Publications

induction of apoptosis by the oolong tea polyphenol theasinensin a through cytochrome c release and activation of caspase-9 and caspase-3 in human u937 cells.	this study examined the growth inhibitory effects of theasinensin a (from oolong tea) and black tea polyphenols, including theaflavin (tf-1), a mixture (tf-2) of theaflavin-3-gallate (tf-2a) and theaflavin-3'-gallate (tf-2b), and theaflavin-3,3'-digallate (tf-3) in human cancer cells. theasinensin a, tf-1, and tf-2 displayed strong growth inhibitory effects against human histolytic lymphoma u937, with estimated ic50 values of 12 microm, but were less effective against human acute t cell leukemia ...	2000	11312805
analysis of glycosidically bound aroma precursors in tea leaves. 2. changes in glycoside contents and glycosidase activities in tea leaves during the black tea manufacturing process.	glycosides are known to be precursors of the alcoholic aroma compounds of black tea. they are hydrolyzed by endogenous glycosidases during the manufacturing process. changes in the amounts of these glycosides during the manufacturing process were investigated by using a capillary gas chromatographic--mass spectrometric analysis after trifluoroacetyl derivatization of the tea glycosidic fractions. primeverosides were 3-fold more abundant than glucosides in fresh leaves, but they decreased greatly ...	2001	11308343
centrifugal precipitation chromatography -- a novel chromatographic system for fractionation of polymeric pigments from black tea and red wine.	a novel chromatographic system was developed and first applied to the fractionation of polymeric pigments from black tea and red wine. centrifugal precipitation chromatography (cpc) generates solvent gradients through a long separation channel under a centrifugal force field. tea and wine extracts are precipitated in a hexane- or methyl tert-butyl ether-rich environment and are exposed to a gradually increasing ethanol concentration. this causes a repetitive precipitation and dissolution of the ...	2001	11308318
apoptosis-inducing activity of high molecular weight fractions of tea extracts.	high molecular weight fractions of green tea, black tea, oolong tea, and pu-erh tea were found to induce apoptosis in human monoblastic leukemia u937 cells by examination of their ability to inhibit cell proliferation and to induce apoptotic body formation and dna ladder formation. these tea fractions were also shown to induce apoptosis in stomach cancer mkn-45 cells. in addition to known antitumor-promoting activity of tea high molecular weight fractions, their apoptosis-inducing activity may c ...	2001	11302190
anti-cariogenic properties of tea (camellia sinensis).	various components in green and black tea, the beverages made by infusing appropriately processed dried leaves of camellia sinensis, notably simple catechins, have properties in vitro that suggest an anti-cariogenic activity. these include: a direct bactericidal effect against streptococcus mutans and s. sobrinus; prevention of bacterial adherence to teeth; inhibition of glucosyl transferase, thus limiting the biosynthesis of sticky glucan; inhibition of human and bacterial amylases. studies in ...	2001	11289514
pharmacokinetics of gallic acid and its relative bioavailability from tea in healthy humans.	gallic acid (ga), a food component that is especially abundant in tea, is an antimutagenic, anticarcinogenic and anti-inflammatory agent. we conducted a study using acidum gallicum tablets that contained 10% ga and 90% glucose and a black tea brew that contained 93% of its ga in free form to determine the pharmacokinetics and relative bioavailability of ga in healthy humans. after the administration of a single oral dose of acidum gallicum tablets or tea (each containing 0.3 mmol ga) to 10 volun ...	2001	11285327
analysis of catechins and caffeine in tea extracts by micellar electrokinetic chromatography.	cancer chemotherapy is a new and important medical science and much interest has been focused on catechins, not only for their antioxidant activity, but also because of their known antimutagenic and antitumorigenic properties. green tea and black tea, which are among the most popular beverages consumed worldwide, contain many different catechins. we developed an analytical method capable of separating six different catechins and caffeine in tea by micellar electrokinetic chromatography in only 2 ...	2000	11271481
organization of 5s ribosomal rna genes in tea (camellia sinensis).	the 5s rrna genes in the camellia sinensis (l.) o. kuntze (tea) genome are arranged as tandem repeat units of 300 and 325 bps. the 2 classes of tandem repeats were discovered by southern hybridisation of tea genomic dna with a 5s rrna gene pcr product.	2001	11269350
antiinflammatory and antioxidant property of saponins of tea [camellia sinensis (l) o. kuntze] root extract.	two groups of saponins, ts-1 and ts-2, isolated from tea root extract (tre) were tested for antiinflammatory and in vitro antioxidant activity. both ts-1 and ts-2 inhibited carrageenan-induced paw oedema in rats. the antioxidant activity of these compounds was evaluated using the xanthine-xanthine oxidase system. the study indicated that the previously observed antitumour activity of tre might be mediated through scavenging of free radicals by saponins and their antiinflammatory activity.	2001	11268124
addition of milk does not affect the absorption of flavonols from tea in man.	tea is a major source of flavonols, a subclass of antioxidant flavonoids present in plant foods which potentially are beneficial to human health. milk added to tea, a frequent habit in the united kingdom, could inhibit absorption of tea flavonoids, because proteins can bind flavonoids effectively. eighteen healthy volunteers each consumed two out of four supplements during three days: black tea, black tea with milk, green tea and water. a cup of the supplement was consumed every 2 hours each day ...	2001	11264903
anthocyanins from red flower tea (benibana-cha), camellia sinensis.	three anthocyanins were isolated from the leaves of red flower tea (benibana-cha), camellia sinensis, and their structures were determined by means of chemical and spectroscopic analyses. two are the anthocyanins, delphinidin and cyanidin 3-o-beta-d-galactosides, respectively. whereas the third, delphinidin 3-0-beta-d-(6-(e)-p-coumaryl)galactopyranoside. the anthocyanins were also contained in the flowers of benibana-cha in different compositions.	2001	11249101
the effects of phenolic components of tea on the production of pro- and anti-inflammatory cytokines by human leukocytes in vitro.	epidemiological evidence suggests protective effects of dietary flavonoids against cardiovascular disease. tea provides a major source of dietary flavonoids in many countries and its polyphenolic components have well-recognised antioxidant properties. however, scavenging of free radicals may not be the sole mechanism by which tea-derived polyphenols exert their protective effects. this study investigates the effects of four major tea-derived catechins and a black tea extract on the production of ...	2001	11243706
