| dietary intervention with iron and black tea infusion in reducing cytotoxicity of arsenic. | the relative efficacy of infusion of black tea leaf, camellia sinensis (linn.) o. kuntze, (theaceae), and iron as freshly prepared aqueous solution of ferrous sulphate in reducing the cytotoxic effects of arsenic, was tested in bone marrow cells of laboratory bred swiss albino mice. ferrous sulphate and tea given alone did not induce chromosomal breakage to any appreciable extent. tea decreased chromosome damage induced by arsenic to a significant extent, while the addition of ferrous sulphate d ... | 2004 | 15462183 |
| flavonoid biosynthesis in the tea plant camellia sinensis: properties of enzymes of the prominent epicatechin and catechin pathways. | leaves of tea (camellia sinensis l.) contain extraordinary large amounts of (-)-epigallocatechin, (-)-epicatechin, (+)-gallocatechin, and (+)-catechin and derivatives of these compounds that show positive effects on human health. the health-promoting effects of flavan 3-ols, especially those of green tea, are of scientific and public interest. furthermore, they play a crucial role in defense against pathogens of tea. therefore, biosynthesis of these flavonoid compounds was investigated. the anth ... | 2004 | 15464723 |
| potential chemoprotective effects of the coffee components kahweol and cafestol palmitates via modification of hepatic n-acetyltransferase and glutathione s-transferase activities. | coffee drinking has been associated with reduced incidence of colorectal cancer, possibly via chemoprotection/modification of the metabolism of dietary heterocyclic amine carcinogens such as 2-amino-1-methyl-6-phenylimidazo-[4,5-b]pyridine (phip) by kahweol and cafestol palmitates (k/c), two components of unfiltered coffee. using the phip-exposed male fisher f344 rat as a model, k/c have been shown to reduce colonic phip-dna adducts by > 50%. we have used the male f344 rat to investigate the eff ... | 2004 | 15468054 |
| in vitro anti-beta-secretase and dual anti-cholinesterase activities of camellia sinensis l. (tea) relevant to treatment of dementia. | the primary target of licensed drugs for the treatment of alzheimer's disease is the inhibition of the enzyme acetylcholinesterase, although preventing beta-amyloidosis is a prime target for drugs in development. the in vitro dual anti-cholinesterase and beta-secretase activities of camellia sinensis l. extract (tea) is reported. green and black tea inhibited human acetylcholinesterase (ache) with ic(50) values of 0.03 mg/ml and 0.06 mg/ml respectively, and human butyrylcholinesterase (buche) wi ... | 2004 | 15476306 |
| antioxidant properties of black tea in alcohol intoxication. | food ingredients such as alcohol may modify cellular redox state. ethanol metabolism is accompanied by generation of free radicals that can damage cell components especially when antioxidant mechanisms are no able to neutralize them. however black tea is a source of polyphenol antioxidants that may enhance cellular antioxidant abilities. the aim of this study was to investigate the effect of black tea on antioxidant abilities of the liver, blood serum and brain of 12-months old rats sub-chronica ... | 2004 | 15500941 |
| in vitro cytotoxicity of epigallocatechin gallate and tea extracts to cancerous and normal cells from the human oral cavity. | this study compared the in vitro responses of malignant and normal cells from the human oral cavity to tea extracts and to its main polyphenolic component, (-)-epigallocatechin gallate (egcg). the antiproliferative effects of tea polyphenolic extracts and egcg were more pronounced towards immortalized, tumourigenic (cal27, hsc-2, and hsg(1)) and non-tumourigenic (s-g) cells than towards normal (gn56 and hgf-1) fibroblasts and green tea was more toxic than black tea. as the addition of tea extrac ... | 2004 | 15504155 |
| exobasidium vexans infection of camellia sinensis increased 2,3-cis isomerisation and gallate esterification of proanthocyanidins. | infection of leaves of tea (camellia sinensis (kuntze) l, cv tri 2025) which was susceptible to blister blight (exobasidium vexans massee), resulted in a shift of the proanthocyanidin stereochemistry away from 2,3-trans (e.g. catechin and gallocatechin) and towards 2,3-cis (e.g. epicatechin and epigallocatechin). infection also resulted in increased gallic acid esterification of the initiating subunits of proanthocyanidins. this was shown by both mass spectroscopy and phloroglucinolysis. proanth ... | 2004 | 15504433 |
| formation of antioxidants from (-)-epigallocatechin gallate in mild alkaline fluids, such as authentic intestinal juice and mouse plasma. | the oxidative dimerization of (-)-epigallocatechin gallate (egcg), the major catechin of tea leaves (camellia sinensis l.), in authentic intestinal juice (ph 8.5) and mouse plasma (ph 7.8) was investigated. egcg was unstable in the alkaline solutions over ph 7.4. the content of egcg was decreased to 19.4% and 60.7% at 5 minutes in the intestinal juice and plasma, respectively. three products-p-1 (theasinensin a), p-2 (a new dimerized product reported in a previous paper), and p-3 (theasinensin d ... | 1999 | 15539294 |
