Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| theacrine (1,3,7,9-tetramethyluric acid) synthesis in leaves of a chinese tea, kucha (camellia assamica var. kucha). | theacrine (1,3,7,9-tetramethyluric acid) and caffeine were the major purine alkaloids in the leaves of an unusual chinese tea known as kucha (camellia assamica var. kucha). endogenous levels of theacrine and caffeine in expanding buds and young leaves were ca. 2.8 and 0.6-2.7% of the dry wt, respectively, but the concentrations were lower in the mature leaves. radioactivity from s-adenosyl-l-[methyl-14c]methionine was incorporated into theacrine as well as theobromine and caffeine by leaf disks ... | 2002 | 12009315 |
| aflatoxin in detannin coffee and tea and its destruction. | the aflatoxins produced byaspergillus parasiticus var. globosus imi 12090 in detannin-caffeinated coffee and black tea were five times more concentrated than in regular coffee and tea. the activity of caffeine and tannin on the fungus growth and aflatoxin production in liquid broth was tested at three levels: viz. 0.1, 0.3, and 0.6%. tannin and caffeine induced 95% inhibition in aflatoxins at 0.3% and 0.6%, respectively. the antiaflatoxigenic properties of regular coffee and tea appear to be due ... | 2002 | 12009113 |
| [cancer prevention with green tea: reality and wishful thinking]. | different processing of the leaves of the tea plant camellia sinensis yields green or black tea, the subject of numerous investigations on the preventive effects on chronic degenerative diseases. the tea polyphenols, in particular (-)-epigallocatechin gallate (egcg) were found to account for most of the protective effects. since the concentration of egcg is 5 times higher in green than in black tea, it is assumed that green tea possesses a greater preventive potential. protection against cancer ... | 2002 | 11998565 |
| novel epr characterization of the antioxidant activity of tea leaves. | electron paramagnetic resonance (epr) spectroscopy is utilized to investigate several categories of green and black tea: twining green tea (tgt), chinese green tea (cgt), red-labels black tea (rbt). basically, two epr signals from all the studied samples are observed: one of them is a very weak sharp epr signal with deltahpp approximately 10 g and g-factor = 2.00023 superimposed on the other broad signal with deltahpp approximately 550 g and g-factor = 2.02489. the broad signal is a characterist ... | 2002 | 11993474 |
| multielement determination and speciation of major-to-trace elements in black tea leaves by icp-aes and icp-ms with the aid of size exclusion chromatography. | a multielement determination of major-to-trace elements in black tea leaves and their tea infusions was carried out by icp-aes (inductively coupled plasma atomic emission spectrometry) and icp-ms (inductively coupled plasma mass spectrometry). tea infusions were prepared as usual tea beverage by brewing black tea leaves in boiling water for 5 min. about 40 elements in tea leaves and tea infusions could be determined over the wide concentration range in 8 orders of magnitude. the extraction effic ... | 2001 | 11990615 |
| tea polyphenols inhibit the formation of mutagens during the cooking of meat. | powerful mutagens are formed during the broiling or frying of meat. these mutagens cause specific cancers in animal models, and epidemiological studies suggest that they increase the risk of breast and colon cancer. it is important, therefore, to inhibit the formation of these mutagens. application of tea polyphenols, polyphenon 60 from green tea, and polyphenon b from black tea, to both surfaces of ground beef before cooking inhibits the formation of the mutagens in a dose-related fashion. this ... | 2002 | 11943606 |
| effects of black tea extract on carbon tetrachloride-induced lipid peroxidation in liver, kidneys, and testes of rats. | previous studies have shown that green tea and black tea have antioxidant effects and chemopreventive activity against chronic disease including some forms of cancer. we have, therefore, examined the effects of an aqueous extract of black tea against carbon tetrachloride-induced lipid peroxidation as determined by the formation of thiobarbituric acid reactive substances in liver, kidneys and testes of rats. a 0.7% black tea extract was used which contained 2 mg of black tea extract solids per ml ... | 2002 | 11933136 |
| anti-invasive effects of green tea polyphenol epigallocatechin-3-gallate (egcg), a natural inhibitor of metallo and serine proteases. | several reports have attributed to green tea chemopreventive and therapeutic properties. epidemiological studies have linked the regular use of green tea to a reduced incidence of breast and colon carcinomas. tea contains several antioxidants, including polyphenols of the catechin (green tea) and theaflavin (black tea) groups. green tea derivatives have been shown to act in vitro and in vivo as anti-inflammatory, anti-viral and anti-tumor drugs. despite the extensive body of data only few studie ... | 2002 | 11928805 |
| antioxidant activity of black tea vs. green tea. | 2002 | 11925478 | |
| evaluation of the antigenotoxic potential of monomeric and dimeric flavanols, and black tea polyphenols against heterocyclic amine-induced dna damage in human lymphocytes using the comet assay. | the polyphenolic dimers, epicatechin-4beta-8-catechin (b1), epicatechin-4beta-8-epicatechin (b2), catechin-4beta-8-catechin (b3), catechin-4beta-8-epicatechin (b4), and the gallate ester epicatechin-4beta-8-epicatechin gallate (b'2g) were isolated from grape seeds, and theaflavins and theafulvins from black tea brews. the ability of these naturally-occurring polyphenols to afford protection against the genotoxicity of the heterocyclic amine 3-amino-1-methyl-5h-pyrido[4,3-b]indole (trp-p-2) was c ... | 2002 | 11909753 |
| signal transduction pathways: targets for chemoprevention of skin cancer. | chemoprevention can be defined as the use of substances to interfere with the process of cancer development. although substantial progress has been made in elucidating the basis of carcinogenesis, further advances are needed to identify molecular and cellular targets for effective use of chemopreventive agents. hundreds of compounds have been identified as potential chemopreventive agents. however, the safety and efficacy of each substance must be thoroughly investigated. carcinogenesis is a mul ... | 2000 | 11905657 |
| synthesis of theaflavin from epicatechin and epigallocatechin by plant homogenates and role of epicatechin quinone in the synthesis and degradation of theaflavin. | oxidation products of (-)-epicatechin and (-)-epigallocatechin by treatment with homogenates of 62 plants belonging to 49 families were compared. forty-six plants were capable of synthesizing theaflavin, a black tea pigment, regardless of whether they contained catechins. loquat, japanese pear, and blueberry had activities higher than that of fresh tea leaves after 5 h of treatment; furthermore, these plants oxidized theaflavin to theanaphthoquinone. an additional new metabolite, dehydrotheasine ... | 2002 | 11902970 |