mediterranean diet and longevity.	mortality statistics from the who database covering the period 1960 to 1990 have provided intriguing evidence that something unusual has been affecting in a beneficial way the health of the mediterranean population. in recent papers, which evaluated the evidence accumulated over the last three decades, it was concluded that the traditional mediterranean diet meets several important criteria for a healthy diet. direct evidence in support of the beneficial properties of the mediterranean diet has ...	2000	11242471
antimutagenic activity of green tea and black tea extracts studied in a dynamic in vitro gastrointestinal model.	an in vitro gastrointestinal model, which simulates the conditions in the human digestive tract, was used to determine potential antimutagenic activity of extracts of black tea and green tea. in this paper, results are presented on the availability for absorption of potential antimutagenic compounds present in tea and on the influence of the food matrix on this activity. between 60 and 180min after the tea was introduced into the model, antimutagenic activity was recovered from the jejunal compa ...	2001	11239964
red wine is a poor source of bioavailable flavonols in men.	red wine is a source of polyphenolic antioxidants, of which flavonols such as quercetin are representatives. red wine might therefore prevent ldl oxidation and atherosclerosis. however, data on the bioavailability of flavonols from wine are lacking. therefore, we compared the bioavailability of flavonols, especially quercetin, from red wine with that from the major dietary sources, yellow onions and black tea. twelve healthy men consumed 750 ml red wine, 50 g fried onions or 375 ml of black tea, ...	2001	11238754
consumption of high doses of chlorogenic acid, present in coffee, or of black tea increases plasma total homocysteine concentrations in humans.	in population studies, high intakes of coffee are associated with raised concentrations of plasma homocysteine, a predictor of risk of cardiovascular disease. chlorogenic acid is a major polyphenol in coffee; coffee drinkers consume up to 1 g chlorogenic acid/d.	2001	11237928
tea catechins and related polyphenols as anti-cancer agents.	epigallocatechin gallate (egcg) and theaflavins, a major constituent of green tea infusion and the constituents of black tea, respectively, were found to inhibit matrix metalloproteinases (mmps) which are intimately associated with tumor invasion and metastasis. egcg and related polyphenols exhibited apoptosis-inducing activity for several cancer cell lines including human stomach and colon cancer cells. comparison of the activity of these compounds revealed the importance of the number and the ...	2000	11237204
mechanisms of inhibition of carcinogenesis by tea.	tea (camellia sinensis) preparations have been shown to inhibit tumorigenesis at the initiation, promotion, and progression stages in different animal models. the anti-proliferative effects of tea polyphenols may be a key mechanism, especially in the nnk-induced lung tumorigenesis model with mice. studies with cell lines have demonstrated that tea polyphenols inhibit cell proliferation and induce apoptosis. the effective concentrations used in these studies (20-100 microm) are usually higher tha ...	2000	11237203
black and green tea and heart disease: a review.	tea is the second most consumed beverage around the world behind water. epidemiological evidence points to both green and black tea consumption being protective with respect to heart disease. however, epidemiological evidence does not prove cause and effect and is potentially flawed by confounding variables. the recent evidence with respect to teas' beneficial effects from in vitro and in vivo studies in both animals and humans will be covered in this review. the comparative benefits of green vs ...	2000	11237171
effects of food factors on signal transduction pathways.	consumption of plant-derived foods, especially fruits and vegetables, has been linked to decreased risk of cancer. laboratory studies with animals and cells in culture have shown cancer preventive activity of chemicals isolated from soy, tea, rice and many green, yellow and orange fruits and vegetables. using cell culture, transgenic mice and knockout mice models to examine the anti-cancer effects of these dietary factors at the molecular level, we found that (11) (-)-epigallocatechin gallate (e ...	2000	11216482
an approach to cancer risk assessment for the food constituent 2-hexenal on the basis of 1,n2-propanodeoxyguanosine adducts of 2-hexenal in vivo.	2-hexenal is formed by plants, and humans are regularly exposed to this mutagenic/genotoxic compound via vegetable foods. 2-hexenal has not been tested for carcinogenicity, but it forms exocyclic 1,n2-propanodeoxyguanosine adducts like other carcinogenic alpha,beta-unsaturated carbonyl compounds. to quantify the respective dna adducts as an approach to a theoretical cancer risk assessment, we used a newly developed 32p-postlabelling technique based on nuclease p1 enrichment, allowing a detection ...	2000	11201673
effect of black tea on lipid peroxide and glutathione levels in female rats.	the effects of black tea (camellia sinensis l.) on lipid peroxidation and glutathione (gsh) levels in carbon tetrachloride (ccl4)-treated female wistar rats were examined. two control groups and one treatment group were tested. the control groups were fed with a standard diet, while the black tea group was fed the standard diet plus 6% by weight dried black tea leaves. at the end of 2 months, a single dose of ccl4 (1 ml/kg, i.p.) in olive oil was administered to rats in one of the control groups ...	2000	11201308
effects of black tea extract on transplantable and solid tumors in swiss albino mice.	the chemopreventive effects of green tea and its polyphenols are well documented in the literature. epidemiological studies have suggested that green tea consumption might be effective in the prevention of certain human cancers. about 80% of the tea is consumed as black tea. limited studies have been carried out to assess the usefulness of black tea as anti-carcinogen. the present set of investigations were initiated to study the anti-tumorigenic potential of aqueous black tea extract (ate) in s ...	2000	11198223
black tea extract, thearubigin fraction, counteract the effects of botulinum neurotoxins in mice.	botulinum neurotoxin type a (bont/a, 1.5 nm) completely inhibited indirectly evoked twitches in in vitro mouse phrenic nerve-diaphragm preparations within 40 - 45 min. black tea extract, thearubigin fraction (trb), mixed with bont/a blocked the inhibitory effect of the toxin. the protective effect of trb extended to botulinum neurotoxins types b and e (bont/b and bont/e) and tetanus toxin, but not to tetrodotoxin. trb was also effective against oral toxicity of bont/a, b and e. thus, trb may be ...	2001	11181419
green, oolong and black tea extracts modulate lipid metabolism in hyperlipidemia rats fed high-sucrose diet.	the main goal of this study was to compare effects of ethanol-soluble fractions prepared from various types of teas on sucrose-induced hyperlipidemia in 5-week old male sprague-dawley rats. rats (n = 6-8 per group) weighed approximately 200 g were randomly divided into control diet, sucrose-rich diet, green tea, oolong tea and black tea groups. control-diet group was provided with modified ain-93 diet while the others consumed sucrose-rich diet. tea extracts (1% w/v) were supplied in the drink f ...	2001	11179857