| antibacterial effect of water-soluble tea extracts on foodborne pathogens in laboratory medium and in a food model. | the microbial inhibition of foodborne pathogens was determined in brain heart infusion broth with 10% (wt/vol) water-soluble extracts of green, jasmine, black, dungglre, and oolong tea against escherichia coli o157:h7, salmonella enterica serovar enteritidis, listeria monocytogenes, and staphylococcus aureus. the mixed culture (approximately 6.0 log cfu/ml), which was composed of the four pathogens, was inoculated into brain heart infusion broth with and without tea extracts. after incubation at ... | 2004 | 15553649 |
| nuclei of tea flowers as targets for flavanols. | the tea plant (camellia sinensis l.) is famous for its flavanol-based constituents being valuable for human health. these flavanols associate with the nuclei of tea flowers, which is demonstrated histochemically by blue colouration using the selective staining reagent p-dimethylaminocinnamaldehyde (dmaca). sepals, petals, stamens, pollen tubes, ovaries and ovules were studied. all these organs were shown to contain flavanols in vacuolar compartments, in nuclei and, exceptionally, also in the cyt ... | 2004 | 15570474 |
| effective control of glycemic status and toxicity in zucker diabetic fatty rats with an orally administered vanadate compound. | a novel black tea decoction containing vanadate has successfully replaced insulin in a rat model of insulin-dependent diabetes but is untested in non-insulin-dependent diabetic animals. a tea-vanadate decoction (tv) containing 30 or 40 mg sodium orthovanadate was administered by oral gavage to two groups of zucker diabetic fatty rats and a conventional water vehicle containing 30 or 40 mg of sodium orthovanadate to two others. in the latter group receiving the 30-mg dose, vanadate induced diarrh ... | 2004 | 15573149 |
| antimicrobial activity of 10 different plant polyphenols against bacteria causing food-borne disease. | the antibacterial activities of 10 different plant polyphenols were evaluated by comparing their minimum inhibitory concentrations (mics) against several food-borne pathogenic bacteria, staphylococcus aureus (20 strains), some serotypes of the genus salmonella (26 strains), escherichia coli (23 strains), and some species of the genus vibrio (27 strains). the polyphenols examined were epigallocatechin (1), epigallocatechin-3-o-gallate (2), punicalagin (3), tannic acid (4), castalagin (5), prodelp ... | 2004 | 15577214 |
| ameliorative effects of black tea extract on aflatoxin-induced lipid peroxidation in the liver of mice. | we have evaluated the ameliorative effect of black tea extract on aflatoxin-induced lipid peroxidation in the liver of mice. adult male albino mice were orally administered with 25 and 50 microg of aflatoxin in 0.2 ml olive oil/animal/day for 30 days. results revealed dose-dependent and significantly (p<0.05) higher lipid peroxidation in the liver of aflatoxin-treated mice than that of vehicle control. as compared with vehicle control, the levels of non-enzymatic antioxidants such as glutathione ... | 2005 | 15582201 |
| anticancer therapeutic potential of soy isoflavone, genistein. | genistein (4'5, 7-trihydroxyisoflavone) occurs as a glycoside (genistin) in the plant family leguminosae, which includes the soybean (glycine max). a significant correlation between the serum/plasma level of genistein and the incidence of gender-based cancers in asian, european and american populations suggests that genistein may reduce the risk of tumor formation. other evidence includes the mechanism of action of genistein in normal and cancer cells. genistein inhibits protein tyrosine kinase ... | 2004 | 15584372 |
| mediation of the in vitro cytotoxicity of green and black tea polyphenols by cobalt chloride. | the effects of co2+ (as cocl2) on the cytotoxicity of green tea polyphenol (gtp) and black tea polyphenol (btp) extracts towards proliferation of immortalized human gingival epithelial-like s-g cells were studied. the 24 h potencies of gtp and btp extracts, as determined with the neutral red (nr) cell viability assay, were greatly reduced in the presence of 250, but not of 50, microm co2+. the cytotoxicities of the gtp and btp extracts were due, in part, to their generation of hydrogen peroxide ... | 2005 | 15585375 |
| in vitro studies of baicalin alone or in combination with salvia miltiorrhiza extract as a potential anti-cancer agent. | traditional chinese herbal medicines (tcm) that for centuries have been used in disease prevention and treatment are finding use as alternatives to western cancer therapies. from a panel of tcm, we chose four compounds representing two functional classes of botanicals, the purified plant flavins scutellarin (a circulatory stimulant) and baicalin (antipyretic), and two extracts purified from salvia miltiorrhiza (sm-470, circulatory stimulant) and camellia sinensis (cam-300, antipyretic), and exam ... | 2005 | 15586243 |