| acute effects of ingestion of black tea on postprandial platelet aggregation in human subjects. | results of population studies suggest that black tea can reduce cardiovascular risk. effects of black-tea polyphenols to reduce platelet aggregability may help to explain any benefits. given that black tea is often consumed with and after meals, and man spends much of his life in the postprandial state, the objective of the present study was to investigate the acute effects of ingestion of black tea on postprandial platelet aggregation ex vivo. twenty healthy participants had platelet aggregatio ... | 2002 | 11895166 |
| antibacterial activity of black tea (camelia sinensis) extract against salmonella serotypes causing enteric fever. | alcoholic extract of black tea (camelia sinensis) was assayed for its antibacterial activity against salmonella serotypes causing enteric fever viz., salmonella typhi and salmonella paratyphi a. while all strains of s. paratyphi a tested were found sensitive, only 42.19% of s. typhi strains were inhibited by this extract. further minimum inhibitory concentration (mic) and minimum bactericidal concentration (mbc) of black tea extract against s. paratyphi a was less compared with that against s. t ... | 2001 | 11883337 |
| catechins from green tea (camellia sinensis) inhibit bovine and human cartilage proteoglycan and type ii collagen degradation in vitro. | polyphenolic compounds from green tea have been shown to reduce inflammation in a murine model of inflammatory arthritis, but no studies have been undertaken to investigate whether these compounds are protective to joint tissues. we therefore investigated the effects of catechins found in green tea on cartilage extracellular matrix components using in vitro model systems. bovine nasal and metacarpophalangeal cartilage as well as human nondiseased, osteoarthritic and rheumatoid cartilage were cul ... | 2002 | 11880552 |
| congou tea drinking and oesophageal cancer in south china. | the study from a large hospital-based case-control for 1248 cases with oesophageal cancer and the same number of controls in south china showed that congou, a grade of chinese black tea, may protect against cancers of the oesophagus and reduce the risk of a combination of alcohol drinking and smoking (especially smoking), regardless of temperature when drinking. | 2002 | 11875696 |
| interactions between flavonoids and proteins: effect on the total antioxidant capacity. | flavonoids are potent antioxidants. it is also known that flavonoids bind to proteins. the effect of the interaction between tea flavonoids and proteins on the antioxidant capacity was examined. their separate and combined antioxidant capacities were measured with the trolox equivalent antioxidant capacity (teac) assay. it was observed that the antioxidant capacity of several components of green and black tea with alpha-, beta-, and kappa-casein or albumin is not additive; that is, a part of the ... | 2002 | 11853501 |
| nanoparticles in plant extracts: influence of drugs on the formation of nanoparticles and precipitates in black tea infusions. | the influence of the neuroleptics fluphenazine and promethazine on the formation of nanoparticles in aqueous tea infusions was investigated using photon correlation spectroscopy. formation of nanoparticles and of precipitates was observed in decaffeinated tea and caffeine-containing tea. the amount of drug in the nanoparticle fraction was determined at different starting concentrations using high-performance liquid chromatography. in the case of fluphenazine, between 8 and 30% are assigned to th ... | 2002 | 11849911 |
| regular ingestion of black tea improves brachial artery vasodilator function. | a higher intake of black tea has been associated with lower cardiovascular disease risk. the antioxidant effects of tea polyphenols may enhance endothelial function and thereby reduce the risk of coronary events. the objective of the present study was to determine whether regular ingestion of black tea can improve brachial artery vasodilator function. the effects of regular ingestion of 5 cups per day of black tea for 4 weeks were compared with control conditions (hot water ingestion) in 21 subj ... | 2002 | 11834139 |
| substrate specificity of beta-primeverosidase, a key enzyme in aroma formation during oolong tea and black tea manufacturing. | we synthesized nine kinds of diglycosides and a monoglycoside of 2-phenylethanol to investigate the substrate specificity of the purified beta-primeverosidase from fresh leaves of a tea cultivar (camellia sinensis var. sinensis cv. yabukita) in comparison with the apparent substrate specificity of the crude enzyme extract from tea leaves. the crude enzyme extract mainly showed beta-primeverosidase activity, although monoglycosidases activity was present to some extent. the purified beta-primever ... | 2001 | 11826969 |
| tea flavonoids: bioavailability in vivo and effects on cell signaling pathways in vitro. | the elucidation of the potential health benefits of tea beverage continues to be a focus of research in many laboratories. beneficial effects of tea have been particularly evident in animal tumorigenesis models, with green and black tea frequently demonstrating similar effectivity. human data are now emerging to support a beneficial role for tea in cardiovascular disease, but the data with respect to cancer risk at various sites remain inconclusive. the constituent flavonoids of green and black ... | 2001 | 11813977 |
| tea pigments inhibit the production of type 1 (t(h1)) and type 2 (t(h2)) helper t cell cytokines in cd4(+) t cells. | tea pigments are oxidized products of polyphenols derived from tea leaves (camellia sinensis). theaflavins are constituents of tea pigments with antioxidant, antineoplastic and antiinflammatory properties similar to their parent compounds. the biological properties of polyphenols and theaflavins have been linked to their capacity to inhibit the activation of nuclear factor-kappab (nf-kappab), a transcription factor, which is critically involved in the molecular regulation of a number of proinfla ... | 2002 | 11807963 |
| inhibition of carcinogenesis by tea. | tea has received a great deal of attention because tea polyphenols are strong antioxidants, and tea preparations have inhibitory activity against tumorigenesis. the bioavailability and biotransformation of tea polyphenols, however, are key factors limiting these activities in vivo. the inhibition of tumorigenesis by green or black tea preparations has been demonstrated in animal models on different organ sites such as skin, lung, oral cavity, esophagus, forestomach, stomach, small intestine, col ... | 2002 | 11807163 |
| diurnal variation of photosynthesis and photoinhibition in tea: effects of irradiance and nitrogen supply during growth in the field. | diurnal changes in the rate of photosynthesis (a) of mature tea (camellia sinensis (l.) o. kuntze) bushes grown at high elevation in the field in sri lanka, were related to environmental conditions. bushes were either unshaded, receiving 100% of incident photosynthetically active radiation (par), moderately shaded, (65% par) or heavily shaded (30% par). these treatments were combined with nitrogen fertilizer applications of 0, 360 and 720 kg ha(-1) year(-1). when recently fully expanded leaves w ... | 2002 | 11807135 |
