Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| effects of theaflavins on n-nitrosomethylbenzylamine-induced esophageal tumorigenesis. | the purpose of this experiment was to compare the inhibitory effects of the polyphenol fraction of black tea, theaflavins (tf), the polyphenol fraction of green tea, and (-)-epigallocatechin-3-gallate (egcg) in the rat esophageal tumor model. the tea fractions were administered in the drinking water at concentrations of 360 and 1,200 ppm for two weeks before administration of the esophageal carcinogen n-nitrosomethylbenzylamine (nmba). nmba was administered subcutaneously in 10% dimethyl sulfoxi ... | 1997 | 9383778 |
| inhibitory effect of black tea on the growth of established skin tumors in mice: effects on tumor size, apoptosis, mitosis and bromodeoxyuridine incorporation into dna. | female cd-1 mice were initiated with a single topical application of 7,12-dimethylbenz[a]anthracene and promoted with 12-o-tetradecanoylphorbol-13-acetate. mice with established papillomas were then treated with black tea or decaffeinated black tea (approximately 4 mg tea solids/ml) as the sole source of drinking fluid for 11-15 weeks. in four separate experiments, oral administration of black tea inhibited the growth of papillomas (increase in tumor volume/mouse) by an average of 35%, 37%, 41% ... | 1997 | 9395217 |
| effects of green tea, black tea and dietary lipophilic antioxidants on ldl oxidizability and atherosclerosis in hypercholesterolaemic rabbits. | the hypothesis that tea or dietary lipid-soluble antioxidants reduce atherogenesis by lowering the oxidizability of low-density lipoprotein (ldl) was investigated. five groups of 20 female new zealand white rabbits were fed a restricted amount of a high-fat (30 en%) semipurified diet supplemented with cholesterol (0.15%, w/w) for 21 weeks. the vitamin e content of the control diet was 40 mg/kg diet. the animals received either green tea or black tea in their drinking water or vitamin e (200 mg/k ... | 1997 | 9395271 |
| microbiological screening of indian medicinal plants with special reference to enteropathogens. | the world health organisation (who) has recommended that all member states actively promote native medicines in their country. ten indian medicinal plants were screened for antibacterial activity specific to enteropathogens. diffusion and dilution methods were used to measure the antibacterial activity. allium sativum, camellia sinensis, and chamaesyce hirta showed higher activity when compared to the rest. they had a minimum bactericidal concentration (mbc) of < 100 micrograms/ml and gave inhib ... | 1997 | 9395690 |
| effects of tea and chlorophyllin on the mutagenicity of n-hydroxy-iq: studies of enzyme inhibition, molecular complex formation, and degradation/scavenging of the active metabolites. | green tea and black tea inhibit the formation of carcinogen-dna adducts and colonic aberrant crypts in rats given 2-amino-3-methylimidazo[4, 5-f]quinoline (iq), a mutagen from cooked meat. the salmonella mutagenicity assay was used in the present study to test individual constituents of tea as inhibitors of 2-hydroxyamino-3-methylimidazo[4, 5-f]quinoline (n-hydroxy-iq), a direct-acting metabolite of iq. testing of pure compounds at doses relevant to their levels in tea identified epigallocatechi ... | 1997 | 9435888 |
| inhibition of carcinogenesis by tea: the evidence from experimental studies. | in its various forms, tea is one of the most widely consumed beverages in the world. elucidation of the chemical components of tea has revealed that the beverage is a rich repository of antioxidants. among these are the polyphenolics, common to green tea, but also found in black teas together with oxidized polymers that in part account, for the darkened color. consumption of tea on a regular basis has been associated with reduced risk of several forms of cancer in human populations, with the str ... | 1997 | 9447274 |
| black tea constituents, theaflavins, inhibit 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (nnk)-induced lung tumorigenesis in a/j mice. | the present study investigated the inhibitory activity against lung tumorigenesis by a group of characteristic black tea polyphenols, theaflavins. in a short-term study, female a/j mice were treated with a single dose of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (nnk; 103 mg/kg b.w., i.p.) on day 0, and 0.1 and 0.3% theaflavins were administered as the sole source of drinking fluid starting 24 h after nnk treatment. the proliferation index of the lung tissues was measured by the incorporati ... | 1997 | 9450482 |
| [comparison between black tea and gargles on inhibition of the infectivity of influenza virus]. | 1997 | 9455060 | |
| carbonic anhydrase from camelia sinensis (tea) leaves. | carbonic anhydrase (ca) (carbonate hydrolyase; e,c,4.2.1.1) from leaves of mature camelia sinensis was purified and characterized. the purification level was 53 fold. the optimum temperature for maximal enzyme activity is 50 degrees c. the optimum ph was 6.8 and this ph varied between 6.5 and 7.5. each enzyme molecule is a hexamer with an m(r) of 169,000 with subunits of m(r) = 28,000. | 1997 | 9413559 |
| protective effects of tea polyphenols against oxidative damage to red blood cells. | tea polyphenols (tpp) from black and green teas were evaluated for their antioxidant effects on normal red blood cells (rbc) and beta-thalassemic rbc membranes challenged with exogenous oxidants in vitro. the tpp of both types protected rbc against primaquine-induced lysis; they also protected the whole cells and the membranes against h2o2-induced lipid peroxidation so that about 80% protection was reached at [tpp] = 10 microg/ml. tpp from black tea at the same concentration protected normal rbc ... | 1997 | 9374417 |
| consumption of green or black tea does not increase resistance of low-density lipoprotein to oxidation in humans. | epidemiologic studies indicated that tea consumption reduces the risk of cardiovascular disease. we assessed the effect of green or black tea consumption on resistance of low-density lipoprotein (ldl) to oxidation ex vivo and on serum lipid concentrations in healthy volunteers. in a 4-wk parallel comparison trial, 45 volunteers consumed 900 ml (6 cups) mineral water, green tea, or black tea/d. blood samples drawn while subjects were fasting were obtained before and after the study. the effect on ... | 1997 | 9356529 |
| purification and characterization of a novel class iii peroxidase isoenzyme from tea leaves. | a novel, basic (isoelectric point > 10), heme peroxidase isoenzyme (tp; relative molecular weight = 34,660 +/- 10, mean +/- se) that can account for a significant part of the ascorbate peroxidase activity in tea (camellia sinensis) leaves has been purified to homogeneity. the ultraviolet/visible absorption spectrum is typical of heme-containing plant peroxidases, with a soret peak at 406 nm (epsilon = 115 mm-1 cm-1) and an a406/a280 value of 3.4. the enzyme has a high specific activity for ascor ... | 1997 | 9276947 |
