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
determination of total aluminum, chromium, copper, iron, manganese, and nickel and their fractions leached to the infusions of black tea, green tea, hibiscus sabdariffa, and ilex paraguariensis (mate) by eta-aas.	total aluminum, chromium, copper, iron, manganese, and nickel were determined in black tea, green tea, hibiscus sabdariffa, and ilex paraguariensis (mate) by electrothermal atomic absorption spectrometry after nitric/perchloric acid digestion. in each case, one ground sample of commercially available leafy material was prepared and three 0.5-g subsamples were run in parallel. the infusions were also analyzed and the percentage of each element leached into the liquor was evaluated. the obtained r ...	2000	11314985
[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
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
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
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
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
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
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
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
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
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
[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
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
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
trolox equivalent antioxidant capacity (teac) of ginkgo biloba flavonol and camellia sinensis catechin metabolites.		2000	10898173
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
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
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
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
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
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
signal transduction pathways: targets for chemoprevention of skin cancer.	chemoprevention can be defined as the use of substances to interfere with the process of cancer development. although substantial progress has been made in elucidating the basis of carcinogenesis, further advances are needed to identify molecular and cellular targets for effective use of chemopreventive agents. hundreds of compounds have been identified as potential chemopreventive agents. however, the safety and efficacy of each substance must be thoroughly investigated. carcinogenesis is a mul ...	2000	11905657
effect of black tea on teeth.	dental caries is the prime cause of premature loss of teeth in children. tea contains high percentage of fluoride along with polyphenolic constituents which act on gtf of s. mutans in plaque synthesis. combination of fluoride and polyphenolic constituents inhibit caries activity.	2000	11601182
differentiation of tea (camellia sinensis) varieties and their geographical origin according to their metal content.	the metal content of 46 tea samples, including green, black, and instant teas, was analyzed. al, ba, ca, cu, fe, k, mg, mn, na, sr, ti, and zn were determined by icp-aes. potassium, with an average content of 15145.4 mg kg(-1) was the metal with major content. calcium, magnesium, and aluminum had average contents of 4252.4, 1978.2, and 1074.0 mg kg(-1), respectively. the average amount of manganese was 824.8 mg kg(-1). there were no clear differences between the metal contents of green and black ...	2001	11600020
effects of regular ingestion of black tea on haemostasis and cell adhesion molecules in humans.	to assess the effects in humans of regular ingestion of black tea on haemostasis-related variables and cell adhesion molecules.	2001	11593350
guidelines for the intake of vegetables and fruit: the mediterranean approach.	various studies have demonstrated that the nutrient and non-nutrient substances present in vegetables and fruit (v&f) are most likely to be responsible for the beneficial effect of the increased v&f consumption. urged by scientific evidence, current dietary guidelines strongly recommend the consumption of v&f in substantial amounts. in a recent paper (brit. j. nutr. 2000; 84, 549-556) v&f availability in 10 european countries was compared with the who recommendations (minimum combined v&f intake ...	2001	11582835
profiles of purine and pyrimidine nucleotides in fresh and manufactured tea leaves.	profiles of nucleotide levels in two varieties of japanese green teas (cv. yabukita and saemidori), a chinese green tea (longjing), and two japanese black teas (cv. benifuuki and benihikari) were determined and compared with that of fresh tea leaves. the concentration of 5'-nucleotides in green tea was much higher than in black tea. nucleoside diphosphates were present in larger amounts than nucleoside triphosphates in manufactured green and black teas, whereas the triphosphates predominated in ...	2001	11559141