effect of dietary quercetin on oxidative dna damage in healthy human subjects.	the effect of dietary intake of flavonols (predominantly quercetin) on oxidative dna damage was studied in thirty-six healthy human subjects (sixteen men, twenty women). the study was a randomised crossover study, comprising two 14 d treatments of either a low-flavonol (lf) or high-flavonol (hf) diet with a 14 d wash-out period between treatments. subjects were asked to avoid foods containing flavonols, flavones and flavanols during the lf dietary treatment period and to consume one 150 g onion ...	2000	11177210
novel approaches to chemoprevention of skin cancer.	protection against sun-induced damage leading to photocarcinogenesis in skin is a highly desirable goal. among various strategies, chemopreventive approaches utilizing non-toxic agents to prevent the occurrence of precancerous lesions or their surrogate markers are potentially attractive. epidemiological and experimental studies provide evidence that some naturally occurring chemical agents in the human diet can diminish cancer risk. aside from water, tea is the most common beverage consumed wor ...	2000	11138532
[amounts of selected minerals in green and black teas].	the paper contains the results of 19 minerals (ca, k, p, na, mg, zn, fe, mn, cu, f, ni, co, cr, li, sr, al, cd, hg, pb) determined in green and black species of market teas. the examined minerals (except phosphorus, fluoride and mercury) were determined by asa-method using air-acetylene flame (aluminium was determined in the nitrous oxide-acetylene flame). mercury was determined by cold vapour method. the phosphorus and fluoride was determined by spectrophotometry methods (phosphorus in the form ...	2000	11138481
inhibition of human ldl lipid peroxidation by phenol-rich beverages and their impact on plasma total antioxidant capacity in humans.	mounting evidence shows that phenol-rich beverages exert strong antioxidant activity. however, in vivo evidence has produced conflicting results. in the present study, we studied the impact of the ingestion of 300 ml of black and green tea, alcohol-free red wine, alcohol-free white wine, or water on plasma total antioxidant capacity in five healthy volunteers. red wine has the highest content of phenolics (3.63 +/- 0.48 g qe/l), followed by green tea (2.82 +/- 0.07 g qe/l), black tea (1.37 +/- 0 ...	2000	11137897
chemical composition and antioxidant activity of strobilanthes crispus leaf extract.	this study investigated the components present in and the total antioxidant activity of leaves of strobilanthes crispus (l.) bremek or saricocalyx crispus (l.) bremek (acanthacea). proximate analyses and total antioxidant activity using ferric thiocyanate and thiobarbituric acid methods were employed. minerals content was determined using the atomic absorption spectrophotometer, whereas the water-soluble vitamins were determined by means of the uv-vis spectrophotometer (vitamin c) and fluorimete ...	2000	11137889
the bio-availability of fluoride from black tea.	to investigate the oral retention of fluoride from tea and its association with the tooth surface and acquired pellicle.	2001	11137634
construction of a genetic linkage map for camellia sinensis (tea).	genetic maps are a vital tool in cultivar improvement programmes for woody perennial tree crops such as tea (camellia sinensis). a population thought to be derived from two known, noninbred parents was scored for rapd and aflp markers, in order to develop a linkage map. however, a very high proportion of the markers exhibited unexpected segregation ratios in the light of their configurations in the parents, and an exploratory statistical analysis revealed patterns in the marker scores which can ...	2000	11122412
dermatomal pruritus precipitated by drinking excessive quantities of black tea.		2000	11122071
differential effects of theaflavin monogallates on cell growth, apoptosis, and cox-2 gene expression in cancerous versus normal cells.	theaflavin (tf-1), theaflavin-3-monogallate and theaflavin-3'-monogallate mixture (tf-2), and theaflavin-3,3'-digallate (tf-3) are the major black tea polyphenols. here we compared the effects of these polyphenols on cell growth, apoptosis, and gene expression in normal and cancerous cells. we showed that tf-2 (10-50 microm) inhibited the growth of sv40 transformed wi38 human cells (wi38va) and caco-2 colon cancer cells but had little effect on the growth of their normal counterparts. the ic50s ...	2000	11103814
consumption of black tea elicits an increase in plasma antioxidant potential in humans.	epidemiological studies suggest that the consumption of tea flavonoids may be associated with reduced risk of coronary heart disease, stroke and cancer-related deaths. the flavonoids are polyphenols which in vitro exhibit antioxidant properties. tea flavonoids are known to be rapidly absorbed into the circulation following oral ingestion. to date few studies have demonstrated that these bioavailable flavonoids retain antioxidant properties in vivo. nine healthy subjects aged between 26 and 59 (o ...	2000	11103296
apolipoprotein e polymorphisms and concentration in chronic diseases and drug responses.	apolipoprotein (apo) e is an important circulating and tissue protein involved in cholesterol homeostasis and many other functions. the common polymorphism in the coding region of the gene, four polymorphisms in the promoter region, other additional single nucleotide polymorphisms, as well as several apo e variants have been identified. the common coding polymorphism strongly influences the lipid metabolism and the circulating concentration of apo e itself. this polymorphism is at the origin of ...	2000	11097338
protection against nitric oxide toxicity by tea.	it is found that green tea and black tea are able to protect against nitric oxide (no()) toxicity in several ways. both green tea and black tea scavenge no() and peroxynitrite, inhibit the excessive production of no() by the inducible form of nitric oxide synthase (inos), and suppress the lps-mediated induction of inos. the no() scavenging activity of tea was less than that of red wine. the high activity found in the polyphenol fraction of black tea (btp) could not be explained by the mixed ...	2000	11087552
inhibitory effects of tea catechins and o-methylated derivatives of (-)-epigallocatechin-3-o-gallate on mouse type iv allergy.	the inhibitory effects of tea catechins, the o-methylated derivatives of (-)-epigallocatechin-3-o-gallate (egcg), and the polyphenol extracts from tea leaves (camellia sinensis l.) on oxazolone-induced type iv allergy in male icr mice were investigated. four major tea catechins and two o-methylated derivatives, (-)-epigallocatechin-3-o-(3-o-methyl)gallate (egcg3' 'me) and (-)-epigallocatechin-3-o-(4-o-methyl)gallate (egcg4' 'me), showed significant inhibitory effects on mouse type iv allergy aft ...	2000	11087533