| effect of tea flavonoid supplementation on the susceptibility of low-density lipoprotein to oxidative modification. | dietary flavonoid intake has been reported to be inversely associated with the incidence of coronary artery disease. to clarify the possible role of tea flavonoids in the prevention of atherosclerosis, we investigated the effects of tea flavonoids on the susceptibility of low-density lipoprotein (ldl) to oxidative modification. in an in vitro study, catechins or theaflavins (25-400 mumol/l) were added to plasma and incubated for 3 h at 37 degrees c. then, the ldl fraction was separated by ultrac ... | 1997 | 9250103 |
| effect of black tea drinking on blood lipids, blood pressure and aspects of bowel habit. | thirty-one men (47 (sd 14) years) and thirty-four women (35 (sd 13) years) took part in a 4-week randomized cross-over trial to compare the effect of six mugs of black tea daily v. placebo (water, caffeine, milk and sugar) on blood lipids, bowel habit and blood pressure, measured during a run-in period and at the end of weeks 2, 3 and 4 of the test periods. compliance was established by adding a known amount of p-aminobenzoic acid (paba) to selected tea bags, and then measuring its excretion in ... | 1997 | 9292758 |
| chemoprotection: a review of the potential therapeutic antioxidant properties of green tea (camellia sinensis) and certain of its constituents. | 1997 | 9211396 | |
| the influence of coffee with milk and tea with milk on the bioavailability of tetracycline. | the effect of milk added to coffee or black tea on the bioavailability of tetracycline was evaluated in 12 healthy volunteers according to a crossover design. results showed that even a small volume of milk containing extremely small amounts of calcium severely impair the absorption of the drug, so that the presence of this metal ion should be carefully controlled in order to avoid decreasing the available tetracycline. | 1997 | 9210983 |
| effects of tea, decaffeinated tea, and caffeine on uvb light-induced complete carcinogenesis in skh-1 mice: demonstration of caffeine as a biologically important constituent of tea. | oral administration of green or black tea inhibited uvb light-induced complete carcinogenesis in the skin of skh-1 mice. green tea was a more effective inhibitor than black tea. oral administration of decaffeinated green or black tea resulted in substantially less inhibitory activity than did administration of the regular teas, and in one experiment, administration of a high-dose level of the decaffeinated teas enhanced the tumorigenic effect of uvb. oral administration of caffeine alone had a s ... | 1997 | 9205068 |
| reproducibility of self-administered questionnaire in epidemiological surveys. | we evaluated the reproducibility of data on intake frequency of 33 food items, beverage intake frequency of 3 items, drinking and smoking habits, and past history of 10 diseases obtained from a self-administered questionnaire. the survey subjects consisted of 263 aged 39 to 79 years individuals in the general population. after about one year interval these subjects consecutively participated in two surveys and were unintentionally requested to answer to the same questionnaire. the means of perce ... | 1997 | 9255026 |
| antioxidant flavonols and ischemic heart disease in a welsh population of men: the caerphilly study. | antioxidant flavonols and their major food source, black tea, have been associated with a lower risk of ischemic heart disease (ihd) and stroke in dutch men. we investigated whether flavonol intake predicted a lower rate of ihd in 1900 welsh men aged 45-59 y, who were followed up for 14 y. flavonol intake, mainly from tea to which milk is customarily added, was not related to ihd incidence [relative risk (rr), highest compared with lowest quartile: 1.0; 95% ci: 0.6, 1.6; p for trend = 0.996; n = ... | 1997 | 9129481 |
| [chemical constituents of seeds of camellia sinensis var. assamica]. | five compounds were isolated from the acid-hydrolytic products of n-butanol extract and ethanol extract of the seeds of camellia sinensis var. assamica. their structures were elucidated by chemical and spectroscopic analyses as octacosane, three new acyl-sapogenins: 22-o-angeloyl theasapogenol b, 22-o-angeloyl theasapogenol e and 22-o-angeloyl theasapogenol a, and naringenin respectively. | 1997 | 10743215 |
| tea and health: a historical perspective. | in many parts of the world, green tea and black tea are produced from the plant camellia sinensis. tea is one of the most widely consumed beverages, second only to water. it is one of the safest beverages since it is made with boiling, sterile water and has been popular for over 4000 years. dogma has it that people knew it might have health promoting properties since it was frequently used as fluid supply for patients suffering from infectious diseases. however, detailed, focused research on the ... | 1997 | 9103320 |
| a rp-hplc method for the determination of tea catechins. | an hplc method with gradient elution for the quantification of catechins ((-)-epigallocatechin (egc), (+)-catechin (c), (-)-epicatechin (ec), (-)-epigallocatechingallate (egcg) and (-)-epicatechingallate (ecg)) in tea was developed. the method was used to determine catechins in black tea, green tea and oolong tea. sample preparation was simple because only filtration and adjustment of ph was required. the levels of catechins in different teas varied between <5 and 287 (egc), 17 and 94 (ec), 18 a ... | 1997 | 9103282 |
| an investigation of the antioxidant activity of black tea using enhanced chemiluminescence. | antioxidants are important species which possess the ability to protect the body from damage caused by free radical-induced oxidative stress. a variety of free radical-scavenging antioxidants exist within the body many of which are derived from dietary sources. there is currently much interest in the antioxidant role of flavonoids and other polyphenols found in tea, wine, fruit and vegetables. enhanced chemiluminescence is a simple technique which can be used as a rapid and sensitive assay for m ... | 1997 | 9161850 |
| chemopreventive effect of green tea (camellia sinensis) against cigarette smoke-induced mutations (sce) in humans. | green tea (camellia sinensis) is consumed daily between the meals or after meals in japan and other asian countries. in recent years, green tea and its major polyphenolics have been demonstrated to prevent chemically induced tumors in a variety of experimental animal models system. the exact mechanism(s) of its anticarcinogenic activity remains to be elucidated, but green tea polyphenolics have demonstrated antimutagenic, anticarcinogenic, antioxidant, and antipromotional effects, including inhi ... | 1997 | 9591195 |