| black tea intake modulates the excretion of urinary mutagens in rats exposed to 6-aminochrysene: induction of cytochromes p450 by 6-aminochrysene in the rat. | rats were exposed to black tea (2.5% w/v) as their sole drinking liquid for either 1 day (short-term) or 1 month (long-term), while controls received water. after exposure, all animals received a single oral dose of 6-aminochrysene and urine was collected for 72 h. urinary mutagenicity was determined in the ames test using an activation system comprising hepatic cytosol from aroclor 1254-induced rats and utilizing the salmonella typhimurium o-acetylase overexpressing bacterial strain yg1024. bot ... | 2004 | 15598702 |
| effect of black tea intake on the excretion of mutagens in the urine of volunteers taking a beef meal. | the objective of this study was to investigate in a crossover study conducted in human volunteers whether black tea intake modulates the metabolism of heterocyclic amines, consumed in the form of well-cooked beefburgers, as exemplified by the excretion of mutagens in the urine. mutagens were extracted from urine with blue rayon, and mutagenic activity was determined in the ames test, in the presence of an activation system derived from aroclor 1254-induced rats, and employing the salmonella typh ... | 2004 | 15598780 |
| transactivation of peroxisome proliferator-activated receptor alpha by green tea extracts. | tea is a popular beverage. recently, green tea was reported to increase the number of peroxisomes in rats. in this study, to find out whether the green tea-induced proliferation of peroxisomes is mediated by pparalpha , a transient transfection assay was carried out to investigate the interactions of tea extracts (green tea, black tea,oolong tea and doongule tea) and tea components (epigallocatechin gallate, epigallocatechin, epicatechin gallate, epicatechin and gallic acid), with mouse cloned p ... | 2004 | 15613816 |
| dissipation behavior of propargite--an acaricide residues in soil, apple (malus pumila) and tea (camellia sinensis). | propargite, recently introduced in india, is an effective acaricide on a large number of crops most of which are consumed by human beings directly or after processing. therefore, it has become important to check the dissipation behavior of propargite in edible raw commodities, processed products and in the environment. in the present study, dissipation of residue of this acaricide in soil, apple fruit and tea (green tea leaves, manufactured tea, infusion and spent leaves) was studied. analysis w ... | 2005 | 15621197 |
| anti-inflammatory activity of indian black tea (sikkim variety). | in this study, the anti-inflammatory (in reference to the cardinal signs of inflammation) and other related pharmacological activities of the hot water extract of black tea (camellia sinensis, sikkim variety) were evaluated along with certain standard drugs. the extract showed significant inhibitory activity against carrageenin, histamine, serotonin and prostaglandin-induced pedal inflammation. the extract inhibited exudative inflammation. the tea extract also inhibited cotton pellet-induced gra ... | 2005 | 15629264 |
| black tea extract suppresses transformation of aryl hydrocarbon receptor induced by dioxin. | dioxins cause various adverse effects through binding to an aryl hydrocarbon receptor (ahr) and transformation of the receptor. in this study, we investigated whether black tea extract suppresses ahr transformation. dried black tea leaves were extracted with 75% ethanol, and the extract was pretreated to the rat liver cytosol fraction 10 min prior to addition of 2,3,7,8-tetrachlorodibenzo-p-dioxin (tcdd). transformed ahr was detected by electrophoretic gel mobility shift assay. black tea extract ... | 2004 | 15630227 |
| comparative studies on the hypolipidemic and growth suppressive effects of oolong, black, pu-erh, and green tea leaves in rats. | the four major commercial teas, oolong, black, pu-erh, and green teas, have been manufactured in southeast asia. in this study, we evaluated the growth suppressive and hypolipidemic effect of these four different tea leaves by oral feeding to male sprague-dawley rats for 30 weeks. the results showed that the suppression of body weights of tea leaves-fed groups were in the order: oolong tea > pu-erh tea > black tea > green tea. pu-erh tea and oolong tea could lower the levels of triglyceride more ... | 2005 | 15656692 |
| tea and circulating estrogen levels in postmenopausal chinese women in singapore. | the role of tea in the etiology of breast cancer is controversial. we recently provided the first set of human evidence that breast cancer risk is significantly inversely associated with tea intake, largely confined to intake of green tea. since black tea and green tea possess comparable levels of the total tea polyphenols that possess antioxidative activities, reasons for the paradoxical effects of green tea and black tea on breast cancer protection are not apparent. some limited evidence sugge ... | 2005 | 15661801 |