analysis of glycosidically bound aroma precursors in tea leaves. 1. qualitative and quantitative analyses of glycosides with aglycons as aroma compounds.	twenty-six synthetic glycosides constituting aglycons of the main tea aroma compounds ((z)-3-hexenol, benzyl alcohol, 2-phenylethanol, methyl salicylate, geraniol, linalool, and four isomers of linalool oxides) were synthesized in our laboratory as authentic compounds. those compounds were used to carry out a direct qualitative and quantitative determination of the glycosides as aroma precursors in different tea cultivars by capillary gas chromatographic-mass spectrometric (gc-ms) analyses after ...	2000	11087494
isolation of black tea pigments using high-speed countercurrent chromatography and studies on properties of black tea polymers.	isolation of theaflavins and epitheaflavic acids from black tea using high-speed countercurrent chromatography (hsccc) on a preparative scale is demonstrated. hsccc also enabled the isolation of a polymeric fraction from black tea. according to roberts' classification, the polymeric fraction mainly consisted of sii thearubigins (tr). hplc analysis showed that the isolated material is free of any known chromatographically resolved tea constituents and eluted from reversed-phase packings as a conv ...	2000	11087459
bioactive saponins and glycosides. xvii. inhibitory effect on gastric emptying and accelerating effect on gastrointestinal transit of tea saponins: structures of assamsaponins f, g, h, i, and j from the seeds and leaves of the tea plant.	following the investigation of assamsaponins a, b, c, d, and e, four new saponins termed assamsaponins f, g, h, and i were isolated from the seeds of the tea plant (camellia sinensis l. var. assamica pierre), while assamsaponin j was isolated from its leaves. the structures of assamsaponins f-j were elucidated on the basis of chemical and physicochemical evidence and found to be 16,22-o-diacetyl-21-o-angeloyltheasapogenol e 3-o-[beta-d-galactopyranosyl (1-->2)][beta-d-glucopyranosyl(1 -->2)- alp ...	2000	11086901
consumption of black and green tea had no effect on inflammation, haemostasis and endothelial markers in smoking healthy individuals.	firstly, to study the effect of tea and tea polyphenols on cardiovascular risk indicators of the inflammatory system (il6, il1beta and tnf-alpha, crp), and on haemostasis and endothelial proteins with an acute phase behaviour (fibrinogen, vwf, pai-1, fviia and u-pa). secondly, to study the relationship between plasma levels of antioxidants (alpha-tocopherol, beta-carotene and vitamin c) and these acute-phase, cardiovascular risk indicators.	2000	11083483
effect of black and green tea polyphenols on c-jun phosphorylation and h(2)o(2) production in transformed and non-transformed human bronchial cell lines: possible mechanisms of cell growth inhibition and apoptosis induction.	the biological activities of theaflavin (tf), theaflavin gallate (tfg) and theaflavin digallate (tfdig) from black tea and (-)-epigallocatechin 3-gallate (egcg) and (-)-epigallocatechin (egc) from green tea were investigated using sv40-immortalized (33bes) and ha-ras gene transformed (21bes) human bronchial epithelial cell lines. growth inhibition and cell viability were measured by trypan blue dye exclusion assay following 24 h treatment with the tea polyphenols. tfdig, egc and egcg displayed c ...	2000	11062165
effects of black tea, green tea and wine extracts on intestinal carcinogenesis induced by azoxymethane in f344 rats.	we investigated whether polyphenolic extracts from black tea, green tea or red wine affect azoxymethane (aom)-induced intestinal carcinogenesis. male f344 rats were treated 10 times (1 week apart) with aom (7.4 mg/kg, s.c.) and then allocated into groups receiving black tea, green tea or red wine extracts mixed in the diet at a dose of 50 mg/kg body weight for 16 weeks. in the rats treated with black tea or wine extracts, there were significantly fewer colorectal tumours than in controls (the me ...	2000	11062155
separation and identification of twelve catechins in tea using liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry.	a method has been developed for the direct microscale determination of 12 catechins in green and black tea infusions. the method is based on liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (lc/apci-ms). standard catechin mixtures and tea infusions were analyzed by lc/apci-ms with detection of protonated molecular ions and characteristic fragment ions for each compound. the identities of eight major catechins and caffeine in tea were established based on lc retent ...	2000	11055724
comparison of antioxidant and antimicrobial activities of tilia (tilia argentea desf ex dc), sage (salvia triloba l.), and black tea (camellia sinensis) extracts.	the antioxidant activity of the water extract of tilia argentea desf ex dc was determined by the thiocyanate method. the antioxidant activity of the water extract increased with the increasing amount of lyophilized extract (50-400 microg) added into the linoleic acid emulsion. statistically significant effect was determined in 100 microg and higher amounts. antioxidant activities of water extracts of tilia (tilia argentea desf ex dc), sage (salvia triloba l.), and two turkish black teas commerci ...	2000	11052773
inhibition of 1,2-dimethylhydrazine-induced oxidative dna damage in rat colon mucosa by black tea complex polyphenols.	the effect of black tea polyphenols on 1,2-dimethylhydrazine (dmh)-induced oxidative dna damage in rat colon mucosa has been investigated. fischer 344 rats were treated orally with thearubigin (tr) or theafulvin (tfu) for 10 days (40 mg/kg), injected ip with dmh (20 mg/kg) or saline and sacrificed 24 hr after dmh administration. the levels of 8-hydroxy-2'-deoxyguanosine (8-ohdg) were measured in colonic mucosa dna and expressed as a ratio relative to 2'-deoxyguanosine (2dg). control rat mucosa h ...	2000	11033196
eat to live, not live to eat.	most of the prevailing chronic diseases in the world have an important nutritional component by directly causing a specific disease, enhancing the risk through phenomena of promotion, exerting a beneficial effect in decreasing risk, or preventing the disease. international studies in geographic pathology have shown that a given disease may have vastly different incidence and mortality as a function of residence. laboratory research in animal models can reproduce fairly accurately what is learned ...	2000	11032452
flavonoids protect against oxidative damage to ldl in vitro: use in selection of a flavonoid rich diet and relevance to ldl oxidation resistance ex vivo?	the ability of a range of dietary flavonoids to inhibit low-density lipoprotein (ldl) oxidation in vitro was tested using a number of different methods to assess oxidative damage to ldl. overall quercetin was the most effective inhibitor of oxidative damage to ldl in vitro. on this basis, a diet enriched with onions and black tea was selected for a dietary intervention study that compared the effect on the cu2+ ion-stimulated lag-time of ldl oxidation ex vivo in healthy human subjects of a high ...	2000	11022850
inhibition of non-haem iron absorption in man by polyphenolic-containing beverages.	the effects of different polyphenol-containing beverages on fe absorption from a bread meal were estimated in adult human subjects from the erythrocyte incorporation of radio-fe. the test beverages contained different polyphenol structures and were rich in either phenolic acids (chlorogenic acid in coffee), monomeric flavonoids (herb teas, camomile (matricaria recutita l.), vervain (verbena officinalis l.), lime flower (tilia cordata mill.), pennyroyal (mentha pulegium l.) and peppermint (mentha ...	1999	10999016
