetic studies in various crops. we found variable repeats of 5s rdna gene in the genome of tea (camellia sinensis (l.) o. kuntze) during southern hybridization. variability in the repeats of 5s rdna with specific restriction endonucleases (sau3ai, bamhi, and apoi) was analyzed in 28 different tea clones representing 3 types of tea. our results clearly show that the 5s rdna gene in tea could be used as a molecular marker t ... | 2006 | 16462906 |
| clinical studies to determine the effectiveness of a whitening toothpaste at reducing stain (using a forced stain model). | two single centre, randomized single-blind, crossover studies were performed, to compare the effect of a test toothpaste with a conventional fluoride paste in the inhibition and removal of extrinsic dental stain promoted by repeated chlorhexidine/tea rinses. | 2005 | 16451374 |
| characterization of the key aroma compounds in the beverage prepared from darjeeling black tea: quantitative differences between tea leaves and infusion. | by application of the aroma extract dilution analysis on the volatile fraction isolated from a black tea infusion (darjeeling gold selection), vanillin (vanilla-like), 4-hydroxy-2,5-dimethyl-3(2h)-furanone (caramel), 2-phenylethanol (flowery), and (e,e,z)-2,4,6-nonatrienal (oat-flake-like) were identified with the highest flavor dilution (fd) factors among the 24 odor-active compounds detected in the fd factor range of 4-128. quantitative measurements performed by means of stable isotope dilutio ... | 2006 | 16448203 |
| stimulated parametric emission microscopy. | we propose a novel microscopy technique based on the four-wave mixing (fwm) process that is enhanced by two-photon electronic resonance induced by a pump pulse along with stimulated emission induced by a dump pulse. a ti:sapphire laser and an optical parametric oscillator are used as light sources for the pump and dump pulses, respectively. we demonstrate that our proposed fwm technique can be used to obtain a one-dimensional image of ethanol-thinned coumarin 120 solution sandwiched between a ho ... | 2006 | 19503398 |
| the role of tea and tea flavonoids in cardiovascular health. | consumption of green or black tea has been inversely associated with the development and progression of cardiovascular diseases. in this review, the current knowledge about protective effects of tea and tea constituents, particularly flavonoids, on the cardiovascular system is summarized. underlying mechanisms for the beneficial effects of tea include vasculoprotective, antioxidative, antithrombogenic, anti-inflammatory, and lipid-lowering properties of tea flavonoids. although promising experim ... | 2006 | 16404706 |
| catechin transformation as influenced by aluminum. | polyphenols (catechins) are vital biomolecules in tea plants (camellia sinensis), which are well-known as typical al accumulators. however, the interaction between al and catechin remains obscured. the objective of the present study was to investigate the effect of al on the transformation of (+)-catechin. solutions with oh/al molar ratios of 2.5 (ph 5.5) and 3.0 (ph 7.0) prepared at al/catechin molar ratios (r) of 0, 0.2, 0.4, 0.6, 0.8, and 1.0 were aged for 7 and 30 days, respectively. the pre ... | 2006 | 16390201 |
| hepatotoxicity associated with supplements containing chinese green tea (camellia sinensis). | | 2006 | 16389263 |
| green tea consumption in everyday life and mental health. | green tea has been widely acknowledged in japan to induce a pleasurable mental feeling. recent laboratory studies have suggested positive psychological effects as a result of consuming green tea. the present study examined whether green tea consumption in everyday life in japan is associated with positive mental health. | 2005 | 16372926 |
| the effect of an herbal supplement containing black tea and caffeine on metabolic parameters in humans. | the objective of this study was to test an herbal supplement containing black tea (the fully oxidized form of camellia sinensis) and caffeine for stimulation of thermogenesis. | 2005 | 16366740 |
| consumption of coffee, but not black tea, is associated with decreased risk of premenopausal breast cancer. | caffeine has been suggested as a possible risk factor for breast cancer, potentially through its effect of facilitating the development of benign breast disease. however, coffee and tea also contain polyphenols, which exhibit anticarcinogenic properties. a hospital-based, case-control study was conducted to evaluate the role of coffee, decaffeinated coffee, and black tea in breast cancer etiology. study participants included 1932 cases with primary, incident breast cancer and 1895 hospital contr ... | 2006 | 16365077 |