| paradoxical effects of green tea (camellia sinensis) and antioxidant vitamins in diabetic rats: improved retinopathy and renal mitochondrial defects but deterioration of collagen matrix glycoxidation and cross-linking. | we tested the hypothesis that green tea prevents diabetes-related tissue dysfunctions attributable to oxidation. diabetic rats were treated daily with tap water, vitamins c and e, or fresh japanese green tea extract. after 12 months, body weights were decreased, whereas glycated lysine in aorta, tendon, and plasma were increased by diabetes (p < 0.001) but unaffected by treatment. erythrocyte glutathione and plasma hydroperoxides were improved by the vitamins (p < 0.05) and green tea (p < 0.001) ... | 2005 | 15677510 |
| short-term administration of (-)-epigallocatechin gallate reduces hepatic steatosis and protects against warm hepatic ischemia/reperfusion injury in steatotic mice. | hepatic steatosis increases the extent of cellular injury incurred during ischemia/reperfusion (i/r) injury. (-)-epigallocatechin gallate (egcg), the major flavonoid component of green tea (camellia sinensis) is a potent antioxidant that inhibits fatty acid synthase (fas) in vitro. we investigated the effects of egcg on hepatic steatosis and markers of cellular damage at baseline and after i/r injury in ob/ob mice. animals were pretreated with 85 mg/kg egcg via intraperitoneal (ip) injection for ... | 2005 | 15719408 |
| inhibition of benzo[a]pyrene induced mutagenicity and genotoxicity by black tea polyphenols theaflavins and thearubigins in multiple test systems. | this study investigated the antimutagenic and anticlastogenic effects of black tea polyphenols, theaflavins (tf) and thearubigins (tr) in salmonella assay in vitro and in vivo in bone marrow cells of mice as measured by chromosomal aberrations (ca) and sister chromatid exchange (sce) against a known carcinogen, benzo[a]pyrene (b[a]p). a significant decrease in mutagenicity in salmonella assay and both ca and sce were observed in all the different concentrations of tf and tr plus b[a]p treated se ... | 2005 | 15721207 |
| genetic diversity of upasi tea clones (camellia sinensis (l.) o. kuntze) on the basis of total catechins and their fractions. | tea leaf catechins and the ratio of dihydroxylated to trihydroxylated catechin fractions were analysed to identify the genetic diversity of 26 upasi released tea clones. principal component analysis (pca) based on regression factor separated tea clones into five groups according to their jats (jats are region based rays for e.g., assam, china and cambod origin) as well as their quality constituents (such as total polyphenols, total catechins, amino acids in the green leaves and liquor characteri ... | 2005 | 15721948 |
| nuclear magnetic resonance spectroscopic based studies of the metabolism of black tea polyphenols in humans. | epidemiological studies indicate that a high intake of flavonoids is associated with an improved health status. tea is one of the most abundant sources of flavonoids in the human diet. the bioavailability and biotransformation of tea flavonoids are, however, not clearly understood. the aim of the present study was to investigate the metabolism of black tea via a nonspecific screening method. (1)h nuclear magnetic resonance (nmr) spectroscopy was used to obtain nonselective profiles of urine samp ... | 2005 | 15740018 |
| inhibition of lung tumorigenesis by tea. | tea and tea constituents have been shown by different investigators to inhibit lung tumorigenesis in different animal model systems. this includes lung tumorigenesis in a/j mice induced by 4-(methylnitrosamino)-1-(3pyridyl)-1-butanone (nnk), n-nitrosodiethylamine, benzo[a]pyrene, n-nitrosomethylurea, or cisplatin. inhibition of lung tumorigenesis has also been demonstrated in c3h mice treated with n-nitrosodiethylamine. in most of these experiments, reduction in tumor number and tumor size has b ... | 2005 | 15765923 |
| changes in electric charge and phospholipids composition in erythrocyte membrane of ethanol--poisoned rats after administration of teas. | erythrocyte membrane components and electric charge can be modified by ethanol and by compounds formed as a result of its metabolism, particularly be reactive oxygen species (ros). the effects of ros can be neutralized by administering preparations with antioxidant properties. the natural preparations of this kind are teas. for this reason, it has been the purpose of this work to determine effect of green and black tea on membrane electric charge and phospholipids composition of an erythrocyte m ... | 2004 | 15794343 |
| in vitro antimycotic activity of some plant extracts towards yeast and yeast-like strains. | as part of screening aimed at the selection of novel antimycotic compounds of vegetable origin, leaf extracts of camellia sinensis l., cupressus sempervirens l. and pistacia lentiscus l. and the seed extract of glycine soja sieb. et zucc. were tested against yeast and yeast-like species implicated in human mycoses. of the extracts only those of c. sinensis (obtained from a commercial preparation of green tea) exhibited broad activity towards candida glabrata, clavispora lusitatiae, cryptococcus ... | 2005 | 15798996 |