effect of black tea on lipid peroxidation in carbon tetrachloride treated male rats.	this study examined the effects of black tea (camellia sinensis l.) on lipid peroxidation and glutathione levels in carbon tetrachloride (ccl4)-treated male wistar rats. three groups of rats formed two control groups and one treatment group. the control groups were fed with a standard diet, while the black tea group were fed the standard diet plus 6% by weight dried black tea leaves. after two months, the rats in the black tea group and in one control group were administered a single dose of ccl ...	2000	10962644
[organochlorine pesticide residues in tea].	organochlorine pesticides still exist as environmental pollutants in many countries. in this paper, the results of monitoring of organochlorine pesticides in teas taken from the polish market in 1998 year are presented. the monitoring included analysis of organochlorine insecticides and their metabolites (sigma ddt, sigma hch, hcb, heptachlor, epoxide heptachlor, and aldrin) in samples of black and green tea, and fruit tea. the mean concentration of the organochlorine compounds in the black tea ...	2000	10959192
green tea.	tea is one of the most widely consumed beverages in the world today, second only to water, and its medicinal properties have been widely explored. the tea plant, camellia sinensis, is a member of the theaceae family, and black, oolong, and green tea are produced from its leaves. it is an evergreen shrub or tree and can grow to heights of 30 feet, but is usually pruned to 2-5 feet for cultivation. the leaves are dark green, alternate and oval, with serrated edges, and the blossoms are white, frag ...	2000	10956382
preparative separation of polyphenols from tea by high-speed countercurrent chromatography.	high-speed countercurrent chromatography (hsccc) was applied to the separation of polyphenols from tea leaves (camellia sinensis l.). the capability of hsccc to isolate pure tea polyphenols from complex mixtures on a preparative scale was demonstrated for catechins, flavonol glycosides, proanthocyanidins, and strictinin from green and black tea. the purity and identity of isolated compounds was confirmed by (1)h nmr and hplc-esi-ms/ms. gram quantities of polyphenols from tea can be isolated with ...	2000	10956128
antioxidant potential of green and black tea determined using the ferric reducing power (frap) assay.	tea is one of the most commonly consumed beverages in the world and is rich in polyphenolic compounds collectively known as the tea flavonoids. tea flavonoids possess antioxidant properties in vitro and have been proposed as key protective dietary components, reducing risk of coronary heart disease and some cancers. the present study aimed to evaluate the possible effects of different preparation methods on the antioxidant properties of green and black tea. antioxidant potentials of tea infusate ...	2000	10945114
inhibition of ultraviolet b-induced ap-1 activation by theaflavins from black tea.	theaflavins are believed to be key active components in black tea for chemoprevention of cancer. however, the molecular mechanisms underlying the inhibitory effects of theaflavins are not clear. with the jb6 mouse epidermal cell line, we investigated the effects of theaflavins on ultraviolet (uv) b radiation-induced activator protein-1 (ap-1)-dependent transcriptional activation and compared them with (-)-epigallocatechin-3-gallate (egcg), a major green tea polyphenol that has cancer chemopreven ...	2000	10942531
tandem mass spectrometry studies of green tea catechins. identification of three minor components in the polyphenolic extract of green tea.	liquid chromatography/electrospray ionization mass and tandem mass spectrometry (ms/ms) techniques were used to identify two minor components and one new compound in the polyphenolic extract of green tea (camellia sinensis). identification and structure assignments were based on previously reported sub-structural features in the ms/ms product, precursor and neutral loss scans of reference samples. the structures of two minor components, related to the known green tea components epicatechin galla ...	2000	10934439
protease from sporosarcina sp. rrlj 1.	protease was isolated from sporosarcina rrlj1 which was collected from acid tea (camellia sinensis) plantations. it showed potential for production of the enzyme for commercial purposes. the study revealed that optimum ph for growth of the organism was 6.5-7 and supplement of casein (1%) in the medium was required for production of protease. enzyme production and enzyme activity was maximum in 72 hr old broth culture. maximum activity of the enzyme was found at ph 6.5.	2000	10927879
tea intake and squamous cell carcinoma of the skin: influence of type of tea beverages.	differences in tea drinking habits are likely to vary by populations and could contribute to the inconsistencies found between studies comparing tea consumption and cancer risk. a population-based case-control study was used to evaluate how usual tea consumption patterns of an older population (n = 450) varied with history of squamous cell carcinoma (scc) of the skin. a detailed tea questionnaire was developed to assess specific tea preparation methods and patterns of drinking. in this southwest ...	2000	10919744
kombucha, the fermented tea: microbiology, composition, and claimed health effects.	kombucha is a slightly sweet, slightly acidic tea beverage consumed worldwide, but historically in china, russia, and germany. kombucha is prepared by fermenting sweetened black tea preparations with a symbiotic culture of yeasts and bacteria. potential health effects have created an increased interest in kombucha. yet, only a few research studies have shown that kombucha has in vitro antimicrobial activity and enhances sleep and pain thresholds in rats. furthermore, kombucha consumption has pro ...	2000	10914673
comparative analysis of tea catechins and theaflavins by high-performance liquid chromatography and capillary electrophoresis.	this paper describes the simultaneous determination of catechins and theaflavins in green and black teas, using reversed-phase high-performance liquid chromatography (hplc) and capillary electrophoresis (ce). the tea polyphenols analyzed included (+)-catechin, catechin gallate, (-)-epicatechin, epicatechin-3-gallate, epigallocatechin, epigallocatechin-3-gallate, theaflavin, theaflavin-3-monogallate, theaflavin-3'-monogallate and theaflavin-3,3'-gallate. these polyphenols together with six other ...	2000	10905726
trolox equivalent antioxidant capacity (teac) of ginkgo biloba flavonol and camellia sinensis catechin metabolites.		2000	10898173
electrospray characterization of selected medicinal plant extracts.	extracts of selected medicinal plants were examined by electrospray mass spectrometry (esi-ms). this technique allowed identification of the main components of each extract, thereby providing a typical finger-print of the examined plants. more specifically, anthocyanins (vaccinium myrtillus), isoflavones (glycine max, soybean), flavonol-glycosides and terpenes (ginkgo biloba), triterpenes (centella asiatica), caffeoyl-quinic acids (cynara scolymus, artichoke), ginsenosides (panax ginseng), catec ...	2000	10898155