| genetic integrity of somaclonal variants in tea (camellia sinensis (l.) o kuntze) as revealed by inter simple sequence repeats. | adoption of inter simple sequence repeats (issr) technique to analyze the genetic variability of somatic embryo derived tea plants was evaluated. morphological characterisation of the field grown plants revealed no identical character aligning with the parent, upasi-10. out of 40 primers, 15 exhibited concurrent polymorphism were selected for the study. genetic variability of somaclones derived from single line cotyledonary culture ranged from 33.0 to 55.0%. a unique fragment of 1.2kb was visibl ... | 2006 | 16360228 |
| tealeaves may release or absorb fluoride, depending on the fluoride content of water. | as the tea plant (camellia sinensis) is known to accumulate fluoride from the soil, the tealeaves may contain high concentrations of fluoride, which is easily released during infusion. in this study, we have tested the possible effect of original fluoride concentration in the water on the fluoride release from tea. moreover, we wanted to test the possible capacity of tealeaves (commercially available tea) to absorb fluoride from high-fluoride water. in low-fluoride water, fluoride is easily rele ... | 2006 | 16356534 |
| theaflavin-3, 3'-digallate induces epidermal growth factor receptor downregulation. | black tea is one of the most popular beverages worldwide and especially in western nations. theaflavins, a mixture of theaflavin (tf-1), theaflavin-3-gallate (tf-2a), theaflavin-3'-gallate (tf-2b), and theaflavin-3,3'-digallate (tf-3) are the major components of black tea. among these black tea components, theaflavin is generally considered to be the more effective component for the inhibition of carcinogenesis. recently, tf-3 has been shown to have an antiproliferative effect on tumor cells, bu ... | 2006 | 16353237 |
| tea consumption and ovarian cancer risk in a population-based cohort. | substantial evidence from laboratory studies indicates that green and black tea preparations may protect against various cancers. few epidemiologic studies, however, have examined the relationship specifically between tea consumption and risk of ovarian cancer. | 2016 | 16344429 |
| copper(ii)-selective fluorimetric bulk optode membrane based on a 1-hydroxy-9,10-anthraquinone derivative having two propenyl arms as a neutral fluorogenic ionophore. | a new optical chemical sensor has been developed for the selective determination of copper(ii) ions in aqueous solutions. the reversible sensing system was prepared by incorporating 1-hydroxy-2-(prop-2'-enyl)-4-(prop-2'-enyloxy)-9,10-anthraquinone (aq) as a neutral cu2+-selective fluoroionophore in the plasticized pvc membrane with potassium tetrakis(p-chlorophenyl borate) as an anionic additive. the response of the sensor is based on the fluorescence quenching of aq by cu2+ ions. at a ph 5.5, t ... | 2006 | 16344241 |
| stereoselective oxidation at c-4 of flavans by the endophytic fungus diaporthe sp. isolated from a tea plant. | the microbial transformation of five flavans (1-5) by endophytic fungi isolated from the tea plant camellia sinensis was investigated. it was found that the endophytic filamentous fungus diaporthe sp. oxidized stereoselectively at c-4 position of (+)-catechin (1) and (-)-epicatechin (2) to give the correspondent 3,4-cis-dihydroxyflavan derivatives (6, 10), respectively. (-)-epicatechin 3-o-gallate (3) and (-)-epigallocatechin 3-o-gallate (4) were also oxidized by the fungus into 3,4-dihydroxyfla ... | 2005 | 16327190 |
| green tea, black tea and breast cancer risk: a meta-analysis of epidemiological studies. | experimental studies have shown that tea and tea polyphenols have anti-carcinogenic properties against breast cancer. a number of epidemiologic studies, both case-control and cohort in design, have examined the possible association between tea intake and breast cancer development in humans. this meta-analysis included 13 papers which examined populations in eight countries and provided data on consumption of either green tea or black tea, or both in relation to breast cancer risk. summary odds r ... | 2006 | 16311246 |
| copper(ii)-selective fluorimetric bulk optode membrane based on a 1-hydroxy-9,10-anthraquinone derivative having two propenyl arms as a neutral fluorogenic ionophore. | a new optical chemical sensor has been developed for the selective determination of copper(ii) ions in aqueous solutions. the reversible sensing system was prepared by incorporating 1-hydrpxy-2-(prop-2'-enyl)-4-(prop-2'-enyloxy)-9,10-anthraquinone (aq) as a neutral cu2+-selective fluoroionophore in the plasticized pvc membrane with potassium tetrakis(p-chlorophenyl borate) as an anionic additive. the response of the sensor is based on the fluorescence quenching of aq by cu2+ ions. at a ph 5.5, t ... | 2006 | 16307904 |