| green tea intake, ace gene polymorphism and breast cancer risk among chinese women in singapore. | experimental and epidemiological data have implicated a potential chemoprotective role of green tea polyphenols and a potential enhancing role of angiotensin ii in the development of breast cancer in humans. angiotensin ii is converted from its precursor by angiotensin-converting enzyme (ace). women with low-activity genotype of the ace gene had a reduced risk of breast cancer compared with those possessing high-activity ace genotype. experimental data showed that green tea polyphenols could inh ... | 2005 | 15802301 |
| effects of tea constituents on cell cycle progression of human leukemia u937 cells. | tea and tea constituents are known to induce apoptosis in a variety of cancerous cells, suggesting their beneficial effects as chemopreventive agents. previous studies have shown that low molecular weight constituent catechins and high molecular weight fractions of tea have the apoptosis-inducing activity, but that their action mechanisms may be different. since cell cycle arrest is known to be one of the underlying mechanisms of apoptosis, we examined the effects of these tea constituents on ce ... | 2005 | 15806977 |
| effect of certain bioactive plant extracts on clinical isolates of beta-lactamase producing methicillin resistant staphylococcus aureus. | ethanolic extracts and some fractions from 10 indian medicinal plants, known for antibacterial activity, were investigated for their ability to inhibit clinical isolates of beta-lactamase producing methicillin-resistant staphylococcus aureus (mrsa) and methicillin-sensitive s. aureus (mssa). synergistic interaction of plant extracts with certain antibiotics was also evaluated. the mrsa test strains were found to be multi-drug resistant and also exhibited high level of resistance to common beta-l ... | 2005 | 15812867 |
| theaflavin derivatives in black tea and catechin derivatives in green tea inhibit hiv-1 entry by targeting gp41. | theaflavin derivatives and catechin derivatives are the major polyphenols in black tea and green tea, respectively. several tea polyphenols, especially those with galloyl moiety, can inhibit hiv-1 replication with multiple mechanisms of action. here we showed that the theaflavin derivatives had more potent anti-hiv-1 activity than catechin derivatives. these tea polyphenols could inhibit hiv-1 entry into target cells by blocking hiv-1 envelope glycoprotein-mediated membrane fusion. the fusion in ... | 2005 | 15823507 |
| potent suppressive effect of green tea polyphenols on tobacco-induced mutagenicity. | antimutagenic activity of green tea (camellia sinensis) was studied using salmonella typhimurium strains (ta 102) (ames test). aqueous tobacco extract was found to be mutagenic to s. typhimurium ta 102 at concentration of 50 mg/plate. green tea polyphenols was found to inhibit the mutagenicity of tobacco in a concentration-dependent manner. concentrations needed for 50% inhibition of mutagen-induced revertant formation was found to be 5 mg/plate. green tea polyphenols was also found to inhibit t ... | 2005 | 15830844 |
| inhibitory effect(s) of polymeric black tea polyphenols on the formation of b(a)p-derived dna adducts in mouse skin. | the biological activities and chemopreventive properties of green tea polyphenols have been demonstrated, while similar information regarding newly formed major polymeric polyphenols in black tea are not available. cancer chemoprevention may be achieved by the inhibition of any stage of carcinogenesis. in the present study, we investigated the anti-initiating effects of five polymeric black tea polyphenol (pbp) fractions, by determining their effects on the formation of [3h]-b(a)p-derived dna ad ... | 2005 | 15831081 |
| black tea protects thymocytes in tumor-bearing animals by differential regulation of intracellular ros in tumor cells and thymocytes. | the accumulated in vitro evidence indicates that many tumors induce t-cell apoptosis as a mechanism of inhibiting antitumor activity. this downregulation of cell-mediated immune functions occurring at the late stages of the disease may be causally related to the thymic involution, because the thymus is the major site of t-cell maturation, extensive proliferation, and differentiation. our results showed that in erhlich's ascites carcinoma cell (eac)-bearing mice, the number of eac was inversely p ... | 2005 | 15831082 |
| antioxidant potential of black tea against 7,12-dimethylbenz(a)anthracene- induced oxidative stress in swiss albino mice. | oxygen free radicals and related reactive species have been implicated in the etiology of many diseases, such as atherosclerosis, neurodegenerative disorders, and cancer. antioxidant enzymes exist in cells to protect against the effects of these free radicals and other oxygen-derived species, which are produced during the oxidative stress. tea (camellia sinensis) is the most commonly consumed beverage worldwide. both green and black tea are known to possess many pharmacological properties, inclu ... | 2005 | 15831083 |
