| statistical analysis of salivary ph changes after the intake of black tea and yerba maté supplemented with sweeteners. | many studies have demonstrated the effect of various beverages on hard tissues of the mouth. sugar consumption has also been avoided because it is associated with caries activity, and artificial sweetener research has been promoted. in this paper, data about the buffer capacity of black tea and yerba mate supplemented with sugar or one of two artificial sweeteners (barny diet and nutrasweet) were examined. salivary ph variations after the ingestion of both infusions were statistically analysed. ... | 1999 | 10453132 |
| proconvulsive effect of tea (camellia sinensis) in mice. | investigations were carried out to evaluate the effect of acute and chronic administration of both black and green tea on three models of experimentally induced convulsions in mice. tea extract (both black and green) significantly accelerated the onset of convulsion, increased the duration of convulsion and mortality in mice. since both the extracts failed to alter the gaba level in brain, based on the earlier report that both black and green tea might act on ca(2+) channels, it can be suggested ... | 1999 | 10441775 |
| effects on blood pressure of drinking green and black tea. | the flavonoid components of tea have been associated in epidemiological studies with a decreased risk of cardiovascular disease. flavonoids have been shown to have antioxidant and vasodilator effects in vitro; we therefore postulated that drinking green or black tea attenuates the well-characterized acute pressor response to caffeine and lowers blood pressure during regular consumption. | 1999 | 10404946 |
| scavenging of hydrogen peroxide and inhibition of ultraviolet light-induced oxidative dna damage by aqueous extracts from green and black teas. | aqueous extracts of green and black teas have been shown to inhibit a variety of experimentally induced animal tumors, particularly ultraviolet (uv) b light-induced skin carcinogenesis. in the present study, we compared the effects of different extractable fractions of green and black teas on scavenging hydrogen peroxide (h2o2), and uv irradiation-induced formation of 8-hydroxy 2'-deoxyguanosine (8-ohdg) in vitro. green and black teas have been extracted by serial chloroform, ethyl acetate and n ... | 1999 | 10401606 |
| genetic and dietary predictors of cyp2e1 activity: a phenotyping study in hawaii japanese using chlorzoxazone. | cytochrome p4502e1 (cyp2e1) is considered to play an important role in the metabolic activation of procarcinogens such as n-nitrosoamines and low molecular weight organic compounds. an rsai polymorphism is present in the 5'-flanking region of the cyp2e1 gene, which could possibly affect its transcription. however, the relationship between genotype and the phenotypic catalytic activity of the enzyme has not been defined. also, the effects in humans of specific dietary factors, other than ethanol, ... | 1999 | 10385138 |
| a review of plants used in the treatment of liver disease: part two. | botanical medicines have been used traditionally by herbalists and indigenous healers worldwide for the prevention and treatment of liver disease. clinical research in this century has confirmed the efficacy of several plants in the treatment of liver disease, while basic scientific research has uncovered the mechanisms by which some plants provide their therapeutic effects. this article is part two in a review of botanicals used in the treatment of liver disease. curcuma longa (turmeric), camel ... | 1999 | 10383482 |
| effects of oral administration of tea, decaffeinated tea, and caffeine on the formation and growth of tumors in high-risk skh-1 mice previously treated with ultraviolet b light. | treatment of skh-1 mice with ultraviolet b light (uv-b, 30 mj/cm2) twice a week for 22-23 weeks resulted in tumor-free animals with a high risk of developing malignant and nonmalignant tumors during the next several months in the absence of further uv-b treatment (high-risk mice). in three separate experiments, oral administration of green tea or black tea (4-6 mg tea solids/ml) as the sole source of drinking fluid for 18-23 weeks to these high-risk mice inhibited the formation and decreased the ... | 1999 | 10368809 |