| anticarcinogenic effect of black tea on pulmonary tumors in swiss albino mice. | the widespread consumption of tea as beverage throughout the world has stimulated interest in the possibility of its use in chemoprevention of cancer. the present set of investigation was carried out to evaluate the anticarcinogenic activity of black tea using lung tumorigenesis model in swiss albino mice. diethylnitrosoamine (den), a known inducer of pulmonary tumors was given at the multiple (total eight) doses of 20mg/kg body weight through oral intubation to swiss albino mice. simultaneously ... | 2002 | 11804740 |
| total phenol, catechin, and caffeine contents of teas commonly consumed in the united kingdom. | levels of total phenol, catechins, and caffeine in teas commonly consumed in the united kingdom have been determined using reversed phase high-performance liquid chromatography. tea bags or tea leaves were purchased from local supermarkets and extracted in boiling water for 5 min. the resulting data showed considerable variability in both total phenols [80.5-134.9 mg/g of dry matter (dm) in black teas and 87-106.2 mg/g of dm in green teas] and catechins (5.6-47.5, 51.5-84.3, and 8.5-13.9 mg/g of ... | 2002 | 11804530 |
| identification and antioxidant activity of several pigments from the residual green tea (camellia sinensis) after hot water extraction. | antioxidant activity of green tea extract or tea-derived polyphenols has been extensively studied. however, antioxidant activity in the non-polyphenolic fraction of green tea has been poorly analyzed. in the present study, we analyzed the antioxidant activity of the non-polyphenolic fraction of the residual green tea (camellia sinensis) after hot water extraction using the aluminum chloride method. the non-polyphenolic fraction of residual green tea caused a significant suppression against hydro ... | 2001 | 11789136 |
| [photoprotective properties of melanins from grape (vitis vinifera) and black tea (thea sinensis)]. | dark pigments of melanin type were extracted from the rind of ripe grapes vitis vinifera (ring "alfa") and pack tea (thea sinensis). the study of photoprotection activity of the extracted pigments have shown that they intensively absorb radiation in the uv and visible. the increase of the photoprotection effect correlates with the concentration of paramagnetic centers in the melanins. the pigments reduce the number of damaged molecules of plasmid dna pbr-322 and inhibition the iuv-induced lipid ... | 2016 | 11785308 |
| regular ingestion of tea does not inhibit in vivo lipid peroxidation in humans. | prospective studies suggest that tea may protect against cardiovascular disease. a potential mechanism for such an effect involves inhibition of lipid peroxidation by polyphenolic antioxidants derived from tea. our objective was to determine whether regular ingestion of tea could inhibit in vivo lipid peroxidation. two controlled intervention studies assessed the effects of regular ingestion of tea on lipid peroxidation determined by measurement of urinary f(2)-isoprostane excretion. study 1: th ... | 2002 | 11773508 |
| prevention of carcinogenesis by tea polyphenols. | tea, an extract of the leaves of the plant camellia sinensis, has been considered a medicine and healthful beverage for ages. the beneficial effects of tea are thought to be due to its polyphenolic components. herein, we discuss the present status of tea as a possible cancer chemopreventive agent, covering basic chemistry and biochemical activity of tea, pharmacokinetics of major tea components, studies in animal and cell lines, epidemiological investigations, and future challenges. tea is one o ... | 2011 | 11768768 |
| tea consumption and the risk of colorectal cancer in sweden. | the association between tea drinking and colorectal cancer risk remains unclear. the evidence for black tea is sparse but may indicate an increased risk with regular use. because black tea is a common beverage in many populations, the significant twofold increased risk of colon cancer recently reported from a large prospective cohort of male finnish smokers is disconcerting. using cox proportional hazards models to estimate relative risks, we examined this association in a large, population-base ... | 2001 | 11759277 |
| black tea polyphenols inhibit igf-i-induced signaling through akt in normal prostate epithelial cells and du145 prostate carcinoma cells. | tea polyphenols have been proposed as potential chemopreventive agents against prostate cancer, primarily because of their high intake by populations with reduced cancer incidence and their reported ability to inhibit proliferation and increase apoptosis in prostate cancer cells in culture. insulin-like growth factor-i (igf-i) has been implicated as a risk factor for the development of prostate cancer by epidemiological studies and has been shown to be causative in animal models. one of the prim ... | 2002 | 11756245 |
| attenuation of 6-hydroxydopamine (6-ohda)-induced nuclear factor-kappab (nf-kappab) activation and cell death by tea extracts in neuronal cultures. | antioxidant and anti-inflammatory therapy approaches have been in the focus of attention in the treatment of neurodegenerative parkinson's and alzheimer's diseases where oxidative stress has been implicated. tea extracts have been previously reported to possess radical scavenger, iron chelating and anti-inflammatory properties in a variety of tissues. the purpose of this study was to investigate potential neuroprotective effects of tea extracts and possible signal pathway involved in a neuronal ... | 2002 | 11754870 |
| black tea polyphenols, theaflavins, prevent cellular dna damage by inhibiting oxidative stress and suppressing cytochrome p450 1a1 in cell cultures. | tea polyphenols have been demonstrated as chemopreventive agents in a number of experimental models. however, less is known about the mechanism of chemoprevention by black tea compared with that of green tea. some beneficial properties of theaflavins, the black tea polyphenols, were investigated in the present study. theaflavins showed inhibitory effects on h(2)o(2)- and tert-butyl hydroperoxide (tbuooh)-induced cytotoxicity (evaluated by tetrazolium bromide reduction), cellular oxidative stress ... | 2002 | 11754570 |
| gastrointestinal enhancement of mri with melanin derived from tea leaves (thea sinensis linn.). | melanin was extracted from tea leaves (thea sinensis linn.) for the first time. characterization of melanin proved similarity of the original compound to standard melanin. the langmuir adsorption isotherms for gadolinium (gd) binding were obtained using melanin. melanin-gd preparation demonstrated low acute toxicity. ld(50) for this preparation was in a range of 1250-1500 mg/kg in mice. magnetic resonance imaging (mri) properties of melanin itself and melanin-gd complexes have been estimated. gd ... | 2002 | 11744298 |
| two types of oxidative dimerization of the black tea polyphenol theaflavin. | theaflavin and its galloyl esters are polyphenolic pigments of black tea. in the course of studies on the oxidation mechanism of tea polyphenols, two theaflavin oxidation products named bistheaflavins a and b were isolated, and their structures were elucidated on the basis of ms and nmr spectroscopic analyses. treatment of a mixture of (-)-epicatechin and (-)-epigallocatechin with banana fruit homogenate yielded bistheaflavin a together with theaflavin and theanaphthoquinone. the symmetrical str ... | 2001 | 11743764 |