| more tea for septic patients?--green tea may reduce endotoxin-induced release of high mobility group box 1 and other pro-inflammatory cytokines. | despite recent advances in antibiotic therapy and intensive care, sepsis remains widespread problems in critically ill patients. the high mortality of sepsis is in part mediated by bacterial endotoxin, which stimulates macrophages/monocytes to sequentially release early (e.g., tnf, il-1, and ifn-gamma) and late (e.g., hmgb1) pro-inflammatory cytokines. in light of our recent discovery of hmgb1 as a late mediator of lethal systemic inflammation, and the observation that green tea (camellia sinens ... | 2006 | 16266789 |
| black tea may be as good as green. | | 2005 | 16259081 |
| puerins a and b, two new 8-c substituted flavan-3-ols from pu-er tea. | pu-er tea is a special treated fermented tea produced from crude green tea, which is prepared from the leaves of camellia sinensis var. assamica. it is a traditional beverage having been used in china, particularly the southern areas, for a long time. chemical investigation led to the identification of two new 8-c substituted flavan-3-ols, puerins a (1) and b (2), and two known cinchonain-type phenols, epicatechin-[7,8-bc]-4alpha-(4-hydroxyphenyl)-dihydro-2(3h)-pyranone (3) and cinchonain ib (4) ... | 2005 | 16248561 |
| analytical separation of tea catechins and food-related polyphenols by high-speed counter-current chromatography. | high-speed counter-current chromatography (hsccc) using the type-j coil planet centrifuge was applied to compositional analysis of tea catechins and separation of other food-related polyphenols. the hsccc separation of nine different standard compounds and those from extracts of commercial tea leaves was performed with a two-phase solvent system composed of tert-butyl methyl ether-acetonitrile-0.1% aqueous trifluoroacetic acid (tfa) (2:2:3, v/v/v) by eluting the upper organic phase at a flow rat ... | 2006 | 16239007 |
| green tea leaf extract improves lipid and glucose homeostasis in a fructose-fed insulin-resistant hamster model. | the present study evaluated the effect of green tea (camellia sinensis l.) leaf extract on triglyceride and glucose homeostasis in a fructose-fed hypertriglyceridemic, insulin-resistant hamster model. there was a significant decrease in plasma triglyceride levels following supplementation of the green tea epigallocatechin gallate-enriched extract (42% at 150 mg/(kg day) to 62% at 300 mg/(kg day) for 4 weeks). compared to baseline, the fructose control group at the end of the study showed elevate ... | 2006 | 16202550 |
| creaming in black tea. | tea cream is the precipitate formed as tea cools. its formation has been studied by x-ray scattering, and it is shown that a higher tea concentration leads to earlier onset of creaming and larger particles and that addition of theaflavin and calcium promotes creaming. association constants between the major components of black tea have been obtained using nmr and show that calcium and glucose enhance the self-association of caffeine, polyphenols, and theaflavin but have little effect on hetero-a ... | 2005 | 16190662 |
| a novel black tea pigment and two new oxidation products of epigallocatechin-3-o-gallate. | during tea fermentation, oxidation-reduction dismutation of a number of quinone metabolites of tea catechins yields numerous minor products, which make it difficult to separate and purify black tea polyphenols. in this study, epigallocatechin-3-o-gallate was enzymatically oxidized and then the unstable quinone metabolites in the oxidation mixture were hydrogenated with 2-mercaptoethanol to reduce production of inseparable minor dismutation products. as a result, three new oxidation products incl ... | 2005 | 16159188 |
| fulminant hepatitis during self-medication with hydroalcoholic extract of green tea. | despite an ancient reputation for potential phytotherapeutic effects and innocuity, traditional herbal medicine has previously been implicated in severe adverse events. exolise is an 80% ethanolic dry extract of green tea (camellia sinensis) standardized at 25% catechins expressed as epigallocatechin gallate, containing 5-10% caffeine. it has been available in france, belgium, spain and the united kingdom since 1999, as an adjuvant therapy for use in weight loss programmes. in various studies, g ... | 2005 | 16148563 |
| [acute hepatitis induced by camellia sinensis (green tea)]. | | 2005 | 16145729 |
