Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| [study on the adsorption behaviors of cadmium and lead ions on green tea and black tea by icp-aes]. | the adsorption behaviors of cd(ii) and pb(ii) on green tea and black tea in aqueous solution as well as the influences of time, acidity and temperature on the adsorption have been studied. it was found that cd(ii) and pb(ii) can been adsorbed strongly by green tea and black tea samples. the adsorption effects depend on the ph strongly when ph<4. the recovery of pb(ii) on tea samples is more than that of cd(ii) when ph<6 and it is opposite when ph>6. it is difficult to elute cd(ii) and pb(ii) fro ... | 2004 | 15762500 |
| [preparation and component analysis of tea pigments]. | to prepare tea pigments. | 2004 | 15727181 |
| diet-derived phenols in plasma and tissues and their implications for health. | this paper seeks to catalyse a reappraisal of the nature, fate and biological significance in humans of phenols, polyphenols and tannins (ppt) consumed in normal diets, and in particular questions the primacy of ppt radical-scavenging mechanisms for the supposed health benefits of diets rich in fruits and vegetables. ppt are classified by structure and function. arguments are presented to show that cinnamates and derived polyphenols make significantly larger contributions to the total ppt intake ... | 2004 | 15643541 |
| [determination of theaflavins in black tea by high performance liquid chromatography]. | a high performance liquid chromatographic method for the determination of theaflavins has been established. separation was carried out on an ods column (shim-pack vp-ods column, 4.6 mm i.d. x 150 mm) at 40 degrees c with a linear gradient elution of acetonitrile-ethyl acetate (21:3, v/v) and aqueous acetic acid (2%), and uv detection at 280 nm. the experimental results showed a good linear relationship between the peak area and the concentration of theaflavins (r = 0.9990-0.9992). the average re ... | 2004 | 15712875 |
| dietary patterns and risk of gastric cancer: a case-control study in uruguay. | gastric cancer is a frequent malignancy in the uruguayan population. in northern counties, incidence rates reach high figures (age-standardized rates [asr], 37.3 per 100,000 men and 18.3 per 100,000 women). diet is a major determinant in gastric carcinogenesis. because foods or food groups have the advantage over nutrients in being most directly related to dietary recommendations, we decided to conduct a case-control study on the relationships between food groups and risk of gastric cancer. for ... | 2004 | 15616769 |
| a study on the determination of chromium as chromate at a carbon paste electrode modified with surfactants. | a procedure for the determination of chromium is described based on synergistic pre-concentration of the chromate anion at a carbon paste electrode modified in situ with quarternary ammonium salts such as 1-ethoxycarbonylpentadecyltrimethylammonium bromide (septonex((r))), cetyltrimethylammonium bromide (ctab) or cetylpyridinium bromide (cpb). the proper electrochemical detection utilises the reduction cr(vi) --> cr(iii) performed in the differential pulse cathodic voltammetric mode. in discussi ... | 2004 | 18969679 |
| new dibenzotropolone derivatives characterized from black tea using lc/ms/ms. | theaflavins and thearubigins are major pigments in black tea, and it is generally accepted that they are produced by oxidation of flavan-3-ols (catechins) during tea fermentation. in the course of studies on the oxidation mechanism of tea polyphenols, especially the formation of thearubigins, a method combining the enzymatic synthesis and lc/esi-ms/ms analysis was developed to search for new higher molecular weight polymers from black tea. three new dibenzotropolones, theadibenzotropolone a, b, ... | 2004 | 15142559 |
| effect of black tea aqueous non-dialysate onhelicobacter pylori infection in mongolian gerbils. | recently, the appearance ofhelicobacter pylori (h. pylori) resistant to antibiotics has been reported. the development of an antibiotic therapy which would not induce resistant strains ofh. pylori is anticipated. in the present study, the antibiotic effect of black tea aqueous non-dialysate (btnd), the fraction different from tea catechins, onh. pylori was investigated using mongolian gerbils infected withh. pylori. | 2004 | 21432329 |
| anti-inflammatory activity of tea (camellia sinensis) root extract. | pharmacological studies were carried out with methanol-water (1:1) extract of dried tea (camellia sinensis) root extract (tre). tre was found to possess anti-inflammatory, analgesic and antipyretic activities at 1/10th of its ld50 dose of 100 mg/kg i.p. it was found that tre inhibited the arachidonic acid-induced paw oedema in rats which indicated that tre produced the anti-inflammatory activity by inhibiting both the cyclooxygenase and lypooxygenase pathways of arachidonic acid metabolism. tre ... | 2004 | 14761665 |
| inhibitory effects on phospholipase a2 and antivenin activity of melanin extracted from thea sinensis linn. | antivenin activity of melanin extracted from black tea (mebt) was reported for the first time. the antagonistic effect of mebt was evaluated for agkistrodon contortrix laticinctus (broadbanded copperhead), agkistrodon halys blomhoffii (japanese mamushi), and crotalus atrox (western diamondback rattlesnake) snake venoms administered i.p. to icr mice. mebt was injected i.p. immediately after the venom administration in dose of 3 mg per mouse in the same place of venom injection. mebt demonstrated ... | 2004 | 14967198 |
| anticancer therapeutic potential of soy isoflavone, genistein. | genistein (4'5, 7-trihydroxyisoflavone) occurs as a glycoside (genistin) in the plant family leguminosae, which includes the soybean (glycine max). a significant correlation between the serum/plasma level of genistein and the incidence of gender-based cancers in asian, european and american populations suggests that genistein may reduce the risk of tumor formation. other evidence includes the mechanism of action of genistein in normal and cancer cells. genistein inhibits protein tyrosine kinase ... | 2004 | 15584372 |
| black tea intake modulates the excretion of urinary mutagens in rats exposed to 6-aminochrysene: induction of cytochromes p450 by 6-aminochrysene in the rat. | rats were exposed to black tea (2.5% w/v) as their sole drinking liquid for either 1 day (short-term) or 1 month (long-term), while controls received water. after exposure, all animals received a single oral dose of 6-aminochrysene and urine was collected for 72 h. urinary mutagenicity was determined in the ames test using an activation system comprising hepatic cytosol from aroclor 1254-induced rats and utilizing the salmonella typhimurium o-acetylase overexpressing bacterial strain yg1024. bot ... | 2004 | 15598702 |
| effect of black tea intake on the excretion of mutagens in the urine of volunteers taking a beef meal. | the objective of this study was to investigate in a crossover study conducted in human volunteers whether black tea intake modulates the metabolism of heterocyclic amines, consumed in the form of well-cooked beefburgers, as exemplified by the excretion of mutagens in the urine. mutagens were extracted from urine with blue rayon, and mutagenic activity was determined in the ames test, in the presence of an activation system derived from aroclor 1254-induced rats, and employing the salmonella typh ... | 2004 | 15598780 |