joint effects of citrus peel use and black tea intake on the risk of squamous cell carcinoma of the skin.	differences in tea drinking habits and/or citrus peel use are likely to vary by populations and could contribute to the inconsistencies found between studies comparing their consumption and cancer risk.	2001	11527506
decrease in concentration of free catechins in tea over time determined by micellar electrokinetic chromatography.	cancer chemoprevention 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. due to the instability of catechins in solutions with neutral or basic ph values the concentrations of catechins in tea decrease in time. in this pr ...	2001	11521904
comparison of the antioxidant content of fruits, vegetables and teas measured as vitamin c equivalents.	most of the health benefits of black, green and oolong teas made from camellia sinensis are attributed to their antioxidant content. many plants and spices have been used to make infusions that are erroneously referred to as 'teas'. the term 'rich in antioxidants' is often used to describe such infusions, often without scientific support. we have used the dpph method to quantify the total radical scavenging capacity (rsc) of a wide range of 'teas', fruits and vegetables. the results are presente ...	2001	11518612
processing procedures of brick tea and their influence on fluorine content.	china is the only country that produces brick tea, and more than 90% of the brick tea is consumed in the western minority nationality regions of china. the high fluorine content of brick tea is possibly associated with the special processing procedures, but no investigation has been conducted in this field. to explore the characteristic features of brick tea manufacturing and the alterations in fluorine content during the processing procedures, we performed a field survey involving two brick tea ...	2001	11498273
biochemical responses of camellia sinensis (l.) o. kuntze to heavy metal stress.	three heavy metals-mercury (ii), copper (ii) and nickel (ii), each at a concentration of 10 and 100 micrograms/ml, were tested for their effects on various biochemical constituents of tea leaves. both ni (ii) and hg (ii) decreased the phenolic contents, while cu (ii) increased it to some extent. the metal treatments enhanced the activity of phenyl alanine ammonia lyase (pal), while the activity of poly phenol oxidase (ppo) showed a decline. heavy metal stress also decreased the chlorophyll conte ...	2001	11480349
catechin intake might explain the inverse relation between tea consumption and ischemic heart disease: the zutphen elderly study.	epidemiologic studies suggest that tea consumption may reduce the risk of cardiovascular diseases, but results are inconsistent. catechins, which belong to the flavonoid family, are the main components of tea and may be responsible for the alleged protective effect. taking catechin sources other than tea into account might clarify the reported associations.	2001	11470725
black tea; white teeth. research suggests beverage may be powerful cavity-fighting tool.		2001	11462338
analysis of black tea theaflavins by non-aqueous capillary electrophoresis.	in this study a new capillary electrophoresis (ce) method was developed to quantify the four major theaflavins occurring in black tea. where aqueous based ce methods showed poor selectivity and considerable band broadening, non-aqueous ce achieved baseline separation of the theaflavins within 10 min. the effects of the organic solvent composition and background electrolyte concentration on the separation selectivity and electrophoretic mobilities were investigated. our optimized separation solut ...	2001	11459305
comparison of the antioxidant activity of commonly consumed polyphenolic beverages (coffee, cocoa, and tea) prepared per cup serving.	in this study, the in vitro low-density lipoprotein oxidation model was used to assess the relative antioxidant activity of the polyphenolic beverages tea, coffee, and cocoa on a cup-serving basis. the beverages were prepared as 0.7-2.5% soluble coffee and 1.5-3.5% cocoa; teas (green, black, or herbal) were prepared as one tea bag infused over 5 min in 220 ml of hot water. under these standard cup serving conditions, the antioxidant activity as determined by the lag time was in the range of 292- ...	2001	11453788
change in the flavor of black tea drink during heat processing.	heat processing during canning is responsible for the change in flavor of black tea infusion. the quantitative change in the volatile components of the black tea infusion during heat processing is not sufficient for explaining the sensory evaluation. in this study, application of aroma extract dilution analysis using the volatile fraction before and after black tea (darjeeling) samples were heat processed resulted in the detection of 10 odor-active peaks for which flavor dilution (fd) factors ch ...	2001	11453767