| 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 |
| anticlastogenic effects of black tea (world blend) and its two active polyphenols theaflavins and thearubigins in vivo in swiss albino mice. | this study investigated the inhibition of cyclophosphamide (cp) and dimethylbenz(a)anthracene (dmba) induced genetic damage by black tea (world blend) and its two active polyphenols theaflavins (tf) and thearubigins (tr) in swiss albino mice as measured by chromosome aberrations (ca) and sister chromatid exchanges (sce). three different concentrations (5, 10 and 20%) of tea and a single dose of tf and tr were tested for their anticlastogenic effects against dmba (50 mg/kg body weight) and cp (20 ... | 2001 | 11720078 |
| green tea upregulates the low-density lipoprotein receptor through the sterol-regulated element binding protein in hepg2 liver cells. | green tea from camellia sinensis lowers plasma cholesterol in animal models of hypercholesterolemia. the aim of this study was to determine the effects of green tea on the expression of the hepatic low-density lipoprotein (ldl) receptor, a cell surface protein involved in the control of plasma cholesterol. incubating human hepg2 liver cells in culture with green tea increased both ldl receptor binding activity and protein. an ethyl acetate extract of green tea, containing 70% (w/w) catechins, al ... | 2001 | 11714371 |
| analysis of glycosidically bound aroma precursors in tea leaves. 3. change in the glycoside content of tea leaves during the oolong tea manufacturing process. | a direct qualitative and quantitative determination of the glycosides of tea aroma compounds at the four stages of the oolong tea manufacturing process (plucking, solar withering, indoor withering, and oolong tea product) was carried out by a capillary gas chromatographic-mass spectrometric analysis after trifluoroacetyl derivatization of the glycosidic fractions. sixteen glucosides and primeverosides were identified and quantified in cv. chin-shin-oolong and cv. chinhsuan-oolong. a comparison o ... | 2001 | 11714333 |
| factors affecting the caffeine and polyphenol contents of black and green tea infusions. | the effects of product and preparation variables on the in-cup chemical composition of tea extracts is of interest because the appearance and taste characteristics and the possible health effects of a tea liquor arise from the chemical components extracted from the leaf during tea preparation. a comprehensive study was therefore undertaken to determine the contributions of product and preparation variables on the total soluble solids, caffeine, and polyphenol contents of tea extracts. the result ... | 2001 | 11714326 |
| aqueous extracts of crinum latifolium (l.) and camellia sinensis show immunomodulatory properties in human peripheral blood mononuclear cells. | in vietnamese and chinese traditional medicine, hot aqueous extract of crinum latifolium is used because of its antitumor activity. the genus crinum is thought to possess antiviral and immunostimulative properties. green and black tea derived from camellia sinensis have similar qualities. a growing body of evidence suggests that moderate consumption of green and black tea may protect, e.g., against several forms of cancer, cardiovascular diseases, and bacterial infections. in this study, the imm ... | 2001 | 11710543 |
| effects of purified green and black tea polyphenols on cyclooxygenase- and lipoxygenase-dependent metabolism of arachidonic acid in human colon mucosa and colon tumor tissues. | the effects of green and black tea polyphenols on cyclooxygenase (cox)- and lipoxygenase (lox)-dependent arachidonic acid metabolism in normal human colon mucosa and colon cancers were investigated. at a concentration of 30 microg/ml, (-)-epigallocatechin-3-gallate (egcg), (-)-epigallocatechin (egc), and (-)-epicatechin-3-gallate (ecg) from green tea and theaflavins from black tea inhibited lox-dependent activity by 30-75%. the formation of 5-, 12-, and 15-lox metabolites was inhibited to a simi ... | 2001 | 11705450 |
| the erosive effect of herbal tea on dental enamel. | the aim of this study was to determine whether conventional black tea and a herbal tea were capable of eroding dental enamel. a further aim was to investigate whether herbal tea of the type tested eroded dental hard tissues to a greater or lesser extent than conventional black tea. | 2001 | 11700200 |
| effect of herbal teas on hepatic drug metabolizing enzymes in rats. | we have investigated the effect of herbal teas (peppermint, chamomile and dandelion) on the activity of hepatic phase i and phase ii metabolizing enzymes using rat liver microsomes. female wistar rats were divided into six groups (n = 5 each). three groups had free access to a tea solution (2%) while the control group had water. two groups received either green tea extract (0.1%) or aqueous caffeine solution (0.0625%). after four weeks of pretreatment, different cytochrome p450 (cyp) isoforms an ... | 2001 | 11697539 |
| antimutagenic effect of black tea extract using 'rodent dominant lethal mutation assay'. | the antimutagenic effect of black tea extract has been evaluated with the 'dominant lethal assay' in swiss albino mice using benzo[a]pyrene [bap] as a mutagen. bap was given through the intraperitoneal (i.p.) route at a single dose of 100 mg/kg b.w. to male mice once only. the animals were given 1, 2 and 4% aqueous solution of black tea as sole source of drinking solution prior to bap. the pregnant females were analyzed for living implants, pre- and post-implantation losses. the results revealed ... | 2001 | 11684324 |
| nanoparticles in plant extracts--factors which influence the formation of nanoparticles in black tea infusions. | the influence of different factors on the formation of nanoparticles in freshly brewed tea extracts was investigated. a black tea infusion was observed during cooling using photon correlation spectroscopy (pcs). the mean particle size and the number of the nanoparticles increase with decreasing temperature. in the presence of caffeine more particles are formed within the infusion. to study the influence of slight structural differences between methylxanthines, the effect of the addition of caffe ... | 2001 | 11683125 |
| effect of black tea on teeth. | dental caries is the prime cause of premature loss of teeth in children. tea contains high percentage of fluoride along with polyphenolic constituents which act on gtf of s. mutans in plaque synthesis. combination of fluoride and polyphenolic constituents inhibit caries activity. | 2000 | 11601182 |
| differentiation of tea (camellia sinensis) varieties and their geographical origin according to their metal content. | the metal content of 46 tea samples, including green, black, and instant teas, was analyzed. al, ba, ca, cu, fe, k, mg, mn, na, sr, ti, and zn were determined by icp-aes. potassium, with an average content of 15145.4 mg kg(-1) was the metal with major content. calcium, magnesium, and aluminum had average contents of 4252.4, 1978.2, and 1074.0 mg kg(-1), respectively. the average amount of manganese was 824.8 mg kg(-1). there were no clear differences between the metal contents of green and black ... | 2001 | 11600020 |