| purification and characterization of caffeine synthase from tea leaves. | caffeine synthase (cs), the s-adenosylmethionine-dependent n-methyltransferase involved in the last two steps of caffeine biosynthesis, was extracted from young tea (camellia sinensis) leaves; the cs was purified 520-fold to apparent homogeneity and a final specific activity of 5.7 nkat mg-1 protein by ammonium sulfate fractionation and hydroxyapatite, anion-exchange, adenosine-agarose, and gel-filtration chromatography. the native enzyme was monomeric with an apparent molecular mass of 61 kd as ... | 1999 | 10364410 |
| tea and health: the underlying mechanisms. | detailed multidisciplinary research on the effect of tea and the associated tea polyphenols has led to major advances on the underlying mechanisms. in most studies, green and black tea have similar effects, four of which are reviewed in this paper. 1) tea polyphenols are powerful antioxidants that may play a role in lowering the oxidation of ldl-cholesterol, with a consequent decreased risk of heart disease, and also diminish the formation of oxidized metabolites of dna, with an associated lower ... | 1999 | 10202402 |
| inhibitory effect of green and black tea on tumor growth. | the administration of green tea, black tea, or (-)-epigallocatechin gallate inhibited the growth of established nonmalignant and malignant tumors in tumor-bearing mice. in experiments with black tea, we found that its oral administration inhibited dna synthesis and enhanced apoptosis in both nonmalignant and malignant tumors in tumor-bearing mice. | 1999 | 10202394 |
| preclinical efficacy studies of green and black tea extracts. | | 1999 | 10202390 |
| plasma and lipoprotein levels of tea catechins following repeated tea consumption. | epidemiological studies suggest that antioxidant flavonoids in tea may reduce the risk of cardiovascular disease, possibly via protection of low-density lipoproteins (ldl) against oxidation. however, the extent of absorption of tea flavonoids and their accumulation in ldl during regular consumption of tea is not clear. therefore we investigated plasma and lipoprotein levels of catechins during tea consumption and the impact on ldl oxidizability ex vivo. eighteen healthy adults consumed, in an in ... | 1999 | 10202389 |
| theaflavin-3,3'-digallate from black tea blocks the nitric oxide synthase by down-regulating the activation of nf-kappab in macrophages. | nitric oxide (no) plays an important role in inflammation and also in multiple stages of carcinogenesis. we investigated the effects of various tea polyphenols, including theaflavin, a mixture of theaflavin-3-gallate and theaflavin-3'-gallate, theaflavin-3,3'-digallate, thearubigin, and (-)-epigallocatechin-3-gallate on the induction of no synthase in lipopolysaccharide-activated murine macrophages, raw 264.7 cells. theaflavin-3,3'-digallate was found to be stronger than (-)-epigallocatechin-3-g ... | 1999 | 10079014 |
| protection by black tea and green tea against uvb and uva + b induced skin cancer in hairless mice. | the effects of green and black tea consumption on the early indices of uvb and uva + b skin damage in hairless mice have been studied in the absence of any chemical tumour initiators or promoters. black tea consumption was associated with a reduction in the number of sunburn cells in the epidermis of mice 24 h after uva + b irradiation, although there was no effect of green tea. other indices of early damage such as necrotic cells or mitotic figures were not affected. neutrophil infiltration as ... | 1998 | 9920445 |
| biokinetic studies in humans with stable isotopes as tracers. part 2: uptake of molybdenum from aqueous solutions and labelled foodstuffs. | molybdenum (mo) has been identified as an essential trace mental for humans. the present study was aimed at the assessment of data on intestinal mo absorption from aqueous solutions and from foodstuffs in humans applying the methodology for intrinsic labelling described in part 1. the intestinal absorption of mo was investigated by means of a double tracer method in 3 healthy volunteers on a total of 15 occasions. when administered as aqueous solution, almost complete uptake of mo was observed u ... | 1998 | 9919682 |
| protection by tea against uv-a + b-induced skin cancers in hairless mice. | consumption of tea, especially green tea, has been shown to reduce the incidence of ultraviolet (uv)-related skin tumors in hairless mice. because milk is added to much of the tea consumed in western cultures, we have studied the effects of including milk in the tea consumed by hairless mice receiving simulated solar radiation. under these conditions, mice consuming tea with 10% whole milk had 30% fewer papillomas, 50% fewer tumors, and 55% smaller lesions than mice consuming water. mice consumi ... | 1998 | 9919614 |