a review of latest research findings on the health promotion properties of tea.	important progress has been made in the past five years concerning the effects of green and black tea on health. experimentation with new accurate tools provide useful information about the metabolism of tea components in the body, their mode of action as antioxidants at the cellular level and their protective role in the development of cancer, cardiovascular disease and other pathologies. the use of tea components as nutraceuticals and functional foods are also discussed.	2001	11448616
short- and long-term black tea consumption reverses endothelial dysfunction in patients with coronary artery disease.	epidemiological studies suggest that tea consumption decreases cardiovascular risk, but the mechanisms of benefit remain undefined. endothelial dysfunction has been associated with coronary artery disease and increased oxidative stress. some antioxidants have been shown to reverse endothelial dysfunction, and tea contains antioxidant flavonoids. methods and results-- to test the hypothesis that tea consumption will reverse endothelial dysfunction, we randomized 66 patients with proven coronary a ...	2001	11447078
the irreplaceable image: black tea delays recovery from iron-deficiency anemia.		2001	11410431
reproducibility and relative validity of a questionnaire to assess intake of black tea polyphenols in epidemiological studies.	epidemiological studies suggest that tea drinking may reduce the risk of cardiovascular diseases and cancers. although tea is an important source of antioxidant phytochemicals, variation in preparation techniques may translate to variation in antioxidant capacity. however, most large-scale epidemiological studies use regular food frequency questionnaires to estimate tea intake, and nationally available nutrient analysis databases do not include levels of black tea polyphenols. the arizona tea qu ...	2001	11401918
effect of acute and chronic tea consumption on platelet aggregation in patients with coronary artery disease.	epidemiological studies suggest that tea consumption is associated with a decreased risk of cardiovascular events, but the mechanisms of benefit remain undefined. platelet aggregation is a precipitating event in cardiovascular disease, and tea contains antioxidant flavonoids that are known to decrease platelet aggregation in vitro. to test the effect of tea consumption on platelet aggregation, we randomized 49 patients with coronary artery disease to either 450 ml of black tea or water consumed ...	2001	11397724
catechins are bioavailable in men and women drinking black tea throughout the day.	tea consumption has been associated with reduced risk of both cancer and cardiovascular disease in population studies, but clinical data demonstrating bioavailability of the individual catechins and other polyphenolic components of tea are limited. this study assessed the apparent bioavailability of the prominent catechins from black tea in humans drinking tea throughout the day. after 5 d of consuming a low flavonoid diet, subjects drank a black tea preparation containing 15.48, 36.54, 16.74, a ...	2001	11385060
[application and improvement of aflatoxin analysis in foods using a multifunctional column and hplc].	in an earlier report, we developed a rapid, sensitive and clean method consisting of non-chloroform extraction, clean-up on a commercial multifunctional cartridge column and hplc with fluorescence detection for the analyses of aflatoxins. in this report, we applied this method to analyze aflatoxins in nuts, giant corn, cereals, spice and black teas. the method was effective for macadamia nuts, walnuts, hazelnuts, brazil nuts, giant corn, rice, wheat and buckwheat, and the recoveries of aflatoxin ...	2001	11383158
[cause of bisphenol a migration from cans for drinks and assessment of improved cans].	in the previous investigation, we found that some cans for coffee and black tea drinks released large amounts of bisphenol a (bpa) into their contents. equivalent cans were obtained and the cause of bpa migration was investigated. equivalent cans a, b and d contained high levels of bpa in the side seam, in the bottom, and in the bottom and the side seam, respectively, while can c contained some level of bpa in the body, which has a large area, therefore, all of them contained high amounts of bpa ...	2001	11383151
occurrence of the toxigenic fungi (producers of aflatoxins and ochratoxin a) in foodstuffs in the czech republic 1999-2000.	the occurrence of toxigenic fungi producing aflatoxins and ochratoxin a in foodstuffs was studied in the czech republic. twenty five commodities were collected at twelve collection places in the czech republic (300 food samples). the presence of potentially toxigenicaspergillus flavus was observed in 28% of the sampled foods (black pepper, caraway seeds, fruit tea, black tea, oat flakes, fine flour, rolled oat flakes and semolina) in the year 1999, and in 25% of the sampled foods (black pepper, ...	2001	23605869