| black tea (camellia sinensis) as a chemopreventive agent in oral precancerous lesions. | oral carcinoma is the most common malignancy found in adult indian men and the third most common in adult indian women. about half of all cases are found to be associated with precancerous lesions, chiefly leukoplakia. we wanted to explore the possible benefits of black tea (camellia sinensis) administered to patients with oral leukoplakia. eighty-two subjects with oral leukoplakia underwent micronuclei and chromosomal assays on exfoliated oral mucosal epithelium, after which they received black ... | 2005 | 15831086 |
| the theaflavin fraction is responsible for the facilitatory effect of black tea at the skeletal myoneural junction. | the effect of various fractions of black tea [(camellia sinensis) (l) o. kuntze (theaceae)] on the function of mammalian skeletomotor apparatus was studied. the theaflavin fraction (tfs) produced a concentration- dependent facilitation of indirect twitch responses of the rat phrenic nerve diaphragm preparation and the facilitation was dependent on the amount of calcium present in the bathing fluid. nifedipine reduced the facilitatory effect of tfs as a function of its concentration. tfs failed t ... | 2005 | 15850600 |
| [relationship between plant community succession and fertility variation of mountain yellow soil in east chongqing]. | based on the analyses of soil physical and chemical properties, this paper studied the relationship between plant community succession and fertility variation of mountain yellow soil in east chongqing. the results showed that the values of integrated soil fertility index of pinus massoniana, cunninghamia lanceolata, deciduous oak, camellia sinensis and evergreen broad-leaved forest soils were 0.1256, 0.2085, 0.3514, 0.2479 and 0.9329, respectively, implying that soil development had a close rela ... | 2005 | 15852912 |
| black and green teas equally inhibit diabetic cataracts in a streptozotocin-induced rat model of diabetes. | green and black teas were given at 1.25% in the drinking water to streptozotocin-induced diabetic rats for 3 months. normal and diabetic control groups were also studied. as expected, diabetic animals had significantly increased glucose in lens and plasma. lens and red blood cell sorbitol were significantly increased as a result of the aldose reductase pathway activation. plasma and lens lipid thiobarbituric acid-reactive substances and protein glycation were also significantly elevated. both te ... | 2005 | 15853424 |
| ilex paraguariensis extracts are potent inhibitors of nitrosative stress: a comparative study with green tea and wines using a protein nitration model and mammalian cell cytotoxicity. | due to the increasing importance of nitrosative stress in pathology and the efficacy displayed by flavonoids in cancelling the effects of peroxynitrite, we decided to conduct a comparative study of three commonly used beverages with the highest polyphenol contents and proven antioxidant properties: mate (ilex paraguariensis); green tea (camelia sinensis) extracts and white and red wines of the main varietals. we directly evaluated and compared the extracts and wines as protein nitration inhibito ... | 2005 | 15878361 |
| p38 mitogen-activated protein kinase activates enos in endothelial cells by an estrogen receptor alpha-dependent pathway in response to black tea polyphenols. | black tea has been shown to improve endothelial function in patients with coronary artery disease and recent data indicate the polyphenol fraction of black tea enhances endothelial nitric oxide synthase (enos) activity through p38 map kinase (p38 mapk) activation. because the mechanisms for this phenomenon are not yet clear, we sought to elucidate the signaling events in response to black tea polyphenols. bovine aortic endothelial cells (baecs) exposed to black tea polyphenols demonstrated enos ... | 2005 | 15879307 |
| pesticide-induced alteration in mice hepato-oxidative status and protective effects of black tea extract. | this study investigates the role of black tea extract in protection against oxidative damage induced in mice by a subacute oral dose of a combination of pesticides. | 2005 | 15885683 |
| differential display-mediated identification of three drought-responsive expressed sequence tags in tea [camellia sinensis (l.) o. kuntze]. | there is no information on drought-modulated gene(s) in tea [camellia sinensis (l.) o. kuntze], a woody and perennial plant of commercial importance. using differential display of mrna, three drought-modulated expressed sequence tags (ests) were identified. northern and blast analysis revealed that clone dr1 (drought-responsive), induced only by drought but not by aba, showed significant scores with pr-5 (pathogenesis related) family of pr-protein gene. another clone dr2, repressed by drought bu ... | 2005 | 15886459 |