| transactivation of peroxisome proliferator-activated receptor alpha by green tea extracts. | tea is a popular beverage. recently, green tea was reported to increase the number of peroxisomes in rats. in this study, to find out whether the green tea-induced proliferation of peroxisomes is mediated by pparalpha , a transient transfection assay was carried out to investigate the interactions of tea extracts (green tea, black tea,oolong tea and doongule tea) and tea components (epigallocatechin gallate, epigallocatechin, epicatechin gallate, epicatechin and gallic acid), with mouse cloned p ... | 2004 | 15613816 |
| the impact of ph and calcium on the uptake of fluoride by tea plants (camellia sinensis l.). | tea plants (camellia sinensis l.) accumulate large amounts of fluoride (f) from soils containing normal f concentrations. the present experiments examined the effects of ph and ca on f uptake by this accumulating plant species. | 2004 | 14644914 |
| combined inhibition of estrogen-dependent human breast carcinoma by soy and tea bioactive components in mice. | breast cancer is significantly less prevalent among asian women, whose diets contain high intake of soy products and tea. the objective of our present study was to identify the combined effects of dietary soy phytochemicals and tea components on breast tumor progression in a clinically relevant in vivo model of mcf-7 androgen-dependent human breast tumor in female scid mice. mcf-7 tumor growth, tumor cell proliferation and apoptosis, microvessel density, and expressions of tumor estrogen recepto ... | 2004 | 14618609 |
| antibacterial effect of water-soluble tea extracts on foodborne pathogens in laboratory medium and in a food model. | the microbial inhibition of foodborne pathogens was determined in brain heart infusion broth with 10% (wt/vol) water-soluble extracts of green, jasmine, black, dungglre, and oolong tea against escherichia coli o157:h7, salmonella enterica serovar enteritidis, listeria monocytogenes, and staphylococcus aureus. the mixed culture (approximately 6.0 log cfu/ml), which was composed of the four pathogens, was inoculated into brain heart infusion broth with and without tea extracts. after incubation at ... | 2004 | 15553649 |
| nuclei of tea flowers as targets for flavanols. | the tea plant (camellia sinensis l.) is famous for its flavanol-based constituents being valuable for human health. these flavanols associate with the nuclei of tea flowers, which is demonstrated histochemically by blue colouration using the selective staining reagent p-dimethylaminocinnamaldehyde (dmaca). sepals, petals, stamens, pollen tubes, ovaries and ovules were studied. all these organs were shown to contain flavanols in vacuolar compartments, in nuclei and, exceptionally, also in the cyt ... | 2004 | 15570474 |
| effective control of glycemic status and toxicity in zucker diabetic fatty rats with an orally administered vanadate compound. | a novel black tea decoction containing vanadate has successfully replaced insulin in a rat model of insulin-dependent diabetes but is untested in non-insulin-dependent diabetic animals. a tea-vanadate decoction (tv) containing 30 or 40 mg sodium orthovanadate was administered by oral gavage to two groups of zucker diabetic fatty rats and a conventional water vehicle containing 30 or 40 mg of sodium orthovanadate to two others. in the latter group receiving the 30-mg dose, vanadate induced diarrh ... | 2004 | 15573149 |
| antimicrobial activity of 10 different plant polyphenols against bacteria causing food-borne disease. | the antibacterial activities of 10 different plant polyphenols were evaluated by comparing their minimum inhibitory concentrations (mics) against several food-borne pathogenic bacteria, staphylococcus aureus (20 strains), some serotypes of the genus salmonella (26 strains), escherichia coli (23 strains), and some species of the genus vibrio (27 strains). the polyphenols examined were epigallocatechin (1), epigallocatechin-3-o-gallate (2), punicalagin (3), tannic acid (4), castalagin (5), prodelp ... | 2004 | 15577214 |
| changes in electric charge and phospholipids composition in erythrocyte membrane of ethanol--poisoned rats after administration of teas. | erythrocyte membrane components and electric charge can be modified by ethanol and by compounds formed as a result of its metabolism, particularly be reactive oxygen species (ros). the effects of ros can be neutralized by administering preparations with antioxidant properties. the natural preparations of this kind are teas. for this reason, it has been the purpose of this work to determine effect of green and black tea on membrane electric charge and phospholipids composition of an erythrocyte m ... | 2004 | 15794343 |
| black tea extract suppresses transformation of aryl hydrocarbon receptor induced by dioxin. | dioxins cause various adverse effects through binding to an aryl hydrocarbon receptor (ahr) and transformation of the receptor. in this study, we investigated whether black tea extract suppresses ahr transformation. dried black tea leaves were extracted with 75% ethanol, and the extract was pretreated to the rat liver cytosol fraction 10 min prior to addition of 2,3,7,8-tetrachlorodibenzo-p-dioxin (tcdd). transformed ahr was detected by electrophoretic gel mobility shift assay. black tea extract ... | 2004 | 15630227 |
| inhibition of tumour promotion in mouse skin by extracts of rooibos (aspalathus linearis) and honeybush (cyclopia intermedia), unique south african herbal teas. | the modulating effect of ethanol/acetone (e/a) soluble fractions, prepared from methanolic extracts of processed and unprocessed rooibos (aspalathus linearis) and honeybush (cyclopia intermedia) as well as green (camellia sinensis) teas was established in a two-stage mouse skin carcinogenesis assay. topical application of the tea fractions prior to the tumour promoter, 12-o-tetradecanoylphorbol-13-acetate (tpa), on icr mouse skin initiated with 7,12-dimethylbenz[a]anthracene (dmba) suppressed sk ... | 2004 | 15914270 |
| occurrence of vitamin b12 in green, blue, red, and black tea leaves. | vitamin b12 contents of green (0.046-0.263 and 0.125-0.535 microg/100 g dry weight), blue (0.068-0.081 and 0.525-0.528 microg/l00 g dry weight), red (0.061 and 0.663 microg/100 g dry weight), and black (0.104-0.859 and 0.305-1.20 microg/100 dry weight) tea leaves were obtained by intrinsic factor-chemiluminescence and microbiological methods, respectively. although vitamin b12 was found in all tea leaves tested by both assay methods, the higher values by the microbiological method were not due t ... | 2004 | 15895521 |
| metabolite profiling using (1)h nmr spectroscopy for quality assessment of green tea, camellia sinensis (l.). | a set of 191 green teas from different countries was collected and analyzed by (1)h nmr. it was proposed to establish if the teas could be discriminated according to the country of origin or with respect to quality. both principal component analysis (pca) and cluster analysis were applied to the data. some separation of chinese and non-chinese teas was observed. the present results did not allow allocation of samples to individual countries, but cluster analysis suggested that it might be possib ... | 2004 | 14969518 |
| characterization of corrinoid compounds from a japanese black tea (batabata-cha) fermented by bacteria. | a japanese fermented black tea (batabata-cha) contained a considerable amount of vitamin b(12) (456 +/- 39 ng per 100 g dry tea leaves and 2.0 +/- 0.3 ng per 100 ml of tea drink). a corrinoid compound was partially purified and characterized from the tea leaves. the patterns of the purified compound by the silica gel 60 thin-layer chromatography and c18 reversed phased high-performance liquid chromatography were identical to those of authentic vitamin b(12). when 20 week old vitamin b(12) defici ... | 2004 | 14969549 |