consumption of flavonoids in onions and black tea: lack of effect on f2-isoprostanes and autoantibodies to oxidized ldl in healthy humans.	oxidative damage to lipids in vivo may be involved in the development of atherosclerosis and cancer. onions and black tea are foods rich in flavonoids, predominantly the flavonoid quercetin, which is a potent in vitro inhibitor of membrane lipid peroxidation and ldl oxidation.	2001	11382657
studies on the effect of polyvinyl pyrrolidone on the activity of chlorhexidine mouthrinses: plaque and stain.	polyvinyl pyrrolidone (pvp) was shown in vitro to reduce chlorhexidine induced, dietary staining without affecting the uptake of the antiseptic to the test substrate. the aim of these studies in vivo was to determine whether pvp affected plaque and dietary staining by a low concentration chlorhexidine rinse.	2001	11350523
tooth surface ph during drinking of black tea.	to investigate the composition of black tea in terms of its erosive potential. to determine the ph profile at the palatal surface of anterior and posterior sites of the dentition after drinking black tea.	2001	11338040
the (3r,9r)-3-hydroxy-7,8-dihydro-beta-ionol disaccharide glycoside is an aroma precursor in tea leaves.	the disaccharide glycoside, (3r,9r)-3-hydroxy-7,8-dihydro-beta-ionyl 6-o-beta-d-apiofuranosyl-beta-d-glucopyranoside was isolated as an aroma precursor from the leaves of camellia sinensis var. sinensis cv. yabukita. its stereochemistry was elucidated on the basis of spectral data and chemical synthesis.	2001	11324911
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
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
multielement determination and speciation of major-to-trace elements in black tea leaves by icp-aes and icp-ms with the aid of size exclusion chromatography.	a multielement determination of major-to-trace elements in black tea leaves and their tea infusions was carried out by icp-aes (inductively coupled plasma atomic emission spectrometry) and icp-ms (inductively coupled plasma mass spectrometry). tea infusions were prepared as usual tea beverage by brewing black tea leaves in boiling water for 5 min. about 40 elements in tea leaves and tea infusions could be determined over the wide concentration range in 8 orders of magnitude. the extraction effic ...	2001	11990615
substrate specificity of beta-primeverosidase, a key enzyme in aroma formation during oolong tea and black tea manufacturing.	we synthesized nine kinds of diglycosides and a monoglycoside of 2-phenylethanol to investigate the substrate specificity of the purified beta-primeverosidase from fresh leaves of a tea cultivar (camellia sinensis var. sinensis cv. yabukita) in comparison with the apparent substrate specificity of the crude enzyme extract from tea leaves. the crude enzyme extract mainly showed beta-primeverosidase activity, although monoglycosidases activity was present to some extent. the purified beta-primever ...	2001	11826969
identification and antioxidant activity of several pigments from the residual green tea (camellia sinensis) after hot water extraction.	antioxidant activity of green tea extract or tea-derived polyphenols has been extensively studied. however, antioxidant activity in the non-polyphenolic fraction of green tea has been poorly analyzed. in the present study, we analyzed the antioxidant activity of the non-polyphenolic fraction of the residual green tea (camellia sinensis) after hot water extraction using the aluminum chloride method. the non-polyphenolic fraction of residual green tea caused a significant suppression against hydro ...	2001	11789136
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
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
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
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
tea consumption and the risk of colorectal cancer in sweden.	the association between tea drinking and colorectal cancer risk remains unclear. the evidence for black tea is sparse but may indicate an increased risk with regular use. because black tea is a common beverage in many populations, the significant twofold increased risk of colon cancer recently reported from a large prospective cohort of male finnish smokers is disconcerting. using cox proportional hazards models to estimate relative risks, we examined this association in a large, population-base ...	2001	11759277
two types of oxidative dimerization of the black tea polyphenol theaflavin.	theaflavin and its galloyl esters are polyphenolic pigments of black tea. in the course of studies on the oxidation mechanism of tea polyphenols, two theaflavin oxidation products named bistheaflavins a and b were isolated, and their structures were elucidated on the basis of ms and nmr spectroscopic analyses. treatment of a mixture of (-)-epicatechin and (-)-epigallocatechin with banana fruit homogenate yielded bistheaflavin a together with theaflavin and theanaphthoquinone. the symmetrical str ...	2001	11743764
