Publications

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
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
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
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
effects of black tea consumption on plasma catechins and markers of oxidative stress and inflammation in patients with coronary artery disease.	we previously demonstrated that black tea consumption reverses endothelial dysfunction in patients with coronary artery disease. to investigate potential mechanisms of this effect, we examined plasma catechins and systemic markers of oxidation, inflammation, and antioxidant protection from 66 subjects enrolled in that study. we collected samples at baseline, 2 h after 450 ml of black tea (acute), after 4 weeks of 900 ml of black tea per day (chronic), and after acute and chronic consumption of w ...	2005	15649652
the perceived effect of various foods and beverages on stool consistency.	some people believe that chocolate and other foods or beverages may cause constipation. this study was undertaken to quantify the effect of potentially constipating foods and beverages on apparently healthy and constipated populations of german individuals.	2005	15647650
acute effects of tea on fasting and postprandial vascular function and blood pressure in humans.	effects of regular exposure to polyphenolic compounds found in tea, leading to improved endothelial function and blood pressure, may reduce cardiovascular disease risk. controlled trials in humans have found that ingestion of tea can improve endothelial function, but also cause a rapid onset acute increase in blood pressure.	2005	15643124
consumption of both black tea and green tea results in an increase in the excretion of hippuric acid into urine.	a major portion of the catechins in green tea is not absorbed in the small intestine. bacteria in the colon convert nonabsorbed catechins into simpler phenolic compounds, which may also be absorbed. during the production of black tea, most catechins are polymerized to complex molecules called thearubigins. little is known about the microbial degradation of these complex polyphenols, but hippuric acid has been identified as a major excretion product associated with black tea consumption.	2005	15640488
polyphenols in foods are more complex than often thought.	dietary polyphenols show a great diversity of structures, ranging from rather simple molecules (monomers and oligomers) to polymers. higher-molecular-weight structures (with molecular weights of > 500) are usually designated as tannins, which refers to their ability to interact with proteins. among them, condensed tannins (proanthocyanidins) are particularly important because of their wide distribution in plants and their contributions to major food qualities. all phenolic compounds are highly u ...	2005	15640485
antioxidant and lipid lowering activities of indian black tea.	indian black tea; ctc leaf and dust, produced by tata tea limited, kolkata, (india) was studiedin vitro as potential scavenger of oxygen free radicals. super oxide anions were generated in a system containing xanthine-xanthine oxidase (enzymic system) and by nadh- phenozine methosulphate (non enzymic system). anions were assayed in terms of uric acid formation and reduction of nitroblue tetrazolium salt, which were shown to be suppressed by tea extracts. extracts from both leaf and dust also inh ...	2005	23105515
concentrations and health risk of polycyclic aromatic hydrocarbons in tea.	sixteen polycyclic aromatic hydrocarbons (pahs) were simultaneously measured in 8 brands of tea and in infusions of one brand of black tea. it was observed that the total contents of the 16 pahs (summation pahs) in the tea samples ranged from 323 to 8800 microg/kg with the highest summation pahs found in a black tea. pahs (3-4 rings) were dominant in all tea samples, with a contribution of 77.7-98.7% of the summation pahs. infusion times from 10 to 120 min were studied during which 3.03-7.69% of ...	2005	15582194
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
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
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
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
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
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