| chemoprevention of basal cell carcinomas in the ptc1+/- mouse--green and black tea. | skin cancers are a rising menace as their incidence increases, attributed in part to increasing ultraviolet radiation exposure. this increasing problem has stimulated efforts to devise useful preventive approaches. the uncertain efficacy of exhortations to avoid sun exposure and to use protective clothing and sunscreens to reduce damage when exposed argue for the development of an oral chemopreventive agent. bickers and others have studied the effects and mechanisms of tea and of its putative ac ... | 2001 | 11598435 |
| effects of regular ingestion of black tea on haemostasis and cell adhesion molecules in humans. | to assess the effects in humans of regular ingestion of black tea on haemostasis-related variables and cell adhesion molecules. | 2001 | 11593350 |
| effects of (-)-epigallocatechin-3-gallate, the main component of green tea, on the cloned rat brain kv1.5 potassium channels. | the interaction of (-)-epigallocatechin-3-gallate (egcg), the main component of green tea (camellia sinensis), with rat brain kv1.5 channels (rkv1.5) stably expressed in chinese hamster ovary (cho) cells was investigated using the whole-cell patch-clamp technique. egcg inhibited rkv1.5 currents at +50 mv in a concentration-dependent manner, with an ic50 of 101.2+/-6.2 microm. pretreatment with protein tyrosine kinase (ptk) inhibitors (10 microm genistein, 100 microm ag1296), a tyrosine phosphata ... | 2001 | 11585049 |
| guidelines for the intake of vegetables and fruit: the mediterranean approach. | various studies have demonstrated that the nutrient and non-nutrient substances present in vegetables and fruit (v&f) are most likely to be responsible for the beneficial effect of the increased v&f consumption. urged by scientific evidence, current dietary guidelines strongly recommend the consumption of v&f in substantial amounts. in a recent paper (brit. j. nutr. 2000; 84, 549-556) v&f availability in 10 european countries was compared with the who recommendations (minimum combined v&f intake ... | 2001 | 11582835 |
| antioxidant activity of some foods containing phenolic compounds. | this study was designed to determine the total phenols (tp) and total antioxidant activity (taa) of some liquid and solid plant foods that are commonly consumed in turkey. total phenols were analysed according to the folin-ciocalteu method and antioxidant activities of these compounds in aqueous phase were assessed by measuring their direct abts.- radical scavenging abilities. total phenols varied from 68 to 4162 mg/l for liquid foods and from 735 to 3994 mg/kg for solid foods. taa of liquid and ... | 2001 | 11570016 |
| profiles of purine and pyrimidine nucleotides in fresh and manufactured tea leaves. | profiles of nucleotide levels in two varieties of japanese green teas (cv. yabukita and saemidori), a chinese green tea (longjing), and two japanese black teas (cv. benifuuki and benihikari) were determined and compared with that of fresh tea leaves. the concentration of 5'-nucleotides in green tea was much higher than in black tea. nucleoside diphosphates were present in larger amounts than nucleoside triphosphates in manufactured green and black teas, whereas the triphosphates predominated in ... | 2001 | 11559141 |
| catechins are not major components responsible for anti-genotoxic effects of tea extracts against nitroarenes. | the anti-genotoxic properties of tea leaf extracts were examined in a salmonella umu-test. seven non-fermented teas (green tea), one semi-fermented tea (oolong tea), two fermented teas (black tea and chinese pu er tea) and two other teas were examined for their anti-genotoxic abilities and for their catechins contents. this was to study the relationship between catechins contents and anti-genotoxic activity of various tea leaf extracts. all types of tea extracts showed more potent suppressive ef ... | 2001 | 11551482 |
| theaflavins in black tea and catechins in green tea are equally effective antioxidants. | green tea catechins, including (-)-epicatechin (ec), (-)-epicatechin gallate (ecg), (-)-epigallocatechin (egc) and (-)-epigallocatechin gallate (egcg), are oxidized and dimerized during the manufacture of black tea and oolong tea to form orange-red pigments, theaflavins (tf), a mixture of theaflavin (tf1), theaflavin-3-gallate (tf2a), theaflavin-3'-gallate (tf2b) and theaflavin-3,3'-digallate (tf3). the present study was designed to compare the antioxidant activities of individual tf with that o ... | 2001 | 11533262 |
| analysis of theaflavins in biological fluids using liquid chromatography-electrospray mass spectrometry. | a hplc-ms procedure for the sensitive and specific analysis of the black tea flavonoid theaflavin in human plasma and urine was developed. levels were measured after enzymatic deconjugation, extraction into ethyl acetate, and separation by hplc, using tandem mass spectrometry as a detecting system. two healthy volunteers consumed 700 mg theaflavins, equivalent to about 30 cups of black tea. the maximum concentration detected in blood plasma was 1.0 microg l(-1) in a sample collected after 2 h. t ... | 2001 | 11530986 |
| joint effects of citrus peel use and black tea intake on the risk of squamous cell carcinoma of the skin. | differences in tea drinking habits and/or citrus peel use are likely to vary by populations and could contribute to the inconsistencies found between studies comparing their consumption and cancer risk. | 2001 | 11527506 |
| anticariogenic effects of black tea (camellia sinensis) in caries prone-rats. | black tea (camellia sinensis) may have anticariogenic properties. the present study was designed to determine whether consumption of black tea influences cariogenesis in young, caries-prone rats. | 2001 | 11526894 |
| induction of apoptosis and cell cycle arrest in cancer cells by in vivo metabolites of teas. | the present study was conducted to determine in vivo possibilities of inducing apoptosis and cell cycle arrest in rat cancer cells by green, oolong, and black teas and also to further identify the mechanisms inhibiting cancer cell proliferation by the sera from tea-treated rats. the tea extracts from these three kinds of tea, the rat sera obtained after oral intubation of the tea extracts, and the tea polyphenolic compounds, (-)-epigallocatechin-3-gallate, (-)-epigallocatechin, (-)-epicatechin-3 ... | 2000 | 11525605 |
| decrease in concentration of free catechins in tea over time determined by micellar electrokinetic chromatography. | cancer chemoprevention is a new and important medical science and much interest has been focused on catechins, not only for their antioxidant activity, but also because of their known antimutagenic and antitumorigenic properties. green tea and black tea, which are among the most popular beverages consumed worldwide, contain many different catechins. due to the instability of catechins in solutions with neutral or basic ph values the concentrations of catechins in tea decrease in time. in this pr ... | 2001 | 11521904 |