anticlastogenic effects of black tea (world blend) and its two active polyphenols theaflavins and thearubigins in vivo in swiss albino mice.	this study investigated the inhibition of cyclophosphamide (cp) and dimethylbenz(a)anthracene (dmba) induced genetic damage by black tea (world blend) and its two active polyphenols theaflavins (tf) and thearubigins (tr) in swiss albino mice as measured by chromosome aberrations (ca) and sister chromatid exchanges (sce). three different concentrations (5, 10 and 20%) of tea and a single dose of tf and tr were tested for their anticlastogenic effects against dmba (50 mg/kg body weight) and cp (20 ...	2001	11720078
analysis of glycosidically bound aroma precursors in tea leaves. 3. change in the glycoside content of tea leaves during the oolong tea manufacturing process.	a direct qualitative and quantitative determination of the glycosides of tea aroma compounds at the four stages of the oolong tea manufacturing process (plucking, solar withering, indoor withering, and oolong tea product) was carried out by a capillary gas chromatographic-mass spectrometric analysis after trifluoroacetyl derivatization of the glycosidic fractions. sixteen glucosides and primeverosides were identified and quantified in cv. chin-shin-oolong and cv. chinhsuan-oolong. a comparison o ...	2001	11714333
factors affecting the caffeine and polyphenol contents of black and green tea infusions.	the effects of product and preparation variables on the in-cup chemical composition of tea extracts is of interest because the appearance and taste characteristics and the possible health effects of a tea liquor arise from the chemical components extracted from the leaf during tea preparation. a comprehensive study was therefore undertaken to determine the contributions of product and preparation variables on the total soluble solids, caffeine, and polyphenol contents of tea extracts. the result ...	2001	11714326
the erosive effect of herbal tea on dental enamel.	the aim of this study was to determine whether conventional black tea and a herbal tea were capable of eroding dental enamel. a further aim was to investigate whether herbal tea of the type tested eroded dental hard tissues to a greater or lesser extent than conventional black tea.	2001	11700200
antimutagenic effect of black tea extract using 'rodent dominant lethal mutation assay'.	the antimutagenic effect of black tea extract has been evaluated with the 'dominant lethal assay' in swiss albino mice using benzo[a]pyrene [bap] as a mutagen. bap was given through the intraperitoneal (i.p.) route at a single dose of 100 mg/kg b.w. to male mice once only. the animals were given 1, 2 and 4% aqueous solution of black tea as sole source of drinking solution prior to bap. the pregnant females were analyzed for living implants, pre- and post-implantation losses. the results revealed ...	2001	11684324
nanoparticles in plant extracts--factors which influence the formation of nanoparticles in black tea infusions.	the influence of different factors on the formation of nanoparticles in freshly brewed tea extracts was investigated. a black tea infusion was observed during cooling using photon correlation spectroscopy (pcs). the mean particle size and the number of the nanoparticles increase with decreasing temperature. in the presence of caffeine more particles are formed within the infusion. to study the influence of slight structural differences between methylxanthines, the effect of the addition of caffe ...	2001	11683125
chain-breaking antioxidant capability of some beverages as determined by the clark electrode technique.	the protective effects of red wine, tea, and coffee on cancer, atheroclerosis, and other diseases are attributed to the antioxidant activity (aoa) of polyphenols, which are abundant in those beverages. we present a rational procedure for determining the total chain-breaking aoa of beverages with the use of the clark electrode technique. the procedure is based on the steady monitoring of oxygen consumption accompanying the chain peroxidation of methyl linoleate in triton x-100 aqueous micelles in ...	2001	12639404
tea consumption modulates hepatic drug metabolizing enzymes in wistar rats.	the antioxidant, antimutagenic and anticarcinogenic activities of green tea and its polyphenols have been reported. as bioactivation of the precarcinogens and detoxification of ultimate carcinogens are mainly carried out by hepatic metabolizing enzymes, we have investigated the modulation of these enzyme activities subsequent to tea consumption in rats. female wistar rats were divided into eight groups (n = 5). six groups were given aqueous solutions (2%, w/v) of six different teas (new zealand ...	2001	11341376
tea flavonoids and cardiovascular health.	tea is rich in antioxidant polyphenols (catechins, flavonols, theaflavins and thearubigins). epidemiological evidence relating regular consumption of tea or related polyphenols to chd is equivocal. catechins are absorbed from tea, but low plasma concentrations are attained. the bioavailability of theaflavins and thearubigins is unknown. tea does not reduce blood pressure or plasma lipids in well-controlled human trials. tea polyphenols inhibit ldl lipid peroxidation in vitro, but the effect ex v ...	2001	11353103