on-line high-performance liquid chromatography analysis of the antioxidant activity of phenolic compounds in green and black tea.	teas represent a rich source of dietary antioxidants. this paper describes analysis of the antioxidant potential of individual tea phenolics using an on-line high-performance liquid chromatography (hplc) method. tea phenolics from kenyan green and black teas were identified using liquid chromatography--mass spectrometry (lc-ms(n)) in conjunction with the analysis of their 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (abts+) radical scavenging ability. antioxidant potential of flavan-3-o ...	2005	15602765
polyphenols and antioxidant capacity of bulgarian medicinal plants.	extracts of 21 plants used in bulgarian phytotherapy for the treatment of respiratory, gastrointestinal and other inflammatory disorders were screened in vitro for antioxidant activity and phenolic compounds content. plant extracts were prepared as herbal teas following the ethnic use. the water-phase teac (trolox equivalent antioxidant capacity) of the teas were compared to that of the famous tea-like beverages mate, rooibos and honeybush, and to that of green and black tea, well known for thei ...	2005	15588663
salivary proteins interact with dietary constituents to modulate tooth staining.	dietary components rich in polyphenols-for example, tea and red wine-are thought to cause tooth staining. in the present study, hydroxyapatite was used as a model of enamel for study of the influence of salivary proteins on the binding of different polyphenols to hydroxyapatite in vitro. neither salivary protein pellicles nor salivary proteins in solution significantly altered the binding of the small polyphenol epigallocatechin to hydroxyapatite. however, hydroxyapatite binding of anthocyanin, ...	2005	15615880
[chemical and sensory characterization of tea (thea sinensis) consumed in chile].	by means of descriptive analysis four varieties of tea (thea sinensis) were assesed: argentinean op (orange pekoe) tea (black), brazilian op tea (black), ceylan op tea (black) and darjeeling op tea (green). the appearance of dry tea leaves were qualitatively characterized comparing with dry leaves standard. the attributes: colour, form, regularity of the leaves, fibre and stem cutting were evaluated the differences obtained were related to the differences produced by the effect of the fermentati ...	2005	16187684
about the cover illustration: thea sinensis - the common tea plant.		2005	15976762
oxidation of tea extracts and tea catechins by molecular oxygen.	tea polyphenols (pp) are known as potent antioxidants. at the same time, pp have been repeatedly reported to oxidize by molecular oxygen with the formation of active forms of oxygen. in this work, the clark electrode technique was applied to study the kinetics of the autoxidation of tea extracts and individual tea pp as well as model pp, catechol, gallic acid, and pyrogallol. aqueous extracts of both green and black teas were found to undergo extensive autoxidation under physiological conditions ...	2005	15913321
novel chemiluminescence-inducing cocktails, part ii: measurement of the anti-oxidant capacity of vitamins, thiols, body fluids, alcoholic beverages and edible oils.	using two luminescence-inducing cocktails, two distinct patterns of inhibition of light by different anti-oxidants have been identified, comprising group a, in which a complete inhibition of light emission which is then followed by re-emergence of light, forming apparent s-shaped curves or similar shapes. this light pattern is induced by the "classical" anti-oxidants, ascorbate, vitamin e, uric acid, thiols, deferoxamine, as well as by anti-oxidant agents present in plasma, saliva, urine and in ...	2004	15901412
phenolic constituents and antioxidant activity of wendita calysina leaves (burrito), a folk paraguayan tea.	burrito tea originates from the leaves of wendita calysina, an indigenous paraguayan plant, which is commonly consumed in south america and in western countries. phytochemical investigation of this species has led to the isolation of 14 constituents, among them 2 new flavanonols, dihydroquercetagetin (1) and 3,5,6,7,4'-pentahydroxyflavanonol (2), in addition to several known methoxyflavones, methoxyflavonols, phenylethanoid glycosides, and benzoic acid derivatives (4-14). all structures were elu ...	2004	15366833
cryopreservation of tea (camellia sinensis l.) seeds and embryonic axes.	this study investigated the tolerance to desiccation and freezing of tea seeds, embryonic axes (eas) and cotyledonary embryonic axes (ceas, consisting of eas with portions of cotyledons still attached). no seeds germinated after desiccation and cryopreservation. eas extracted from seeds desiccated to 18.9% moisture content (fresh weight basis) and cryopreserved showed 20.7% survival but plantlet production from these eas was impossible. when eas and ceas were extracted from seeds before being su ...	2004	12391481
