| efficacy and safety of herbal stimulants and sedatives in sleep disorders. | world-wide use of herbal medicines is increasing, following regulatory and manufacturing developments. herbs are attractive alternative medications to many patients with sleep disorders, who may be averse to using conventional drugs. we review here the most common herbal stimulants and sedatives. caffeine, in herbal teas, black tea, coffee, soft drinks and pharmaceuticals, is used widely to control sleepiness, but more research is needed on its use in sleep disorders. ephedra, and its constituen ... | 2000 | 12531167 |
| accumulation of epigallocatechin quinone dimers during tea fermentation and formation of theasinensins. | production and accumulation of catechin dimer quinones during tea fermentation were chemically confirmed for the first time by trapping as phenazine derivatives. direct treatment of the fermented tea leaves with o-phenylenediamine yielded five phenazine derivatives (8-12) of o-quinones of an epigallocatechin dimer and its galloyl esters (13-16), in which two flavan units were linked at the b-rings through a c-c bond. atrop isomerism of the biphenyl bonds was shown to be the r configuration, sugg ... | 2002 | 12444680 |
| cloning of beta-primeverosidase from tea leaves, a key enzyme in tea aroma formation. | a beta-primeverosidase from tea (camellia sinensis) plants is a unique disaccharide-specific glycosidase, which hydrolyzes aroma precursors of beta-primeverosides (6-o-beta-d-xylopyranosyl-beta-d-glucopyranosides) to liberate various aroma compounds, and the enzyme is deeply concerned with the floral aroma formation in oolong tea and black tea during the manufacturing process. the beta-primeverosidase was purified from fresh leaves of a cultivar for green tea (c. sinensis var sinensis cv yabukit ... | 2002 | 12481100 |
| 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 |
| a mechanism of the thearubigin fraction of black tea (camellia sinensis) extract protecting against the effect of tetanus toxin. | the aim of the present study was to elucidate the mechanism of the protective effect of black tea extract's thearubigin fraction against the action of tetanus toxin. the effects of thearubigin fraction extracted from a black tea infusion were examined for neuromuscular blocking action on tetanus toxin in mouse phrenic nerve-diaphragm preparations and on the binding of this toxin to the synaptosomal membrane preparations of rat cerebral cortices. the interaction between tetanus toxin and thearubi ... | 2002 | 12533914 |
| apoptogenic effects of black tea on ehrlich's ascites carcinoma cell. | next to water, tea is the most ancient and widely consumed beverage in the world. epidemiological studies have suggested a cancer protective effect, but the results obtained so far are not conclusive. in the current study, mechanisms of the apoptogenic effect of black tea extract were delineated. black tea administration to ehrlich's ascites carcinoma (eac)-bearing swiss albino mice caused a significant decrease in the tumor cell count in a dose-dependent manner. flowcytometric analysis showed a ... | 2003 | 12538351 |
| soy phytochemicals and tea bioactive components synergistically inhibit androgen-sensitive human prostate tumors in mice. | although high doses of single bioactive agents may have potent anticancer effects, the chemopreventive properties of the asian diet may result from interactions among several components that potentiate the activities of any single constituent. in asia, where intake of soy products and tea consumption are very high, aggressive prostate cancer is significantly less prevalent in asian men. the objective of the present study was to identify possible synergistic effects between soy and tea components ... | 2003 | 12566493 |
| inhibitory effects of tea and caffeine on uv-induced carcinogenesis: relationship to enhanced apoptosis and decreased tissue fat. | oral administration of green tea or caffeine to hairless skh-1 mice for 2 weeks stimulated uv-induced increases in apoptotic sunburn cells in the epidermis, and a similar effect was observed when caffeine was applied topically immediately after uv. in mice pretreated with uv for 22 weeks (high-risk mice without tumors), topical applications of caffeine 5 days a week for 18 weeks with no further uv treatment inhibited carcinogenesis and stimulated apoptosis in the tumors. oral administration of g ... | 2002 | 12570332 |
| ntp toxicology and carcinogenesis studies of theophylline (cas no. 58-55-9) in f344/n rats and b6c3f1 mice (feed and gavage studies). | theophylline is an alkaloid found in tea (thea sinensis) and chocolate and is structurally related to caffeine and theobromine. theophylline is used as a pharmaceutical agent. it stimulates the heart and central nervous system, relaxes the smooth muscles of the bronchi and blood vessels, and causes diuresis. the drug is used mainly as a bronchodilator in obstructive airway diseases, such as bronchial asthma, and for myocardial stimulation. theophylline was nominated for toxicologic and carcinoge ... | 1998 | 12571677 |
| [experimental studies on antioxidation of extracts from several plants used as both medicines and foods in vitro]. | the scavenging effects of 8 extracts from several plants used as both medicines and foods on oxygen free radicals were studied in vitro. | 2000 | 12575260 |
| buckwheat honey increases serum antioxidant capacity in humans. | honey has been known to exert significant in vitro antioxidant activity, in part due to its phenolic content. however, conclusions that the antioxidants in honey are or are not efficacious in the human body cannot be reached if its antioxidant action is not assessed as part of a human study. in the present study, the acute effect of consumption of 500 ml of water, water with buckwheat honey, black tea, black tea with sugar, or black tea with buckwheat honey on serum oxidative reactions was exami ... | 2003 | 12590505 |
| indonesian medicinal plants. xxv. cancer cell invasion inhibitory effects of chemical constituents in the parasitic plant scurrula atropurpurea (loranthaceae). | six fatty acids (1-6), two xanthines (7, 8), two flavonol glycosides (9, 10), one monoterpene glucoside (11), one lignan glycoside (12), and four flavanes (13-16) were clarified by a bioassay-guided separation as chemical constituents of scurrula atropurpurea (loranthaceae), a parasitic plant of the tea plant thea sinensis (theaceae). among these constituents, it was found that the alkynic fatty acid octadeca-8,10,12-triynoic acid (6) exhibits a more potent inhibitory effect on cancer cell invas ... | 2003 | 12612428 |
| regulation of hazardous exposure by protective exposure: modulation of phase ii detoxification and lipid peroxidation by camellia sinensis and swertia chirata. | many natural compounds are now known to have a modulatory role on physiological functions and biotransformation reactions involved in the detoxification process, thereby affording protection from cytotoxic, genotoxic, and metabolic actions of environmental toxicants. as part of a programme on evaluation of food, beverage, and traditional medicinal plants for their anticarcinogenic activity, their effects on detoxification enzymes were also studied. the present report deals with camellia sinensis ... | 2003 | 12616622 |
| antigenotoxic potential of certain dietary constituents. | the human diet contains a variety of compounds that exhibit chemopreventive effects towards an array of xenobiotics. in the present study, the antigenotoxic potential of selected dietary constituents including diallyl sulfide (das), indole-3-carbinol (i3c), curcumin (cur), and black tea polyphenols (btp) has been evaluated in the salmonella typhimurium reverse mutation and mammalian in vivo cytogenetic assays. in addition, the anticlastogenic effect of the above dietary constituents was identifi ... | 2003 | 12616623 |