| cancer rates among drinkers of black tea. | studies in experimental animals have shown that compounds in tea can inhibit the process of carcinogenesis, with the beneficial effects accruing to both green and black teas. herein epidemiologic studies around the world are reviewed to assess the rates and risks of cancer among black tea drinkers. ecologic data suggest at most a modest benefit on total cancer, as there is considerable international variation in black tea consumption but generally small differences in overall cancer rates. cohor ... | 1997 | 9447273 |
| use of herbal products, coffee or black tea, and over-the-counter medications as self-treatments among adults with asthma. | there are few data on the use of alternative therapies in adult asthma and their impact on health outcomes. | 1997 | 9438488 |
| dietary patterns in japanese migrants to southeastern brazil and their descendants. | this paper describes the dietary patterns of people of japanese ancestry living in são paulo, brazil. two cross-sectional surveys using a food frequency questionnaire (in 1989 and 1995) and self-administered three-day food record (only in 1995) were carried out in randomly chosen first-generation (japan-born) and second-generation (brazil-born) japanese living in the city of são paulo (n = 166), aged 40-69 years at the time of the first survey (1989). daily intake of rice, bread, milk, fruits an ... | 1997 | 9465543 |
| somatic embryogenesis and plant regeneration from the immature cotyledonary tissues of cultivated tea (camellia sinensis (l).o. kuntze). | embryogenic callus development, plant regeneration, and plant recovery were achieved from immature cotyledon explants of cultivated tea, when cultured on ms basal medium. the somatic embryo induction frequency was influenced when the medium was supplemented with 1 μm auxin (naa, noa, 2,4-d, tpb, and pboa) in combination with cytokinin (0.5 μm ba, kin) or 10% cm. the highest somatic embryo induction frequency was obtained using pboa + ba or pboa + kin treatments. all auxins except 2,4-d stimulate ... | 1996 | 24177554 |
| cis- and trans-linalool 3,7-oxides and methyl salicylate glycosides and (z)-3-hexenyl beta-d-glucopyranoside as aroma precursors from tea leaves for oolong tea. | two new alcoholic aroma precursors, cis- and trans-linalool, 3,7-oxides 6-o-beta-d-apiofuranosyl-beta-d-glucopyranosides (1 and 2), as well as two already known compounds, (z)-3-hexenyl beta-d-glucopyranoside (3) and methyl salicylate 6-o-beta-d-xylopyranosyl-beta-d-glucopyranoside (beta-primeveroside: 4), and another new monoterpendiol glycoside, 8-hydroxygeranyl beta-primeveroside (5) have recently been isolated as aroma precursors in tea leaves (camellia sinensis var. sinensis cv. maoxie) rea ... | 1996 | 8987857 |
| effects of tea (camellia sinensis) chemical compounds on ethanol metabolism in icr mice. | the effects of a green tea (camellia sinensis) extract on ethanol metabolism in icr male mice were studied. a crude green tea extract (gte) and the tea components as (-)-epigallocatechin gallate (egcg), (-)-epigallocatechin (egc), and caffeine were administered before the tests. one hour later, the mice were orally given 2g/kg body weight (b.w.) of ethanol (20% ethanol w/v). the results show that the levels in the blood and liver of ethanol and acetaldehyde were lower, and that the levels of ace ... | 1996 | 8987593 |
| antioxidant properties of ethanolic and aqueous extracts of green tea compared to black tea. | 1996 | 8878934 | |
| re: consumption of black tea and cancer risk: a prospective cohort study. | 1996 | 8637037 | |
| geranyl 6-o-alpha-l-arabinopyranosyl-beta-d-glucopyranoside isolated as an aroma precursor from leaves of a green tea cultivar. | a new glycosidic aroma precursor was isolated from green tea leaves (camellia sinensis var. sinensis cv. yabukita) along with the known primeverosides of cis-linalool 3,6-oxide, linalool and geraniol. these glycosides were separated by chromatographic isolation on amberlite xad-2, ods flash chromatography, and finally hplc. the chemical structure of the new unknown glycoside was confirmed as geranyl 6-o-alpha-l-arabinopyranosyl-beta-d-glucopyranoside (geranyl beta-vicianoside) by spectrometric a ... | 1996 | 8704326 |
| thermospray-lc-ms analysis of various groups of polyphenols in tea. ii: chlorogenic acids, theaflavins and thearubigins. | an account is given of the application of thermospray lc-ms in the analysis of caffeoyl- and p-coumaroylquinic acids, theaflavins and thearubigins in black tea. all compounds, except for the thearubigens, could be detected as the pseudo-molecular ion [m + h]+. in addition to [m + h]+, other species such as adducts with sodium, ammonium and potassium, as well as solvent clusters were observed. the formation of those adducts depended upon on the structure of the compound. a fragmentation of chloro ... | 1996 | 8638432 |
| dietary flavonoids, antioxidant vitamins, and incidence of stroke: the zutphen study. | epidemiological studies suggested that consumption of fruit and vegetables may protect against stroke. the hypothesis that dietary antioxidant vitamins and flavonoids account for this observation is investigated in a prospective study. | 1996 | 8629875 |
| classification of tea samples by their chemical composition using discriminant analysis. | multivariate analysis in combination with pattern recognition procedures has been applied to samples of green and black tea. discriminant analysis has been used for classification purposes. aqueous extract, polyphenols, amino acids, caffeine, theobromine and theophylline were used as chemical descriptors. | 1996 | 18966503 |
| chemopreventive effects of green and black tea on pulmonary and hepatic carcinogenesis. | the chemopreventive effects of decaffeinated green and black tea treatment on liver and lung tumorigenesis were examined in carcinogen-treated mice. male c3h mice were given decaffeinated green or decaffeinated black tea in their drinking water prior to, during, and after treatment with diethylnitrosamine (50 micrograms/kg bw, i.p., once per week for 8 weeks). after 40 weeks of tea treatment, mice were sampled and examined for pulmonary and hepatic tumors. mice treated with both dena and tea dis ... | 1996 | 8742322 |
| consumption of black tea and cancer risk: a prospective cohort study. | tea is one of the most frequently consumed beverages in the world. antioxidant polyphenol compounds (such as catechins and flavonols) are abundantly present in both green and black teas and have been observed to have anticarcinogenic properties in cell and animal model studies. in black tea, however, most of the catechins have been oxidized to forms that may have reduced anticarcinogenic properties. despite indications from experimental studies that tea may protect against cancer, epidemiologic ... | 1996 | 8537983 |
| inhibiting effect of browned processed foods on trypsin. | inhibition of proteases was examined in browned foods including soy pastes, soy sauces, fish sauce, sauces, teas, coffees, and others in association with melanoidin, a maillard product, which had been found to be a potent inhibitor of trypsin. most of the foods were effective in restraining trypsin activity based on hydrolysis of n-α-benzoyl-dl-arginine-p-nitroanilide, while being ineffective on chymotrypsin except for black tea and cola. especially, teas were noted for their strong inhibitory e ... | 1996 | 27281148 |