| inhibitory effects of green tea polyphenols on the production of a virulence factor of the periodontal-disease-causing anaerobic bacterium porphyromonas gingivalis. | the effect of polyphenolic compounds isolated from green tea (camellia sinensis) on the production of toxic end metabolites of porphyromonas gingivalis was investigated. green tea polyphenols completely inhibited the production of n-butyric acid and propionic acid at a concentration of 1.0-2.0 mg/ml in general anaerobic medium (gam). (-)-epigallocatechin gallate (egcg), which is a major component of tea polyphenols also inhibited the production of phenylacetic acid at 0.5 mg/ml in gam broth. in ... | 2004 | 15030231 |
| short-term black tea intake modulates the excretion of urinary mutagens in rats treated with 2-amino-3-methylimidazo-[4,5-f]quinoline (iq): role of cyp1a2 upregulation. | rats were exposed to black tea (2.5% w/v) as their sole drinking liquid for either 1 day or 1 month, while controls were maintained on water. after this treatment period, all animals received a single oral dose iq (2-amino-3-methylimidazo-[4,5-f]quinoline), and urine was collected for 48 h. mutagenic activity of the urine was determined in the ames test in the presence and absence of an activation system. the excretion of direct-acting mutagens was markedly reduced following tea intake, and was ... | 2004 | 15034640 |
| ex vivo modulation of chemical-induced mutagenesis by subcellular liver fractions of rats treated with rooibos (aspalathus linearis) tea, honeybush (cyclopia intermedia) tea, as well as green and black (camellia sinensis) teas. | male fischer rats were given unprocessed (not oxidized) and processed (oxidized) rooibos and honeybush teas as well as green and black teas as a sole source of drinking fluid for 10 weeks, and sub cellular liver fractions were prepared. cytosolic fractions of rats consuming the unprocessed herbal teas, green and black teas significantly (p < 0.05) protected against 2-acetylaminofluorene (2-aaf)-induced mutagenesis in the salmonella mutagenicity test with strain ta 98, using aroclor 1254-induced ... | 2004 | 15036128 |
| tea polyphenols inhibit acetyl-coa:1-alkyl-sn-glycero-3-phosphocholine acetyltransferase (a key enzyme in platelet-activating factor biosynthesis) and platelet-activating factor-induced platelet aggregation. | tea extracts have antiallergic and anti-inflammatory actions in rats and mice. however the mechanism through which tea polyphenols act in vivo are still incompletely understood. we found inhibitory effects of black tea extracts on an fmlp-induced aggregating response in a rabbit platelet-polymorphonuclear leukocyte (pmn) system. | 2004 | 15051936 |
| dietary habits and cancer mortality among middle aged and older japanese living in hokkaido, japan by cancer site and sex. | dietary factors are thought to be closely associated with the development of human cancers and hence numerous studies in this area have already been conducted in the united states and other western countries. comparatively few prospective studies have been published in japan, especially for hokkaido people. the present investigation was therefore performed to assess links between four leading cancers and some of the japanese common dietary factors through a cohort study (1984-2002) in hokkaido b ... | 2004 | 15075007 |
| screening for antioxidant activity in edible plant products: comparison of low-density lipoprotein oxidation assay, dpph radical scavenging assay, and folin-ciocalteu assay. | oxidation of low-density lipoprotein (ldl) has been implicated in atherogenesis. antioxidants that prevent ldl from oxidizing may reduce atherosclerosis. this study investigated ldl antioxidant activity in edible plant products for development of dietary supplementation to prevent atherosclerosis. fifty-two kinds of edible plants were extracted using 70% aqueous ethanol solution, and the antioxidant activity of the extracts, which inhibit human ldl oxidation induced by copper ion, was determined ... | 2004 | 15080652 |
| strong inhibitory effects of common tea catechins and bioflavonoids on the o-methylation of catechol estrogens catalyzed by human liver cytosolic catechol-o-methyltransferase. | in the present investigation, we studied the inhibitory effects of three tea catechins [catechin, epicatechin, and (-)-epigallocatechin-3-o-gallate] and two bioflavonoids (quercetin and fisetin) on the o-methylation of 2- and 4-hydroxyestradiol (2-oh-e(2) and 4-oh-e(2), respectively) by human liver cytosolic catechol-o-methyltransferase (comt). we found that catechin and epicatechin each inhibited the o-methylation of 2-oh-e(2) and 4-oh-e(2) in a concentration-dependent manner. the ic(50) values ... | 2004 | 15100171 |
| modulation of beta-lactam resistance in staphylococcus aureus by catechins and gallates. | aqueous extracts of japanese green tea (camellia sinensis) are able to reverse beta-lactam resistance in methicillin-resistant staphylococcus aureus (mrsa). we have attributed the capacity to reverse oxacillin resistance in the homogeneous pbp2a producer bb568 and in emrsa-16 to (-)-epicatechin gallate (ecg) and (-)-catechin gallate (cg). minimum inhibitory concentration (mic) values for oxacillin were reduced from 256 and 512 to 1-4 mg/l, respectively, in the presence of these polyphenols. in a ... | 2004 | 15120724 |
| antioxidants of the beverage tea in promotion of human health. | tea that contains many antioxidants is a pleasant and safe drink that is enjoyed by people across the globe. tea leaves are manufactured as black, green, or oolong. black tea represents approximately 78% of total consumed tea in the world, whereas green tea accounts for approximately 20% of tea consumed. the concept of "use of tea for promotion of human health and prevention and cure of diseases" has become a subject of intense research in the last decade. diseases for which tea drinkers appear ... | 2004 | 15130283 |
| inhibitory effect of some herbal extracts on adherence of streptococcus mutans. | the objective of this study was to investigate the inhibitory effect of the crude extracts from some herbs on adherence of streptococcus mutans (s. mutans) atcc 25175 and tpf-1 in vitro. six herbs, andrographis paniculata; cassia alata; chinese black tea (camellia sinensis); guava (psidium guajava); harrisonia perforata and streblus asper, were extracted with 50 or 95% ethanol and dried. herbal extracted solution at 0.5% concentration (w/v) was initially tested for bacterial adherence on glass s ... | 2004 | 15138013 |
| flavonoids from argentine tagetes (asteraceae) with antimicrobial activity. | the flavonoids, constituting one of the most numerous and widespread groups of natural plant constituents, are important to humans not only because they contribute to plant colors but also because many members are physiologically active. these low-molecular-weight substances, found in all vascular plants, are phenylbenzopyrones. over 4000 structures have been identified in plant sources, and they are categorized into several groups. primarily recognized as pigments responsible for the autumnal b ... | 2004 | 15156042 |
| black tea protects immunocytes from tumor-induced apoptosis by changing bcl-2/bax ratio. | it is known that cancer is associated with altered immune function. we demonstrated earlier that black tea inhibits tumor growth in a dose-dependent manner. here, we report that apoptosis was the cause of immunocyte death in ehrlich's ascites carcinoma (eac)-bearing mice and anti-tumor dose of black tea restored eac-induced immunosuppression by inhibiting apoptosis. a search for the molecular mechanism revealed that eac burden increased the expression of the pro-apoptotic proteins p53 and bax in ... | 2004 | 15159016 |