| assessment of membrane protection by traditional chinese medicines using a flow cytometric technique: preliminary findings. | in this preliminary study, we used a 'living cell' flow-cytometric approach to membrane protection by four traditional chinese medicines (tcms). cells were incubated, separately, for 30 min with aqueous extracts (1.5% w/v) of lingzhi (ganoderma lucidum), ginger (zingiber officianale), ginseng (panax ginseng), and green tea (camellia sinensis). membranes were labelled with a fluorescent probe, cells were then incubated with cumene hydroperoxide, and site-specific oxidation induced by iron/ascorba ... | 2003 | 12631441 |
| an anticlastogenic in vivo micronucleus assay for tea. | common use of antimutagens and anticarcinogens in everyday life is an effective measure for preventing human cancer and genetic diseases. antioxidant properties of tea have vast potential as protective agents against diverse toxic effects. the present study was aimed to evaluate the role of aqueous clonal tea extracts (green tea, oolong tea and black tea) in modulating the genotoxic damage induced by cyclophosphamide (cp), a commonly used chemotherapeutic drug and a well-known mutagen and clasto ... | 2002 | 12674376 |
| structures of (-)-epicatechin glucuronide identified from plasma and urine after oral ingestion of (-)-epicatechin: differences between human and rat. | (-)-epicatechin is one of the most potent antioxidants present in the human diet. particularly high levels are found in black tea, apples, and chocolate. high intake of catechins has been associated with reduced risk of cardiovascular diseases. there have been several reports concerning the bioavailability of catechins, however, the chemical structure of (-)-epicatechin metabolites in blood, tissues, and urine remains unclear. in the present study, we purified and elucidated the chemical structu ... | 2003 | 12654472 |
| effects of black tea theafulvins on aflatoxin b(1) mutagenesis in the ames test. | black tea theafulvins, a fraction of thearubigins isolated from black tea aqueous infusions, potentiated the mutagenic activity of the mycotoxin aflatoxin b(1) in the ames test, in the presence of a hepatic s9 activation system derived from aroclor 1254-treated rats. in contrast, when the s9 activation system was replaced with isolated microsomes, theafulvins suppressed the mutagenicity of the mycotoxin. when microsomal metabolism was terminated after metabolic activation of the mycotoxin, incor ... | 2003 | 12621070 |
| dna degradation by water extract of green tea in the presence of copper ions: implications for anticancer properties. | in recent years a number of reports have documented the chemopreventive effect of green tea consumption on various types of cancers such as those of bladder, prostate, esophagus and stomach. this property is attributed to the presence in green tea of polyphenols known as catechins. these include epigallocatechin-3-gallate, epigallocatechin and epicatechin. in addition to their antioxidant properties plant derived polyphenolics are also capable of oxidative dna damage particularly in the presence ... | 2003 | 12722140 |
| antidiarrhoeal activity of hot water extract of black tea (camellia sinensis). | the effect of a hot water extract of black tea (camellia sinensis (l.) o. kuntze, theaceae) on upper gastrointestinal transit and on diarrhoea was investigated employing conventional rodent models of diarrhoea. black tea extract was found to possess antidiarrhoeal activity in all the models of diarrhoea used. naloxone (0.5 mg/kg i.p.) significantly inhibited the antidiarrhoeal activity of the extract as well as loperamide, thus indicating a role of the opioid system in the antidiarrhoeal activit ... | 2003 | 12722145 |
| direct reduction of n-acetoxy-phip by tea polyphenols: a possible mechanism for chemoprevention against phip-dna adduct formation. | the chemopreventive effect of tea against 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (phip)-dna adduct formation and its mechanism were studied. rats were exposed to freshly prepared aqueous extracts of green tea (3% (w/v)) as the sole source of drinking water for 10 days prior to administration with a single dose of phip (10 mg/kg body weight) by oral gavage. phip-dna adducts in the liver, colon, heart, and lung were measured using the 32p-postlabelling technique. rats pre-treated with tea ... | 2003 | 12628517 |
| elimination of deleterious effects of free radicals in murine skin carcinogenesis by black tea infusion, theaflavins & epigallocatechin gallate. | in recent years, numerous reports have been published on the identification of novel, naturally occurring antioxidants from plants, animals, microbial sources and processed food products. most natural antioxidants are phenolic compounds, which have a modulatory role on physiological functions and biotransformation reactions involved in the detoxification process, thereby affording protection from cytotoxic, genotoxic and metabolic actions of environmental toxicants. as part of our program on eva ... | 2002 | 12718579 |
| inhibition of cell proliferation and induction of apoptosis during azoxymethane induced colon carcinogenesis by black tea. | tea (camellia sinensis) is one of the most popular beverages, consumed worldwide. the health promoting properties of tea have been attributed to its antioxidative polyphenolic constituents and their oxidative products. the aim of the present study was to evaluate the chemopreventive efficacy of a black tea infusion on azoxymethane induced colonic preneoplastic lesions, the aberrant crypt foci in sprague-dawley rats. rats were injected with azoxymethane (15mg/kg.b.w.) and received oral administra ... | 2002 | 12718607 |
| [effects of tea on aberrant crypt foci and colorectal tumors in rats]. | the present study was designed to investigate the chemopreventive effects of green tea and tea pigments (the main component of black tea) on 1,2-dimethylhydrazine (dmh)-induced rat colorectal carcinogenesis. compared with the positive control group, green tea and tea pigments groups had less numbers of aberrant crypt foci (acf) (p < 0.01) at the end of week 16. at the end of week 32, all rats in the positive control group developed colorectal tumors with an average of 2.6 tumors per rat, and a m ... | 2000 | 12725046 |
| [isolation and determination of an antidote for botulinum neurotoxin from black tea extract]. | the botulinum neurotoxin produced by clostridium botulinum exhibits the strongest neurotoxicity, and causes botulism in mammals. we have found an inactivator for clostridial neurotoxins in black tea extract (thearubigin fraction) as a natural foodstuff. in this study, we have isolated and identified the inactivators. the activity against the neuromuscular blocking action of botulinus neurotoxin type a was examined in mouse phrenic nerve diaphram preparation. the purification procedure of the ina ... | 2002 | 12491801 |
| epigallocatechin-3-gallate selectively inhibits interleukin-1beta-induced activation of mitogen activated protein kinase subgroup c-jun n-terminal kinase in human osteoarthritis chondrocytes. | activation of mitogen activated protein kinases (mapk) is a critical event in pro-inflammatory cytokine-induced signaling cascade in synoviocytes and chondrocytes that lead to the production of several mediators of cartilage damage in an arthritic joint. green tea (camellia sinensis) is a widely consumed beverage and we earlier showed that polyphenols present in green tea (gtp) inhibit the development of inflammation and cartilage damage in an animal model of arthritis. in this study we evaluate ... | 2003 | 12507586 |
