Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| antihemolytic effect of rooibos tea (aspalathus linearis) on red blood cells of japanese quails. | the antihemolytic activity of rooibos and black tea on japanese quail erythrocytes was studied. peroxide and hypotonic hemolysis of the red blood cells of quails, either fed with rooibos tea supplemented food or fed without tea, was performed. long-term consumption of rooibos tea did not change the erythrocyte fragility to either peroxide or hypotonia induced hemolysis. however, rooibos and black teas decreased peroxide induced hemolysis of erythrocytes incubated with each of them, but not hemol ... | 2000 | 11409839 |
| alpha-tocopherol content in 62 edible tropical plants. | vitamin e was determined by the high-performance liquid chromatography (hplc) method. all the plants tested showed differences in their alpha-tocopherol content and the differences were significant (p < 0.05). the highest alpha-tocopherol content was in sauropus androgynus leaves (426.8 mg/kg edible portion), followed by citrus hystrix leaves (398.3 mg/kg), calamus scipronum (193.8 mg/kg), starfruit leaves averrhoa belimbi (168.3 mg/kg), red pepper capsicum annum (155.4 mg/kg), local celery apiu ... | 2001 | 11410015 |
| 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 |
| the irreplaceable image: black tea delays recovery from iron-deficiency anemia. | 2001 | 11410431 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| black tea; white teeth. research suggests beverage may be powerful cavity-fighting tool. | 2001 | 11462338 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| induction of apoptosis and cell cycle arrest in cancer cells by in vivo metabolites of teas. | the present study was conducted to determine in vivo possibilities of inducing apoptosis and cell cycle arrest in rat cancer cells by green, oolong, and black teas and also to further identify the mechanisms inhibiting cancer cell proliferation by the sera from tea-treated rats. the tea extracts from these three kinds of tea, the rat sera obtained after oral intubation of the tea extracts, and the tea polyphenolic compounds, (-)-epigallocatechin-3-gallate, (-)-epigallocatechin, (-)-epicatechin-3 ... | 2000 | 11525605 |
| 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 |
| 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 |
| 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 |
| catechins are not major components responsible for anti-genotoxic effects of tea extracts against nitroarenes. | the anti-genotoxic properties of tea leaf extracts were examined in a salmonella umu-test. seven non-fermented teas (green tea), one semi-fermented tea (oolong tea), two fermented teas (black tea and chinese pu er tea) and two other teas were examined for their anti-genotoxic abilities and for their catechins contents. this was to study the relationship between catechins contents and anti-genotoxic activity of various tea leaf extracts. all types of tea extracts showed more potent suppressive ef ... | 2001 | 11551482 |
| 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 |
| antioxidant activity of some foods containing phenolic compounds. | this study was designed to determine the total phenols (tp) and total antioxidant activity (taa) of some liquid and solid plant foods that are commonly consumed in turkey. total phenols were analysed according to the folin-ciocalteu method and antioxidant activities of these compounds in aqueous phase were assessed by measuring their direct abts.- radical scavenging abilities. total phenols varied from 68 to 4162 mg/l for liquid foods and from 735 to 3994 mg/kg for solid foods. taa of liquid and ... | 2001 | 11570016 |
| 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 |
| effects of (-)-epigallocatechin-3-gallate, the main component of green tea, on the cloned rat brain kv1.5 potassium channels. | the interaction of (-)-epigallocatechin-3-gallate (egcg), the main component of green tea (camellia sinensis), with rat brain kv1.5 channels (rkv1.5) stably expressed in chinese hamster ovary (cho) cells was investigated using the whole-cell patch-clamp technique. egcg inhibited rkv1.5 currents at +50 mv in a concentration-dependent manner, with an ic50 of 101.2+/-6.2 microm. pretreatment with protein tyrosine kinase (ptk) inhibitors (10 microm genistein, 100 microm ag1296), a tyrosine phosphata ... | 2001 | 11585049 |
| 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 |
| chemoprevention of basal cell carcinomas in the ptc1+/- mouse--green and black tea. | skin cancers are a rising menace as their incidence increases, attributed in part to increasing ultraviolet radiation exposure. this increasing problem has stimulated efforts to devise useful preventive approaches. the uncertain efficacy of exhortations to avoid sun exposure and to use protective clothing and sunscreens to reduce damage when exposed argue for the development of an oral chemopreventive agent. bickers and others have studied the effects and mechanisms of tea and of its putative ac ... | 2001 | 11598435 |
| 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 |
| 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 |
| 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 |
| 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 |