| in vivo antioxidant effect of green and black tea in man. | evaluation of the vitro antioxidant activity of green and black tea, their in vivo effect on plasma antioxidant potential in man and the effect of milk addition. | 1996 | 8617188 |
| inhibition of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (phip) mutagenicity by black and green tea extracts and polyphenols. | solutions of lyophilized preparations of standard black and green tea extracts were made and tested over a range of six concentrations as inhibitors of the mutagenicity caused by the fool mutagen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (phip) in the salmonella typhimurium ta98 assay containing s9 fraction from rats induced with alpha-naphthoflavone and phenobarbital. extracts of both black and green tea were equally good inhibitors of mutagenicity. purified polyphenols were prepared from ... | 1996 | 8618547 |
| reduction of oxalate content of foods by the oxalate degrading bacterium, eubacterium lentum wyh-1. | urinary oxalate may contribute far more than urinary calcium to the pathogenesis of urinary calculi. urinary oxalate may be reduced by restricting the intake of foods high in oxalate. the oxalate content foods might be reduced by oxalate-degrading bacteria. the purpose of this experiment was to reduce the oxalate content of foods with an oxalate-degrading bacterium which was isolated from the feces of japanese male. | 1996 | 8646596 |
| relationship between antimutagenic activity and major components of various teas. | the objectives of this study were to determine the major components in tea leaves and tea extracts and to study the relationship between chemical content and antimutagenic activity of various tea extracts. the amount of catechins in various tea extracts was in the order: green tea (26.7%) > oolong tea (23.2%) > pouchong tea (15.8%) > black tea (4.3%). the amounts of caffeine and phenolic compounds in oolong tea extracts were 8.3 and 32.4%, respectively; these amounts were greater than those in t ... | 1996 | 8671713 |
| the effect of teas on the in vitro mutagenic potential of heterocyclic aromatic amines. | water extracts of eight brands (five types: 'green', 'black', 'oolong', decaffeinated and instant) of common teas (derived from camellia sinensis) and infusions of six randomly selected herbal teas were examined for inhibitory or potentiating effects on the mutagenicity of eight heterocyclic aromatic amines (haa) using the ames salmonella typhimurium ta98 and s-9 assay. haa, produced in foods during regular heat processing of meat, exhibit mutagenic/carcinogenic activities. tea extracts from c. ... | 1996 | 8690310 |
| inhibitory effects of green tea polyphenols on growth and cellular adherence of an oral bacterium, porphyromonas gingivalis. | effects of polyphenolic compounds isolated from green tea (camellia sinensis) on the growth and adherence of porphyromonas gingivalis onto human buccal epithelial cells were investigated. green tea polyphenols, especially (-)-epigallocatechin gallate (egcg) which is a dominant component of tea polyphenols, completely inhibited the growth and adherence of p. gingivalis onto the buccal epithelial cells at concentrations of 250-500 micrograms/ml. among the polyphenolic compounds, (-)-epicatechin ga ... | 1996 | 8704303 |
| protection by green tea, black tea, and indole-3-carbinol against 2-amino-3-methylimidazo[4,5-f]quinoline-induced dna adducts and colonic aberrant crypts in the f344 rat. | male f344 rats were exposed for 8 weeks to extracts of green tea (2% w/v) or black tea (1% w/v), or to 0.1% dietary indole-3-carbinol (i3c). in weeks 3 and 4 of the study, rats were given 2-amino-3-methylimidazo[4,5-f]quinoline (iq) every other day by oral gavage (50 mg/kg body wt) in order to induce aberrant crypt foci (acf) in the colon. compared with controls given iq alone, all three inhibitors reduced the number of total aberrant crypts per colon, and green tea and i3c inhibited significant ... | 1996 | 8706244 |
| [antimicrobial and anti-inflammatory actions of tea-leaf saponin]. | antimicrobial and anti-inflammatory actions of tea-leaf saponin, which was a mixture of saponin separated from leaves of camellia sinensis var. sinensis, were investigated. tea-leaf saponin showed relatively high antimicrobial activity against pathogenic dermal fungi and its mic value for microsporum audouinii was 10 microgam/ml. on the other hand, tea-leaf saponin inhibited rat paw edema induced by carrageenin in a dose dependent manner. activation of hyaluronidase, one of the enzymes involved ... | 1996 | 8721352 |
| caffeine induces cytochrome p4501a2: induction of cyp1a2 by tea in rats. | previous reports indicated that treatment of rats with green tea or black tea extracts increased cyp1a2 activity, but such an induction was not observed with decaffeinated green tea in our preliminary study. herein we report a comparative study on the induction of cyp1a2 with different tea preparations and caffeine as an inducer. when green tea (2%) or black tea (2%) was given to male fischer 344 rats as the sole source of drinking fluid for 21 days, a 2.4- or 2.7-fold induction, respectively, o ... | 1996 | 8723732 |
| inhibitory effect of six green tea catechins and caffeine on the growth of four selected human tumor cell lines. | green tea is an aqueous infusion of dried unfermented leaves of camellia sinensis (family theaceae) from which numerous biological activities have been reported including antimutagenic, antibacterial, hypocholesterolemic, antioxidant, antitumor and cancer preventive activities. from the aqueous-alcoholic extract of green tea leaves, six compounds (+)-gallocatechin (gc), (-)-epicatechin (ec), (-)-epigallocatechin (egc), (-)-epicatechin gallate (ecg), (-)-epigallocatechin gallate (egcg) and caffei ... | 1996 | 8826614 |
| black tea, green tea, and tea polyphenols. effects on trace element status in weanling rats. | previous studies have shown that tea consumption can impair trace element metabolism, particularly iron status, and increase the risk of anemia in humans and animals. more recently, however, evidence has been accumulating to show that, in animals, consumption of green tea or its polyphenols is associated with a reduction of the incidence and severity of a variety of experimentally induced cancers. in this study we have monitored the growth, trace element status, including hematological parameter ... | 1996 | 8862735 |
| aflatoxin and cyclopiazonic acid production by a sclerotium-producing aspergillus tamarii strain. | the production of aflatoxins b1 and b2 by aspergillus tamarii (subgenus circumdati section flavi) is reported for the first time. the fungus was isolated from soil collected from a tea (camellia sinensis) field in miyazaki prefecture, japan. three single-spore cultures, nrrl 25517, nrrl 25518, and nrrl 25519, were derived from subcultures of the original isolate 19 (mz2). each of these single-spore cultures of a. tamarii produced aflatoxins b1 and b2 and cyclopiazonic acid, as well as black, pea ... | 1996 | 8899995 |