| effect of green tea in the prevention and reversal of fasting-induced intestinal mucosal damage. | epidemiologic studies have suggested that high consumption of green tea protects against the development of chronic active gastritis and decreases the risk of stomach cancer. the effect of green tea on the intestinal mucosa was not studied previously, so we examined the effects of green tea on the intestinal mucosa of fasting rats in a controlled experimental setting. | 2003 | 12781855 |
| in vitro inhibition of human cytochrome p450-mediated metabolism of marker substrates by natural products. | spices, herbal and black teas, and soybean products were analyzed for their capacity to inhibit in vitro metabolism of drug marker substrates by human cytochrome p-450 (cyp) isoforms. inhibition of drug metabolism was determined using aliquots or infusions from these products in a fluorescence-detection assay. aliquots and infusions of all natural product categories inhibited 3a4 metabolism to some extent. of the 26 aliquots from teas and spices further tested with 2c9, 2c19 and 2d6, many demons ... | 2003 | 12809364 |
| hepatic and intestinal cytochrome p450 and conjugase activities in rats treated with black tea theafulvins and theaflavins. | theaflavins and theafulvins, a fraction of thearubigins, were isolated from aqueous infusions of black tea, and their effects on the hepatic and intestinal cytochrome p450 system, and on the glutathione s-transferase, epoxide hydrolase, glucuronosyl transferase and sulphotransferase enzyme systems were investigated in rats following oral intake for four weeks. neither theafulvins nor theaflavins influenced cytochrome p450 activity in the liver as exemplified by the o-dealkylations of methoxy-, e ... | 2003 | 12842182 |
| antioxidant activity of a botanical extract preparation of ilex paraguariensis: prevention of dna double-strand breaks in saccharomyces cerevisiae and human low-density lipoprotein oxidation. | we analyzed the antioxidant properties of ilex paraguariensis infusion (ip) popularly known as mate (mä'tā), by using two experimental models: the induction of dna double-strand breaks (dsb) by hydrogen peroxide (h(2)o(2)) and lethality in saccharomyces cerevisiae, as well as peroxide and lipoxygenase-induced human low-density lipoprotein (ldl) oxidation. diploid yeast cells were exposed to different concentrations of h(2)o(2) (5-10 mmol/l) in the absence or presence of ip infusion (10(-1) v/v) ... | 2003 | 12816626 |
| black tea prevents cigarette smoke-induced oxidative damage of proteins in guinea pigs. | cigarette smoke (cs) causes oxidative damage and tea polyphenols have strong antioxidant properties. therefore, we studied the effect of a black tea (bt) infusion on cs-induced oxidative damage of proteins both in vitro and in vivo. in the in vitro experiment, bovine serum albumin (bsa) or a guinea pig tissue microsomal suspension was incubated with an aqueous extract of cs (cs-solution) in the presence or absence of the bt infusion. protein oxidation was measured by immunoblotting of the dinitr ... | 2003 | 12888648 |
| suppression of fatty acid synthase in mcf-7 breast cancer cells by tea and tea polyphenols: a possible mechanism for their hypolipidemic effects. | tea is a heavily consumed beverage world wide because of its unique aroma, less cost and broad availability. fatty acid synthase (fas) is a key enzyme in lipogenesis. fas is overexpressed in the malignant human breast carcinoma mcf-7 cells and its expression is further enhanced by the epidermal growth factor (egf). the egf-induced expression of fas was inhibited by green and black tea extracts. the expression of fas was also suppressed by the tea polyphenol (-)-epigallocatechin 3-gallate (egcg), ... | 2003 | 12931129 |
| phenolic acid metabolites as biomarkers for tea- and coffee-derived polyphenol exposure in human subjects. | tea and coffee are rich in polyphenols with a variety of biological activities. many of the demonstrated activities are consistent with favourable effects on the risk of chronic diseases. 4-o-methylgallic acid (4omga) and isoferulic acid are potential biomarkers of exposure to polyphenols derived from tea and coffee respectively. 4omga is derived from gallic acid in tea, and isoferulic acid is derived from chlorogenic acid in coffee. our major objective was to explore the relationships of tea an ... | 2004 | 14756917 |
| tea can protect against aberrant crypt foci formation during azoxymethane induced rat colon carcinogenesis. | tea shows many health promoting activities including chemopreventive action during carcinogenesis due to the presence of antioxidative polyphenolic constituents. the present experiment evaluated the anticarcinogenic role of black tea infusion on azoxymethane induced colonic preneoplastic lesions, the aberrant crypt foci in sprague-dawley rats. rats were injected with azoxymethane (15 mg/kg b.w.) and received oral administration of 1% and 2% (w/v) tea infusions from first day of carcinogen applic ... | 2003 | 12866568 |
| screening of chemopreventive tea polyphenols against pah genotoxicity in breast cancer cells by a xre-luciferase reporter construct. | polycyclic aromatic hydrocarbons (pahs) are established cancer initiators that can be found in our food and environment. some dietary plant polyphenols are strong inhibitors to pah-induced mutagenesis, whereas others may not be as effective. to identify the chemopreventive compounds from a huge volume of dietary components, the development of an efficient screening method is required. in this study, a xenobiotic response element (xre)-luciferase reporter plasmid was constructed to screen for som ... | 2003 | 12925309 |
| the prevalence of tongue lesions in 5150 turkish dental outpatients. | the aim of this study was to assess the prevalence of nine tongue conditions and relate to data obtained about oral hygiene or habits in turkish dental outpatients. | 2003 | 12974518 |
| characterization of corrinoid compounds from a japanese black tea (batabata-cha) fermented by bacteria. | a japanese fermented black tea (batabata-cha) contained a considerable amount of vitamin b(12) (456 +/- 39 ng per 100 g dry tea leaves and 2.0 +/- 0.3 ng per 100 ml of tea drink). a corrinoid compound was partially purified and characterized from the tea leaves. the patterns of the purified compound by the silica gel 60 thin-layer chromatography and c18 reversed phased high-performance liquid chromatography were identical to those of authentic vitamin b(12). when 20 week old vitamin b(12) defici ... | 2004 | 14969549 |
| mechanisms of cancer prevention by tea constituents. | consumption of tea (camellia sinensis) has been suggested to prevent cancer, heart disease and other diseases. animal studies have shown that tea and tea constituents inhibit carcinogenesis of the skin, lung, oral cavity, esophagus, stomach, liver, prostate and other organs. in some studies, the inhibition correlated with an increase in tumor cell apoptosis and a decrease in cell proliferation. studies with human cancer cell lines have demonstrated that epigallocatechin-3-gallate (egcg), a major ... | 2003 | 14519824 |