gallic acid metabolites are markers of black tea intake in humans.	gallic acid is one of the main phenolic components of black tea. the objective of this study was to identify urinary gallic acid metabolites with potential for use as markers of black tea intake. in an initial study, nine compounds, assessed by using gas chromatography-mass spectrometry, were found to increase in concentration in urine after 3 cups of black tea over 3 h. a subsequent study employed a controlled crossover design in which 10 subjects consumed 5 cups per day of black tea or water f ...	2000	10888536
reanalysis of blanc pd et al, "use of herbal products, coffee or black tea, and over-the-counter medications as self treatments among adults with asthma".		2000	10887326
comparative study of antioxidant potential of tea with and without additives.	oxidative damage is one of the many mechanism leading to chronic diseases. therefore interest is growing in the protection afforded by antioxidant nutrients against free radical reactions. more recently, the attention has shifted to polyphenols. polyphenols are secondary plant metabolites occurring widely in plant food. they possess outstanding antioxidant properties, suggesting a possible protective role in man. tea (camellia sinensis) is a widely consumed beverage throughout the world containi ...	2000	10846639
tea polyphenols: prevention of cancer and optimizing health.	the tea plant camellia sinesis is cultivated in >30 countries. epidemiologic observations and laboratory studies have indicated that polyphenolic compounds present in tea may reduce the risk of a variety of illnesses, including cancer and coronary heart disease. most studies involved green tea, however; only a few evaluated black tea. results from studies in rats, mice, and hamsters showed that tea consumption protects against lung, forestomach, esophagus, duodenum, pancreas, liver, breast, colo ...	2000	10837321
tea and other beverage consumption and prostate cancer risk: a canadian retrospective cohort study.	using participants in the 1970-1972 nutrition canada survey (ncs), a retrospective cohort study was conducted to assess the relationship between tea, as well as coffee, cola and alcohol, and the risk of developing prostate cancer. the mortality and cancer experience of male ncs participants aged 50-84 years was determined up to 31 december 1993. among the 3400 survey participants included in the study, 145 developed prostate cancer. no association was observed between tea (predominantly black te ...	2000	10830580
triterpenoid saponins from the roots of tea plant (camellia sinensis var. assamica).	three olean-12-ene type triterpenoid saponins, named tr-saponins a, b and c, were isolated as methyl esters from tea roots (camellia sinesis var. assamica) after treatment with diazomethane. their structures were established as the methyl esters of 3-o-alpha-l-arabinopyranosyl (1-->3)-beta-d-glucuronopyranosyl-21, 22-di-o-angeloyl-r1-barrigenol-23-oic acid, 3-o-alpha-l-arabinopyranosyl (1-->3)-beta-d-glucuronopyranosyl-21-o-angeloyl-22-o-2-me thylbutanoyl-r1- barrigenol-23-oic acid and 3-o-alpha ...	2000	10820808
catechin contents of foods commonly consumed in the netherlands. 2. tea, wine, fruit juices, and chocolate milk.	catechins, compounds that belong to the flavonoid class, are potentially beneficial to human health. to enable an epidemiological evaluation of catechins, data on their contents in foods are required. hplc with uv and fluorescence detection was used to determine the levels of (+)-catechin, (-)-epicatechin, (+)-gallocatechin (gc), (-)-epigallocatechin (egc), (-)-epicatechin gallate (ecg), and (-)-epigallocatechin gallate (egcg) in 8 types of black tea, 18 types of red and white wines, apple juice ...	2000	10820090
acute effects of ingestion of black and green tea on lipoprotein oxidation.	tea has been associated with a reduced risk of cardiovascular disease. one proposed mechanism of this risk reduction involves inhibition of lipoprotein oxidation in vivo by antioxidant polyphenolic compounds derived from tea. however, controlled interventions uniformly failed to show that ingestion of tea can inhibit ldl oxidation ex vivo. the absence of effects in previous studies may be due to the isolation of ldl particles from polyphenolic compounds that are present in the aqueous phase of s ...	2000	10799371
tea as a potential chemopreventive agent in phip carcinogenesis: effects of green tea and black tea on phip-dna adduct formation in female f-344 rats.	the heterocyclic amine 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (phip) is formed during the cooking of proteinaceous animal foods (meat, chicken, and fish). phip is a carcinogen in the fischer 344 (f-344) rat; it induces mammary tumors in female rats and lymphomas and colon and prostate tumors in male rats. in f-344 rats, phip forms dna adducts in various organs, including the target organs. inhibition of phip-dna adduct formation is likely to lead to inhibition of phip tumorigenicity. we ...	2000	10798216
sickle cell anemia: a potential nutritional approach for a molecular disease.	a certain population of red blood cells in patients with sickle cell anemia has an elevated density and possesses an abnormal membrane. these "dense cells" have a tendency to adhere to neutrophils, platelets, and vascular endothelial cells, and, thus, they could trigger vasoocclusion and the subsequent painful crisis from which these patients suffer. we developed a laboratory method of preparing such dense cells and found that nutritional antioxidant supplements, hydroxyl radical scavengers, and ...	2000	10793299
cancer chemoprevention by tea polyphenols.	tea is one of the most widely consumed beverages, second only to water. many experimental researches in laboratory animals demonstrated that tea components had an inhibitory effect on carcinogenesis at a number of organ sites. the inhibitory effects of tea against carcinogenesis have been attributed to the biologic activities of the polyphenol fraction in tea. this review summarizes experimental data on chemopreventive effects of tea polyphenols in various tumor bioassay systems. many laboratory ...	2000	10786933
correlation of chemopreventive efficacy data from the human epidermal cell assay with in vivo data.	continuous exposure to low doses of potentially mutagenic and carcinogenic chemicals over the human lifetime makes the identification of agents, which could reduce the ensuing risk of cancer, beneficial. the human epidermal cell (hec) assay includes multiple exposures to low, non-toxic doses of propane sultone, which increases cellular growth and inhibits differentiation, and co-exposure to potential chemopreventive agents to determine their ability to inhibit the increased growth or increase di ...	2000	10769631
synergistic effects of thearubigin and genistein on human prostate tumor cell (pc-3) growth via cell cycle arrest.	there is evidence that habitual consumption of green tea by japanese men is correlated with a reduction in cancers, including prostate; soybean isoflavones are also associated with increased protection. the present study compared the anti-proliferative effect of black tea (camellia sinensis) polyphenol, thearubigin (tr), alone or combined with the isoflavone genistein, on human prostate (pc-3) carcinoma cells. tr administered alone did not result in any alteration of cell growth. when combined w ...	2000	10766429