| ascorbyl radical scavenging activity of polyphenols. | a variety of tannin and lignin-related compounds were compared for their ability to modify the ascorbyl radical intensity of sodium ascorbate. hot-water extracts prepared from green tea, black tea and pine cone (pinus parviflora sieb. et zucc.), and various wines potently scavenged ascorbyl radical intensity. low molecular weight tannins and phenylpropenoid monomers showed the greatest scavenging activity, whereas the dehydrogenation polymers of phenylpropenoids were much less active. on the oth ... | 1996 | 8917403 |
| tea polyphenols as inhibitors of mutagenicity of major classes of carcinogens. | previous research suggested that the mutagenicity of some genotoxic carcinogens, mainly heterocyclic amines, was decreased by green or black tea extracts, or tea polyphenol fractions. thus, it seemed important to test a variety of genotoxic carcinogens with distinct chemical structures and means of biochemical activation as regards modification of mutagenicity in appropriate strains of salmonella typhimurium by 3 concentrations of polyphenols 60, 100, or b, standard commercial polyphenol prepara ... | 1996 | 8950350 |
| inhibitory effects of tea catechins, black tea extract and oolong tea extract on hepatocarcinogenesis in rat. | inhibitory effects of individual tea catechins ((--)-epicatechin, (--)-epigallocatechin, (--)-epicatechin gallate, (--)-epigallocatechin gallate), black tea extract and oolong tea extract on hepatocarcinogenesis were investigated. male f344 rats received a single dose of diethylnitrosamine (200 mg/kg, i.p.), and thereafter phenobarbital (0.05%) was administered in the drinking water for a period of 6 weeks. tea catechins, black tea extract or oolong tea extract were given during the entire exper ... | 1996 | 8957060 |
| a comparison of the antimutagenic potential of green, black and decaffeinated teas: contribution of flavanols to the antimutagenic effect. | the present study was undertaken to compare the antimutagenic activity of aqueous extracts, at the concentrations used for human consumption, from green, black and decaffeinated black tea. antimutagenic potential was evaluated against three indirect-acting dietary carcinogens, glu-p-1, benzo(a)pyrene and nitrosopyrrolidine. all three types of tea gave rise to strong and concentration-dependent suppression of the mutagenicity of the three premutagens in the presence of an activation system. no ma ... | 1996 | 8962430 |
| fungicidal and insect controlling properties of proteus strain rrlj 16, isolated from tea, camellia sinensis (l) o kuntze, plantations. | a strain of proteus rrlj 16, isolated from acid (ph 4.5-5.5) iron rich tea (camellia sinensis) plantation soil, produced siderophores with single absorption peak at 370 nm when cultured in iron free medium. extracted crude fraction of siderophores and live cultures showed in vitro antibiosis against five species of pathogenic fungi. when the strain was cultured in a normal bacteriological medium without iron stress, it produced an insect repellent compound. the culture filtrate sprayed (dilution ... | 1996 | 8979512 |
| [effect of tea-leaf saponin on blood pressure of spontaneously hypertensive rats]. | the antihypertensive effect of tea-leaf saponin (the saponin mixture isolated from leaves of camellia sinensis var. sinensis) was examined in spontaneously hypertensive rats (shr). tea-leaf saponin reduced a time-dependent increase in blood pressure dose-dependently when it was administered orally to young shr (7 weeks old) for 5 d. oral administration of tea-leaf saponin to elder shr (15 weeks old) for 5 d decreased the mean blood pressure by 29.2 mmhg at the dose of 100mg/kg compared to the co ... | 1996 | 9019528 |
| tea in chemoprevention of cancer. | this review summarizes available information on epidemiological and experimental data showing an association of tea consumption with cancer prevention. studies showing cancer risk associated with tea consumption are also summarized. tea is grown in about 30 countries and, next to water, is the most widely consumed beverage in the world. experimental studies demonstrating the chemopreventive effects of tea have been conducted principally with green tea; limited studies have also assessed the usef ... | 1996 | 21544351 |
| development of cell culture techniques for assessment of the toxicity of plant products. | plant products consumed by humans contain a wide variety of both beneficial and toxic compounds. studies have been undertaken to explore the utility of cell culture techniques in testing plant products for toxicity and antitoxicity. preliminary results are reported on the cytotoxic effects of aqueous and methanol extracts of a range of conventional and herb teas and a variety of vegetables. the teas were tested in primary cultures of rat hepatocytes, using lactate dehydrogenase release and inhib ... | 1996 | 20650184 |
| polyphenols as cancer chemopreventive agents. | this article summarizes available data on the chemopreventive efficacies of tea polyphenols, curcumin and ellagic acid in various model systems. emphasis is placed upon the anticarcinogenic activity of these polyphenols and their proposed mechanism(s) of action. tea is grown in about 30 countries and, next to water, is the most widely consumed beverage in the world. tea is manufactured as either green, black, or oolong; black tea represents approximately 80% of tea products. epidemiological stud ... | 1995 | 8538195 |
| the yeast spectrum of the 'tea fungus kombucha'. | the tea fungus 'kombucha' is a symbiosis of acetobacter, including acetobacter xylinum as a characteristic species, and various yeasts. a characteristic yeast species or genus has not yet been identified. kombucha is mainly cultivated in sugared black tea to produce a slightly acidulous effervescent beverage that is said to have several curative effects. in addition to sugar, the beverage contains small amounts of alcohol and various acids, including acetic acid, gluconic acid and lactic acid, a ... | 1995 | 8559192 |
| endotoxin induced production of interleukin-6 is enhanced by vitamin e deficiency and reduced by black tea extract. | studies were performed to investigate the effect of a polyphenol rich extract from black tea and vitamin e on bacterial lipopolysaccharide (endotoxin) induced il-6 production, alterations in liver glutathione and antioxidant acute phase protein (caeruloplasmin) concentration, in rats fed on a synthetic diet for 21 days. in the vitamin e sufficient group a significantly lower il-6 concentration than in vitamin e deficient animals was observed. addition of tea extract to the diet produced a simila ... | 1995 | 8564528 |
| dietary modulation of the carcinogenicity of the heterocyclic amines. | heterocyclic amines (hcas) are potent mutagens and carcinogens formed during cooking of meats or fish. they are, therefore, widely consumed by humans. | 1995 | 8844815 |