| structures of new acylated oleanene-type triterpene oligoglycosides, theasaponins e1 and e2, from the seeds of tea plant, camellia sinensis (l.) o. kuntze. | two new acylated oleanene-type triterpene oligoglycosides, theasaponins e1 and e2, were isolated from the seeds of tea plant [camellia sinensis (l.) o. kuntze]. the structures of theasaponins e1 and e2 were elucidated on the basis of chemical and physicochemical evidence to be expressed as 21-o-angeloyl-22-o-acetyltheasapogenol e 3-o-[beta-d-galactopyranosyl(1-->2])[beta-d-xylopyranosyl(1-->2)-alpha-l - arabinopyranosyl (1-->3)]-beta-d-glucopyranosiduronic acid and 21-o-angeloyl-28-o-acetyltheas ... | 1998 | 9880909 |
| identification of endogenous gibberellins in the leaves and xylem sap of tea plants. | endogenous gibberellins (gas) in the young leaves and xylem sap of tea plants (camellia sinensis l.) were analyzed by gc-ms. the following gas were identified by comparing their mass spectra and kris with those of authentic specimens: ga9 and ga20 in the leaves; ga9, ga12, ga15, ga20, ga44, ga51 and ga53 in the xylem sap. | 1999 | 27392877 |
| clinical trial on the effect of regular tea drinking on iron accumulation in genetic haemochromatosis. | black tea is known to be a potent inhibitor of intestinal absorption of non-haem iron at least in healthy subjects. | 1998 | 9824354 |
| the effects of black tea and other beverages on aspects of cognition and psychomotor performance. | nineteen healthy volunteers ingested 400 ml black tea, coffee, caffeinated water, decaffeinated tea or plain water on three occasions through the day (0900, 1400 and 1900 hours). a 2 x 2 factorial design with caffeine (0, 100 mg) and beverage type (water, tea) was employed, with coffee (100 mg caffeine) as a positive internal control, based on a five-way crossover. a psychometric test battery comprising critical flicker fusion (cff), choice reaction time (crt), short-term memory (stm) and subjec ... | 1998 | 9784078 |
| effect of green and black tea supplementation on lipids, lipid oxidation and fibrinogen in the hamster: mechanisms for the epidemiological benefits of tea drinking. | there is considerable epidemiological evidence that tea drinking lowers the risk of heart disease. however, the mechanism by which tea can be protective is unknown. hamsters were fed a normal or high cholesterol diet for 2 weeks and drank green or black tea ad libitum. the plasma lipid profile was significantly improved by both teas compared to controls. also in vivo lipid oxidation as measured by plasma lipid peroxides and ldl+vldl oxidizability were significantly decreased by the teas. in the ... | 1998 | 9738930 |
| [flavonols, flavone and anthocyanins as natural antioxidants of food and their possible role in the prevention of chronic diseases]. | flavonoids are non-nutritive compounds of plants that have been intensively investigated during the past years due to their possible protective effects against chronic diseases. in vitro studies were able to demonstrate for flavonols, flavones, and most recently also for anthocyanins a considerable antioxidative activity, mainly based on scavenging of oxygen radicals. flavonols and anthocyanins are commonly found in european fruits and vegetables. in addition, black tea and red wine may have a h ... | 1998 | 9698642 |
| hplc method for evaluation of the free radical-scavenging activity of foods by using 1,1-diphenyl-2-picrylhydrazyl. | an hplc method for evaluation of the free radical-scavenging activity of foods by using 1,1-diphenyl-2-picrylhydrazyl (dpph) is reported. the activity was evaluated by measuring the decrease of dpph detected at 517 nm. by using this novel method, we determined the free radical-scavenging activity of several antioxidants: ascorbic acid, alpha-tocopherol, trolox, and cysteine. the results gave good correlation between the radical-scavenging activity determined by hplc and by conventional colorimet ... | 1998 | 9692204 |
| tea and coffee consumption and risk of colon and rectal cancer in middle-aged finnish men. | the association between coffee and black tea consumption and the subsequent risk of colon and rectal cancer was investigated within a finnish clinical trial cohort. one hundred eleven cases of colon cancer and 83 cases of rectal cancer were diagnosed over a median of 9.0 years of follow-up. proportional hazards regression models were used to derive adjusted relative risk (rr) and 95% confidence intervals (ci) for the association between coffee and tea consumption and cancer incidence. after cont ... | 1998 | 9682247 |