| medicinal benefits of green tea: part ii. review of anticancer properties. | currently there is wide interest in the medicinal benefits of green tea (camellia sinensis). tea is one of the most widely consumed beverages in the world, and extracts of tea leaves are also sold as dietary supplements. green tea extracts contain a unique set of catechins that possess biologic activity in antioxidant, antiangiogenesis, and antiproliferative assays that are potentially relevant to the prevention and treatment of various forms of cancer. with the increasing interest in the health ... | 2005 | 16131288 |
| risk factors for kidney cancer in a japanese population: findings from the jacc study. | the incidence of kidney cancer is high in western and northern europe and north america, and low in asia. although the incidence of kidney cancer in japan is lower than the rates in the other industrialized countries, there is no doubt that it is increasing. | 2005 | 16127235 |
| influence of tea drinking on manganese intake, manganese status and leucocyte expression of mnsod and cytosolic aminopeptidase p. | since black tea contains high levels of manganese (mn), we investigated the relationship between dietary mn intake, circulating mn levels and leucocyte expression of two mn-dependent enzymes in tea drinkers and non-tea drinkers. | 2006 | 16118651 |
| comparative evaluation of the chemopreventive efficacy of green and black tea polyphenols in the hamster buccal pouch carcinogenesis model. | to evaluate the comparative chemopreventive efficacy of green tea polyphenols (polyphenon-e) and black tea polyphenols (polyphenon-b) on 7,12-dimethylbenz[a]anthracene (dmba)-induced hamster buccal pouch (hbp) carcinogenesis. | 2005 | 16098960 |
| associations between black tea and coffee consumption and risk of lung cancer among current and former smokers. | although cigarette smoking is a clear risk factor for lung cancer, the other determinants of lung cancer risk among smokers are less clear. tea and coffee contain catechins and flavonoids, which have been shown to exhibit anticarcinogenic properties. conversely, caffeine may elevate cancer risk through a variety of mechanisms. the current study investigated the effects of regular consumption of black tea and coffee on lung cancer risk among 993 current and former smokers with primary incident lu ... | 2005 | 16090999 |
| separation of catechin constituents from five tea cultivars using high-speed counter-current chromatography. | catechins were extracted from five different tea (camellia sinensis l.) cultivars. high-speed counter-current chromatography was found to be an efficient method for the separation of seven catechins from the catechin extracts. high-performance liquid chromatography was used to assess the purity of the catechins isolated. epigallocatechin gallate (egcg), epicatechin gallate (ecg) and epigallocatechin (egc) of high purity (91-99%) were isolated in high yield after a single high-speed counter-curre ... | 2005 | 16078712 |
| xanthine oxidase activity in vitro: effects of food extracts and components. | there is significant interest in the direct antioxidant activities of dietary polyphenols, due to associations between consumption of polyphenol-rich foods, such as fruits and vegetables, and decreased incidence of oxidative-stress related disease. however, indirect antioxidant action, such as the inhibition of ros-producing enzymes, may be equally relevant to health benefits through a general reduction in oxidative stress in vivo. to this end, the effects of food extracts and individual compoun ... | 2005 | 16076142 |
| seasonal variations of phenolic compounds in australia-grown tea (camellia sinensis). | seasonal variations of phenolic compounds in fresh tea shoots grown in australia were studied using an hplc method. three principal tea flavanols [epigallocatechin gallate (egcg), epicatechin gallate (ecg), and epigallocatechin (egc)] and four grouped phenolics [total catechins (cs), total catechin gallates (cgs), total flavanols (fla), and total polyphenols (pps)] in fresh tea shoots were analyzed and compared during the commercial harvest seasons from april 2000 to may 2001. the levels of egcg ... | 2005 | 16076137 |
| [tea and coffee consumption among russian population]. | aim of present study was the getting data on black and green tea and coffee consumption among russian population in 1995-2003. the consumption of beverages tea and coffee was estimated by 24-hour recall of dietary intake in course of russian longitudinal monitoring surveys of economics and health. about 82% of population have consumed the black tea and only 2.2%--the green tea. mean daily black and green tea intake among all population were 446 ml and 10 ml, correspondingly. the prevalence of bl ... | 2005 | 16044841 |