polycyclic aromatic hydrocarbons: pollution and source analysis of a black tea.	investigations into the manufacturing process of one kind of black tea revealed that it included five steps: withering, rolling, fermentation, drying, and drying and sorting. a total of 16 polycyclic aromatic hydrocarbons (pahs) were simultaneously measured in fresh leaves, withered leaves, rolled leaves, fermented leaves, crude black tea, and black tea sampled after each manufacturing stage and in the indoor and outdoor air of the drying house. it was observed that the total contents of the 16 ...	2004	15612828
effects of pu-erh tea on oxidative damage and nitric oxide scavenging.	the effects of pu-erh tea, which is prepared by fermentation of tea, on oxidative damage and nitric oxide scavenging, compared with various other brands of tea were investigated. the total antioxidant activity was determined using the trolox equivalent antioxidant capacity (teac) assay. the results showed that teac values of the 200 microg/ml water extracts of pu-erh tea (wept), green tea, oolong tea, and black tea were 86.3, 85.3, 87.4, and 80.3 (microg/ml), respectively, indicating that wept s ...	2004	15612813
aba associated biochemical changes during somatic embryo development in camellia sinensis (l.) o. kuntze.	the effect of aba on reserve accumulation in maturing somatic embryos of tea was compared with and without aba treatment. changes in the levels of starch, total soluble sugars (tss), proteins, and phenols were studied in the somatic embryos at different stages of development (globular, heart, torpedo and germinating embryos) in order to investigate whether aba could trigger accumulation of storage reserves and thereby overcome the problem of poor germination. after aba treatment (5.0 mg l(-1)) f ...	2004	15602818
bioavailability and antioxidant activity of tea flavanols after consumption of green tea, black tea, or a green tea extract supplement.	green and black tea polyphenols have been extensively studied as cancer chemopreventive agents. many in vitro experiments have supported their strong antioxidant activity. additional in vivo studies are needed to examine the pharmacokinetic relation of absorption and antioxidant activity of tea polyphenols administered in the form of green or black tea or tea extract supplements.	2004	15585768
lung cancer risk among nonsmoking women in relation to diet and physical activity.	to investigate the relationship between diet, physical activity, and the risk of lung cancer among female nonsmokers, and to compare it with female smokers in the same population, we conducted a case-control study. data collected by personal interviews from 419 cases and 1593 controls were analyzed using unconditional logistic regression. as expected, among 130 nonsmoking cases, adenocarcinoma was the predominant cell type (49.2%), followed by squamous cell (20.2%) and small cell cancers (10.5%) ...	2004	15190423
black tea increases coronary flow velocity reserve in healthy male subjects.	epidemiologic studies suggest that tea consumption decreases the risk for cardiovascular events. however, there has been no clinical report examining the effects of tea consumption on coronary circulation. the purpose of this study was to evaluate the effects of black tea on coronary flow velocity reserve (cfvr) using transthoracic doppler echocardiography (ttde). this was a double-blind crossover study of 10 healthy male volunteers conducted to compare the effects of black tea and caffeine on c ...	2004	15165919
[hepatotoxicity due to camelia sinensis].		2004	15153351
hplc-msn analysis of phenolic compounds and purine alkaloids in green and black tea.	tea is a complex mixture containing a range of compounds from simple phenolics to complex thearubigins, many of which have well-recognized antioxidant properties. this paper describes the application of high-performance liquid chromatography-mass spectrometry (hplc-ms(n)) methods for the rapid and routine analysis of more than 30 phenolics in tea. green and black tea infusions were injected directly onto a reversed phase hplc column, and the phenolics eluted using two different mobile phase grad ...	2004	15137818