| antioxidant effects of tea: evidence from human clinical trials. | tea remains the most consumed drink in the world after water, well ahead of coffee, beer, wine and carbonated soft drinks. an accumulated number of population studies suggests that consumption of green and black tea beverages may bring positive health effects (1). one hypothesis explaining such effects is that the high levels of flavonoids in tea can protect cells and tissues from oxidative damage by scavenging oxygen-free radicals. chemically, the flavonoids found in green and black tea are ver ... | 2003 | 14519827 |
| antimutagenic effects of black tea in the salmonella typhimurium reverse mutation assay. | black tea (camellia sinensis) is one of the most widely consumed beverages worldwide. its chemopreventive effects are well documented in the literature. in the present set of investigations antimutagenic effects of aqueous black tea extract (ate) and black tea polyphenols (btp) were evaluated in the ames test using salmonella typhimurium tester strains ta 98 and ta 100. addition of benzo(a)pyrene (bap) and cyclophosphamide (cp), two well known mutagens, at the concentrations of 20 and 15 microg/ ... | 2003 | 14507238 |
| modulation of arsenic induced cytotoxicity by tea. | arsenic, a naturally ocurring chemical element, is considered hazardous to human health. inorganic arsenic compounds were found to induce cytotoxicity in chinese hamster v-79 cells in culture. the arsenite form was more toxic than arsenate. extracts of green and two varieties of black tea, as well as their principal polyphenols, (-)-epigallocatechingallate and theaflavin, efficiently counteracted the cytotoxic effects of arsenic compounds. on the basis of the amount of tea extract that afforded ... | 2003 | 14507244 |
| catechin attenuates 6-hydroxydopamine (6-ohda)-induced cell death in primary cultures of mesencephalic cells. | past studies have shown the protective effects of tea catechins on oxidative cell damage induced by 6-ohda in pc12 cells. in this study we verified whether or not catechin prevents 6-ohda-induced oxidative cell damage in primary cultures of rat mesencephalic cells. on exposure to 6-ohda (200 microm), the cultures showed a marked decrease in cell viability, disturbances in lipid peroxidation, and an increased generation of no, as assayed by mtt, tbars and nitrite assays, respectively. introductio ... | 2003 | 14559299 |
| green tea polyphenol epigallocatechin-3-gallate (egcg) differentially inhibits interleukin-1 beta-induced expression of matrix metalloproteinase-1 and -13 in human chondrocytes. | interleukin-1beta (il-1beta)-induced inflammatory response in arthritic joints include the enhanced expression and activity of matrix metalloproteinases (mmps), and their matrix degrading activity contribute to the irreversible loss of cartilage and may also be associated with sustained chronic inflammation. we have earlier shown that green tea (camellia sinensis) polyphenol epigallocatechin-3-gallate (egcg) was non-toxic to human chondrocytes [singh r, ahmed s, islam n, goldberg vm, and haqqi t ... | 2004 | 14600251 |
| tea intake, comt genotype, and breast cancer in asian-american women. | there is substantial in vitro and in vivo evidence implicating tea polyphenols as chemopreventive agents against various cancers. in a case-control study conducted among asian-american women in los angeles county, we reported a significant inverse relationship between intake of green tea and risk of breast cancer (a. h. wu et al., int. j. cancer, 106: 574-579, 2003). because catechol-containing tea polyphenols are very rapidly o-methylated by human catechol-o-methyltransferase (comt), we are int ... | 2003 | 14612555 |
| modulation of beta-lactam resistance in staphylococcus aureus by catechins and gallates. | aqueous extracts of japanese green tea (camellia sinensis) are able to reverse beta-lactam resistance in methicillin-resistant staphylococcus aureus (mrsa). we have attributed the capacity to reverse oxacillin resistance in the homogeneous pbp2a producer bb568 and in emrsa-16 to (-)-epicatechin gallate (ecg) and (-)-catechin gallate (cg). minimum inhibitory concentration (mic) values for oxacillin were reduced from 256 and 512 to 1-4 mg/l, respectively, in the presence of these polyphenols. in a ... | 2004 | 15120724 |
| combined inhibition of estrogen-dependent human breast carcinoma by soy and tea bioactive components in mice. | breast cancer is significantly less prevalent among asian women, whose diets contain high intake of soy products and tea. the objective of our present study was to identify the combined effects of dietary soy phytochemicals and tea components on breast tumor progression in a clinically relevant in vivo model of mcf-7 androgen-dependent human breast tumor in female scid mice. mcf-7 tumor growth, tumor cell proliferation and apoptosis, microvessel density, and expressions of tumor estrogen recepto ... | 2004 | 14618609 |
| cancer prevention by tea polyphenols is linked to their direct inhibition of antiapoptotic bcl-2-family proteins. | epidemiological data and in vitro studies on cancer chemoprevention by tea polyphenols have gained attention recently from the scientific community, nutritionists, the pharmaceutical industry, and the public. despite the several efforts made recently to elucidate the molecular basis for the anticancer activity of these natural products, little correlation has been found thus far between the putative protein targets of compounds found in tea extracts and levels found in plasma after tea consumpti ... | 2003 | 14678963 |
| tea polyphenols regulate nicotinamide adenine dinucleotide phosphate oxidase subunit expression and ameliorate angiotensin ii-induced hyperpermeability in endothelial cells. | out-of-control reactive oxygen species (ros) signaling is one of the key events in the pathogenesis of endothelial dysfunction and essential hypertension. we observed that tea polyphenols decreased the production of ros via regulation of the protein expression of nicotinamide adenine dinucleotide phosphate (nadph) oxidase in bovine carotid artery endothelial cells (bcaecs). both green tea polyphenols (gtp) and black tea polyphenols (btp) down-regulated the expression of nadph oxidase subunits p2 ... | 2003 | 14621186 |
| the impact of ph and calcium on the uptake of fluoride by tea plants (camellia sinensis l.). | tea plants (camellia sinensis l.) accumulate large amounts of fluoride (f) from soils containing normal f concentrations. the present experiments examined the effects of ph and ca on f uptake by this accumulating plant species. | 2004 | 14644914 |
| epigallocatechin-3-gallate is absorbed but extensively glucuronidated following oral administration to mice. | epigallocatechin-3-gallate (egcg), the most abundant catechin in green tea (camellia sinensis), has shown cancer preventive activity in animal models. the bioavailability of egcg in the most commonly used animal species, mice, is poorly understood. moreover, the pharmacokinetic parameters of egcg have not been reported previously in mice. here we report that after administration of egcg intravenously at 21.8 micro mol/kg or intragastrically at 163.8 micro mol/kg, the peak plasma levels of egcg i ... | 2003 | 14652367 |
| influence of tea on intrinsic colour of previously bleached enamel. | aim of the study was to evaluate the influence of tea applied at various time intervals after bleaching of enamel on intrinsic tooth colour. ninety bovine specimens were distributed among six groups (a-f, n=15). the samples of group a-d were bleached with the 10% carbamide peroxide (cp) gel vivastyle for 8 h, followed by storing in artificial saliva for the remaining period of the day. the specimens were removed from the saliva at different intervals (a: 0 min, b: 60 min, c: 240 min) and immerse ... | 2003 | 12752928 |