| stability of black tea polyphenol, theaflavin, and identification of theanaphthoquinone as its major radical reaction product. | in the current study, we have focused on isolation and detection of major radical oxidation products from theaflavin in order to better understand antioxidation mechanisms of this compound. theanaphthoquinone was identified as a major oxidation product of theaflavin from two different oxidant model systems: dpph and peroxidase/hydrogen peroxide. this result indicated that the benzotropolone moiety in theaflavin may play an important role in its antioxidant properties. the stability of theaflavin ... | 2005 | 16029009 |
| medicinal benefits of green tea: part i. review of noncancer health benefits. | tea, in the form of green or black tea, is one of the most widely consumed beverages in the world. extracts of tea leaves also are sold as dietary supplements. however, with the increasing interest in the health properties of tea and a significant rise in scientific investigation, this review covers recent findings on the medicinal properties and noncancer health benefits of both green and black tea. in part ii, a review of anticancer properties of green tea extracts is presented. green tea cont ... | 2005 | 15992239 |
| assessment of desiccation sensitivity of tea embryos for cryopreservation. | tea (camellia sinensis (l.) o. kuntze) has been reported as a species with recalcitrant seeds. the seeds can be stored for less than one year under high humidity conditions in a refrigerator at 5-7 degrees c. an efficient cryopreservation protocol for tea embryos using embryonic axes with portions of cotyledons still attached as drying material was established, which led to survival percentages around 92%. however, understanding the pattern of desiccation sensitivity, which is the key-limiting f ... | 2009 | 19827256 |
| all teas are not created equal: the chinese green tea and cardiovascular health. | tea is one of the most widely consumed beverages in the world, next only to water. it can be categorized into three types, depending on the level of fermentation, i.e., green (unfermented), oolong (partially fermented) and black (fermented) tea. in general, green tea has been found to be superior to black tea in terms of antioxidant activity owing to the higher content of (-)-epigallocatechin gallate. the processes used in the manufacture of black tea are known to decrease levels of the monometr ... | 2006 | 15978686 |
| [the green tea, a good choice for cardiovascular disease prevention?]. | tea (camellia sinensis) has been used for centuries as a medical drink. around two-thirds of the world's population drink tea. it is originated from southern china and entensive cultivated in asia and in central african countries. tea can be grouped into three main types, black, oolong, and green tea. green tea is not fermented and is a major beverage consumed in asian countries. green tea is produced from freshly harvest leaves of the tea plant and they contain water, proteins, carbohydrates, m ... | 2004 | 15969262 |
| purification and partial characterization of beta-glucosidase from fresh leaves of tea plants (camellia sinensis (l.) o. kuntze). | beta-glucosidases are important in the formation of floral tea aroma and the development of resistance to pathogens and herbivores in tea plants. a novel beta-glucosidase was purified 117-fold to homogeneity, with a yield of 1.26%, from tea leaves by chilled acetone and ammonium sulfate precipitation, ion exchange chromatography (cm-sephadex c-50) and fast protein liquid chromatography (fplc; superdex 75, resource s). the enzyme was a monomeric protein with specific activity of 2.57 u/mg. the mo ... | 2005 | 15944750 |
| novel inhibitors of fatty-acid synthase from green tea (camellia sinensis xihu longjing) with high activity and a new reacting site. | recent studies have shown that fas (fatty acid synthase) is a potential therapeutic target of obesity. in the present paper we report that extract of green tea (camellia sinensis xihu longjing) inhibits fas effectively with an ic50 value of 12.2 microg dry weight/ml. the ability of gte (green tea extract) to inhibit fas is more potent than that of two known inhibitors in green tea leaves, egcg (epigallocatechin gallate) and ecg (epicatechin gallate). we find that (-)-cg (catechin gallate) is a v ... | 2006 | 15943584 |