black tea is a powerful chemopreventor of reactive oxygen and nitrogen species: comparison with its individual catechin constituents and green tea.	production of black tea [bt] results in biotransformation of catechins of green tea [gt] to theaflavins and thearubigins. bt was found to be more efficient than gt and its individual catechin constituents in proportionate amounts in abrogating production of no and o2(-) in activated murine peritoneal macrophages. in a reconstitution system of bt that is free of all catechins, stepwise addition of catechins showed that though all the constituents contributed to the overall effect of bt, theaflavi ...	2001	11374887
role of reduced glutathione and nitric oxide in the black tea extract-mediated protection against ulcerogen-induced changes in motility and gastric emptying in rats.	the aim of the present study was to investigate the underlying mechanism of the role of hot water extract of black tea [camellia sinensis (l). o. kuntze theaceae] in normalizing the changes in intestinal transit and gastric emptying induced by various ulcerogenic agents in experimental rats. intestinal transit as well as gastric emptying were significantly reduced in rats treated with glutathione (gsh) depleting agents, diethyl maleate (dem), indoacetamide (ida) and n-ethyl maleimide (nem). prio ...	2001	11388638
distribution characteristics of fluoride and aluminum in soil profiles of an abandoned tea plantation and their uptake by six woody species.	distribution characteristics of fluoride (f) and aluminum (al) in soil profiles of an abandoned tea plantation in hong kong and their uptake by six woody species namely camellia sinensis, melastoma affine, sterculia lanceolata, ardisia crenata, acacia formosa and machilus thunbergii were investigated. c. sinensis accumulated both f (656 mg/kg in the leaves) and al (8910 mg/kg in the leaves). m. affine only accumulated al (9932 mg/kg in the leaves), while s. lanceolata, a. crenata, a. formosa and ...	2001	11392749
black tea extract, thearubigin fraction, counteracts the effect of tetanus toxin in mice.	the aim of this study was to find an inactivating substance for tetanus toxin in natural foodstuff. tetanus toxin (4 micrograms/ml) abolished indirect twitches in in vitro mouse phrenic nerve-diaphragm preparations within 2.5 hr. hot water infusion of black tea mixed with tetanus toxin blocked the inhibitory effect of the toxin. mixing the toxin with thearubigin fraction extracted from black tea infusion produced an identical result. furthermore, thearubigin fraction mixed with the toxin protect ...	2001	11395929
combination effect of lignin f and natural products.	we investigated the effect of lignin f, isolated from the alkaline extract of the cone of pinus parviflora sieb. et zucc, on the cytotoxic activity and radical intensity (measured by esr spectroscopy) of various natural products. lignin f slightly inhibited the proliferation of human oral tumor cell lines (human squamous cell carcinoma hsc-2, human salivary gland tumor hsg), but not that of human gingival fibroblast hgf, suggesting its tumor specific cytotoxic action. lignin f enhanced the cytot ...	2001	11396189
spectrophotometric determination of the tannin contents of various turkish black tea, beer and wine samples.	this study reports tannin contents of various tea (19), beer (6) and wine (6) samples, produced or sold in turkey under different brand names. determinations were carried out by employing a previously reported uv-vis spectrophotometric method. the standard addition procedure was also compared to the direct determination procedure and found to be more reliable. the tannin contents of hot water extracts of tea, tea bag and herbal tea samples ranged between 6.20-8.33, 8.03-6.59 and 2.76-6.54 percen ...	2001	11400478
flavonoid (myricetin, quercetin, kaempferol, luteolin, and apigenin) content of edible tropical plants.	studies were conducted on the flavonoids (myricetin, quercetin, kaempferol, luteolin, and apigenin) contents of 62 edible tropical plants. the highest total flavonoids content was in onion leaves (1497.5 mg/kg quercetin, 391.0 mg/kg luteolin, and 832.0 mg/kg kaempferol), followed by semambu leaves (2041.0 mg/kg), bird chili (1663.0 mg/kg), black tea (1491.0 mg/kg), papaya shoots (1264.0 mg/kg), and guava (1128.5 mg/kg). the major flavonoid in these plant extracts is quercetin, followed by myrice ...	2001	11410016
antioxidative activities of phenylethanoid glycosides from ligustrum purpurascens.	tea and kudingcha (bitter tea) are the two most popular beverages consumed in china. tea derived from the leaves of camellia sinensis has been well studied for its various health benefits, but there are very limited data on the biological activities of bitter tea derived from the leaves of ligustrum purpurascens (lp). the present study was carried out to characterize the antioxidants present in the bitter tea brewed from the leaves of lp. it was found that the crude glycoside fraction possessed ...	2001	11410017