| antioxidant properties of green and black tea, and their potential ability to retard the progression of eye lens cataract. | aqueous extracts of green and black tea are shown to quench reactive oxygen species such as singlet oxygen, superoxide and hydroxyl radicals, prevent the oxidative cross-linking of test proteins and inhibit single strand breakage of dna in whole cells. they are also seen to be able to counteract the oxidative insult mounted by cigarette smoke. in rats in which cataract was induced by subcutaneous injection of selenite, administration of green or black tea extracts led to a retardation of the pro ... | 2001 | 11520114 |
| comparison of the antioxidant content of fruits, vegetables and teas measured as vitamin c equivalents. | most of the health benefits of black, green and oolong teas made from camellia sinensis are attributed to their antioxidant content. many plants and spices have been used to make infusions that are erroneously referred to as 'teas'. the term 'rich in antioxidants' is often used to describe such infusions, often without scientific support. we have used the dpph method to quantify the total radical scavenging capacity (rsc) of a wide range of 'teas', fruits and vegetables. the results are presente ... | 2001 | 11518612 |
| fumonisins b1 and b2 in black tea and medicinal plants. | fumonisins are mycotoxins produced by fusarium moniliforme that are prevalent in cereals and other agricultural products. these mycotoxins have been pointed to as a natural cause of equine leukoencephalomalacia, porcine pulmonary edema, and human esophageal cancer. a total of 87 samples, 18 black tea samples and 69 samples of four different medicinal plants (chamomile, leaves of the orange tree, leaves and flowers of the linden tree, and corn silk), for infusions preparations were acquired from ... | 2001 | 11510675 |
| green tea extracts decrease carcinogen-induced mammary tumor burden in rats and rate of breast cancer cell proliferation in culture. | epidemiological evidence suggests tea (camellia sinensis l.) has chemopreventive effects against various tumors. green tea contains many polyphenols, including epigallocatechin-3 gallate (egcg), which possess anti-oxidant qualities. reduction of chemically induced mammary gland carcinogenesis by green tea in a carcinogen-induced rat model has been suggested previously, but the results reported were not statistically significant. here we have tested the effects of green tea on mammary tumorigenes ... | 2001 | 11500915 |
| processing procedures of brick tea and their influence on fluorine content. | china is the only country that produces brick tea, and more than 90% of the brick tea is consumed in the western minority nationality regions of china. the high fluorine content of brick tea is possibly associated with the special processing procedures, but no investigation has been conducted in this field. to explore the characteristic features of brick tea manufacturing and the alterations in fluorine content during the processing procedures, we performed a field survey involving two brick tea ... | 2001 | 11498273 |
| the distribution of minerals and flavonoids in the tea plant (camellia sinensis). | camellia sinensis is a plant growing in india, sri lanka, java, japan and its properties were known 4000 years ago. since then, traditional chinese medicine has recommended this plant for headaches, body aches and pains, digestion, depression, detoxification, as an energiser and, in general, to prolong life. tea contains volatile oils, vitamins, minerals, purines, polyphenols, particularly carechins. we have analysed ten commercial teas from various countries to determine their mineral compositi ... | 2001 | 11482766 |
| biochemical responses of camellia sinensis (l.) o. kuntze to heavy metal stress. | three heavy metals-mercury (ii), copper (ii) and nickel (ii), each at a concentration of 10 and 100 micrograms/ml, were tested for their effects on various biochemical constituents of tea leaves. both ni (ii) and hg (ii) decreased the phenolic contents, while cu (ii) increased it to some extent. the metal treatments enhanced the activity of phenyl alanine ammonia lyase (pal), while the activity of poly phenol oxidase (ppo) showed a decline. heavy metal stress also decreased the chlorophyll conte ... | 2001 | 11480349 |
| catechin intake might explain the inverse relation between tea consumption and ischemic heart disease: the zutphen elderly study. | epidemiologic studies suggest that tea consumption may reduce the risk of cardiovascular diseases, but results are inconsistent. catechins, which belong to the flavonoid family, are the main components of tea and may be responsible for the alleged protective effect. taking catechin sources other than tea into account might clarify the reported associations. | 2001 | 11470725 |
| black tea; white teeth. research suggests beverage may be powerful cavity-fighting tool. | 2001 | 11462338 | |
| analysis of black tea theaflavins by non-aqueous capillary electrophoresis. | in this study a new capillary electrophoresis (ce) method was developed to quantify the four major theaflavins occurring in black tea. where aqueous based ce methods showed poor selectivity and considerable band broadening, non-aqueous ce achieved baseline separation of the theaflavins within 10 min. the effects of the organic solvent composition and background electrolyte concentration on the separation selectivity and electrophoretic mobilities were investigated. our optimized separation solut ... | 2001 | 11459305 |
| comparison of the antioxidant activity of commonly consumed polyphenolic beverages (coffee, cocoa, and tea) prepared per cup serving. | in this study, the in vitro low-density lipoprotein oxidation model was used to assess the relative antioxidant activity of the polyphenolic beverages tea, coffee, and cocoa on a cup-serving basis. the beverages were prepared as 0.7-2.5% soluble coffee and 1.5-3.5% cocoa; teas (green, black, or herbal) were prepared as one tea bag infused over 5 min in 220 ml of hot water. under these standard cup serving conditions, the antioxidant activity as determined by the lag time was in the range of 292- ... | 2001 | 11453788 |
| change in the flavor of black tea drink during heat processing. | heat processing during canning is responsible for the change in flavor of black tea infusion. the quantitative change in the volatile components of the black tea infusion during heat processing is not sufficient for explaining the sensory evaluation. in this study, application of aroma extract dilution analysis using the volatile fraction before and after black tea (darjeeling) samples were heat processed resulted in the detection of 10 odor-active peaks for which flavor dilution (fd) factors ch ... | 2001 | 11453767 |
| a review of latest research findings on the health promotion properties of tea. | important progress has been made in the past five years concerning the effects of green and black tea on health. experimentation with new accurate tools provide useful information about the metabolism of tea components in the body, their mode of action as antioxidants at the cellular level and their protective role in the development of cancer, cardiovascular disease and other pathologies. the use of tea components as nutraceuticals and functional foods are also discussed. | 2001 | 11448616 |