| identification of the astringent taste compounds in black tea infusions by combining instrumental analysis and human bioresponse. | application of taste dilution analyses on freshly prepared black tea infusions revealed neither the high molecular weight thearubigen-like polyphenols nor the catechins and theaflavins, but a series of 14 flavon-3-ol glycosides as the main contributors to the astringent taste perceived upon black tea consumption. among these glycosides, the apigenin-8-c-[alpha-l-rhamnopyranosyl-(1-->2)-o-beta-d-glucopyranoside] was identified for the first time in tea infusions. depending on the structure, the f ... | 2004 | 15161222 |
| polyphenolic compounds, antioxidant capacity, and quinone reductase activity of an aqueous extract of ardisia compressa in comparison to mate (ilex paraguariensis) and green (camellia sinensis) teas. | aqueous extracts of the leaves of ardisia compressa (ac) have been used in folk medicine to treat various liver disorders including liver cancer. the objective of this study was to partially characterize and determine the total polyphenol content, antioxidant capacity, and quinone reductase activity of a. compressa tea in comparison to mate (ilex paraguariensis, mt) and green (camellia sinensis,gt) teas. total polyphenol content, antioxidant capacity, and phase ii enzyme induction capacity were ... | 2004 | 15161234 |
| green and black teas inhibit atherosclerosis by lipid, antioxidant, and fibrinolytic mechanisms. | tea is the most widely consumed beverage in the world, second only to water. most laypersons and scientists believe that green tea is healthier than black tea due to the low incidence of heart disease and cancer in the orient. here, we report the first dose-response comparison of a green and black tea on normal hamsters after long-term supplementation and on a hamster model of atherosclerosis. both teas were equally effective in inhibiting atherosclerosis with the lower dose decreasing it 26-46% ... | 2004 | 15161246 |
| heavy metals in black tea samples produced in turkey. | 2004 | 15200002 | |
| ros-related enzyme expressions in endothelial cells regulated by tea polyphenols. | elevation of reactive oxygen species (ros), especially the level of superoxide is a key event in many forms of cardiovascular diseases. to study the mechanism of tea polyphenols against cardiovascular diseases, we observed the expressions of ros-related enzymes in endothelial cells. | 2004 | 15202862 |
| inhibition of lung carcinogenesis and effects on angiogenesis and apoptosis in a/j mice by oral administration of green tea. | oral administration of tea (camellia sinensis) has been shown to inhibit the formation and growth of several tumor types in animal models. the present study investigated the effects of treatment with different concentrations of green tea on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (nnk)-induced lung tumorigenesis in female a/j mice. two days after a single dose of nnk (100 mg/kg body weight, i.p.), the mice were given 0.1, 0.2, 0.4, and 0.6% green tea solution (1, 2, 4, and 6 g of tea soli ... | 2004 | 15203377 |
| inhibitory effect(s) of polymeric black tea polyphenol fractions on the formation of [(3)h]-b(a)p-derived dna adducts. | five polymeric black tea polyphenol fractions (pbp-1-5) were isolated from a popular brand of black tea. the effect of these pbps and epigallocatechin gallate (egcg), a major green tea polyphenol, was studied on the formation of [(3)h]-b(a)p-derived dna adducts in vitro, employing rat liver microsomes. pbp-1-3 inhibited microsome-catalyzed [(3)h]-b(a)p-derived dna adduct formation in vitro in a dose-dependent manner. this inhibition was further enhanced on preincubation of microsomes with each o ... | 2004 | 15212478 |
| increased microbicidal activity of green tea (camellia sinensis) in combination with butylated hydroxyanisole. | we have demonstrated that green tea (camellia sinensis) shows increased antimicrobial activity against bacteria and fungi when used in combination with butylated hydroxyanisole (bha). glycolic extract taken from green tea showed only limited activity against streptococcus mutans and no activity against candida albicans and certain strains of escherichia coli. bha, at non inhibitory concentrations, increased the microbicidal activity of green tea against 10(10) s. mutans (p<0.01), non-susceptible ... | 2004 | 15216944 |
| evidence for a prospective anti-osteoporosis effect of black tea (camellia sinensis) extract in a bilaterally ovariectomized rat model. | the purpose of this study was to examine whether whole aqueous black tea extract (bte) prevents bone loss induced by ovarian hormone deficiency. eighteen 95-100 days old female albino rats were randomly assigned to three treatment groups [sham -operated control (sham); bilaterally ovariectomized (ovx) and ovx + aqueous black tea extract (bte) ] and sacrificed after 28 days. all animals were fed a standard laboratory diet with free access to deionized water except on days of urinary parameter stu ... | 2004 | 15228990 |
| fluoride content in tea and its relationship with tea quality. | the tea plant is known as a fluorine accumulator. fluoride (f) content in fresh leaves collected from 14 plantations in china was investigated. the f increased with maturity, and the f variation was remarkable in the tender shoots. furthermore, significant negative relationships were observed between f content and the content of the quality parameters total polyphenols and amino acids. these substances are rich in young leaves and poor in mature ones. with regard to quality of tea products, the ... | 2004 | 15237954 |
| caffeine in tea plants [camellia sinensis (l) o. kuntze]: in situ lowering by bacillus licheniformis (weigmann) chester. | tea plants (camellia sinensis) contain 5-6% caffeine that is responsible for the stimulating effect of the beverage. as the tolerance to caffeine varies among individuals, low caffeine tea would be an ideal alternative. while assessing the potential of a few selected bacteria-bacillus licheniformis, b. subtilis and b. firmus, to multiply on nutrient medium supplemented with glucose (5%) and tea leaf extract (2%), it was observed that only b. licheniformis could proliferate on this medium. hence, ... | 2004 | 15260108 |
| green tea flavan-3-ols and oligomeric proanthocyanidins inhibit the motility of infective larvae of teladorsagia circumcincta and trichostrongylus colubriformis in vitro. | the effects of a hot water infusion and an aqueous acetone extract of green tea (camellia sinensis) on the motility of infective larvae of the sheep nematodes teladorsagia circumcincta and trichostrongylus colubriformis were investigated under in vitro conditions. the infusion and extract dose-dependently inactivated the infective larvae as assessed by the larval migration inhibition (lmi) assay. to determine the components responsible for the inhibitory activity, the hot water infusion and aque ... | 2004 | 15276775 |
| antioxidants in chinese herbal medicines: a biochemical perspective. | recently, intense interest has focused on the antioxidant properties of natural products. in particular, chinese herbal medicines (chm) have become hot topics for life science researchers since many are reported to possess cardioprotective compounds, many of which remain to be identified. indeed, the exact mechanisms by which chm work remain unknown. although many of these herbal remedies are undoubtedly efficacious, few have been scientifically investigated for their active chemical constituent ... | 2004 | 15282631 |