| effect of herbal teas on hepatic drug metabolizing enzymes in rats. | we have investigated the effect of herbal teas (peppermint, chamomile and dandelion) on the activity of hepatic phase i and phase ii metabolizing enzymes using rat liver microsomes. female wistar rats were divided into six groups (n = 5 each). three groups had free access to a tea solution (2%) while the control group had water. two groups received either green tea extract (0.1%) or aqueous caffeine solution (0.0625%). after four weeks of pretreatment, different cytochrome p450 (cyp) isoforms an ... | 2001 | 11697539 |
| 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 |
| effects of purified green and black tea polyphenols on cyclooxygenase- and lipoxygenase-dependent metabolism of arachidonic acid in human colon mucosa and colon tumor tissues. | the effects of green and black tea polyphenols on cyclooxygenase (cox)- and lipoxygenase (lox)-dependent arachidonic acid metabolism in normal human colon mucosa and colon cancers were investigated. at a concentration of 30 microg/ml, (-)-epigallocatechin-3-gallate (egcg), (-)-epigallocatechin (egc), and (-)-epicatechin-3-gallate (ecg) from green tea and theaflavins from black tea inhibited lox-dependent activity by 30-75%. the formation of 5-, 12-, and 15-lox metabolites was inhibited to a simi ... | 2001 | 11705450 |
| aqueous extracts of crinum latifolium (l.) and camellia sinensis show immunomodulatory properties in human peripheral blood mononuclear cells. | in vietnamese and chinese traditional medicine, hot aqueous extract of crinum latifolium is used because of its antitumor activity. the genus crinum is thought to possess antiviral and immunostimulative properties. green and black tea derived from camellia sinensis have similar qualities. a growing body of evidence suggests that moderate consumption of green and black tea may protect, e.g., against several forms of cancer, cardiovascular diseases, and bacterial infections. in this study, the imm ... | 2001 | 11710543 |
| 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 |
| 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 |
| green tea upregulates the low-density lipoprotein receptor through the sterol-regulated element binding protein in hepg2 liver cells. | green tea from camellia sinensis lowers plasma cholesterol in animal models of hypercholesterolemia. the aim of this study was to determine the effects of green tea on the expression of the hepatic low-density lipoprotein (ldl) receptor, a cell surface protein involved in the control of plasma cholesterol. incubating human hepg2 liver cells in culture with green tea increased both ldl receptor binding activity and protein. an ethyl acetate extract of green tea, containing 70% (w/w) catechins, al ... | 2001 | 11714371 |
| 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 |
| inhibitory effects of polyphenolic catechins from chinese green tea on hiv reverse transcriptase activity. | three polyphenolic catechins, epigallocatechin (1), epicatechin-3-o-gallate (2) and epigallocatechin-3-o-gallate (3), were isolated from chinese green tea, ti-kaun-yin (camellia sinensis) and demonstrated as a new class of human immunodeficiency virus-reverse transcriptase (hiv-rt) inhibitor. the concentrations required for 50% inhibition for the compounds (1), (2) and (3) were 7.80, 0.32 and 0.68 &mgr;m, respectively. the polyphenolic catechins with a galloyl group at the 3 position were potent ... | 1994 | 11725021 |
| 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 |
| gastrointestinal enhancement of mri with melanin derived from tea leaves (thea sinensis linn.). | melanin was extracted from tea leaves (thea sinensis linn.) for the first time. characterization of melanin proved similarity of the original compound to standard melanin. the langmuir adsorption isotherms for gadolinium (gd) binding were obtained using melanin. melanin-gd preparation demonstrated low acute toxicity. ld(50) for this preparation was in a range of 1250-1500 mg/kg in mice. magnetic resonance imaging (mri) properties of melanin itself and melanin-gd complexes have been estimated. gd ... | 2002 | 11744298 |
| black tea polyphenols, theaflavins, prevent cellular dna damage by inhibiting oxidative stress and suppressing cytochrome p450 1a1 in cell cultures. | tea polyphenols have been demonstrated as chemopreventive agents in a number of experimental models. however, less is known about the mechanism of chemoprevention by black tea compared with that of green tea. some beneficial properties of theaflavins, the black tea polyphenols, were investigated in the present study. theaflavins showed inhibitory effects on h(2)o(2)- and tert-butyl hydroperoxide (tbuooh)-induced cytotoxicity (evaluated by tetrazolium bromide reduction), cellular oxidative stress ... | 2002 | 11754570 |
| attenuation of 6-hydroxydopamine (6-ohda)-induced nuclear factor-kappab (nf-kappab) activation and cell death by tea extracts in neuronal cultures. | antioxidant and anti-inflammatory therapy approaches have been in the focus of attention in the treatment of neurodegenerative parkinson's and alzheimer's diseases where oxidative stress has been implicated. tea extracts have been previously reported to possess radical scavenger, iron chelating and anti-inflammatory properties in a variety of tissues. the purpose of this study was to investigate potential neuroprotective effects of tea extracts and possible signal pathway involved in a neuronal ... | 2002 | 11754870 |