| selective inhibition of adamts-1, -4 and -5 by catechin gallate esters. | three mammalian adamts enzymes, adamts-1, -4 and -5, are known to cleave aggrecan at certain glutamyl bonds and are considered to be largely responsible for cartilage aggrecan catabolism observed during the development of arthritis. we have previously reported that certain catechins, polyphenolic compounds found in highest concentration in green tea (camellia sinensis), are capable of inhibiting cartilage aggrecan breakdown in an in vitro model of cartilage degradation. we have now cloned and ex ... | 2003 | 12755694 |
| black and green tea polyphenols attenuate blood pressure increases in stroke-prone spontaneously hypertensive rats. | oxidative stress was reported to be involved not only in cardiovascular diseases, but also in hypertension. epidemiologic studies indicated that tea consumption slightly reduces blood pressure. we conducted two studies to determine whether black and green tea can lower blood pressure (bp) in stroke-prone spontaneously hypertensive rats (shrsp). male shrsp (n=15) were allowed to recover for 2 wk after a transmitter for measuring bp was implanted in the peritoneal cavity. the rats were divided int ... | 2004 | 14704290 |
| ros-related enzyme expressions in endothelial cells regulated by tea polyphenols. | elevation of reactive oxygen species (ros), especially the level of superoxide is a key event in many forms of cardiovascular diseases. to study the mechanism of tea polyphenols against cardiovascular diseases, we observed the expressions of ros-related enzymes in endothelial cells. | 2004 | 15202862 |
| modulation of phosphatidylinositol-3-kinase/protein kinase b- and mitogen-activated protein kinase-pathways by tea polyphenols in human prostate cancer cells. | we have earlier shown that oral infusion of a polyphenolic fraction isolated from green tea, at a human achievable dose (equivalent to six cups of green tea per day), significantly inhibits prostate cancer (pca) development and metastasis in transgenic adenocarcinoma of mouse prostate (tramp) model that closely mimics progressive form of human prostatic disease (gupta et al. [2001]: proc. natl. acad. sci. u.s.a. 98:10350-10355.). a complete understanding of the mechanism(s) and molecular targets ... | 2004 | 14743383 |
| effects of a controlled diet and black tea drinking on the fecal microflora composition and the fecal bile acid profile of human volunteers in a double-blinded randomized feeding study. | although diet has been clearly associated with human health many potential mechanisms remain undefined. for instance, although the intestinal bacterial microflora has long been postulated to contribute to human health, little is known about the effects of diet on the bacterial microflora composition and the specific contributions of the microflora to human health. thus, we analyzed 1) changes in the fecal microflora composition by fluorescent in-situ hybridization (fish) and denaturing gradient ... | 2004 | 14747691 |
| iron bioavailability and weight gains to iron-deficient rats fed a commonly consumed tunisian meal 'bean seeds ragout' with or without beef and with green or black tea decoction. | the fe bioavailability and the weight gains were evaluated in rats fed a commonly consumed tunisian meal 'bean seeds ragout' (bsr), with or without beef and with black or green tea decoction. the fe bioavailability was evaluated in fe-deficient rats by the hemoglobin repletion method and the fe stored in the liver. the addition of beef to the bsr significantly increased the fe bioavailability from this meal by 147% and the reserve of fe stored in the liver by 77% (p < 0.001). in contrast, both b ... | 2003 | 14968927 |
| metabolite profiling using (1)h nmr spectroscopy for quality assessment of green tea, camellia sinensis (l.). | a set of 191 green teas from different countries was collected and analyzed by (1)h nmr. it was proposed to establish if the teas could be discriminated according to the country of origin or with respect to quality. both principal component analysis (pca) and cluster analysis were applied to the data. some separation of chinese and non-chinese teas was observed. the present results did not allow allocation of samples to individual countries, but cluster analysis suggested that it might be possib ... | 2004 | 14969518 |
| inhibitory effects on phospholipase a2 and antivenin activity of melanin extracted from thea sinensis linn. | antivenin activity of melanin extracted from black tea (mebt) was reported for the first time. the antagonistic effect of mebt was evaluated for agkistrodon contortrix laticinctus (broadbanded copperhead), agkistrodon halys blomhoffii (japanese mamushi), and crotalus atrox (western diamondback rattlesnake) snake venoms administered i.p. to icr mice. mebt was injected i.p. immediately after the venom administration in dose of 3 mg per mouse in the same place of venom injection. mebt demonstrated ... | 2004 | 14967198 |
| comparison of cytotoxicity and radical scavenging activity between tea extracts and chinese medicines. | three hot water extracts of black tea, green tea and powdered green tea and five chinese medicines (shosaiko-tou, orengedoku-tou, goshuyu-tou, choto-san, keishininjinn-tou) were investigated for their ability to modify nitric oxide (no) production by lipopolysaccharide (lps)-stimulated mouse macrophage-like raw 264.7 cells, and for their cytotoxicity, radical intensity and scavenging activity. all eight materials significantly reduced the extracellular concentration of no in the lps-stimulated r ... | 2003 | 14758724 |
| anti-inflammatory activity of tea (camellia sinensis) root extract. | pharmacological studies were carried out with methanol-water (1:1) extract of dried tea (camellia sinensis) root extract (tre). tre was found to possess anti-inflammatory, analgesic and antipyretic activities at 1/10th of its ld50 dose of 100 mg/kg i.p. it was found that tre inhibited the arachidonic acid-induced paw oedema in rats which indicated that tre produced the anti-inflammatory activity by inhibiting both the cyclooxygenase and lypooxygenase pathways of arachidonic acid metabolism. tre ... | 2004 | 14761665 |
| antioxidants in chinese herbal medicines: a biochemical perspective. | recently, intense interest has focused on the antioxidant properties of natural products. in particular, chinese herbal medicines (chm) have become hot topics for life science researchers since many are reported to possess cardioprotective compounds, many of which remain to be identified. indeed, the exact mechanisms by which chm work remain unknown. although many of these herbal remedies are undoubtedly efficacious, few have been scientifically investigated for their active chemical constituent ... | 2004 | 15282631 |
| inhibitory effects of green tea polyphenols on the production of a virulence factor of the periodontal-disease-causing anaerobic bacterium porphyromonas gingivalis. | the effect of polyphenolic compounds isolated from green tea (camellia sinensis) on the production of toxic end metabolites of porphyromonas gingivalis was investigated. green tea polyphenols completely inhibited the production of n-butyric acid and propionic acid at a concentration of 1.0-2.0 mg/ml in general anaerobic medium (gam). (-)-epigallocatechin gallate (egcg), which is a major component of tea polyphenols also inhibited the production of phenylacetic acid at 0.5 mg/ml in gam broth. in ... | 2004 | 15030231 |