| short- and long-term black tea consumption reverses endothelial dysfunction in patients with coronary artery disease. | epidemiological studies suggest that tea consumption decreases cardiovascular risk, but the mechanisms of benefit remain undefined. endothelial dysfunction has been associated with coronary artery disease and increased oxidative stress. some antioxidants have been shown to reverse endothelial dysfunction, and tea contains antioxidant flavonoids. methods and results-- to test the hypothesis that tea consumption will reverse endothelial dysfunction, we randomized 66 patients with proven coronary a ... | 2001 | 11447078 |
| inhibitory effects of orally administered green tea, black tea, and caffeine on skin carcinogenesis in mice previously treated with ultraviolet b light (high-risk mice): relationship to decreased tissue fat. | treatment of skh-1 hairless mice with ultraviolet b light (uvb; 30 mj/cm(2)) twice a week for 22 weeks resulted in tumor-free animals with a high risk of developing malignant and nonmalignant skin tumors during the next several months in the absence of additional uvb treatment (high-risk mice). oral administration of green tea or black tea (6 mg tea solids/ml) to uvb-pretreated high-risk skh-1 mice for 23 weeks after stopping uvb treatment decreased the number of tumors/mouse, decreased the size ... | 2001 | 11431333 |
| the irreplaceable image: black tea delays recovery from iron-deficiency anemia. | 2001 | 11410431 | |
| antioxidative activities of phenylethanoid glycosides from ligustrum purpurascens. | tea and kudingcha (bitter tea) are the two most popular beverages consumed in china. tea derived from the leaves of camellia sinensis has been well studied for its various health benefits, but there are very limited data on the biological activities of bitter tea derived from the leaves of ligustrum purpurascens (lp). the present study was carried out to characterize the antioxidants present in the bitter tea brewed from the leaves of lp. it was found that the crude glycoside fraction possessed ... | 2001 | 11410017 |
| flavonoid (myricetin, quercetin, kaempferol, luteolin, and apigenin) content of edible tropical plants. | studies were conducted on the flavonoids (myricetin, quercetin, kaempferol, luteolin, and apigenin) contents of 62 edible tropical plants. the highest total flavonoids content was in onion leaves (1497.5 mg/kg quercetin, 391.0 mg/kg luteolin, and 832.0 mg/kg kaempferol), followed by semambu leaves (2041.0 mg/kg), bird chili (1663.0 mg/kg), black tea (1491.0 mg/kg), papaya shoots (1264.0 mg/kg), and guava (1128.5 mg/kg). the major flavonoid in these plant extracts is quercetin, followed by myrice ... | 2001 | 11410016 |
| alpha-tocopherol content in 62 edible tropical plants. | vitamin e was determined by the high-performance liquid chromatography (hplc) method. all the plants tested showed differences in their alpha-tocopherol content and the differences were significant (p < 0.05). the highest alpha-tocopherol content was in sauropus androgynus leaves (426.8 mg/kg edible portion), followed by citrus hystrix leaves (398.3 mg/kg), calamus scipronum (193.8 mg/kg), starfruit leaves averrhoa belimbi (168.3 mg/kg), red pepper capsicum annum (155.4 mg/kg), local celery apiu ... | 2001 | 11410015 |
| antihemolytic effect of rooibos tea (aspalathus linearis) on red blood cells of japanese quails. | the antihemolytic activity of rooibos and black tea on japanese quail erythrocytes was studied. peroxide and hypotonic hemolysis of the red blood cells of quails, either fed with rooibos tea supplemented food or fed without tea, was performed. long-term consumption of rooibos tea did not change the erythrocyte fragility to either peroxide or hypotonia induced hemolysis. however, rooibos and black teas decreased peroxide induced hemolysis of erythrocytes incubated with each of them, but not hemol ... | 2000 | 11409839 |
| reproducibility and relative validity of a questionnaire to assess intake of black tea polyphenols in epidemiological studies. | epidemiological studies suggest that tea drinking may reduce the risk of cardiovascular diseases and cancers. although tea is an important source of antioxidant phytochemicals, variation in preparation techniques may translate to variation in antioxidant capacity. however, most large-scale epidemiological studies use regular food frequency questionnaires to estimate tea intake, and nationally available nutrient analysis databases do not include levels of black tea polyphenols. the arizona tea qu ... | 2001 | 11401918 |
| spectrophotometric determination of the tannin contents of various turkish black tea, beer and wine samples. | this study reports tannin contents of various tea (19), beer (6) and wine (6) samples, produced or sold in turkey under different brand names. determinations were carried out by employing a previously reported uv-vis spectrophotometric method. the standard addition procedure was also compared to the direct determination procedure and found to be more reliable. the tannin contents of hot water extracts of tea, tea bag and herbal tea samples ranged between 6.20-8.33, 8.03-6.59 and 2.76-6.54 percen ... | 2001 | 11400478 |
| effect of acute and chronic tea consumption on platelet aggregation in patients with coronary artery disease. | epidemiological studies suggest that tea consumption is associated with a decreased risk of cardiovascular events, but the mechanisms of benefit remain undefined. platelet aggregation is a precipitating event in cardiovascular disease, and tea contains antioxidant flavonoids that are known to decrease platelet aggregation in vitro. to test the effect of tea consumption on platelet aggregation, we randomized 49 patients with coronary artery disease to either 450 ml of black tea or water consumed ... | 2001 | 11397724 |
| combination effect of lignin f and natural products. | we investigated the effect of lignin f, isolated from the alkaline extract of the cone of pinus parviflora sieb. et zucc, on the cytotoxic activity and radical intensity (measured by esr spectroscopy) of various natural products. lignin f slightly inhibited the proliferation of human oral tumor cell lines (human squamous cell carcinoma hsc-2, human salivary gland tumor hsg), but not that of human gingival fibroblast hgf, suggesting its tumor specific cytotoxic action. lignin f enhanced the cytot ... | 2001 | 11396189 |
| black tea extract, thearubigin fraction, counteracts the effect of tetanus toxin in mice. | the aim of this study was to find an inactivating substance for tetanus toxin in natural foodstuff. tetanus toxin (4 micrograms/ml) abolished indirect twitches in in vitro mouse phrenic nerve-diaphragm preparations within 2.5 hr. hot water infusion of black tea mixed with tetanus toxin blocked the inhibitory effect of the toxin. mixing the toxin with thearubigin fraction extracted from black tea infusion produced an identical result. furthermore, thearubigin fraction mixed with the toxin protect ... | 2001 | 11395929 |