| piperine enhances the bioavailability of the tea polyphenol (-)-epigallocatechin-3-gallate in mice. | (-)-epigallocatechin-3-gallate (egcg), from green tea (camellia sinensis), has demonstrated chemopreventive activity in animal models of carcinogenesis. previously, we reported the bioavailability of egcg in rats (1.6%) and mice (26.5%). here, we report that cotreatment with a second dietary component, piperine (from black pepper), enhanced the bioavailability of egcg in mice. intragastric coadministration of 163.8 micromol/kg egcg and 70.2 micromol/kg piperine to male cf-1 mice increased the pl ... | 2004 | 15284381 |
| total phenolics and antioxidant activities of fenugreek, green tea, black tea, grape seed, ginger, rosemary, gotu kola, and ginkgo extracts, vitamin e, and tert-butylhydroquinone. | the total phenolics and antioxidant activities of fenugreek, green tea, black tea, grape seed, ginger, rosemary, gotu kola, and ginkgo extracts, vitamin e, and tert-butylhydroquinone, were determined. grape seed and green tea were analyzed for their phenolic constituents using high-performance liquid chromatography. the total phenolics of the plant extracts, determined by the folin-ciocalteu method, ranged from 24.8 to 92.5 mg of chlorogenic acid equivalent/g dry material. the antioxidant activi ... | 2004 | 15291494 |
| preventive effect of thea sinensis melanin against acetaminophen-induced hepatic injury in mice. | the preventive effect of thea sinensis melanin (tsm) against overdoses of n-acetyl-p-aminophenol (napap) was studied on icr mice. animals were given 400 mg/kg intraperitoneally (i.p.) of napap, and tsm was injected i.p. in doses 10-40 mg/kg 2 h before intoxication. the protective effects were evidenced by a complete blockage of the napap-induced elevation of plasma alanine aminotransferase (alt) activity, decreased concentration of thiobarbituric acid reactive substances (tbars) to the control l ... | 2004 | 15291509 |
| inhibition of interleukin-1beta-stimulated collagenase and stromelysin expression in human tendon fibroblasts by epigallocatechin gallate ester. | the medicinal benefits of green tea (camellia sinensis) consumption have been attributed to bioavailable polyphenols, notably epigallocatechin gallate (egcg). we have assessed the effects of egcg and its non-esterified counterpart egc on the expression of the collagenases, matrix metalloproteinases (mmp)-1 and -13, and the stromelysin, mmp-3, in human tendon-derived fibroblasts. interleukin (il)-1beta increased mmp-1, -3 and -13 mrna and output at least 30-fold. egcg reduced this stimulation, by ... | 2004 | 15296944 |
| [test for urokinase-type plasminogen activator inhibitor of edible plants in vitro]. | to study the effect of anti-progression activity of edible plants using urokinase as the biomarker. | 2004 | 15312585 |
| green tea (camellia sinensis) extract does not alter cytochrome p450 3a4 or 2d6 activity in healthy volunteers. | green tea extract is a widely used dietary supplement. the objective of this study was to assess the influence of a decaffeinated green tea (dgt; camellia sinensis) extract on the activity of the drug-metabolizing enzymes cytochrome p-450 2d6 and 3a4. probe drugs dextromethorphan (30 mg, cyp2d6 activity) and alprazolam (alpz; 2 mg, cyp3a4 activity) were administered orally to healthy volunteers (n = 11) at baseline, and again after treatment with four dgt capsules/day for 14 days. each dgt capsu ... | 2004 | 15319329 |
| preventive effect of traditional herbal formulae against experimental hypercholesterolemia in rats with special reference to blood lipoprotein cholesterol levels. | to investigate the effect of traditional herbal formulae (zhong yao) against experimental hypercholesterolemia, we assayed serum lipoprotein levels and hepatic function in rats administered herbal formulae under cholesterol rich diet. two kinds of herbal formulae; prescription 1 (bupleurum chinense and other 9 kinds of herbs) and 2 (camellia sinensis and other 5 kinds of herbs) were prepared. all of 35 rats were separated into 4 groups, group p fed under cholesterol rich diet for 15 days and adm ... | 2004 | 15325730 |
| determination of fumonisins b1 and b2 in herbal tea and medicinal plants in turkey by high-performance liquid chromatography. | the purpose of this study was to measure the potential levels of fumonisin b1 (fb1) and fumonisin b2 (fb2) contamination in several herbal teas and medicinal plants that are consumed regularly in turkey. fb1 and fb2 were detected using high-performance liquid chromatography with fluorescence detection after derivatization with o-phthaldialdehyde. a total of 115 commercially available herbal tea and medicinal plant samples were analyzed. the recoveries in black tea were 86.9+/-8.42% for fb1 and 1 ... | 2004 | 15330551 |
| activation of endothelial nitric-oxide synthase by the p38 mapk in response to black tea polyphenols. | black tea improves endothelial function in patients with coronary artery disease. we sought to determine the responsible components of black tea and elucidate the underlying cell signaling mechanisms. we exposed porcine aortic endothelial cells to components of black tea and found that the polyphenol fraction acutely enhanced nitric oxide bioactivity. this effect involved endothelial nitric-oxide synthase (enos) phosphorylation at ser-1177 and dephosphorylation at thr-495, consistent with increa ... | 2004 | 15333638 |
| codelivery of a tea extract prevents morbidity and mortality associated with oral vanadate therapy in streptozotocin-induced diabetic rats. | oral administration of vanadate has a strong hypoglycemic effect but results in toxic side effects like life-threatening diarrhea. tea is known to have potent antidiarrhea effects. we investigated the potential of suspending the vanadate in a tea decoction to reduce the diarrheatic action of vanadate. a concentrated extract of lichee black tea was, therefore, added to sodium orthovanadate. streptozotocin (stz)-induced diabetic rats were orally gavaged with vanadate suspended in water or in the t ... | 2004 | 15334376 |
| black tea polyphenol theaflavins inhibit aromatase activity and attenuate tamoxifen resistance in her2/neu-transfected human breast cancer cells through tyrosine kinase suppression. | the aromatase enzyme, which converts androstenedione to oestrone, regulates the availability of oestrogen to support the growth of hormone-dependent breast tumours. in this study, we investigated the inhibitory effects of black tea polyphenols on aromatase activities. we found that black tea polyphenols, tf-1, tf-2 and tf-3, significantly inhibited rat ovarian and human placental aromatase activities. in addition, using an in vivo model, these black tea polyphenols also inhibited the proliferati ... | 2004 | 15341993 |
| in vitro transdermal delivery of the major catechins and caffeine from extract of camellia sinensis. | the aim of this study was to investigate the feasibility of the transdermal delivery of catechins and caffeine from green tea extract. drug-in-adhesive patches containing 1.35, 1.03, 0.68, and 0.32 mg cm(-2) green tea extract were formulated and the dissolution of (-)-epigallocatechin gallate (egcg), (-)-epigallocatechin (egc) and (-)-epicatechin (ec) from these was determined. transdermal delivery was determined across full thickness pig ear skin from saturated solutions of green tea extract in ... | 2004 | 15363500 |