| heteroactivation of cytochrome p450 1a1 by teas and tea polyphenols. | we studied 7-ethoxyresorufin deethylase as an index of cytochrome p4501a1 (cyp1a1) activity in liver microsomes from rats pretreated with 3-methylcholanthrene. the enzyme had complex kinetics compatible with a multisite model. at 1 microm substrate, brewed black, green and white teas had complex effects on enzyme activity consisting of activation at low concentrations and inhibition at higher concentrations. data fit well to a two-site model that allowed us to determine maximal activation (% inc ... | 2005 | 15895106 |
| occurrence of vitamin b12 in green, blue, red, and black tea leaves. | vitamin b12 contents of green (0.046-0.263 and 0.125-0.535 microg/100 g dry weight), blue (0.068-0.081 and 0.525-0.528 microg/l00 g dry weight), red (0.061 and 0.663 microg/100 g dry weight), and black (0.104-0.859 and 0.305-1.20 microg/100 dry weight) tea leaves were obtained by intrinsic factor-chemiluminescence and microbiological methods, respectively. although vitamin b12 was found in all tea leaves tested by both assay methods, the higher values by the microbiological method were not due t ... | 2004 | 15895521 |
| variations of main quality components of tea genetic resources [camellia sinensis (l.) o. kuntze] preserved in the china national germplasm tea repository. | the variations of the main quality components of tea, tea polyphenols, catechins, amino acids, caffeine, and water extract of 596 accessions chinese tea genetic resources, preserved in the china national germplasm tea repository (cngtr), were analyzed. tea polyphenols content on a dry weight basis varied from 13.6 to 47.8%, averaging 28.4%. the tea polyphenols content increases gradually from northern and eastern provinces to southern provinces, the highest is in yunnan tea resources. the conten ... | 2005 | 15898357 |
| black tea polyphenols suppress cell proliferation and induce apoptosis during benzo(a)pyrene-induced lung carcinogenesis. | one of the most promising strategies for cancer prevention is chemoprevention by daily used food and beverages. black tea, the most widely consumed beverage, is a source of compounds with antioxidative, antimicrobial, antimutagenic and anticarcinogenic properties. lung cancer is the most common cause of cancer deaths in both men and women worldwide. over one million people around the world are likely to be killed by lung cancer due to increased tobacco smoking and environmental pollutants, espec ... | 2005 | 15901989 |
| inhibition of tumour promotion in mouse skin by extracts of rooibos (aspalathus linearis) and honeybush (cyclopia intermedia), unique south african herbal teas. | the modulating effect of ethanol/acetone (e/a) soluble fractions, prepared from methanolic extracts of processed and unprocessed rooibos (aspalathus linearis) and honeybush (cyclopia intermedia) as well as green (camellia sinensis) teas was established in a two-stage mouse skin carcinogenesis assay. topical application of the tea fractions prior to the tumour promoter, 12-o-tetradecanoylphorbol-13-acetate (tpa), on icr mouse skin initiated with 7,12-dimethylbenz[a]anthracene (dmba) suppressed sk ... | 2004 | 15914270 |
| black tea theaflavins suppress dioxin-induced transformation of the aryl hydrocarbon receptor. | dioxins cause various adverse effects through transformation of aryl hydrocarbon receptor (ahr). in this study, we investigated whether black tea extract and its components, theaflavins, suppress ahr transformation in vitro. first, we confirmed that black tea extract strongly suppressed ahr transformation compared to green and oolong tea, although the catechin contents did not change significantly among the extracts. then we isolated four theaflavins as active compounds from black tea leaves. th ... | 2005 | 15914905 |
| determination of some organochlorine compounds in herbal colouring agent henna (lawsonia inermis) and in tea (thea sinensis). | henna (lawsonia inermis) has been used for centuries as a herbal hair and skin dye, but very little is known about its additives and contaminants that could adversely affect human health. an analytical method was developed to determine organochlorine compounds in henna, as they are still widely used in the areas where henna is grown. samples were sonicated with n-hexane, extracts cleansed on florisil sorbent and analysed using gas chromatography with electron capture detection. the overall recov ... | 2005 | 15969202 |
| molecular definition of black tea taste by means of quantitative studies, taste reconstitution, and omission experiments. | recently, bioresponse-guided fractionation of black tea infusions indicated that neither the high molecular weight thearubigens nor the theaflavins, but a series of 14 flavon-3-ol glycopyranosides besides some catechins, might be important contributors to black tea taste. to further bridge the gap between pure structural chemistry and human taste perception, in the present investigation 51 putative taste compounds have been quantified in a black tea infusion, and their dose-over-threshold (dot) ... | 2005 | 15969522 |