| plasma concentrations and urinary excretion of the antioxidant flavonols quercetin and kaempferol as biomarkers for dietary intake. | flavonols are antioxidants that may reduce the risk of heart disease. two major flavonols in the diet are quercetin and kaempferol, and their main sources in the netherlands are tea and onions. we investigated whether plasma concentrations and urinary excretion of quercetin and kaempferol in humans could be used as biomarkers of intake. we provided 15 subjects with strong black tea (1600 ml/d) or fried onions (129 g/d) for 3 d each in random order separated by a 4-d washout period. the tea provi ... | 1998 | 9665097 |
| bioavailability of catechins from tea: the effect of milk. | to assess the blood concentration of catechins following green or black tea ingestion and the effect of addition of milk to black tea. | 1998 | 9630386 |
| no effect of consumption of green and black tea on plasma lipid and antioxidant levels and on ldl oxidation in smokers. | intake of flavonoids is associated with a reduced cardiovascular risk. oxidation of ldl is a major step in atherogenesis, and antioxidants may protect ldl from oxidation. because tea is an important source of flavonoids, which are strong antioxidants, we have assessed in a randomized, placebo-controlled study the effect of consumption of black and green tea and of intake of isolated green tea polyphenols on ldl oxidation ex vivo and on plasma levels of antioxidants and lipids. healthy male and f ... | 1998 | 9598844 |
| mass spectrometry of selected components of biological interest in green tea extracts. | mass spectrometric methods including eims, fabms, and lc/esims have been surveyed as tools for the detection of catechins in extracts of green tea (camellia sinensis). eims provide both molecular weight and structure information, including epimer differentiation, on compounds 1, 2, and 4 and some structural information with compounds 5 and 6. fabms gives both molecular weight and structure information, by an retro-diels-alder mechanism, on all compounds. lc/esims provides unambiguous molecular w ... | 1998 | 9584400 |
| black tea consumption does not protect low density lipoprotein from oxidative modification. | to investigate the in vivo and in vitro effects of black tea on the oxidative modification of low density lipoprotein (ldl). | 1998 | 9537306 |
| apolipoprotein e genotype modulates the effect of black tea drinking on blood lipids and blood coagulation factors: a pilot study. | apolipoprotein e (apoe) genotype was determined in sixty-five subjects who had taken part in a 4-week randomized crossover trial to compare the effect of six mugs of black tea per day v. placebo on blood lipids and blood coagulation factors. four apoe genotype variants (seven e2/e3, forty-five e3/e3, twelve e3/e4 and one e4/e4) were found. apoe allele frequency was within the range typical for caucasian populations (apoe-e2 5.4%; apoe-e3 83.8%; apoe-e4 10.8%). individuals bearing at least one e4 ... | 1998 | 9536857 |
| association of coffee, green tea, and caffeine intakes with serum concentrations of estradiol and sex hormone-binding globulin in premenopausal japanese women. | caffeine intake has been proposed to influence breast cancer risk. its effect may be mediated by hormonal changes. the relationships between caffeine-containing beverages (coffee, green tea, black tea, oolong tea, and cola) and serum concentrations of estradiol and sex hormone-binding globulin were evaluated in 50 premenopausal japanese women. intakes of caffeine and caffeine-containing beverages were assessed by a semiquantitative food-frequency questionnaire. blood samples were obtained from e ... | 1998 | 9507508 |
| inhibition of xanthine oxidase by catechins from tea (camellia sinensis). | some epidemiological studies have associated tea drinking with several health benefits, while other such studies have been inconclusive. the liver enzyme, xanthine oxidase (xo) produces uric acid and reactive oxygen species (ros) during the catabolism of purines. excess of the former can lead to gout and of the latter to increased oxidative stress, mutagenesis and possibly cancer. polyphenols are antioxidants, and it has been suggested that they can reduce oxidative stress by their antioxidant p ... | 2016 | 9494537 |