| distribution characteristics of fluoride and aluminum in soil profiles of an abandoned tea plantation and their uptake by six woody species. | distribution characteristics of fluoride (f) and aluminum (al) in soil profiles of an abandoned tea plantation in hong kong and their uptake by six woody species namely camellia sinensis, melastoma affine, sterculia lanceolata, ardisia crenata, acacia formosa and machilus thunbergii were investigated. c. sinensis accumulated both f (656 mg/kg in the leaves) and al (8910 mg/kg in the leaves). m. affine only accumulated al (9932 mg/kg in the leaves), while s. lanceolata, a. crenata, a. formosa and ... | 2001 | 11392749 |
| role of reduced glutathione and nitric oxide in the black tea extract-mediated protection against ulcerogen-induced changes in motility and gastric emptying in rats. | the aim of the present study was to investigate the underlying mechanism of the role of hot water extract of black tea [camellia sinensis (l). o. kuntze theaceae] in normalizing the changes in intestinal transit and gastric emptying induced by various ulcerogenic agents in experimental rats. intestinal transit as well as gastric emptying were significantly reduced in rats treated with glutathione (gsh) depleting agents, diethyl maleate (dem), indoacetamide (ida) and n-ethyl maleimide (nem). prio ... | 2001 | 11388638 |
| catechins are bioavailable in men and women drinking black tea throughout the day. | tea consumption has been associated with reduced risk of both cancer and cardiovascular disease in population studies, but clinical data demonstrating bioavailability of the individual catechins and other polyphenolic components of tea are limited. this study assessed the apparent bioavailability of the prominent catechins from black tea in humans drinking tea throughout the day. after 5 d of consuming a low flavonoid diet, subjects drank a black tea preparation containing 15.48, 36.54, 16.74, a ... | 2001 | 11385060 |
| [application and improvement of aflatoxin analysis in foods using a multifunctional column and hplc]. | in an earlier report, we developed a rapid, sensitive and clean method consisting of non-chloroform extraction, clean-up on a commercial multifunctional cartridge column and hplc with fluorescence detection for the analyses of aflatoxins. in this report, we applied this method to analyze aflatoxins in nuts, giant corn, cereals, spice and black teas. the method was effective for macadamia nuts, walnuts, hazelnuts, brazil nuts, giant corn, rice, wheat and buckwheat, and the recoveries of aflatoxin ... | 2001 | 11383158 |
| [cause of bisphenol a migration from cans for drinks and assessment of improved cans]. | in the previous investigation, we found that some cans for coffee and black tea drinks released large amounts of bisphenol a (bpa) into their contents. equivalent cans were obtained and the cause of bpa migration was investigated. equivalent cans a, b and d contained high levels of bpa in the side seam, in the bottom, and in the bottom and the side seam, respectively, while can c contained some level of bpa in the body, which has a large area, therefore, all of them contained high amounts of bpa ... | 2001 | 11383151 |
| consumption of flavonoids in onions and black tea: lack of effect on f2-isoprostanes and autoantibodies to oxidized ldl in healthy humans. | oxidative damage to lipids in vivo may be involved in the development of atherosclerosis and cancer. onions and black tea are foods rich in flavonoids, predominantly the flavonoid quercetin, which is a potent in vitro inhibitor of membrane lipid peroxidation and ldl oxidation. | 2001 | 11382657 |
| black tea is a powerful chemopreventor of reactive oxygen and nitrogen species: comparison with its individual catechin constituents and green tea. | production of black tea [bt] results in biotransformation of catechins of green tea [gt] to theaflavins and thearubigins. bt was found to be more efficient than gt and its individual catechin constituents in proportionate amounts in abrogating production of no and o2(-) in activated murine peritoneal macrophages. in a reconstitution system of bt that is free of all catechins, stepwise addition of catechins showed that though all the constituents contributed to the overall effect of bt, theaflavi ... | 2001 | 11374887 |
| tea flavonoids and cardiovascular health. | tea is rich in antioxidant polyphenols (catechins, flavonols, theaflavins and thearubigins). epidemiological evidence relating regular consumption of tea or related polyphenols to chd is equivocal. catechins are absorbed from tea, but low plasma concentrations are attained. the bioavailability of theaflavins and thearubigins is unknown. tea does not reduce blood pressure or plasma lipids in well-controlled human trials. tea polyphenols inhibit ldl lipid peroxidation in vitro, but the effect ex v ... | 2001 | 11353103 |
| studies on the effect of polyvinyl pyrrolidone on the activity of chlorhexidine mouthrinses: plaque and stain. | polyvinyl pyrrolidone (pvp) was shown in vitro to reduce chlorhexidine induced, dietary staining without affecting the uptake of the antiseptic to the test substrate. the aim of these studies in vivo was to determine whether pvp affected plaque and dietary staining by a low concentration chlorhexidine rinse. | 2001 | 11350523 |
| tea consumption modulates hepatic drug metabolizing enzymes in wistar rats. | the antioxidant, antimutagenic and anticarcinogenic activities of green tea and its polyphenols have been reported. as bioactivation of the precarcinogens and detoxification of ultimate carcinogens are mainly carried out by hepatic metabolizing enzymes, we have investigated the modulation of these enzyme activities subsequent to tea consumption in rats. female wistar rats were divided into eight groups (n = 5). six groups were given aqueous solutions (2%, w/v) of six different teas (new zealand ... | 2001 | 11341376 |
| tooth surface ph during drinking of black tea. | to investigate the composition of black tea in terms of its erosive potential. to determine the ph profile at the palatal surface of anterior and posterior sites of the dentition after drinking black tea. | 2001 | 11338040 |
| the (3r,9r)-3-hydroxy-7,8-dihydro-beta-ionol disaccharide glycoside is an aroma precursor in tea leaves. | the disaccharide glycoside, (3r,9r)-3-hydroxy-7,8-dihydro-beta-ionyl 6-o-beta-d-apiofuranosyl-beta-d-glucopyranoside was isolated as an aroma precursor from the leaves of camellia sinensis var. sinensis cv. yabukita. its stereochemistry was elucidated on the basis of spectral data and chemical synthesis. | 2001 | 11324911 |
| determination of total aluminum, chromium, copper, iron, manganese, and nickel and their fractions leached to the infusions of black tea, green tea, hibiscus sabdariffa, and ilex paraguariensis (mate) by eta-aas. | total aluminum, chromium, copper, iron, manganese, and nickel were determined in black tea, green tea, hibiscus sabdariffa, and ilex paraguariensis (mate) by electrothermal atomic absorption spectrometry after nitric/perchloric acid digestion. in each case, one ground sample of commercially available leafy material was prepared and three 0.5-g subsamples were run in parallel. the infusions were also analyzed and the percentage of each element leached into the liquor was evaluated. the obtained r ... | 2000 | 11314985 |