pigments in green tea leaves (camellia sinensis) suppress transformation of the aryl hydrocarbon receptor induced by dioxin.	environmental contaminants such as dioxins enter the body mainly through diet and cause various toxicities through transformation of the aryl hydrocarbon receptor (ahr). we previously reported that certain natural flavonoids at the dietary level suppress the ahr transformation induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (tcdd). in this study, we identified lutein and chlorophyll a and b from green tea leaves as the novel antagonists for ahr. these active compounds suppressed ahr transformatio ...	2004	15113147
analysis of theaflavins and thearubigins from black tea extract by maldi-tof mass spectrometry.	black tea contains two major groups of pigments, theaflavins (tfs) and thearubigins (trs). tfs contain a bis-flavan substituted 1,2-dihydroxy-3,4-benzotropolone moiety. unlike the tfs, trs have not yet been characterized. the chemical structure of the trs remains a mystery. the present paper reports our effort to study the structure of tfs and trs using delayed pulsed ion extraction of ions generated via the matrix-assisted laser desorption ionization (maldi) technique, on line with a linear tim ...	2004	15113141
modulation of tea and tea polyphenols on benzo(a)pyrene-induced dna damage in chang liver cells.	the protective effects of three tea extracts (green tea, gte; oolong tea, ote; and black tea, bte) and five tea polyphenols (epicatechin, ec; epicatechin gallate, ecg; epigallocatechin, egc; epigallocatechin gallate, egcg; and theaflavins, thfs) on benzo[a]pyrene (b[a]p)-induced dna damage in chang liver cells were evaluated using the comet assay. b[a]p-induced dna damage in chang liver cells was significantly (p < 0.05) inhibited by gte and ote at a concentration of 10 microg/ml and by bte at 2 ...	2004	15104213
effects of sweet and bitter gustatory stimuli in anorexia nervosa on eeg frequency spectra.	the possible differences in processing gustatory stimuli in anorexic patients compared to healthy control subjects was investigated by electrophysiological methods. the electroencephalogram (eeg) was recorded in outpatients treated with anorexia nervosa (an) and age-matched controls after exposure to sweet (milk chocolate) and bitter (black tea) taste stimuli. power spectrum analysis was performed on eeg epochs recorded in the above conditions. compared to controls a significantly higher percent ...	2004	15094251
development of methods to enhance extrinsic tooth discoloration for comparison of toothpastes. 2. two-product clinical study.	extrinsic staining of teeth is considered to be unsightly and a number of 'whitening' toothpastes have been formulated to inhibit or remove such tooth discoloration. the aim of this study was to compare the stain prevention of two toothpastes.	2004	15058367
determination of ni (ii) in beverages without any sample pretreatment by adsorptive stripping chronopotentiometry (adscp).	the purpose of this paper was to use adsorptive stripping chronopotentiometry for the determination of ni (ii) in worldwide consumed beverages without any sample pretreatment, using dimethilglyoxime (dmg) as complexing agent and a glassy carbon mercury film electrode as the working electrode. ni (dmg)2 complex is adsorbed onto the mercury film at an electrolysis potential of -500 mv for 60 s and then reduced by a -5 microa constant cathodic current. the sensitivity of the method was studied for ...	2004	15053517
reaction of iron(iii) with theaflavin: complexation and oxidative products.	theaflavins are a family of compounds, whose chemistry has been sparsely investigated. they can comprise up to 40% the dry weight of black tea. they are known to chelate metals, however very little knowledge exists on the mechanisms involved. there is some correlation between both of these areas in that following degradation of the iron theaflavin complex, subsequent redox reactions may lead to the formation of similar products on both occasions. the interaction of iron(iii) with theaflavin at p ...	2004	15041246
a clinical study to assess the ability of a powered toothbrush to remove chlorhexidine/tea dental stain.	a single-center, single-blind, two-way crossover study was performed to compare the effects of an electric powered toothbrush with a conventional manual toothbrush at removing chlorhexidine/tea tooth staining.	2004	15016033
role of hydrogen peroxide in bactericidal action of catechin.	catechin (epicatechin (ec), epicatechin gallate (ecg), epigallocatechin (egc) and epigallocatechin gallate (egcg)), which occur in green tea and black tea, possess strong bactericidal action. we observed a reactive oxygen species that was generated from the catechins as the active mechanism: and this reactive oxygen was identified. egcg reacted with the dissolved oxygen in aqueous solution, resulting in the generation of hydrogen peroxide. hydrogen peroxide production derived from egcg rose with ...	2004	14993788