| antibacterial effect of theaflavin, polyphenon 60 (camellia sinensis) and euphorbia hirta on shigella spp.--a cell culture study. | antibacterial effect of compounds extracted from camellia sinensis l. and the methanol extract of euphorbia hirta l. were studied against dysentery causing shigella spp. using the vero cell line. cytotoxicity studies of the extracts were performed using the cell line and the non-cytotoxic concentration of the extract was tested for antibacterial activity against the cytopathic dose of the pathogen. these extracts were found to be non-cytotoxic and effective antibacterial agents. | 1995 | 8847884 |
| inhibition of n-nitrosomethylbenzylamine-induced esophageal tumorigenesis in rats by green and black tea. | in this study, we investigated the effects of green tea and black tea, when given either during or after carcinogen treatment, on esophageal tumorigenesis in male sprague-dawley rats. rats were treated with n-nitrosomethylbenzylamine (nmbza) (2.5 mg/kg, s.c., twice weekly) for 5 weeks; 39 weeks after the initial dose of nmbza, 65% of the rats had esophageal tumors with an average of 1.4 +/- 0.3 tumors per rat. in the groups of rats receiving 0.6% of decaffeinated green tea (dgt) or decaffeinated ... | 1995 | 7554067 |
| anti-ulcer effect of the hot water extract of black tea (camellia sinensis). | the effect of the hot water extract of black tea (camellia sinensis (l.) o. kuntze, theaceae) on ulceration induced by various ulcerogens and by cold restraint stress (crs) was investigated in albino rats. while prior administration of tea extract for 7 days significantly reduced the incidence of ulcer, ulcer number and ulcer index produced by aspirin, indomethacin, ethanol, reserpine and crs, it failed to inhibit the ulcers induced by serotonin and histamine. tea extract also favourably altered ... | 1995 | 7564415 |
| effect of tea (camellia sinensis l.) on lipid peroxidation in rat liver and kidney: a comparison of green and black tea feeding. | the antioxidant effects in the liver and kidney obtained from rat fed diets containing 3% green or black tea leaf powder, which were prepared from the same lot tea leaves, were studied using the tissue slice-antioxidant evaluation method with two lipid peroxidation inducers. after 50 d on the diets, liver slices prepared from green and black tea-supplemented rats showed significant inhibitory effects against tert-butyl hydroperoxide-induced lipid peroxidation. these effects, however, were not pr ... | 1995 | 7581239 |
| anti-hyperglycemic effect of black tea (camellia sinensis) in rat. | investigations were carried out to evaluate the effect of the hot water extract of black tea (camellia sinensis (l.) o. kuntze (theaceae) on streptozotocin (stz)-induced diabetes in rats. the extract significantly reduced the blood glucose level and was found to possess both preventive and curative effects on experimentally produced diabetes in rats. the study reveals that, like green tea, black tea also possesses antidiabetic activity. | 1995 | 7623488 |
| [effect of natural complexes of biologically active substances on liver regeneration in alcohol poisoning]. | hepatoprotective effect of natural substances obtained from extracts of grape combs, leaves of green and black tea were studied in liver tissue of ethanol-consuming rats by means of evaluation of the neutral lipid fractions and phospholipids as well as by measurement of glucose and nicotinamide coenzymes nad+ and nadp in blood. in all the animal groups treated with these vegetable extracts content of total phospholipids, decreased after the ethanol treatment, was increased, while fraction compos ... | 1995 | 7793089 |
| unexplained severe illness possibly associated with consumption of kombucha tea--iowa, 1995. | kombucha tea is a popular health beverage made by incubating the kombucha mushroom in sweet black tea. although advocates of kombucha tea have attributed many therapeutic effects to the drink (1-3), its beneficial and/or adverse effects have not been determined scientifically. during april 1995, cases of unexplained severe illness (including one death) occurred in two persons in a rural town in northwestern iowa who had been drinking kombucha tea daily for approximately 2 months. based on the fi ... | 1995 | 7476846 |
| the comparative tea staining potential of phenolic, chlorhexidine and anti-adhesive mouthrinses. | staining of teeth and mucous membranes is a well-known side-effect with chlorhexidine mouthrinses in which dietary chromogens play an important rôle. the purpose of this study was to determine whether a co-polymer anti-adhesive agent would prevent staining by a low concentration chlorhexidine solution. additionally, the possibility that an essential oil/phenolic rinse product may cause staining was investigated. the rinses studied were the anti-adhesive alone and combined with 0.02% chlorhexidin ... | 1995 | 8613560 |
| antimicrobial properties of tea (camellia sinensis l.). | 1995 | 8585711 | |
| chemopreventive effect of green tea (camellia sinensis) among cigarette smokers. | chemopreventive effects of green tea and coffee among cigarette smokers were examined in 52 clinically healthy male subjects between 20 and 52 years of age. blood specimens were obtained from nonsmokers (group i), smokers (group ii), smokers consuming green tea (group iii), and smokers drinking coffee (group iv). the mean number of cigarette smoking years (> 10 cigarettes/day) in groups ii-iv ranged from 13.4 to 14.7 years. daily intake of green tea and coffee was 2-3 cups/day for 6 months (grou ... | 1995 | 7655335 |
| in vitro regeneration of camellia sinensis (l.) o. kuntze by somatic embryogenesis. | within 3 weeks of culture, excised cotyledon expiants of camellia sinensis (l.) o. kuntze produced somatic embryos without intermediate callus when cultured in murashige and skoog's basal medium with 30 g(-1) sucrose. in medium without plant growth regulators, up to 60% of the cultures developed somatic embryos. embryogenic competence was reduced by increasing concentrations of plant growth regulators tested (i.e. kinetin, 6-benzylaminopurine, and indole butyric acid). the somatic embryos develo ... | 1995 | 24185458 |
| detection of genetic diversity in tea (camellia sinensis) using rapd markers. | camellia sinensis is a beverage tree crop native to southeast asia and introductions have been made into several nonindigenous countries. no systematic assessment of genetic variability in tea has been done anywhere. in this study, random amplified polymorphic dna (rapd) analysis was used to estimate genetic diversity and taxonomic relationships in 38 clones belonging to the three tea varieties, assamica, sinensis, and assamica ssp. lasiocalyx. extensive genetic variability was detected between ... | 1995 | 7774794 |
| [molluscicidal activity of seed of camellia sinensis]. | this paper is a preliminary report on the molluscicidal activity of seed of camellia sinensis (l) o. kuntze (scs). its ld50 and ld90 were 10 and 16 micrograms/ml, respectively. we found also scs inhibited oxygen consumption 65% and glycogen content of oncomelania snail by 80%. the activity of hatching eggs to juvenile snails was inhibited by this seed at 8-16 micrograms/ml. juvenile snails may also be killed by this molluscicide. | 1995 | 7554158 |