| inhibition of sars-cov 3c-like protease activity by theaflavin-3,3'-digallate (tf3). | sars-cov is the causative agent of severe acute respiratory syndrome (sars). the virally encoded 3c-like protease (3cl(pro)) has been presumed critical for the viral replication of sars-cov in infected host cells. in this study, we screened a natural product library consisting of 720 compounds for inhibitory activity against 3cl(pro). two compounds in the library were found to be inhibitive: tannic acid (ic(50) = 3 microm) and 3-isotheaflavin-3-gallate (tf2b) (ic(50) = 7 microm). these two compo ... | 2005 | 15937562 |
| tea (camellia sinensis (l.) o. kuntze) clone with lower period of winter dormancy exhibits lesser cellular damage in response to low temperature. | there is no literature available on the response of tea plant to low temperature. we studied the effect of low temperature on two clones of tea with contrasting periods of winter dormancy, a phenomenon in which the growth of apical shoots of tea is diminished during winter months. clone 'teenali 17/154' (tnl) showed shorter periods of winter dormancy than clone 'kangra jat' (knj). low temperature (5 degrees c) resulted in increase of metabolic superoxide (o2*-) content and cellular damage (as me ... | 2005 | 15907690 |
| water deficit induced oxidative damage in tea (camellia sinensis) plants. | when the tea (camellia sinensis) leaf water potential was -1.1 mpa (moderate water deficit), there was 58% inhibition of photosynthesis accompanied by increased zeaxanthin, malondialdehyde, oxidized proteins and superoxide dismutase activity. when the leaf water potential was -2mpa (severe water deficit), there was nearly complete inhibition of photosynthesis apart from a decrease in chlorophylls, beta-carotene, neoxanthin and lutein. water deficit at this level caused further conversion of viol ... | 2005 | 15900883 |
| black tea induces tumor cell apoptosis by bax translocation, loss in mitochondrial transmembrane potential, cytochrome c release and caspase activation. | recently the anti-cancer role of black tea has gained immense importance. nevertheless, the signaling pathways underlying black tea-induced tumor cell death are still unknown. previously we reported that black tea induces ehrlich's ascites carcinoma (eac) cell apoptosis by changing the balance between pro-and anti-apoptotic proteins. it is now well accepted that many cell death pathways converge at the mitochondria to decrease mitochondrial transmembrane potential (mtp) thereby releasing apoptog ... | 2005 | 15880367 |
| meal-based intake assessment tool: relative validity when determining dietary intake of fe and zn and selected absorption modifiers in uk men. | a computer-based dietary assessment tool, the meal-based intake assessment tool (mbiat), is described. in the current study, dietary intakes of fe and zn fractions (total fe, non-haem fe, haem fe, meat fe, total zn) and dietary components that influence fe and zn absorption (vitamin c, phytate, ca, grams of meat/fish/poultry, black tea equivalents, phytate:zn molar ratio) were assessed. the relative validity of the mbiat was determined in forty-eight uk men aged 40 years and over by comparing it ... | 2005 | 15877881 |
| effects of structure on radical-scavenging abilities and antioxidative activities of tea polyphenols: nmr analytical approach using 1,1-diphenyl-2-picrylhydrazyl radicals. | tea (camellia sinensis) leaves contain various antioxidants such as ascorbic acid (1) and polyphenols. this study tries to clarify the molecular mechanisms underlying the antioxidative and radical-scavenging activities of these antioxidants, and the reactivities of each antioxidant have been compared against that of the stable free radical 1,1-diphenyl-2-picrylhydrazyl (dpph, 2) using nuclear magnetic resonance (nmr) analysis. catechol (3) and (+)-taxifolin (4) were oxidized to o-quinone by 2. h ... | 2005 | 15853407 |
| antioxidative properties of black tea. | black tea, obtained by tea leaves fermentation, is an oxidized product and contains mainly multimeric polyphenols, whose biological activity is not well documented. this paper reviews the available literature on the effects of black tea on health with a focus on its antioxidative activity. | 2005 | 15850895 |
| [studies on antioxidant constituents from black tea]. | qimen black tea has strong inhibitory activity of canola oil oxidation. four antioxidant compounds, theaflavin (tf1), theaflavin-3-gallate (tf2a), theaflavin-3'-gallate (tf2b) and theaflavin digallate (tf3), were isolated from acetic acetate extract of black tea by silica gel and sephadex lh-20 column chromatography. tf1, tf2a, tf2b and tf3, have stronger antioxidant activity than that of bht (butylated hydorxytoluene). | 2004 | 15850353 |