caffeine synthase and related methyltransferases in plants.	caffeine (1,3,7-trimethylxanthine) is a purine alkaloid present in high concentrations in tea and coffee and it is also found in a number of beverages such as coca cola. it is necessary to elucidate the caffeine biosynthetic pathway and to clone the genes related to the production of caffeine not only to determine the metabolism of the purine alkaloid but also to control the content of caffeine in tea and coffee. the available data support the operation of a xanthosine-->7-methylxanthosine-->7-m ...	2004	14977590
effect of a 4-month tea intervention on oxidative dna damage among heavy smokers: role of glutathione s-transferase genotypes.	glutathione s-transferase (gst), a member of the phase ii group of xenobiotic metabolizing enzymes, has been intensively studied at the levels of phenotype and genotype. the gst mu 1 (gstm1) and gst theta 1 (gstt1) genes have a null-allele variant in which the entire gene is absent. the null genotype for both enzymes has been associated with many different types of tumors. the aim of this study was to determine the possible differences in increased oxidative stress susceptibility to smoking with ...	2004	14973088
fluoride and aluminum in teas and tea-based beverages.	to evaluate fluoride and aluminum concentration in herbal, black, ready-to-drink, and imported teas available in brazil considering the risks fluoride and aluminum pose to oral and general health, respectively.	2004	14963548
comparative study of the growth-inhibitory and apoptosis-inducing activities of black tea theaflavins and green tea catechin on murine myeloid leukemia cells.	among the black tea polyphenols, theaflavins are generally considered to be the more effective components for the inhibition of carcinogenesis. in this study, we attempted to compare the growth-inhibitory and apoptosis-inducing activities of the four black tea theaflavins (tf-1, tf-2a, tf-2b and tf-3) with the major green tea catechin epigallocatechin-3-gallate (egcg) on the murine myeloid leukemia wehi-3b jcs cells. all the four black tea theaflavins were shown to exert potent anti-proliferativ ...	2004	14767581
delivery of tea polyphenols to the oral cavity by green tea leaves and black tea extract.	catechins and theaflavins, polyphenolic compounds derived from tea (camellia sinensis, fam. theaceae), have been reported to have a wide range of biological activities including prevention of tooth decay and oral cancer. the present study was undertaken to determine the usefulness of green tea leaves and black tea extract for the delivery of catechins and theaflavins to the oral cavity. after holding either green tea leaves (2 g) or brewed black tea (2 g of black tea leaves in 100 ml) in the mou ...	2004	14744744
impact of tea drinking on iron status in the uk: a review.	the aims of this review are (1) to evaluate the literature on the likely impact of tea drinking on the iron status of different groups within the uk population and (2) to formulate targeted and evidence based advice on tea drinking in the context of iron nutrition in different groups of people.	2004	14718031
foods and beverages in relation to urothelial cancer: case-control study in japan.	the roles of several foods and beverages in the development of bladder cancer remain unclear.	2004	14678179
ellipsometry analysis of the in vitro adsorption of tea polyphenols onto salivary pellicles.	the adsorption of components from black tea and of purified tea polyphenols onto a whole unstimulated salivary pellicle-like protein layer, formed in vitro on hydroxyapatite discs, was studied by in situ ellipsometry. it was found that components from black tea and the purified polyphenols epicatechin-3-gallate (ecg), epigallocatechin-3-gallate (egcg) and theaflavin readily adsorbed onto the pellicle. further investigations showed that under the experimental conditions of this study, no black te ...	2004	15560834
clinical study to compare the effectiveness of a test whitening toothpaste with a commercial whitening toothpaste at inhibiting dental stain.	a single centre, randomised single-blind, three-way crossover study was performed, to compare the effect of an experimental test toothpaste with a commercially available whitening toothpaste and water control at inhibiting extrinsic stain promoted by repeated chlorhexidine/tea rinses.	2004	15560810