| dietary habits and cancer mortality among middle aged and older japanese living in hokkaido, japan by cancer site and sex. | dietary factors are thought to be closely associated with the development of human cancers and hence numerous studies in this area have already been conducted in the united states and other western countries. comparatively few prospective studies have been published in japan, especially for hokkaido people. the present investigation was therefore performed to assess links between four leading cancers and some of the japanese common dietary factors through a cohort study (1984-2002) in hokkaido b ... | 2004 | 15075007 |
| tea polyphenols inhibit acetyl-coa:1-alkyl-sn-glycero-3-phosphocholine acetyltransferase (a key enzyme in platelet-activating factor biosynthesis) and platelet-activating factor-induced platelet aggregation. | tea extracts have antiallergic and anti-inflammatory actions in rats and mice. however the mechanism through which tea polyphenols act in vivo are still incompletely understood. we found inhibitory effects of black tea extracts on an fmlp-induced aggregating response in a rabbit platelet-polymorphonuclear leukocyte (pmn) system. | 2004 | 15051936 |
| short-term black tea intake modulates the excretion of urinary mutagens in rats treated with 2-amino-3-methylimidazo-[4,5-f]quinoline (iq): role of cyp1a2 upregulation. | rats were exposed to black tea (2.5% w/v) as their sole drinking liquid for either 1 day or 1 month, while controls were maintained on water. after this treatment period, all animals received a single oral dose iq (2-amino-3-methylimidazo-[4,5-f]quinoline), and urine was collected for 48 h. mutagenic activity of the urine was determined in the ames test in the presence and absence of an activation system. the excretion of direct-acting mutagens was markedly reduced following tea intake, and was ... | 2004 | 15034640 |
| ex vivo modulation of chemical-induced mutagenesis by subcellular liver fractions of rats treated with rooibos (aspalathus linearis) tea, honeybush (cyclopia intermedia) tea, as well as green and black (camellia sinensis) teas. | male fischer rats were given unprocessed (not oxidized) and processed (oxidized) rooibos and honeybush teas as well as green and black teas as a sole source of drinking fluid for 10 weeks, and sub cellular liver fractions were prepared. cytosolic fractions of rats consuming the unprocessed herbal teas, green and black teas significantly (p < 0.05) protected against 2-acetylaminofluorene (2-aaf)-induced mutagenesis in the salmonella mutagenicity test with strain ta 98, using aroclor 1254-induced ... | 2004 | 15036128 |
| screening for antioxidant activity in edible plant products: comparison of low-density lipoprotein oxidation assay, dpph radical scavenging assay, and folin-ciocalteu assay. | oxidation of low-density lipoprotein (ldl) has been implicated in atherogenesis. antioxidants that prevent ldl from oxidizing may reduce atherosclerosis. this study investigated ldl antioxidant activity in edible plant products for development of dietary supplementation to prevent atherosclerosis. fifty-two kinds of edible plants were extracted using 70% aqueous ethanol solution, and the antioxidant activity of the extracts, which inhibit human ldl oxidation induced by copper ion, was determined ... | 2004 | 15080652 |
| flavonoids from argentine tagetes (asteraceae) with antimicrobial activity. | the flavonoids, constituting one of the most numerous and widespread groups of natural plant constituents, are important to humans not only because they contribute to plant colors but also because many members are physiologically active. these low-molecular-weight substances, found in all vascular plants, are phenylbenzopyrones. over 4000 structures have been identified in plant sources, and they are categorized into several groups. primarily recognized as pigments responsible for the autumnal b ... | 2004 | 15156042 |
| strong inhibitory effects of common tea catechins and bioflavonoids on the o-methylation of catechol estrogens catalyzed by human liver cytosolic catechol-o-methyltransferase. | in the present investigation, we studied the inhibitory effects of three tea catechins [catechin, epicatechin, and (-)-epigallocatechin-3-o-gallate] and two bioflavonoids (quercetin and fisetin) on the o-methylation of 2- and 4-hydroxyestradiol (2-oh-e(2) and 4-oh-e(2), respectively) by human liver cytosolic catechol-o-methyltransferase (comt). we found that catechin and epicatechin each inhibited the o-methylation of 2-oh-e(2) and 4-oh-e(2) in a concentration-dependent manner. the ic(50) values ... | 2004 | 15100171 |
| antioxidants of the beverage tea in promotion of human health. | tea that contains many antioxidants is a pleasant and safe drink that is enjoyed by people across the globe. tea leaves are manufactured as black, green, or oolong. black tea represents approximately 78% of total consumed tea in the world, whereas green tea accounts for approximately 20% of tea consumed. the concept of "use of tea for promotion of human health and prevention and cure of diseases" has become a subject of intense research in the last decade. diseases for which tea drinkers appear ... | 2004 | 15130283 |
| inhibitory effect of some herbal extracts on adherence of streptococcus mutans. | the objective of this study was to investigate the inhibitory effect of the crude extracts from some herbs on adherence of streptococcus mutans (s. mutans) atcc 25175 and tpf-1 in vitro. six herbs, andrographis paniculata; cassia alata; chinese black tea (camellia sinensis); guava (psidium guajava); harrisonia perforata and streblus asper, were extracted with 50 or 95% ethanol and dried. herbal extracted solution at 0.5% concentration (w/v) was initially tested for bacterial adherence on glass s ... | 2004 | 15138013 |
| black tea protects immunocytes from tumor-induced apoptosis by changing bcl-2/bax ratio. | it is known that cancer is associated with altered immune function. we demonstrated earlier that black tea inhibits tumor growth in a dose-dependent manner. here, we report that apoptosis was the cause of immunocyte death in ehrlich's ascites carcinoma (eac)-bearing mice and anti-tumor dose of black tea restored eac-induced immunosuppression by inhibiting apoptosis. a search for the molecular mechanism revealed that eac burden increased the expression of the pro-apoptotic proteins p53 and bax in ... | 2004 | 15159016 |
| anti-trypanosoma cruzi activity of green tea (camellia sinensis) catechins. | the trypanocidal action of green tea catechins against two different developmental stages of trypanosoma cruzi is reported for the first time. this activity was assayed with the nonproliferative bloodstream trypomastigote and with the intracellular replicative amastigote parasite forms. an ethyl acetate fraction from camellia sinensis green tea leaves, which contains most of the polyphenolic compounds and the maximal trypanocidal activity, was obtained by fractionation of the aqueous extract wit ... | 2004 | 14693520 |
| identification of the astringent taste compounds in black tea infusions by combining instrumental analysis and human bioresponse. | application of taste dilution analyses on freshly prepared black tea infusions revealed neither the high molecular weight thearubigen-like polyphenols nor the catechins and theaflavins, but a series of 14 flavon-3-ol glycosides as the main contributors to the astringent taste perceived upon black tea consumption. among these glycosides, the apigenin-8-c-[alpha-l-rhamnopyranosyl-(1-->2)-o-beta-d-glucopyranoside] was identified for the first time in tea infusions. depending on the structure, the f ... | 2004 | 15161222 |