hippuric acid as a major excretion product associated with black tea consumption.	1. nine habitual tea-drinking volunteers were recruited and asked to follow a low-polyphenol and low-caffeine diet for 6 days and to provide daily 24-h urine samples. on day 4 of the experiment strong black tea brewed under standardized conditions was re-introduced to the volunteers' diet. 2. 1h-nmr and hplc profiling of the urine samples indicated that consumption of black tea (6-10 mugs per day) was associated with a significant (p = 0.00017) increase in hippuric acid excretion relative to con ...	2000	10752646
bioactive saponins and glycosides. xv. saponin constituents with gastroprotective effect from the seeds of tea plant, camellia sinensis l. var. assamica pierre, cultivated in sri lanka: structures of assamsaponins a, b, c, d, and e.	the saponin fraction from the seeds of the tea plant, camellia sinensis l. var. assamica pierre cultivated in sri lanka, was found to show a potent protective effect on gastric mucosal lesions induced by ethanol in rats. nine new acylated polyhydroxyoleanene-type triterpene oligoglycosides called assamsaponins a-i were isolated from the active saponin fraction together with three known saponins, theasaponin e1 and e2 and camelliasaponin b1. the structures of assamsaponins a-e were elucidated on ...	1999	10748719
marked reduction in the minimum inhibitory concentration (mic) of beta-lactams in methicillin-resistant staphylococcus aureus produced by epicatechin gallate, an ingredient of green tea (camellia sinensis).	we found that epicatechin gallate, a constituent of an extract of tea leaves (green tea) markedly lowered the minimum inhibitory concentration (mic) of oxacillin and other beta-lactams, but not of other antibacterial agents tested, in strains of methicillin-resistant staphylococcus aureus. the antibacterial action of epicatechin gallate plus oxacillin was a bactericidal one.	1999	10746177
[chemical constituents of seeds of camellia sinensis var. assamica].	five compounds were isolated from the acid-hydrolytic products of n-butanol extract and ethanol extract of the seeds of camellia sinensis var. assamica. their structures were elucidated by chemical and spectroscopic analyses as octacosane, three new acyl-sapogenins: 22-o-angeloyl theasapogenol b, 22-o-angeloyl theasapogenol e and 22-o-angeloyl theasapogenol a, and naringenin respectively.	1997	10743215
insulin-like biological activity of culinary and medicinal plant aqueous extracts in vitro.	to evaluate the possible effects on insulin function, 49 herb, spice, and medicinal plant extracts were tested in the insulin-dependent utilization of glucose using a rat epididymal adipocyte assay. cinnamon was the most bioactive product followed by witch hazel, green and black teas, allspice, bay leaves, nutmeg, cloves, mushrooms, and brewer's yeast. the glucose oxidation enhancing bioactivity was lost from cinnamon, tea, witch hazel, cloves, bay leaf and allspice by poly(vinylpyrrolidone) (pv ...	2000	10725162
tea and tea polyphenols in cancer prevention.	the inhibitory action of tea (camellia sinensis) and tea components against cancer formation has been demonstrated in different animal models involving different organ sites in many laboratories. the possible preventive activity of tea against cancer in humans, however, is not clear. a critical question is whether the information obtained from animal studies is applicable to humans because of possible species differences or the difference in the quantity of tea used in animal studies and that co ...	2000	10721932
progress in cancer chemoprevention: development of diet-derived chemopreventive agents.	because of their safety and the fact that they are not perceived as "medicine," food-derived products are highly interesting for development as chemopreventive agents that may find widespread, long-term use in populations at normal risk. numerous diet-derived agents are included among the >40 promising agents and agent combinations that are being evaluated clinically as chemopreventive agents for major cancer targets including breast, prostate, colon and lung. examples include green and black te ...	2000	10721931
an improved method for the determination of green and black tea polyphenols in biomatrices by high-performance liquid chromatography with coulometric array detection.	tea polyphenols are strong antioxidants and are believed to have beneficial health effects. however, the blood and tissue levels of these compounds are not well characterized because of a lack of suitable analytical methods for the biological resolution of these compounds. previously, we developed methods for the analysis of three green tea catechins. now we report an improved method for the measurement of the levels of the different catechins and theaflavins in biological fluids and tissues. th ...	2000	10706785
inactivation of human type a and b influenza viruses by tea-seed saponins.	the effects of a mixture of tea-seed saponins obtained from the seeds of camellia sinensis var. sinesis on human influenza viruses types a and b were investigated. at the concentrations of 60, 80, and 100 micrograms/ml, respectively, the mixture inactivated viruses a/memphis/1/71 (h3n2), b/lee/40, and a/pr/8/34 (h1n1) almost completely. the mixture also inactivated type a virus a/pr/8/34 after inoculation at concentrations of 1-30 micrograms/ml dose-dependently.	2000	10705466
prokinetic effect of black tea on gastrointestinal motility.	the gastrokinetic effects of hot water extract of black tea [camellia sinensis, (l) o. kuntze (theaceae)] on gastrointestinal motility were studied both in vivo and in vitro. the extract significantly accelerated the gastrointestinal transit (git) in vivo in mice. these facilitatory effect was reduced after pretreatment with atropine, hemicholinium-3, morphine, indomethacin, mcn-a-343 and l-arginine. in guinea pig ileum, the extract facilitated the peristaltic reflex in response to pressures in ...	2000	10698359
a single dose of tea with or without milk increases plasma antioxidant activity in humans.	to investigate the effect of black and green tea consumption, with and without milk, on the plasma antioxidant activity in humans.	2000	10694777
inhibitory effects of tea extracts on the mutagenicity of 1-methyl-1, 2,3,4-tetrahydro-beta-carboline-3-carboxylic acid on treatment with nitrite in the presence of ethanol.	it has been shown that the mutagenicity of 1-methyl-1,2,3, 4-tetrahydro-beta-carboline-3-carboxylic acid (mtcca), a major mutagen precursor in soy sauce on treatment with nitrite and ethanol, was strongly decreased by the addition of hot water extracts of green, black and oolong teas in the reaction mixture when it was treated with 50mm nitrite at ph3.0, 37 degrees c for 60min in the presence of 7.5% ethanol. the mutagenicity-decreasing activity of the teas was scarcely decreased by washing the ...	2000	10685009