[a study on the association between tea consumption and stroke].	the aim of the study was to investigate the association between tea consumption and stroke.	2004	15555387
dietary habits and lung cancer risk among non-smoking women.	a case-control study was conducted to investigate the relationship between diet and the risk of lung cancer among women non-smokers and to compare with women smokers in the same population. data collected by personal interviews from 435 microscopically confirmed cases and 1710 controls were analysed using unconditional logistic regression. in addition to results for all study subjects, associations between diet and lung cancer risk were compared between two highly contrasting groups: smokers (od ...	2004	15548939
will green tea be even better than black tea to increase coronary flow velocity reserve?		2004	15518633
antioxidant activity of plant extracts on the inhibition of citral off-odor formation.	grape seed, pomegranate seed, green tea, and black tea extracts were used to inhibit the off-odor from citral degradation. a 0.1 m citrate buffer (ph 3), containing 100 ppm citral and 200 ppm gallic acid equivalent plant extract, was incubated at 40 degrees c. the reaction mixtures were analyzed by high-performance liquid chromatography (hplc) at days 0, 6, 10, 13, and 16 to monitor degradation of citral and formation of alpha, p-dimethylstyrene, p-cymene-8-ol, and p-methylacetophenone. the addi ...	2004	15497182
theaflavin, a black tea extract, is a novel anti-inflammatory compound.	tea has been around for centuries, and its medicinal properties have been purported in the literature but never fully confirmed. interleukin-8 is a principle neutrophil chemoattractant and activator in humans. we determined the effects of theaflavin, a black tea-derived polyphenol, on tumor necrosis factor-alpha-mediated expression of the interleukin-8 gene in a549 cells.	2004	15483420
chemical forms of aluminum in xylem sap of tea plants (camellia sinensis l.).	to identify the chemical forms of aluminum (al) transported from roots to shoots of tea plants (c. sinensis l.), 27al-nuclear magnetic resonance and 19f nmr spectroscopy were used to analyze xylem sap. the concentration of al in collected xylem sap was 0.29 mm, twice as high as that of f. catechins were not detected in xylem sap. the concentration of malic acid in xylem sap was higher than that of citric acid, whereas the concentration of oxalic acid was negligible. there were two signals in the ...	2004	15474563
is green tea better than black tea in reducing atherosclerosis?		2004	15451816
fluorides in groundwater, soil and infused black tea and the occurrence of dental fluorosis among school children of the gaza strip.	the purpose of this study was to determine the fluoride levels in water, soil and tea, and to identify the major fluoride minerals in soil that supply water with fluoride ions. another aim was to study the prevalence of dental fluorosis in permanent dentition of the school children of the gaza strip. monitoring of fluoride levels in 73 groundwater wells and 20 topsoil samples for the last three years revealed a general trend of increasing from north to south of the gaza strip. a linear regressio ...	2004	15384727
dietary patterns and risk of gastric cancer: a case-control study in uruguay.	gastric cancer is a frequent malignancy in the uruguayan population. in northern counties, incidence rates reach high figures (age-standardized rates [asr], 37.3 per 100,000 men and 18.3 per 100,000 women). diet is a major determinant in gastric carcinogenesis. because foods or food groups have the advantage over nutrients in being most directly related to dietary recommendations, we decided to conduct a case-control study on the relationships between food groups and risk of gastric cancer. for ...	2004	15616769
diet-derived phenols in plasma and tissues and their implications for health.	this paper seeks to catalyse a reappraisal of the nature, fate and biological significance in humans of phenols, polyphenols and tannins (ppt) consumed in normal diets, and in particular questions the primacy of ppt radical-scavenging mechanisms for the supposed health benefits of diets rich in fruits and vegetables. ppt are classified by structure and function. arguments are presented to show that cinnamates and derived polyphenols make significantly larger contributions to the total ppt intake ...	2004	15643541
[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
[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
[preparation and component analysis of tea pigments].	to prepare tea pigments.	2004	15727181
[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