| polyphenolic compounds, antioxidant capacity, and quinone reductase activity of an aqueous extract of ardisia compressa in comparison to mate (ilex paraguariensis) and green (camellia sinensis) teas. | aqueous extracts of the leaves of ardisia compressa (ac) have been used in folk medicine to treat various liver disorders including liver cancer. the objective of this study was to partially characterize and determine the total polyphenol content, antioxidant capacity, and quinone reductase activity of a. compressa tea in comparison to mate (ilex paraguariensis, mt) and green (camellia sinensis,gt) teas. total polyphenol content, antioxidant capacity, and phase ii enzyme induction capacity were ... | 2004 | 15161234 |
| modulation of hepatic drug metabolizing enzymes and oxidative status by rooibos (aspalathus linearis) and honeybush (cyclopia intermedia), green and black (camellia sinensis) teas in rats. | rooibos and honeybush teas significantly (p < 0.05) enhanced the activity of cytosolic glutathione s-transferase alpha. a significant (p < 0.05) to marginal (p < 0.1) increase in the activity of the microsomal udp-glucuronosyl transferase was obtained with unprocessed rooibos and honeybush teas, respectively. oxidized glutathione (gssg) levels were significantly (p < 0.05) reduced in the liver of all tea treated rats while reduced glutathione (gsh) was markedly increased in the liver of the herb ... | 2003 | 14690405 |
| inhibition of lung carcinogenesis and effects on angiogenesis and apoptosis in a/j mice by oral administration of green tea. | oral administration of tea (camellia sinensis) has been shown to inhibit the formation and growth of several tumor types in animal models. the present study investigated the effects of treatment with different concentrations of green tea on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (nnk)-induced lung tumorigenesis in female a/j mice. two days after a single dose of nnk (100 mg/kg body weight, i.p.), the mice were given 0.1, 0.2, 0.4, and 0.6% green tea solution (1, 2, 4, and 6 g of tea soli ... | 2004 | 15203377 |
| inhibitory effect(s) of polymeric black tea polyphenol fractions on the formation of [(3)h]-b(a)p-derived dna adducts. | five polymeric black tea polyphenol fractions (pbp-1-5) were isolated from a popular brand of black tea. the effect of these pbps and epigallocatechin gallate (egcg), a major green tea polyphenol, was studied on the formation of [(3)h]-b(a)p-derived dna adducts in vitro, employing rat liver microsomes. pbp-1-3 inhibited microsome-catalyzed [(3)h]-b(a)p-derived dna adduct formation in vitro in a dose-dependent manner. this inhibition was further enhanced on preincubation of microsomes with each o ... | 2004 | 15212478 |
| fluoride content in tea and its relationship with tea quality. | the tea plant is known as a fluorine accumulator. fluoride (f) content in fresh leaves collected from 14 plantations in china was investigated. the f increased with maturity, and the f variation was remarkable in the tender shoots. furthermore, significant negative relationships were observed between f content and the content of the quality parameters total polyphenols and amino acids. these substances are rich in young leaves and poor in mature ones. with regard to quality of tea products, the ... | 2004 | 15237954 |
| caffeine in tea plants [camellia sinensis (l) o. kuntze]: in situ lowering by bacillus licheniformis (weigmann) chester. | tea plants (camellia sinensis) contain 5-6% caffeine that is responsible for the stimulating effect of the beverage. as the tolerance to caffeine varies among individuals, low caffeine tea would be an ideal alternative. while assessing the potential of a few selected bacteria-bacillus licheniformis, b. subtilis and b. firmus, to multiply on nutrient medium supplemented with glucose (5%) and tea leaf extract (2%), it was observed that only b. licheniformis could proliferate on this medium. hence, ... | 2004 | 15260108 |
| increased microbicidal activity of green tea (camellia sinensis) in combination with butylated hydroxyanisole. | we have demonstrated that green tea (camellia sinensis) shows increased antimicrobial activity against bacteria and fungi when used in combination with butylated hydroxyanisole (bha). glycolic extract taken from green tea showed only limited activity against streptococcus mutans and no activity against candida albicans and certain strains of escherichia coli. bha, at non inhibitory concentrations, increased the microbicidal activity of green tea against 10(10) s. mutans (p<0.01), non-susceptible ... | 2004 | 15216944 |
| piperine enhances the bioavailability of the tea polyphenol (-)-epigallocatechin-3-gallate in mice. | (-)-epigallocatechin-3-gallate (egcg), from green tea (camellia sinensis), has demonstrated chemopreventive activity in animal models of carcinogenesis. previously, we reported the bioavailability of egcg in rats (1.6%) and mice (26.5%). here, we report that cotreatment with a second dietary component, piperine (from black pepper), enhanced the bioavailability of egcg in mice. intragastric coadministration of 163.8 micromol/kg egcg and 70.2 micromol/kg piperine to male cf-1 mice increased the pl ... | 2004 | 15284381 |
| evidence for a prospective anti-osteoporosis effect of black tea (camellia sinensis) extract in a bilaterally ovariectomized rat model. | the purpose of this study was to examine whether whole aqueous black tea extract (bte) prevents bone loss induced by ovarian hormone deficiency. eighteen 95-100 days old female albino rats were randomly assigned to three treatment groups [sham -operated control (sham); bilaterally ovariectomized (ovx) and ovx + aqueous black tea extract (bte) ] and sacrificed after 28 days. all animals were fed a standard laboratory diet with free access to deionized water except on days of urinary parameter stu ... | 2004 | 15228990 |
| green and black teas inhibit atherosclerosis by lipid, antioxidant, and fibrinolytic mechanisms. | tea is the most widely consumed beverage in the world, second only to water. most laypersons and scientists believe that green tea is healthier than black tea due to the low incidence of heart disease and cancer in the orient. here, we report the first dose-response comparison of a green and black tea on normal hamsters after long-term supplementation and on a hamster model of atherosclerosis. both teas were equally effective in inhibiting atherosclerosis with the lower dose decreasing it 26-46% ... | 2004 | 15161246 |
| green tea flavan-3-ols and oligomeric proanthocyanidins inhibit the motility of infective larvae of teladorsagia circumcincta and trichostrongylus colubriformis in vitro. | the effects of a hot water infusion and an aqueous acetone extract of green tea (camellia sinensis) on the motility of infective larvae of the sheep nematodes teladorsagia circumcincta and trichostrongylus colubriformis were investigated under in vitro conditions. the infusion and extract dose-dependently inactivated the infective larvae as assessed by the larval migration inhibition (lmi) assay. to determine the components responsible for the inhibitory activity, the hot water infusion and aque ... | 2004 | 15276775 |
| preventive effect of thea sinensis melanin against acetaminophen-induced hepatic injury in mice. | the preventive effect of thea sinensis melanin (tsm) against overdoses of n-acetyl-p-aminophenol (napap) was studied on icr mice. animals were given 400 mg/kg intraperitoneally (i.p.) of napap, and tsm was injected i.p. in doses 10-40 mg/kg 2 h before intoxication. the protective effects were evidenced by a complete blockage of the napap-induced elevation of plasma alanine aminotransferase (alt) activity, decreased concentration of thiobarbituric acid reactive substances (tbars) to the control l ... | 2004 | 15291509 |