| do leaf surface characteristics affect agrobacterium infection in tea [camellia sinensis (l.) o kuntze]? | the host range specificity of agrobacterium with five tea cultivars and an unrelated species (artemisia parviflora) having extreme surface characteristics was evaluated in the present study. the degree of agrobacterium infection in the five cultivars of tea was affected by leaf wetness, micro-morphology and surface chemistry. wettable leaf surfaces of tv1, upasi-9 and kangra jat showed higher rate (75%) of agrobacterium infection compared to upasi-10 and st-449, whereas non-wettable leaves of a. ... | 2004 | 15381852 |
| in vitro chemopreventive activity of camellia sinensis, ilex paraguariensis and ardisia compressa tea extracts and selected polyphenols. | several herbal teas contain bioactive compounds that have been associated with a lower risk of chronic diseases including cancer. the aim of this study was to evaluate the chemopreventive activity of tea aqueous extracts and selected constituent pure polyphenols using a battery of in vitro marker systems relevant for the prevention of cancer. the effects of (-) epigallocatechin gallate (egcg), quercetin (q), gallic acid (ga), green tea (gt, camellia sinensis), ardisia tea (at, ardisia compressa) ... | 2004 | 15450404 |
| dietary intervention with iron and black tea infusion in reducing cytotoxicity of arsenic. | the relative efficacy of infusion of black tea leaf, camellia sinensis (linn.) o. kuntze, (theaceae), and iron as freshly prepared aqueous solution of ferrous sulphate in reducing the cytotoxic effects of arsenic, was tested in bone marrow cells of laboratory bred swiss albino mice. ferrous sulphate and tea given alone did not induce chromosomal breakage to any appreciable extent. tea decreased chromosome damage induced by arsenic to a significant extent, while the addition of ferrous sulphate d ... | 2004 | 15462183 |
| flavonoid biosynthesis in the tea plant camellia sinensis: properties of enzymes of the prominent epicatechin and catechin pathways. | leaves of tea (camellia sinensis l.) contain extraordinary large amounts of (-)-epigallocatechin, (-)-epicatechin, (+)-gallocatechin, and (+)-catechin and derivatives of these compounds that show positive effects on human health. the health-promoting effects of flavan 3-ols, especially those of green tea, are of scientific and public interest. furthermore, they play a crucial role in defense against pathogens of tea. therefore, biosynthesis of these flavonoid compounds was investigated. the anth ... | 2004 | 15464723 |
| potential chemoprotective effects of the coffee components kahweol and cafestol palmitates via modification of hepatic n-acetyltransferase and glutathione s-transferase activities. | coffee drinking has been associated with reduced incidence of colorectal cancer, possibly via chemoprotection/modification of the metabolism of dietary heterocyclic amine carcinogens such as 2-amino-1-methyl-6-phenylimidazo-[4,5-b]pyridine (phip) by kahweol and cafestol palmitates (k/c), two components of unfiltered coffee. using the phip-exposed male fisher f344 rat as a model, k/c have been shown to reduce colonic phip-dna adducts by > 50%. we have used the male f344 rat to investigate the eff ... | 2004 | 15468054 |
| in vitro anti-beta-secretase and dual anti-cholinesterase activities of camellia sinensis l. (tea) relevant to treatment of dementia. | the primary target of licensed drugs for the treatment of alzheimer's disease is the inhibition of the enzyme acetylcholinesterase, although preventing beta-amyloidosis is a prime target for drugs in development. the in vitro dual anti-cholinesterase and beta-secretase activities of camellia sinensis l. extract (tea) is reported. green and black tea inhibited human acetylcholinesterase (ache) with ic(50) values of 0.03 mg/ml and 0.06 mg/ml respectively, and human butyrylcholinesterase (buche) wi ... | 2004 | 15476306 |
| antioxidant properties of black tea in alcohol intoxication. | food ingredients such as alcohol may modify cellular redox state. ethanol metabolism is accompanied by generation of free radicals that can damage cell components especially when antioxidant mechanisms are no able to neutralize them. however black tea is a source of polyphenol antioxidants that may enhance cellular antioxidant abilities. the aim of this study was to investigate the effect of black tea on antioxidant abilities of the liver, blood serum and brain of 12-months old rats sub-chronica ... | 2004 | 15500941 |
| in vitro cytotoxicity of epigallocatechin gallate and tea extracts to cancerous and normal cells from the human oral cavity. | this study compared the in vitro responses of malignant and normal cells from the human oral cavity to tea extracts and to its main polyphenolic component, (-)-epigallocatechin gallate (egcg). the antiproliferative effects of tea polyphenolic extracts and egcg were more pronounced towards immortalized, tumourigenic (cal27, hsc-2, and hsg(1)) and non-tumourigenic (s-g) cells than towards normal (gn56 and hgf-1) fibroblasts and green tea was more toxic than black tea. as the addition of tea extrac ... | 2004 | 15504155 |
| exobasidium vexans infection of camellia sinensis increased 2,3-cis isomerisation and gallate esterification of proanthocyanidins. | infection of leaves of tea (camellia sinensis (kuntze) l, cv tri 2025) which was susceptible to blister blight (exobasidium vexans massee), resulted in a shift of the proanthocyanidin stereochemistry away from 2,3-trans (e.g. catechin and gallocatechin) and towards 2,3-cis (e.g. epicatechin and epigallocatechin). infection also resulted in increased gallic acid esterification of the initiating subunits of proanthocyanidins. this was shown by both mass spectroscopy and phloroglucinolysis. proanth ... | 2004 | 15504433 |
| green tea polyphenol epigallocatechin-3-gallate (egcg) differentially inhibits interleukin-1 beta-induced expression of matrix metalloproteinase-1 and -13 in human chondrocytes. | interleukin-1beta (il-1beta)-induced inflammatory response in arthritic joints include the enhanced expression and activity of matrix metalloproteinases (mmps), and their matrix degrading activity contribute to the irreversible loss of cartilage and may also be associated with sustained chronic inflammation. we have earlier shown that green tea (camellia sinensis) polyphenol epigallocatechin-3-gallate (egcg) was non-toxic to human chondrocytes [singh r, ahmed s, islam n, goldberg vm, and haqqi t ... | 2004 | 14600251 |
| anti-trypanosoma cruzi activity of green tea (camellia sinensis) catechins. | the trypanocidal action of green tea catechins against two different developmental stages of trypanosoma cruzi is reported for the first time. this activity was assayed with the nonproliferative bloodstream trypomastigote and with the intracellular replicative amastigote parasite forms. an ethyl acetate fraction from camellia sinensis green tea leaves, which contains most of the polyphenolic compounds and the maximal trypanocidal activity, was obtained by fractionation of the aqueous extract wit ... | 2004 | 14693520 |
| black and green tea polyphenols attenuate blood pressure increases in stroke-prone spontaneously hypertensive rats. | oxidative stress was reported to be involved not only in cardiovascular diseases, but also in hypertension. epidemiologic studies indicated that tea consumption slightly reduces blood pressure. we conducted two studies to determine whether black and green tea can lower blood pressure (bp) in stroke-prone spontaneously hypertensive rats (shrsp). male shrsp (n=15) were allowed to recover for 2 wk after a transmitter for measuring bp was implanted in the peritoneal cavity. the rats were divided int ... | 2004 | 14704290 |