| aluminium and fluoride in hospital daily diets and in teas. | the levels of aluminium and fluoride have been determined in hospital daily diets including breakfast, dinner and supper, as well as in black teas and herbal teas purchased from the local market. in tea, aluminium was determined directly in a sample solution by atomic absorption spectroscopy using nitrous oxide and an acetylene flame. for analysis of the hospital diet, samples containing lower levels of aluminium were analysed using a spectrophotometric method which measured aluminium in the for ... | 1995 | 8525696 |
| [ dietary intake of fluorine through of tea prepared by the traditional method in senegal]. | the consumption of tea in senegal is known and called "trois normaux". the use of thea sinensis as drink many times per day with a lot of sugar, may cause some public health problems. in the aim to face that situation, we have analysed the fluor level in the available tea samples in the senegalese market in respect of the ways of the preparation. the fluor level has been analysed by ionometric specific electrode. the concentrations were from 3.8 to 6.1 mg/l in the infusion and from 11.1 mg/l in ... | 1994 | 8654184 |
| molecular cloning of phenylalanine ammonia-lyase cdna and classification of varieties and cultivars of tea plants (camellia sinensis) using the tea pal cdna probe. | tea (camellia sinensis) phenylalanine ammonia-lyase (pal) cdna was cloned using labelled rice pal cdna as a probe. the pal genes of the tea plant were investigated by restriction fragment length polymorphism (rflp) analysis using tea pal cdna. pal genetic variation in tea plants was much larger than predicted due to the presence of various hybridized fragments in the assam hybrids, which are hybrids between c. sinensis var 'assamica' and var 'sinensis'. on the other hand, hybridized band pattern ... | 1994 | 24178009 |
| a new glucuronide saponin from tea leaves (camellia sinensis var. sinensis. | a new glucuronide saponin (1) was isolated as its methyl ester (2) from the leaves of camellia sinensis var. sinensis. on the basis of its spectral data and the results of chemical degradation, the structure was elucidated to be 3-o-[beta-d-galactopyranosyl(1-->2)-[beta-d- xylopyranosyl(1-->2)-alpha-l-arabinopyranosyl(1-->3)]- beta-d-glucuronopyranosyl]-21-o-cinnamoyl-16,22-di-o-acetylbarr ingtogenol c. | 1994 | 7765596 |
| green and black tea consumption by humans: impact on polyphenol concentrations in feces, blood and urine. | the objective of the study was to determine the effects of green tea, black tea and decaffeinated black tea consumption on urinary and fecal excretions and whole blood and blood serum concentrations of polyphenols. the 56 day study was divided into four randomly arranged experimental periods of 14 days each during which the 10 healthy adult subjects consumed a laboratory controlled, constant, measured diet based on ordinary foods. during separate periods, subjects received no tea, green tea, reg ... | 1994 | 7855093 |
| chalcone synthase from camellia sinensis: isolation of the cdnas and the organ-specific and sugar-responsive expression of the genes. | three full-length cdnas (chs1, chs2 and chs3) encoding chalcone synthase (chs; ec 2.3.1.74) were isolated from young leaves of camellia sinensis. each cdna encoded 389 amino acid residues, which showed 93-96% identity to one another. oligonucleotides were synthesized on the basis of the 5'-untranslated sequences of the cdnas and their corresponding transcripts could be distinguished. the chs1, chs2 and chs3 transcripts were abundant in the leaves and stems. after an initial treatment with water ... | 1994 | 7820373 |
| trans- and cis-linalool 3,6-oxide 6-o-beta-d-xylopyranosyl-beta-d-glucopyranosides isolated as aroma precursors from leaves for oolong tea. | new glycosidic aroma precursors (1 and 2) of the main volatile constituents, trans- and cis-linalool 3,6-oxides (linalool oxides i and ii), were isolated from oolong tea leaves (camellia sinensis var. sinensis cv. maoxie). the isolation was guided by an enzymatic hydrolysis with acetone powder prepared from fresh tea leaves (cv. yabukita) followed by gc or gc-ms analyses. chromatographic purification of hot water extracts of the tea leaves on active charcoal, amberlite xad-2, and sephadex lh-20 ... | 1994 | 7765491 |
| (s)-linalyl, 2-phenylethyl, and benzyl disaccharide glycosides isolated as aroma precursors from oolong tea leaves. | three glycosides, 6-o-beta-d-xylopyranosyl-beta-d-glucopyranosides (beta-primeverosides) of the aroma constituents, linalool, 2-phenylethanol, and benzyl alcohol, were isolated as aroma precursors from the tea leaves (camellia sinensis var. sinensis cv. shuixian and maoxie, cultivars for oolong tea). the isolation was guided by acid or enzymatic hydrolysis, and subsequent gc and gc-ms analyses. the linalyl glycoside is the first example of naturally occurring (s)-linalyl beta-primeveroside. | 1994 | 7522061 |
| effect of tea on iron absorption from the typical tunisian meal 'couscous' fed to healthy rats. | black and green tea decoctions are popular beverages in tunisia, especially after eating. our study was performed to examine the effect of graded amounts of black and green tea decoction prepared under realistic tunisian conditions on nonheme iron absorption from a typical tunisian meal, 'couscous', by extrinsic radioiron labeling in rats. concentrations of 300, 200 and 100 micrograms/ml of black tea decreased dramatically nonheme iron bioavailability from couscous, but 50 micrograms/ml did not ... | 1994 | 7832583 |
| antibacterial activity of tea (camellia sinensis) and coffee (coffee arabica) with special reference to salmonella typhimurium. | extracts of black tea, japanese green tea, china tea or coffee inhibited the growth of various bacteria causing diarrhoeal diseases. tea or coffee also showed bactericidal activity against vibrio cholerae, salmonella typhimurium and salmonella typhi. | 1994 | 7868837 |
| effect of flavan-3-ol tannins purified from camellia sinensis on lipid peroxidation of rat heart mitochondria. | we induced lipid peroxidation in rat heart mitochondria with feso4 and compared the inhibitory effect of various flavan-3-ol tannins on it. these tannins were purified from chinese tea (camellia sinensis). oxygen consumption and malondialdehyde formation were used to quantitate the amount of lipid peroxidation. the free radical scavenger activity of tannins was then measured with a diphenyl-p-picrylhydrazyl method. these tannins significantly inhibited lipid peroxidation at micromolar concentrat ... | 1994 | 7872240 |