progress in cancer chemoprevention.	more than 40 promising agents and agent combinations are being evaluated clinically as chemopreventive drugs for major cancer targets. a few have been in vanguard, large-scale intervention trials--for example, the studies of tamoxifen and fenretinide in breast, 13-cis-retinoic acid in head and neck, vitamin e and selenium in prostate, and calcium in colon. these and other agents are currently in phase ii chemoprevention trials to establish the scope of their chemopreventive efficacy and to devel ...	1999	10668477
suppression of lipopolysaccharide-induced nuclear factor-kappab activity by theaflavin-3,3'-digallate from black tea and other polyphenols through down-regulation of ikappab kinase activity in macrophages.	we investigated the inhibition of ikappab kinase (ikk) activity in lipopolysaccharide (lps)-activated murine macrophages (raw 264.7 cell line) by various polyphenols including (-)-epigallocatechin-3-gallate, theaflavin, a mixture of theaflavin-3 gallate and theaflavin-3'-gallate, theaflavin-3,3'-digallate (tf-3), pyrocyanidin b-3, casuarinin, geraniin, and penta-o-galloyl-beta-d-glucose (5gg). tf-3 inhibited ikk activity in activated macrophages more strongly than did the other polyphenols. tf-3 ...	2000	10644043
green tea in chemoprevention of cancer.	the concept of prevention of cancer using naturally occurring substances that could be included in the diet consumed by the human population is gaining increasing attention. tea, next to water, is the most popularly consumed beverage in the world and it is grown in about 30 countries. abundant data, amassed from several laboratories around the world in the last ten years, provided convincing evidence that polyphenolic antioxidants present in tea afford protection against cancer risk in many anim ...	1999	10630599
dietary fat, body weight, and cancer: contributions of studies in rodents to understanding these cancer risk factors in humans.	understanding diet and energy balance as risk factors for breast, colon, and other cancers requires information on the contribution of each factor and of interactions among factors to cancer risk. rodent models for breast cancer provide extensive data on effects of dietary fat and calories, energy balance, body weight gain, and physical activity on tumor development. analyses of the combined data from many studies have shown clearly that quality and quantity of dietary fat and energy balance con ...	1999	10630593
chemopreventive effects of tea extracts and various components on human pancreatic and prostate tumor cells in vitro.	pancreatic and prostate cancers pose serious problems to human health. to determine the potential for chemopreventive intervention against pancreatic and prostate cancers, black and green tea extracts and components of these extracts were examined in vitro for their effect on tumor cell growth. components included a mixture of polyphenols from green tea (gtp), mixtures of polyphenols (btp) and of theaflavins (mf) from black tea, and the purified components epicatechin-3-gallate (ecg) and epigall ...	1999	10624710
comparative chemopreventive mechanisms of green tea, black tea and selected polyphenol extracts measured by in vitro bioassays.	black tea extracts (hot aqueous, polyphenols and theaflavins) and green tea extracts (hot aqueous, polyphenols, epicatechin, epicatechin gallate, epigallocatechin and epigallocatechin gallate) were tested in nine standardized cell culture assays for comparative cancer chemopreventive properties. most black and green tea extracts strongly inhibited neoplastic transformation in mouse mammary organ cultures, rat tracheal epithelial cells and human lung tumor epithelial cells. nearly all tea fractio ...	2000	10607735
comparison of digestion methods for determination of trace and minor metals in plant samples.	in this paper, three dissolution methods using pressure digestion vessels (low-, medium-, and high-pressure vessels) for the determination of metals in plant samples are described. the plackett-burman saturated factorial design was used to identify the significant factors influencing wet ashing and to select optimized dissolution conditions. the three methods were statistically compared (on-way anova) on the same sample; no significant differences were obtained. in all cases the relative standar ...	1999	10606575
application of near-infrared reflectance spectroscopy to the simultaneous prediction of alkaloids and phenolic substances in green tea leaves.	a near-infrared reflectance spectroscopic (nirs) method for the prediction of polyphenol and alkaloid compounds in the leaves of green tea [camellia sinensis (l.) o. kuntze] was developed. reference measurements of the individual catechins, gallic acid, caffeine, and theobromine were performed by reversed-phase hplc. the total polyphenols were determined according to the colorimetric folin-ciocalteu assay. using the partial least-squares algorithm, very good calibration statistics were obtained ...	1999	10606573
fungi associated with black tea and tea quality in the sultanate of oman.	forty-eight samples of four popular commercial brands of black tea (camellia sinensis l.) were purchased from the local markets in muscat area, sultanate of oman. tea leaves were surveyed for mycoflora. five fungal species were isolated with a. niger as the most dominant in all the brands having percentage contamination ranging between 0.66% and 30.34%. other fungi isolated were aspergillusflavus, penicillium spp. and pacelomyces spp. but having average percentages of 0.6%, 0.84% and 0.21% respe ...	1999	10598069
tea and health.	the possible beneficial effects of tea consumption in the prevention of cancer and cardiovascular diseases have been demonstrated in animal models and suggested by studies in vitro. similar beneficial effects, however, have not been convincingly demonstrated in humans: beneficial effects have been demonstrated in some studies but not in others. if such beneficial effects do exist in humans, they are likely to be mild, depending on many other lifestyle-related factors, and could be masked by conf ...	2008	10575676
metabolism of theanine, gamma-glutamylethylamide, in rats.	the metabolism of theanine, one of the major amino acid components in tea (camellia sinensis), was studied in rats. high-performance liquid chromatography (hplc) with fluorometric detection was used to evaluate the nature of theanine's metabolites in plasma, urine, and tissues. in the urine samples collected after administration of 100, 200, and 400 mg each of theanine, intact theanine, l-glutamic acid, and ethylamine, these compounds were detected in a dose-dependent manner. when 200 mg of thea ...	1999	10564022
inhibition of tpa-induced protein kinase c and transcription activator protein-1 binding activities by theaflavin-3,3'-digallate from black tea in nih3t3 cells.	tea is one of the most popular beverages in the world. several reports have shown that both green tea and black tea were able to inhibit tumor cell proliferation in animal models. in this study, we investigated the inhibitory effects of black tea polyphenols including theaflavin (tf-1), the mixture (tf-2) of theaflavin-3-gallate (tf-2a), and theaflavin-3'-gallate (tf-2b), theaflavin-3,3'-digallate (tf-3), thearubigin (tr), and a major green tea polyphenol (-)-epigallocatechin-3-gallate (egcg) on ...	1999	10563991