| modulation of phosphatidylinositol-3-kinase/protein kinase b- and mitogen-activated protein kinase-pathways by tea polyphenols in human prostate cancer cells. | we have earlier shown that oral infusion of a polyphenolic fraction isolated from green tea, at a human achievable dose (equivalent to six cups of green tea per day), significantly inhibits prostate cancer (pca) development and metastasis in transgenic adenocarcinoma of mouse prostate (tramp) model that closely mimics progressive form of human prostatic disease (gupta et al. [2001]: proc. natl. acad. sci. u.s.a. 98:10350-10355.). a complete understanding of the mechanism(s) and molecular targets ... | 2004 | 14743383 |
| effects of a controlled diet and black tea drinking on the fecal microflora composition and the fecal bile acid profile of human volunteers in a double-blinded randomized feeding study. | although diet has been clearly associated with human health many potential mechanisms remain undefined. for instance, although the intestinal bacterial microflora has long been postulated to contribute to human health, little is known about the effects of diet on the bacterial microflora composition and the specific contributions of the microflora to human health. thus, we analyzed 1) changes in the fecal microflora composition by fluorescent in-situ hybridization (fish) and denaturing gradient ... | 2004 | 14747691 |
| phenolic acid metabolites as biomarkers for tea- and coffee-derived polyphenol exposure in human subjects. | tea and coffee are rich in polyphenols with a variety of biological activities. many of the demonstrated activities are consistent with favourable effects on the risk of chronic diseases. 4-o-methylgallic acid (4omga) and isoferulic acid are potential biomarkers of exposure to polyphenols derived from tea and coffee respectively. 4omga is derived from gallic acid in tea, and isoferulic acid is derived from chlorogenic acid in coffee. our major objective was to explore the relationships of tea an ... | 2004 | 14756917 |
| novel chemiluminescence-inducing cocktails, part ii: measurement of the anti-oxidant capacity of vitamins, thiols, body fluids, alcoholic beverages and edible oils. | using two luminescence-inducing cocktails, two distinct patterns of inhibition of light by different anti-oxidants have been identified, comprising group a, in which a complete inhibition of light emission which is then followed by re-emergence of light, forming apparent s-shaped curves or similar shapes. this light pattern is induced by the "classical" anti-oxidants, ascorbate, vitamin e, uric acid, thiols, deferoxamine, as well as by anti-oxidant agents present in plasma, saliva, urine and in ... | 2004 | 15901412 |
| phenolic constituents and antioxidant activity of wendita calysina leaves (burrito), a folk paraguayan tea. | burrito tea originates from the leaves of wendita calysina, an indigenous paraguayan plant, which is commonly consumed in south america and in western countries. phytochemical investigation of this species has led to the isolation of 14 constituents, among them 2 new flavanonols, dihydroquercetagetin (1) and 3,5,6,7,4'-pentahydroxyflavanonol (2), in addition to several known methoxyflavones, methoxyflavonols, phenylethanoid glycosides, and benzoic acid derivatives (4-14). all structures were elu ... | 2004 | 15366833 |
| cryopreservation of tea (camellia sinensis l.) seeds and embryonic axes. | this study investigated the tolerance to desiccation and freezing of tea seeds, embryonic axes (eas) and cotyledonary embryonic axes (ceas, consisting of eas with portions of cotyledons still attached). no seeds germinated after desiccation and cryopreservation. eas extracted from seeds desiccated to 18.9% moisture content (fresh weight basis) and cryopreserved showed 20.7% survival but plantlet production from these eas was impossible. when eas and ceas were extracted from seeds before being su ... | 2004 | 12391481 |
| [chemical and sensory characterization of tea (thea sinensis) consumed in chile]. | by means of descriptive analysis four varieties of tea (thea sinensis) were assesed: argentinean op (orange pekoe) tea (black), brazilian op tea (black), ceylan op tea (black) and darjeeling op tea (green). the appearance of dry tea leaves were qualitatively characterized comparing with dry leaves standard. the attributes: colour, form, regularity of the leaves, fibre and stem cutting were evaluated the differences obtained were related to the differences produced by the effect of the fermentati ... | 2005 | 16187684 |
| about the cover illustration: thea sinensis - the common tea plant. | 2005 | 15976762 | |
| oxidation of tea extracts and tea catechins by molecular oxygen. | tea polyphenols (pp) are known as potent antioxidants. at the same time, pp have been repeatedly reported to oxidize by molecular oxygen with the formation of active forms of oxygen. in this work, the clark electrode technique was applied to study the kinetics of the autoxidation of tea extracts and individual tea pp as well as model pp, catechol, gallic acid, and pyrogallol. aqueous extracts of both green and black teas were found to undergo extensive autoxidation under physiological conditions ... | 2005 | 15913321 |
| variations of main quality components of tea genetic resources [camellia sinensis (l.) o. kuntze] preserved in the china national germplasm tea repository. | the variations of the main quality components of tea, tea polyphenols, catechins, amino acids, caffeine, and water extract of 596 accessions chinese tea genetic resources, preserved in the china national germplasm tea repository (cngtr), were analyzed. tea polyphenols content on a dry weight basis varied from 13.6 to 47.8%, averaging 28.4%. the tea polyphenols content increases gradually from northern and eastern provinces to southern provinces, the highest is in yunnan tea resources. the conten ... | 2005 | 15898357 |
| black tea polyphenols suppress cell proliferation and induce apoptosis during benzo(a)pyrene-induced lung carcinogenesis. | one of the most promising strategies for cancer prevention is chemoprevention by daily used food and beverages. black tea, the most widely consumed beverage, is a source of compounds with antioxidative, antimicrobial, antimutagenic and anticarcinogenic properties. lung cancer is the most common cause of cancer deaths in both men and women worldwide. over one million people around the world are likely to be killed by lung cancer due to increased tobacco smoking and environmental pollutants, espec ... | 2005 | 15901989 |
| hepatoprotective effect of green tea (camellia sinensis) extract against tamoxifen-induced liver injury in rats. | tamoxifen citrate (tam), is widely used for treatment of breast cancer. it showed a degree of hepatic carcinogenesis. the purpose of this study was to elucidate the antioxidant capacity of green tea (camellia sinensis) extract (gte) against tam-induced liver injury. a model of liver injury in female rats was done by intraperitoneal injection of tam in a dose of 45mg kg(-1) day(-1), i.p. for 7 successive days. gte in the concentration of 1.5 %, was orally administered 4 days prior and 14 days aft ... | 2005 | 16202236 |
| black tea theaflavins suppress dioxin-induced transformation of the aryl hydrocarbon receptor. | dioxins cause various adverse effects through transformation of aryl hydrocarbon receptor (ahr). in this study, we investigated whether black tea extract and its components, theaflavins, suppress ahr transformation in vitro. first, we confirmed that black tea extract strongly suppressed ahr transformation compared to green and oolong tea, although the catechin contents did not change significantly among the extracts. then we isolated four theaflavins as active compounds from black tea leaves. th ... | 2005 | 15914905 |