| selection of column and gradient elution system for the separation of catechins in green tea using high-performance liquid chromatography. | a study of a variety of stationary phases and elution conditions for the liquid chromatographic (lc) determination of six biologically active green tea catechins has resulted in the development of two well-defined, reproducible systems for such analyses which overcome limitations of previously described methods. comparison of six reversed-phase columns indicates that deactivated stationary phases, which utilize ultrapure silica and maximize coverage of the silica support, provide significantly i ... | 1998 | 9474785 |
| 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 |
| identification of beverages and beverage stains by gc/ms using aroma components as indicators. | a method to identify brown coloured beverages or beverage stains for criminological purposes was devised using aroma components as indicators. the examined beverages comprised three brands each of beer, coffee, cola and black tea, two brands of oolong tea, and four brands of green tea. aroma components in each sample were efficiently concentrated with a porous polymer beads column (porapak q) and were analyzed by gas chromatography/mass spectrometry (gc/ms) using n-octyl alcohol as the internal ... | 1998 | 9457532 |
| 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 |
| isolation of an aroma precursor of benzaldehyde from tea leaves (camellia sinensis var. sinensis cv. yabukita). | the cyanoglycoside, prunasin, was isolated for the first time as an aroma precursor of benzaldehyde from fresh tea leaves (camellia sinensis var. sinensis cv. yabukita). prunasin was readily hydrolyzed by a crude enzyme prepared from the fresh tea leaves to liberate benzaldehyde. the isomerization of prunasin under neutral conditions was also recognized. | 1998 | 27385456 |
| effects of lifestyle and genetic polymorphisms on consumption of coffee or black tea and urinary caffeine levels. | to find the cause of individual differences in caffeine intake and its metabolism, we investigated the effects of lifestyle and genetic polymorphisms of caffeine metabolic enzymes on coffee or black tea and urinary caffeine levels among 259 male japanese. it was seen that cigarette smokers drank more coffee or black tea than non-smokers (p < 0.001). there was an inverse correlation between the amount of coffee or black tea consumed and age or the frequency of alcohol drinking (p < 0.05). genetic ... | 1998 | 23899363 |
| 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 |
| 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 |
| tea drinking and haemostasis: a randomized, placebo-controlled, crossover study in free-living subjects. | the hypothesis that tea drinking may protect against coronary heart disease (chd) through effects on clotting as measured by plasma fibrinogen, tissue-type plasminogen activator (tpa) and plasminogen activator inhibitor-1 (pai-1) was tested in 65 healthy volunteers (31 men and 34 women; aged 20-74 years) in a randomized, blind, placebo-controlled, crossover study lasting 10 weeks (run-in phase 2 weeks, tea and placebo phases 4 weeks). during the placebo phase, intakes of milk, sugar, water and c ... | 2007 | 8698279 |
| 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 |
| a study on tea aroma formation mechanism: alcoholic aroma precursor amounts and glycosidase activity in parts of the tea plant. | we have shown in molecular basis that alcoholic tea aroma is mainly formed by endogenous enzymatic hydrolysis of glycosidic aroma precursors during manufacturing. amounts of alcoholic aroma precursor and glycosidase activity in each part of the tea shoot (camellia sinensis var. sinensis cv yabukita and a hybrid of var. assamica & var. sinensis cv izumi) were indirectly measured by means of a crude enzyme assay. the aroma precursors were abundant in young leaves and decreased as the leaf aged. gl ... | 2016 | 7546039 |
| 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 |
| 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 |
| prognostic significance of selected lifestyle factors in urinary bladder cancer. | to examine the prognostic significance of lifestyle factors in urinary bladder cancer, we conducted a follow-up study of 258 incident bladder cancer patients, who were originally recruited in a case-control study in metropolitan nagoya. information on individual survivals was obtained from the computer data-file of the tumor registry of the nagoya bladder cancer research group. univariate analyses revealed significant associations of 5-year survivorship with educational attainment, marital statu ... | 1993 | 8294212 |