inhibitory effects of orally administered green tea, black tea, and caffeine on skin carcinogenesis in mice previously treated with ultraviolet b light (high-risk mice): relationship to decreased tissue fat.	treatment of skh-1 hairless mice with ultraviolet b light (uvb; 30 mj/cm(2)) twice a week for 22 weeks resulted in tumor-free animals with a high risk of developing malignant and nonmalignant skin tumors during the next several months in the absence of additional uvb treatment (high-risk mice). oral administration of green tea or black tea (6 mg tea solids/ml) to uvb-pretreated high-risk skh-1 mice for 23 weeks after stopping uvb treatment decreased the number of tumors/mouse, decreased the size ...	2001	11431333
the distribution of minerals and flavonoids in the tea plant (camellia sinensis).	camellia sinensis is a plant growing in india, sri lanka, java, japan and its properties were known 4000 years ago. since then, traditional chinese medicine has recommended this plant for headaches, body aches and pains, digestion, depression, detoxification, as an energiser and, in general, to prolong life. tea contains volatile oils, vitamins, minerals, purines, polyphenols, particularly carechins. we have analysed ten commercial teas from various countries to determine their mineral compositi ...	2001	11482766
green tea extracts decrease carcinogen-induced mammary tumor burden in rats and rate of breast cancer cell proliferation in culture.	epidemiological evidence suggests tea (camellia sinensis l.) has chemopreventive effects against various tumors. green tea contains many polyphenols, including epigallocatechin-3 gallate (egcg), which possess anti-oxidant qualities. reduction of chemically induced mammary gland carcinogenesis by green tea in a carcinogen-induced rat model has been suggested previously, but the results reported were not statistically significant. here we have tested the effects of green tea on mammary tumorigenes ...	2001	11500915
fumonisins b1 and b2 in black tea and medicinal plants.	fumonisins are mycotoxins produced by fusarium moniliforme that are prevalent in cereals and other agricultural products. these mycotoxins have been pointed to as a natural cause of equine leukoencephalomalacia, porcine pulmonary edema, and human esophageal cancer. a total of 87 samples, 18 black tea samples and 69 samples of four different medicinal plants (chamomile, leaves of the orange tree, leaves and flowers of the linden tree, and corn silk), for infusions preparations were acquired from ...	2001	11510675
antioxidant properties of green and black tea, and their potential ability to retard the progression of eye lens cataract.	aqueous extracts of green and black tea are shown to quench reactive oxygen species such as singlet oxygen, superoxide and hydroxyl radicals, prevent the oxidative cross-linking of test proteins and inhibit single strand breakage of dna in whole cells. they are also seen to be able to counteract the oxidative insult mounted by cigarette smoke. in rats in which cataract was induced by subcutaneous injection of selenite, administration of green or black tea extracts led to a retardation of the pro ...	2001	11520114
anticariogenic effects of black tea (camellia sinensis) in caries prone-rats.	black tea (camellia sinensis) may have anticariogenic properties. the present study was designed to determine whether consumption of black tea influences cariogenesis in young, caries-prone rats.	2001	11526894
analysis of theaflavins in biological fluids using liquid chromatography-electrospray mass spectrometry.	a hplc-ms procedure for the sensitive and specific analysis of the black tea flavonoid theaflavin in human plasma and urine was developed. levels were measured after enzymatic deconjugation, extraction into ethyl acetate, and separation by hplc, using tandem mass spectrometry as a detecting system. two healthy volunteers consumed 700 mg theaflavins, equivalent to about 30 cups of black tea. the maximum concentration detected in blood plasma was 1.0 microg l(-1) in a sample collected after 2 h. t ...	2001	11530986
theaflavins in black tea and catechins in green tea are equally effective antioxidants.	green tea catechins, including (-)-epicatechin (ec), (-)-epicatechin gallate (ecg), (-)-epigallocatechin (egc) and (-)-epigallocatechin gallate (egcg), are oxidized and dimerized during the manufacture of black tea and oolong tea to form orange-red pigments, theaflavins (tf), a mixture of theaflavin (tf1), theaflavin-3-gallate (tf2a), theaflavin-3'-gallate (tf2b) and theaflavin-3,3'-digallate (tf3). the present study was designed to compare the antioxidant activities of individual tf with that o ...	2001	11533262