[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
a study on the determination of chromium as chromate at a carbon paste electrode modified with surfactants.	a procedure for the determination of chromium is described based on synergistic pre-concentration of the chromate anion at a carbon paste electrode modified in situ with quarternary ammonium salts such as 1-ethoxycarbonylpentadecyltrimethylammonium bromide (septonex((r))), cetyltrimethylammonium bromide (ctab) or cetylpyridinium bromide (cpb). the proper electrochemical detection utilises the reduction cr(vi) --> cr(iii) performed in the differential pulse cathodic voltammetric mode. in discussi ...	2004	18969679
occurrence of vitamin b12 in green, blue, red, and black tea leaves.	vitamin b12 contents of green (0.046-0.263 and 0.125-0.535 microg/100 g dry weight), blue (0.068-0.081 and 0.525-0.528 microg/l00 g dry weight), red (0.061 and 0.663 microg/100 g dry weight), and black (0.104-0.859 and 0.305-1.20 microg/100 dry weight) tea leaves were obtained by intrinsic factor-chemiluminescence and microbiological methods, respectively. although vitamin b12 was found in all tea leaves tested by both assay methods, the higher values by the microbiological method were not due t ...	2004	15895521
changes in electric charge and phospholipids composition in erythrocyte membrane of ethanol--poisoned rats after administration of teas.	erythrocyte membrane components and electric charge can be modified by ethanol and by compounds formed as a result of its metabolism, particularly be reactive oxygen species (ros). the effects of ros can be neutralized by administering preparations with antioxidant properties. the natural preparations of this kind are teas. for this reason, it has been the purpose of this work to determine effect of green and black tea on membrane electric charge and phospholipids composition of an erythrocyte m ...	2004	15794343
black tea intake modulates the excretion of urinary mutagens in rats exposed to 6-aminochrysene: induction of cytochromes p450 by 6-aminochrysene in the rat.	rats were exposed to black tea (2.5% w/v) as their sole drinking liquid for either 1 day (short-term) or 1 month (long-term), while controls received water. after exposure, all animals received a single oral dose of 6-aminochrysene and urine was collected for 72 h. urinary mutagenicity was determined in the ames test using an activation system comprising hepatic cytosol from aroclor 1254-induced rats and utilizing the salmonella typhimurium o-acetylase overexpressing bacterial strain yg1024. bot ...	2004	15598702
effect of black tea intake on the excretion of mutagens in the urine of volunteers taking a beef meal.	the objective of this study was to investigate in a crossover study conducted in human volunteers whether black tea intake modulates the metabolism of heterocyclic amines, consumed in the form of well-cooked beefburgers, as exemplified by the excretion of mutagens in the urine. mutagens were extracted from urine with blue rayon, and mutagenic activity was determined in the ames test, in the presence of an activation system derived from aroclor 1254-induced rats, and employing the salmonella typh ...	2004	15598780
transactivation of peroxisome proliferator-activated receptor alpha by green tea extracts.	tea is a popular beverage. recently, green tea was reported to increase the number of peroxisomes in rats. in this study, to find out whether the green tea-induced proliferation of peroxisomes is mediated by pparalpha , a transient transfection assay was carried out to investigate the interactions of tea extracts (green tea, black tea,oolong tea and doongule tea) and tea components (epigallocatechin gallate, epigallocatechin, epicatechin gallate, epicatechin and gallic acid), with mouse cloned p ...	2004	15613816
antibacterial effect of water-soluble tea extracts on foodborne pathogens in laboratory medium and in a food model.	the microbial inhibition of foodborne pathogens was determined in brain heart infusion broth with 10% (wt/vol) water-soluble extracts of green, jasmine, black, dungglre, and oolong tea against escherichia coli o157:h7, salmonella enterica serovar enteritidis, listeria monocytogenes, and staphylococcus aureus. the mixed culture (approximately 6.0 log cfu/ml), which was composed of the four pathogens, was inoculated into brain heart infusion broth with and without tea extracts. after incubation at ...	2004	15553649