| [determination of minerals and trace elements in selenium tea from the enschi district, people's republic of china, and in its infusions using inductively coupled plasma-atomic emission spectrometry, graphite furnace atomic absorption spectrometry and instrumental neutron activation analysis]. | the enschi district in hubei province, peoples republic of china is geochemically one of the two seleniferous regions, producing both selenium (se) black tea and the se green tea. three samples of green tea with different se contents and one non-se tea were analysed. the following mineral and trace elements were determined by inductively coupled plasma-atomic emission spectrometry (icp-aes): k, ca, mg, na, p, s, al, mn, fe, ba, sr, co, ni, cu, zn, mo, and cr. except for mo, co, and cr, all other ... | 1993 | 8273425 |
| [contents of aluminum and manganese in tea leaves and tea infusions]. | we measured the contents of aluminum and manganese in tea leaves and tea infusions by means of various standardized infusion conditions, and by using flameless atomic absorption spectrophotometry, and investigated the influence of infusion conditions on the elution of aluminum and manganese into the tea infusions. furthermore, we tried to estimate the daily intake of aluminum and manganese due to drinking tea infusions. the content of aluminum in tea leaves was 1420 micrograms/g in case of wulon ... | 1993 | 8254994 |
| [the results of comprehensive caries prophylaxis in children under endemic goiter conditions]. | caries prevention was carried out in 800 children aged under 7 living in regions endemic for goiter. the complex of preventive measures included natrium fluoratum tablets (polfa, poland), a combination of fluoride lacquer with 3% remodent, azerbaijan black tea tincture with f, 10 mg/l, all of these combined with antistrumin, an iodine-containing drug. clinical data, enamel acid solubility values, data of microbiologic examinations of dental deposit, status of natural antibacterial defense of tis ... | 2013 | 8108830 |
| determination of flavone c-glycosides in tea. | an hplc method for the determination of flavone c-glycosides (fcg) from black tea has been developed. sample clean-up was accomplished by means of polyamide column chromatography, followed by enzyme hydrolysis of interfering compounds such was flavonol glycosides and a second polyamide column chromatographic step. using hplc with gradient elution and photodiode array detection eight fcg were separated. seven fcg were isolated by means of preparative hplc. identification was carried out using co- ... | 1993 | 8237118 |
| the influence of dietary factors on the risk of urinary stone formation. | the action of various beverages and foods on the composition of the urine in the circadian rhythm and in the 24-hour urine has been investigated under standardized conditions. orange juice leads to a significant increase of urinary ph and citric acid excretion. black tea leads to a raised excretion of oxalic acid by only 7.9%. in the short term, beer increases diuresis, but afterwards leads to a compensatory antidiuresis with increased risk of stone formation. depending on their composition, min ... | 1993 | 8146611 |
| geranyl 6-o-beta-d-xylopyranosyl-beta-d-glucopyranoside isolated as an aroma precursor from tea leaves for oolong tea. | a new geranyl glycoside, geranyl 5-o-beta-d-xylopyranosyl-beta-d-glucopyranoside was isolated as an aroma precursor from tea leaves (camellia sinensis var. sinensis cv shuixian) for oolong tea. the isolation was guided by a two-phase acid hydrolysis and/or an enzymatic hydrolysis followed by gc and gc-ms analyses. | 1993 | 7763947 |
| bactericidal catechins damage the lipid bilayer. | the mode of antibacterial action of, the green tea (camellia sinensis) extracts, (-)-epigallocatechin gallate (egcg) and (-)-epicatechin (ec) was investigated. strong bactericidal egcg caused leakage of 5,6-carboxyfluorescein from phosphatidylcholine liposomes (pc), but ec with very weak bactericidal activity caused little damage to the membrane. phosphatidylserine and dicetyl phosphate partially protected the membrane from egcg-mediated damage when reconstituted into the liposome membrane with ... | 1993 | 8466924 |