| studies of cuticle drugs from natural sources. ii. inhibitory effects of prunus plants on melanin biosynthesis. | the inhibitory effects of 50% ethanolic extracts from dried leaves of 38 plants collected in the herbal garden of kinki university were investigated in vitro on melanin biosynthesis which is closely related to hyperpigmentation. of the 38 extracts, prunus yedoensis, p. zippeliana, p. amygdalus, p. persica, p. armeniaca, thea sinensis and chaenomeles sinensis showed a potent inhibition of tyrosinase, the enzyme which converts 3-(3,4-dihydroxyphenyl)alanine (dopa) to dopachrome in the biosynthetic ... | 1994 | 7874069 |
| effect of the hot-water extract of black tea (camellia sinensis) on the rat diaphragm. | 1994 | 7997479 | |
| inhibitory effects of black tea, green tea, decaffeinated black tea, and decaffeinated green tea on ultraviolet b light-induced skin carcinogenesis in 7,12-dimethylbenz[a]anthracene-initiated skh-1 mice. | in a previous study (z. y. wang et al., cancer res., 52: 1162-1170, 1992), we found that administration of a water extract of green tea leaves as the sole source of drinking fluid inhibited ultraviolet b light (uvb)-induced carcinogenesis in skh-1 mice previously initiated with 7,12-dimethylbenz[a]anthracene (dmba). in the present study, we compared the effects of black tea, green tea, decaffeinated black tea, and decaffeinated green tea on uvb-induced skin carcinogenesis in dmba-initiated skh-1 ... | 1994 | 8012962 |
| effects of green and black tea on hepatic xenobiotic metabolizing systems in the male f344 rat. | 1. the induction of phase i and ii enzymes in the liver of the male f344 rat drinking 2% (w/v) solutions of green or black tea for 6 weeks was investigated. also studied were glutathione (gsh) and cyst(e)ine in blood, liver and kidney, as well as serum cholesterol, hdl cholesterol, triglycerides, and total and free testosterone. 2. the total carbon monoxide-discernible liver p450, b5 and nadph-cytochrome c(p450) reductase activities were similar in all groups. 3. there were significant increases ... | 1994 | 8017087 |
| prevention of heterocyclic amine formation by tea and tea polyphenols. | heterocyclic amines (hcas), formed during the cooking of meats and fish, are thought to be the genotoxic carcinogens associated with important types of human cancer in meat-eating populations, such as cancer of the breast, colon or pancreas. we studied the effect of black or green tea, and of the tea polyphenols theaflavine gallate (tfg, black tea) and epigallocatechin gallate (egcg, green tea) on the formation of typical hcas, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (meiqx), and 2-amino-1 ... | 1994 | 8062207 |
| effects of green tea and black tea on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone bioactivation, dna methylation, and lung tumorigenesis in a/j mice. | previous studies in our laboratory showed that decaffeinated green tea and black tea extracts inhibited 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (nnk)-induced tumorigenicity in a/j female mice. in order to understand the mechanism of the inhibitory action, we examined the effects of decaffeinated green tea, black tea, and tea components on the metabolic activation of nnk in vitro and in vivo in this animal model. when added to incubation mixtures containing mouse lung microsomes, decaffein ... | 1994 | 8062257 |
| [inhibition of the infectivity of influenza virus by black tea extract]. | we determined whether black tea extract inhibits the infectivity of influenza virus to mice. when mice were inoculated intranasally with 10(5.3) pfu influenza viruses (10(1.3) ld50), their body weight decreased and all died within 10 days. whereas, when mice were inoculated i.n. with the mixture of influenza viruses and 2% (w/w) black tea extract, 5 min after mixing, all mice showed normal body-weight increase and survived. neutralizing antibody to influenza virus was not detected in nine of 10 ... | 1994 | 8089547 |
| antioxidative effects of black tea theaflavins and thearubigin on lipid peroxidation of rat liver homogenates induced by tert-butyl hydroperoxide. | the antioxidative activity of theaflavins (tfs) and thearubigin (tr) purified from the infusion of black tea leaves was examined using the tert-butyl hydroperoxide-induced lipid peroxidation of rat liver homogenates. the concentrations which produced 50% inhibition of lipid peroxidation (ic50) by theaflavin (tf), theaflavin monogallate-a (tfm-a), and tr were 4.88 x 10(-4), 4.09 x 10(-4), and 4.95 x 10(-4%) (w/v), respectively. the anti-oxidative activity of these compounds was higher than that o ... | 1994 | 8148805 |
| three-month oral repeated administration toxicity study of seed saponins of thea sinensis l. (ryokucha saponin) in rats. | ryokucha saponin (rsp), which is one of the ingredients of green tea, was administered orally to rats for 3 months at dose levels of 50, 150 and 500 mg/kg/day to assess any toxic effects. as positive control, 1200 mg/kg/day of quillaia saponin (qsp), which contains saponins equivalent in amount to those in 500 mg rsp/kg/day, was administered. the no-effect level of rsp was 50 mg/kg/day and the lowest-observed-effect level of rsp was 150 mg/kg/day for both sexes, so that the true no-effect level ... | 1994 | 8206442 |
| dietary tannins from cowpeas and tea transiently alter apparent calcium absorption but not absorption and utilization of protein in rats. | tannins reportedly alter absorption and utilization of protein and minerals. the present study investigated the effect of tannins extracted from 'mississippi silver' cowpeas and black tea when incorporated into nutritionally balanced diets. condensed tannins were incorporated into the diet of weanling male sprague-dawley rats at 0.0, 0.0057, 0.0171 and 0.057 g/100 g diet for 28 d. ingestion of tannin from cowpeas or tea did not change significantly growth rate, protein efficiency ratio, apparent ... | 1994 | 8308578 |
| antioxidative and antimutagenic effects of theaflavins from black tea. | theaflavins, polyphenolic ingredients of black tea, were observed to inhibit in vitro lipid peroxidation in the erythrocyte membrane ghost and microsomal systems. theaflavins also showed inhibition of dna single-strand cleavage and mutagenicity, both induced by hydrogen peroxide. these results suggest that theaflavins scavenge radicals to produce antioxidative and antimutagenic effects. it was also found that the gallic acid moiety of theaflavins is essential for their potent antioxidative activ ... | 1994 | 7508563 |
| 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 |
| genotoxicity testing of different types of beverages in the drosophila wing somatic mutation and recombination test. | five wines and one brandy of spanish origin as well as three herbal teas and ordinary black tea were tested for genotoxicity in the wing somatic mutation and recombination test (smart) which makes use of the two recessive wing cell markers multiple wing hairs (mwh) and flare (flr3) on the left arm of chromosome 3 of drosophila melanogaster. 3-day-old larvae trans-heterozygous for these two markers were fed the beverages at different concentrations and for different feeding periods using drosophi ... | 1994 | 8206441 |