nuclei of tea flowers as targets for flavanols.	the tea plant (camellia sinensis l.) is famous for its flavanol-based constituents being valuable for human health. these flavanols associate with the nuclei of tea flowers, which is demonstrated histochemically by blue colouration using the selective staining reagent p-dimethylaminocinnamaldehyde (dmaca). sepals, petals, stamens, pollen tubes, ovaries and ovules were studied. all these organs were shown to contain flavanols in vacuolar compartments, in nuclei and, exceptionally, also in the cyt ...	2004	15570474
effective control of glycemic status and toxicity in zucker diabetic fatty rats with an orally administered vanadate compound.	a novel black tea decoction containing vanadate has successfully replaced insulin in a rat model of insulin-dependent diabetes but is untested in non-insulin-dependent diabetic animals. a tea-vanadate decoction (tv) containing 30 or 40 mg sodium orthovanadate was administered by oral gavage to two groups of zucker diabetic fatty rats and a conventional water vehicle containing 30 or 40 mg of sodium orthovanadate to two others. in the latter group receiving the 30-mg dose, vanadate induced diarrh ...	2004	15573149
antimicrobial activity of 10 different plant polyphenols against bacteria causing food-borne disease.	the antibacterial activities of 10 different plant polyphenols were evaluated by comparing their minimum inhibitory concentrations (mics) against several food-borne pathogenic bacteria, staphylococcus aureus (20 strains), some serotypes of the genus salmonella (26 strains), escherichia coli (23 strains), and some species of the genus vibrio (27 strains). the polyphenols examined were epigallocatechin (1), epigallocatechin-3-o-gallate (2), punicalagin (3), tannic acid (4), castalagin (5), prodelp ...	2004	15577214
inhibition of tumour promotion in mouse skin by extracts of rooibos (aspalathus linearis) and honeybush (cyclopia intermedia), unique south african herbal teas.	the modulating effect of ethanol/acetone (e/a) soluble fractions, prepared from methanolic extracts of processed and unprocessed rooibos (aspalathus linearis) and honeybush (cyclopia intermedia) as well as green (camellia sinensis) teas was established in a two-stage mouse skin carcinogenesis assay. topical application of the tea fractions prior to the tumour promoter, 12-o-tetradecanoylphorbol-13-acetate (tpa), on icr mouse skin initiated with 7,12-dimethylbenz[a]anthracene (dmba) suppressed sk ...	2004	15914270
black tea extract suppresses transformation of aryl hydrocarbon receptor induced by dioxin.	dioxins cause various adverse effects through binding to an aryl hydrocarbon receptor (ahr) and transformation of the receptor. in this study, we investigated whether black tea extract suppresses ahr transformation. dried black tea leaves were extracted with 75% ethanol, and the extract was pretreated to the rat liver cytosol fraction 10 min prior to addition of 2,3,7,8-tetrachlorodibenzo-p-dioxin (tcdd). transformed ahr was detected by electrophoretic gel mobility shift assay. black tea extract ...	2004	15630227
anticancer therapeutic potential of soy isoflavone, genistein.	genistein (4'5, 7-trihydroxyisoflavone) occurs as a glycoside (genistin) in the plant family leguminosae, which includes the soybean (glycine max). a significant correlation between the serum/plasma level of genistein and the incidence of gender-based cancers in asian, european and american populations suggests that genistein may reduce the risk of tumor formation. other evidence includes the mechanism of action of genistein in normal and cancer cells. genistein inhibits protein tyrosine kinase ...	2004	15584372
green tea polyphenol epigallocatechin-3-gallate (egcg) differentially inhibits interleukin-1 beta-induced expression of matrix metalloproteinase-1 and -13 in human chondrocytes.	interleukin-1beta (il-1beta)-induced inflammatory response in arthritic joints include the enhanced expression and activity of matrix metalloproteinases (mmps), and their matrix degrading activity contribute to the irreversible loss of cartilage and may also be associated with sustained chronic inflammation. we have earlier shown that green tea (camellia sinensis) polyphenol epigallocatechin-3-gallate (egcg) was non-toxic to human chondrocytes [singh r, ahmed s, islam n, goldberg vm, and haqqi t ...	2004	14600251
the impact of ph and calcium on the uptake of fluoride by tea plants (camellia sinensis l.).	tea plants (camellia sinensis l.) accumulate large amounts of fluoride (f) from soils containing normal f concentrations. the present experiments examined the effects of ph and ca on f uptake by this accumulating plant species.	2004	14644914