| flavanols in somatic cell division and male meiosis of tea (camellia sinensis) anthers. | young anthers excised from closed tea flower buds ( camellia sinensis l.) were stained as fresh tissues with p-dimethylaminocinnamaldehyde reagent to localize flavanols associated with nuclei and chromosomes, apart from those flavanols stored in vacuoles. this staining reagent yields a blue colour for flavanols. in the nonsporogenic somatic cells of developing anthers, flavanols were found to be attached to chromosomes at all mitotic stages. male meiosis started at a bud size of about 3.5 mm in ... | 2005 | 15822012 |
| immobilization of tyrosinase in polysiloxane/polypyrrole copolymer matrices. | immobilization of tyrosinase in conducting copolymer matrices of pyrrole functionalized polydimethylsiloxane/polypyrrole (pdms/ppy) was achieved by electrochemical polymerization. the polysiloxane/polypyrrole/tyrosinase electrode was constructed by the entrapment of enzyme in conducting matrices during electrochemical copolymerization. maximum reaction rate (v(max)) and michaelis-menten constant (k(m)) were investigated for immobilized enzyme. enzyme electrodes were prepared in two different ele ... | 2005 | 15811471 |
| in vitro studies on the effect of sodium tripolyphosphate on the interactions of stain and salivary protein with hydroxyapatite. | to study properties of sodium tripolyphosphate (stp) relevant to inhibition or removal of dental stain in vitro. | 2005 | 15781139 |
| plants known as té in spain: an ethno-pharmaco-botanical review. | although the word té (tea) in spanish is derived from the chinese tscha and refers to the oriental plant camellia sinensis, it is popularly used throughout spain to refer to at least 70 different plant species. these are usually collected in the countryside, boiled dry or fresh, and drunk after meals. the drinking of té is a social habit that encourages conversation in a relaxed atmosphere. tés are also commonly used as digestifs and stomachics, and in some cases as laxatives, antidiarrhoeics, a ... | 2005 | 15763359 |
| [study on the adsorption behaviors of cadmium and lead ions on green tea and black tea by icp-aes]. | the adsorption behaviors of cd(ii) and pb(ii) on green tea and black tea in aqueous solution as well as the influences of time, acidity and temperature on the adsorption have been studied. it was found that cd(ii) and pb(ii) can been adsorbed strongly by green tea and black tea samples. the adsorption effects depend on the ph strongly when ph<4. the recovery of pb(ii) on tea samples is more than that of cd(ii) when ph<6 and it is opposite when ph>6. it is difficult to elute cd(ii) and pb(ii) fro ... | 2004 | 15762500 |
| purification and partial characterization of a low temperature responsive mn-sod from tea (camellia sinensis (l.) o. kuntze). | the manganese containing superoxide dismutase (mn-sod) was purified from a tea clone, teenali, which showed the lowest period of winter dormancy. protein was purified using leaves of tea by ammonium sulfate precipitation, followed by column chromatography using deae-cellulose, and silica-based size exclusion chromatography on hplc system. upto 51-fold purification and a specific activity of 56.66 u/mg of protein was achieved, which yielded a single band upon denaturing page. the enzyme had a nat ... | 2005 | 15752731 |
| black tea and cardiovascular disease. | | 2005 | 15743875 |
| [preparation and component analysis of tea pigments]. | to prepare tea pigments. | 2004 | 15727181 |
| arsenic-induced micronuclei formation in mammalian cells and its counteraction by tea. | the gangetic plain of west bengal, india, has been engulfed by a disastrous environmental calamity of arsenic contamination of the ground water. chronic arsenic toxicity caused by drinking arsenic-contaminated water has been one of the worst health hazards gradually affecting nine districts of west bengal since the early 1980s. over and above hyperpigmentation and keratosis,weakness, burning sensation of the eyes, swelling of the legs, liver fibrosis, chronic lung disease, gangrene of the toes, ... | 2005 | 15715508 |
| [determination of theaflavins in black tea by high performance liquid chromatography]. | a high performance liquid chromatographic method for the determination of theaflavins has been established. separation was carried out on an ods column (shim-pack vp-ods column, 4.6 mm i.d. x 150 mm) at 40 degrees c with a linear gradient elution of acetonitrile-ethyl acetate (21:3, v/v) and aqueous acetic acid (2%), and uv detection at 280 nm. the experimental results showed a good linear relationship between the peak area and the concentration of theaflavins (r = 0.9990-0.9992). the average re ... | 2004 | 15712875 |