| organochlorine pesticide residues in black tea, camomile, and linden. | | 1993 | 8467130 |
| antioxidant properties of fractions and polyphenol constituents from green, oolong and black teas. | green, oolong and black teas were extracted with water, and then the water extracts were extracted separately with three types of solvent, chloroform, ethyl acetate and butanol, to obtain eight fractions. major flavanol was extracted by etoac, while most of the alkaloid was in the chloroform fraction. thearubigin was greatest in the butanol fraction, and most of the amino acid remained in the water fraction. all fractions were systematically analyzed by uv spectrophotometer and reverse phase hpl ... | 1993 | 7809277 |
| a multi-institute case-control study on the risk factors of developing pancreatic cancer. | a multi-institute, hospital-based, case-control study on pancreatic cancer was carried out to examine its association with preceding diseases, cigarette smoking, alcohol drinking and dietary factors. analyses were based on 124 newly diagnosed exocrine pancreatic cancer cases and sex-, age- and institute-matched hospital controls in seven hospitals in japan. cigarette smoking showed a positive association with the risk of developing pancreatic cancer. especially among smokers, a risk enhancing ef ... | 1992 | 1434027 |
| tea components: antimutagenic and anticarcinogenic effects. | tea from the camellia sinensis species of the theaceae family is one of the most ancient and, next to water, the most widely consumed beverage in the world. since tea contains several polyphenols and since several other naturally occurring dietary polyphenols have shown antimutagenic effects in bacteria and anticarcinogenic effects in animal bioassay systems, we studied whether polyphenols extracted from chinese green tea (gtp) also possess antimutagenic and anticarcinogenic effects. | 1992 | 1614996 |
| green tea composition, consumption, and polyphenol chemistry. | tea is grown in about 30 countries but is consumed worldwide, although at greatly varying levels. it is the most widely consumed beverage aside from water with a per capita worldwide consumption of approximately 0.12 liter per year. tea is manufactured in three basic forms. green tea is prepared in such a way as to preclude the oxidation of green leaf polyphenols. during black tea production oxidation is promoted so that most of these substances are oxidized. oolong tea is a partially oxidized p ... | 1992 | 1614995 |
| physiological and pharmacological effects of camellia sinensis (tea): first symposium. new york city, march 4-5, 1991. | | 1992 | 1352045 |
| micropropagation of an elite darjeeling tea clone. | shoot cultures of camellia sinensis (l.) o. kuntz var. t-78, an elite darjeeling tea clone, were established from cotyledonary nodes and shoot tips of germinated seedlings as well as from nodal explants of field grown plants. shoot multiplication rate ranged from 4x in nodal explants to 35x in cotyledonary nodes after 18 weeks of culture. rooting was achieved in 80-90% micro-shoots by either placing them on an inductive medium for 10 d and then transferring shoots to hormone-free medium, or by t ... | 1992 | 24213495 |
| preparation of congou black tea from stale green tea. | | 1992 | 27280839 |
| [quantitative analysis of (-)-epigallocatechin gallate in tea leaves by high-performance liquid chromatography]. | the quantitative analysis of (-)-epigallocatechin gallate (egcg) in tea (camellia sinensis l.) was performed by high-performance liquid chromatography (hplc) with a c-18 reversed-phase column. egcg was then eluted within 20 min by using methanol-water-acetic acid (20:75:5 (v/v/v)) as an eluent. as an internal standard, tryptophan was used. the content of egcg in five kinds of green tea (sencha, gyokuro, bancha, matsucha and oolong tea) and in a cup of those was determined by both the extraction ... | 1991 | 1806661 |
| inhibitory effect of chinese tea on n-nitrosation in vitro and in vivo. | the inhibitory effect of 145 samples of chinese tea on the formation of n-nitrosomorpholine was studied in vitro. the rates of inhibition by green tea, crush, tear, curl (ctc) black tea, brick tea, jasmine tea, oolong tea, sun-dried tea and black tea were positively correlated with their polyphenol contents. an inhibitory effect of green and black tea on endogenous n-nitrosation was also confirmed in humans. drinking tea after a meal had a greater effect than drinking it before a meal. | 1991 | 1855915 |