| antibacterial effect of water-soluble tea extracts on foodborne pathogens in laboratory medium and in a food model. | the microbial inhibition of foodborne pathogens was determined in brain heart infusion broth with 10% (wt/vol) water-soluble extracts of green, jasmine, black, dungglre, and oolong tea against escherichia coli o157:h7, salmonella enterica serovar enteritidis, listeria monocytogenes, and staphylococcus aureus. the mixed culture (approximately 6.0 log cfu/ml), which was composed of the four pathogens, was inoculated into brain heart infusion broth with and without tea extracts. after incubation at ... | 2004 | 15553649 |
| total phenolics and antioxidant activities of fenugreek, green tea, black tea, grape seed, ginger, rosemary, gotu kola, and ginkgo extracts, vitamin e, and tert-butylhydroquinone. | the total phenolics and antioxidant activities of fenugreek, green tea, black tea, grape seed, ginger, rosemary, gotu kola, and ginkgo extracts, vitamin e, and tert-butylhydroquinone, were determined. grape seed and green tea were analyzed for their phenolic constituents using high-performance liquid chromatography. the total phenolics of the plant extracts, determined by the folin-ciocalteu method, ranged from 24.8 to 92.5 mg of chlorogenic acid equivalent/g dry material. the antioxidant activi ... | 2004 | 15291494 |
| heavy metals in black tea samples produced in turkey. | | 2004 | 15200002 |
| inhibition of interleukin-1beta-stimulated collagenase and stromelysin expression in human tendon fibroblasts by epigallocatechin gallate ester. | the medicinal benefits of green tea (camellia sinensis) consumption have been attributed to bioavailable polyphenols, notably epigallocatechin gallate (egcg). we have assessed the effects of egcg and its non-esterified counterpart egc on the expression of the collagenases, matrix metalloproteinases (mmp)-1 and -13, and the stromelysin, mmp-3, in human tendon-derived fibroblasts. interleukin (il)-1beta increased mmp-1, -3 and -13 mrna and output at least 30-fold. egcg reduced this stimulation, by ... | 2004 | 15296944 |
| determination of fumonisins b1 and b2 in herbal tea and medicinal plants in turkey by high-performance liquid chromatography. | the purpose of this study was to measure the potential levels of fumonisin b1 (fb1) and fumonisin b2 (fb2) contamination in several herbal teas and medicinal plants that are consumed regularly in turkey. fb1 and fb2 were detected using high-performance liquid chromatography with fluorescence detection after derivatization with o-phthaldialdehyde. a total of 115 commercially available herbal tea and medicinal plant samples were analyzed. the recoveries in black tea were 86.9+/-8.42% for fb1 and 1 ... | 2004 | 15330551 |
| [test for urokinase-type plasminogen activator inhibitor of edible plants in vitro]. | to study the effect of anti-progression activity of edible plants using urokinase as the biomarker. | 2004 | 15312585 |
| green tea (camellia sinensis) extract does not alter cytochrome p450 3a4 or 2d6 activity in healthy volunteers. | green tea extract is a widely used dietary supplement. the objective of this study was to assess the influence of a decaffeinated green tea (dgt; camellia sinensis) extract on the activity of the drug-metabolizing enzymes cytochrome p-450 2d6 and 3a4. probe drugs dextromethorphan (30 mg, cyp2d6 activity) and alprazolam (alpz; 2 mg, cyp3a4 activity) were administered orally to healthy volunteers (n = 11) at baseline, and again after treatment with four dgt capsules/day for 14 days. each dgt capsu ... | 2004 | 15319329 |
| preventive effect of traditional herbal formulae against experimental hypercholesterolemia in rats with special reference to blood lipoprotein cholesterol levels. | to investigate the effect of traditional herbal formulae (zhong yao) against experimental hypercholesterolemia, we assayed serum lipoprotein levels and hepatic function in rats administered herbal formulae under cholesterol rich diet. two kinds of herbal formulae; prescription 1 (bupleurum chinense and other 9 kinds of herbs) and 2 (camellia sinensis and other 5 kinds of herbs) were prepared. all of 35 rats were separated into 4 groups, group p fed under cholesterol rich diet for 15 days and adm ... | 2004 | 15325730 |
| activation of endothelial nitric-oxide synthase by the p38 mapk in response to black tea polyphenols. | black tea improves endothelial function in patients with coronary artery disease. we sought to determine the responsible components of black tea and elucidate the underlying cell signaling mechanisms. we exposed porcine aortic endothelial cells to components of black tea and found that the polyphenol fraction acutely enhanced nitric oxide bioactivity. this effect involved endothelial nitric-oxide synthase (enos) phosphorylation at ser-1177 and dephosphorylation at thr-495, consistent with increa ... | 2004 | 15333638 |
| codelivery of a tea extract prevents morbidity and mortality associated with oral vanadate therapy in streptozotocin-induced diabetic rats. | oral administration of vanadate has a strong hypoglycemic effect but results in toxic side effects like life-threatening diarrhea. tea is known to have potent antidiarrhea effects. we investigated the potential of suspending the vanadate in a tea decoction to reduce the diarrheatic action of vanadate. a concentrated extract of lichee black tea was, therefore, added to sodium orthovanadate. streptozotocin (stz)-induced diabetic rats were orally gavaged with vanadate suspended in water or in the t ... | 2004 | 15334376 |
| in vitro transdermal delivery of the major catechins and caffeine from extract of camellia sinensis. | the aim of this study was to investigate the feasibility of the transdermal delivery of catechins and caffeine from green tea extract. drug-in-adhesive patches containing 1.35, 1.03, 0.68, and 0.32 mg cm(-2) green tea extract were formulated and the dissolution of (-)-epigallocatechin gallate (egcg), (-)-epigallocatechin (egc) and (-)-epicatechin (ec) from these was determined. transdermal delivery was determined across full thickness pig ear skin from saturated solutions of green tea extract in ... | 2004 | 15363500 |
| black tea polyphenol theaflavins inhibit aromatase activity and attenuate tamoxifen resistance in her2/neu-transfected human breast cancer cells through tyrosine kinase suppression. | the aromatase enzyme, which converts androstenedione to oestrone, regulates the availability of oestrogen to support the growth of hormone-dependent breast tumours. in this study, we investigated the inhibitory effects of black tea polyphenols on aromatase activities. we found that black tea polyphenols, tf-1, tf-2 and tf-3, significantly inhibited rat ovarian and human placental aromatase activities. in addition, using an in vivo model, these black tea polyphenols also inhibited the proliferati ... | 2004 | 15341993 |
| flavonoid biosynthesis in the tea plant camellia sinensis: properties of enzymes of the prominent epicatechin and catechin pathways. | leaves of tea (camellia sinensis l.) contain extraordinary large amounts of (-)-epigallocatechin, (-)-epicatechin, (+)-gallocatechin, and (+)-catechin and derivatives of these compounds that show positive effects on human health. the health-promoting effects of flavan 3-ols, especially those of green tea, are of scientific and public interest. furthermore, they play a crucial role in defense against pathogens of tea. therefore, biosynthesis of these flavonoid compounds was investigated. the anth ... | 2004 | 15464723 |