| black tea polyphenols inhibit igf-i-induced signaling through akt in normal prostate epithelial cells and du145 prostate carcinoma cells. | tea polyphenols have been proposed as potential chemopreventive agents against prostate cancer, primarily because of their high intake by populations with reduced cancer incidence and their reported ability to inhibit proliferation and increase apoptosis in prostate cancer cells in culture. insulin-like growth factor-i (igf-i) has been implicated as a risk factor for the development of prostate cancer by epidemiological studies and has been shown to be causative in animal models. one of the prim ... | 2002 | 11756245 |
| 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 |
| prevention of carcinogenesis by tea polyphenols. | tea, an extract of the leaves of the plant camellia sinensis, has been considered a medicine and healthful beverage for ages. the beneficial effects of tea are thought to be due to its polyphenolic components. herein, we discuss the present status of tea as a possible cancer chemopreventive agent, covering basic chemistry and biochemical activity of tea, pharmacokinetics of major tea components, studies in animal and cell lines, epidemiological investigations, and future challenges. tea is one o ... | 2011 | 11768768 |
| regular ingestion of tea does not inhibit in vivo lipid peroxidation in humans. | prospective studies suggest that tea may protect against cardiovascular disease. a potential mechanism for such an effect involves inhibition of lipid peroxidation by polyphenolic antioxidants derived from tea. our objective was to determine whether regular ingestion of tea could inhibit in vivo lipid peroxidation. two controlled intervention studies assessed the effects of regular ingestion of tea on lipid peroxidation determined by measurement of urinary f(2)-isoprostane excretion. study 1: th ... | 2002 | 11773508 |
| [photoprotective properties of melanins from grape (vitis vinifera) and black tea (thea sinensis)]. | dark pigments of melanin type were extracted from the rind of ripe grapes vitis vinifera (ring "alfa") and pack tea (thea sinensis). the study of photoprotection activity of the extracted pigments have shown that they intensively absorb radiation in the uv and visible. the increase of the photoprotection effect correlates with the concentration of paramagnetic centers in the melanins. the pigments reduce the number of damaged molecules of plasmid dna pbr-322 and inhibition the iuv-induced lipid ... | 2016 | 11785308 |
| 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 |
| total phenol, catechin, and caffeine contents of teas commonly consumed in the united kingdom. | levels of total phenol, catechins, and caffeine in teas commonly consumed in the united kingdom have been determined using reversed phase high-performance liquid chromatography. tea bags or tea leaves were purchased from local supermarkets and extracted in boiling water for 5 min. the resulting data showed considerable variability in both total phenols [80.5-134.9 mg/g of dry matter (dm) in black teas and 87-106.2 mg/g of dm in green teas] and catechins (5.6-47.5, 51.5-84.3, and 8.5-13.9 mg/g of ... | 2002 | 11804530 |
| anticarcinogenic effect of black tea on pulmonary tumors in swiss albino mice. | the widespread consumption of tea as beverage throughout the world has stimulated interest in the possibility of its use in chemoprevention of cancer. the present set of investigation was carried out to evaluate the anticarcinogenic activity of black tea using lung tumorigenesis model in swiss albino mice. diethylnitrosoamine (den), a known inducer of pulmonary tumors was given at the multiple (total eight) doses of 20mg/kg body weight through oral intubation to swiss albino mice. simultaneously ... | 2002 | 11804740 |
| diurnal variation of photosynthesis and photoinhibition in tea: effects of irradiance and nitrogen supply during growth in the field. | diurnal changes in the rate of photosynthesis (a) of mature tea (camellia sinensis (l.) o. kuntze) bushes grown at high elevation in the field in sri lanka, were related to environmental conditions. bushes were either unshaded, receiving 100% of incident photosynthetically active radiation (par), moderately shaded, (65% par) or heavily shaded (30% par). these treatments were combined with nitrogen fertilizer applications of 0, 360 and 720 kg ha(-1) year(-1). when recently fully expanded leaves w ... | 2002 | 11807135 |
| inhibition of carcinogenesis by tea. | tea has received a great deal of attention because tea polyphenols are strong antioxidants, and tea preparations have inhibitory activity against tumorigenesis. the bioavailability and biotransformation of tea polyphenols, however, are key factors limiting these activities in vivo. the inhibition of tumorigenesis by green or black tea preparations has been demonstrated in animal models on different organ sites such as skin, lung, oral cavity, esophagus, forestomach, stomach, small intestine, col ... | 2002 | 11807163 |