| determination of some organochlorine compounds in herbal colouring agent henna (lawsonia inermis) and in tea (thea sinensis). | henna (lawsonia inermis) has been used for centuries as a herbal hair and skin dye, but very little is known about its additives and contaminants that could adversely affect human health. an analytical method was developed to determine organochlorine compounds in henna, as they are still widely used in the areas where henna is grown. samples were sonicated with n-hexane, extracts cleansed on florisil sorbent and analysed using gas chromatography with electron capture detection. the overall recov ... | 2005 | 15969202 |
| molecular definition of black tea taste by means of quantitative studies, taste reconstitution, and omission experiments. | recently, bioresponse-guided fractionation of black tea infusions indicated that neither the high molecular weight thearubigens nor the theaflavins, but a series of 14 flavon-3-ol glycopyranosides besides some catechins, might be important contributors to black tea taste. to further bridge the gap between pure structural chemistry and human taste perception, in the present investigation 51 putative taste compounds have been quantified in a black tea infusion, and their dose-over-threshold (dot) ... | 2005 | 15969522 |
| comparative studies on the hypolipidemic and growth suppressive effects of oolong, black, pu-erh, and green tea leaves in rats. | the four major commercial teas, oolong, black, pu-erh, and green teas, have been manufactured in southeast asia. in this study, we evaluated the growth suppressive and hypolipidemic effect of these four different tea leaves by oral feeding to male sprague-dawley rats for 30 weeks. the results showed that the suppression of body weights of tea leaves-fed groups were in the order: oolong tea > pu-erh tea > black tea > green tea. pu-erh tea and oolong tea could lower the levels of triglyceride more ... | 2005 | 15656692 |
| tea and circulating estrogen levels in postmenopausal chinese women in singapore. | the role of tea in the etiology of breast cancer is controversial. we recently provided the first set of human evidence that breast cancer risk is significantly inversely associated with tea intake, largely confined to intake of green tea. since black tea and green tea possess comparable levels of the total tea polyphenols that possess antioxidative activities, reasons for the paradoxical effects of green tea and black tea on breast cancer protection are not apparent. some limited evidence sugge ... | 2005 | 15661801 |
| paradoxical effects of green tea (camellia sinensis) and antioxidant vitamins in diabetic rats: improved retinopathy and renal mitochondrial defects but deterioration of collagen matrix glycoxidation and cross-linking. | we tested the hypothesis that green tea prevents diabetes-related tissue dysfunctions attributable to oxidation. diabetic rats were treated daily with tap water, vitamins c and e, or fresh japanese green tea extract. after 12 months, body weights were decreased, whereas glycated lysine in aorta, tendon, and plasma were increased by diabetes (p < 0.001) but unaffected by treatment. erythrocyte glutathione and plasma hydroperoxides were improved by the vitamins (p < 0.05) and green tea (p < 0.001) ... | 2005 | 15677510 |
| short-term administration of (-)-epigallocatechin gallate reduces hepatic steatosis and protects against warm hepatic ischemia/reperfusion injury in steatotic mice. | hepatic steatosis increases the extent of cellular injury incurred during ischemia/reperfusion (i/r) injury. (-)-epigallocatechin gallate (egcg), the major flavonoid component of green tea (camellia sinensis) is a potent antioxidant that inhibits fatty acid synthase (fas) in vitro. we investigated the effects of egcg on hepatic steatosis and markers of cellular damage at baseline and after i/r injury in ob/ob mice. animals were pretreated with 85 mg/kg egcg via intraperitoneal (ip) injection for ... | 2005 | 15719408 |
| inhibition of benzo[a]pyrene induced mutagenicity and genotoxicity by black tea polyphenols theaflavins and thearubigins in multiple test systems. | this study investigated the antimutagenic and anticlastogenic effects of black tea polyphenols, theaflavins (tf) and thearubigins (tr) in salmonella assay in vitro and in vivo in bone marrow cells of mice as measured by chromosomal aberrations (ca) and sister chromatid exchange (sce) against a known carcinogen, benzo[a]pyrene (b[a]p). a significant decrease in mutagenicity in salmonella assay and both ca and sce were observed in all the different concentrations of tf and tr plus b[a]p treated se ... | 2005 | 15721207 |
| genetic diversity of upasi tea clones (camellia sinensis (l.) o. kuntze) on the basis of total catechins and their fractions. | tea leaf catechins and the ratio of dihydroxylated to trihydroxylated catechin fractions were analysed to identify the genetic diversity of 26 upasi released tea clones. principal component analysis (pca) based on regression factor separated tea clones into five groups according to their jats (jats are region based rays for e.g., assam, china and cambod origin) as well as their quality constituents (such as total polyphenols, total catechins, amino acids in the green leaves and liquor characteri ... | 2005 | 15721948 |
| nuclear magnetic resonance spectroscopic based studies of the metabolism of black tea polyphenols in humans. | epidemiological studies indicate that a high intake of flavonoids is associated with an improved health status. tea is one of the most abundant sources of flavonoids in the human diet. the bioavailability and biotransformation of tea flavonoids are, however, not clearly understood. the aim of the present study was to investigate the metabolism of black tea via a nonspecific screening method. (1)h nuclear magnetic resonance (nmr) spectroscopy was used to obtain nonselective profiles of urine samp ... | 2005 | 15740018 |
| inhibition of lung tumorigenesis by tea. | tea and tea constituents have been shown by different investigators to inhibit lung tumorigenesis in different animal model systems. this includes lung tumorigenesis in a/j mice induced by 4-(methylnitrosamino)-1-(3pyridyl)-1-butanone (nnk), n-nitrosodiethylamine, benzo[a]pyrene, n-nitrosomethylurea, or cisplatin. inhibition of lung tumorigenesis has also been demonstrated in c3h mice treated with n-nitrosodiethylamine. in most of these experiments, reduction in tumor number and tumor size has b ... | 2005 | 15765923 |
| phytoestrogenic effects of black tea extract (camellia sinensis) in an oophorectomized rat (rattus norvegicus) model of osteoporosis. | the adverse side effects of currently available anti-osteoporotic agents warrant the search for compounds with less toxic effects. in this study, we assessed the phytoestrogenic potentiality of whole aqueous extract of black tea (bte) in a bilaterally oophorectomized rat model (2.5%, 1 ml/100 g body weight/day for 28 days). although the supplementation was given for 28 days but, sign of revival of copulation period (estrous stage) from non-receptive diestrous stage was first noticed after 21 day ... | 2005 | 15996685 |
| epigallocatechin gallate (egcg) (teavigo) does not impair nonhaem-iron absorption in man. | a number of studies have shown that tea catechins can inhibit intestinal iron absorption, mostly iron in the nonhaem form. this randomized, double-blind, placebo-controlled, 3-periods cross-over study examined the degree of inhibition of nonhaem iron absorption by pure crystalline epigallocatechin gallate (egcg). the study was designed to show the maximum inhibitory action of egcg by selecting 30 healthy women with low iron stores. treatments were 150 mg, 300 mg egcg and placebo each for 8 conse ... | 2005 | 16008116 |