| protective effect of black tea extract on the levels of lipid peroxidation and antioxidant enzymes in liver of mice with pesticide-induced liver injury. | sub-acute hepatotoxicity was induced in mice by exposure to pesticides. the effect of pretreatment with aqueous black tea extract on lipid peroxidation and antioxidants in the liver was investigated. administering a combination dose of chlorpyriphos and cypermethrin (20 mg kg(-1) each) on alternate days over a 15-day period to male mice resulted in induction of sub-acute toxicity as reflected by elevated levels of liver damage marker enzymes alkaline phosphatase(alp), aspartate transaminase(ast) ... | 2006 | 15991261 |
| phytoestrogenic effects of black tea extract (camellia sinensis) in an oophorectomized rat (rattus norvegicus) model of osteoporosis. | the adverse side effects of currently available anti-osteoporotic agents warrant the search for compounds with less toxic effects. in this study, we assessed the phytoestrogenic potentiality of whole aqueous extract of black tea (bte) in a bilaterally oophorectomized rat model (2.5%, 1 ml/100 g body weight/day for 28 days). although the supplementation was given for 28 days but, sign of revival of copulation period (estrous stage) from non-receptive diestrous stage was first noticed after 21 day ... | 2005 | 15996685 |
| epigallocatechin gallate (egcg) (teavigo) does not impair nonhaem-iron absorption in man. | a number of studies have shown that tea catechins can inhibit intestinal iron absorption, mostly iron in the nonhaem form. this randomized, double-blind, placebo-controlled, 3-periods cross-over study examined the degree of inhibition of nonhaem iron absorption by pure crystalline epigallocatechin gallate (egcg). the study was designed to show the maximum inhibitory action of egcg by selecting 30 healthy women with low iron stores. treatments were 150 mg, 300 mg egcg and placebo each for 8 conse ... | 2005 | 16008116 |
| addition of milk does not alter the antioxidant activity of black tea. | tea is a polyphenol-rich beverage like wine and catechins are its chief polyphenols. catechins have cardio-protective effects as they can scavenge free radicals and inhibit lipid peroxidation. epidemiological studies indicate an inverse relation between tea consumption and the risk of cardiovascular and other chronic diseases. addition of milk to black tea has been reported to adversely affect its beneficial effects, but the data are not unequivocal. therefore, we assessed the effect of the addi ... | 2005 | 16020939 |
| cosmeceuticals containing herbs: fact, fiction, and future. | modern medicine is rooted in ethnobotanical traditions using indigenous flora to treat symptoms of human diseases or to improve specific aspects of the body condition. herbal medicine is now used by over half of the american population. yet the american medical community generally lacks knowledge of the function, metabolism, interaction, adverse reactions, and preparation of herbal products. | 2005 | 16029681 |
| use of black tea in modulating clastogenic effects of arsenic in mice in vivo. | the concentration of arsenic in drinking water has far exceeded the permissible limit of 0.001 mg/l and has reached epidemic proportions, with a maximum of 3.7 mg/l in several districts of west bengal and in the adjoining bangladesh. because inorganic arsenic is a documented human carcinogen, arsenic in drinking water may cause 200,000-270,000 deaths per year from cancer in india alone. tea has a protective effect against the clastogenicity of arsenic. we investigated whether tea extracts could ... | 2005 | 16050804 |
| black tea extract can modulate protein expression of h-ras, c-myc, p53, and bcl-2 genes during pulmonary hyperplasia, dysplasia, and carcinoma in situ. | lung cancer has emerged as one of the leading causes of cancer death in most developed and many developing countries of the world. in the absence of effective screening and early detection methods of lung cancer and overall poor prognosis, the 5-year survival following treatment has not improved significantly over the last two decades. it is hoped that the risk of the disease can be minimized by preventive measures. one aspect of lung cancer prevention emphasizes the cessation of tobacco smoking ... | 2005 | 16050805 |
| supplementation of waste tea fungal biomass as a dietary ingredient for broiler chicks. | the waste tea fungal biomass produced during black tea fermentation was investigated as a dietary ingredient in poultry feeds. a small portion of fungal mat was used as starter culture for the next cycle while the major portion is discarded as waste. hence a trial study was carried out to utilize the waste fungal biomass as a supplementary diet for broiler chicks. the fungal biomass contained 179.38 g of crude protein, 120 g crude fibre, 4.82 g phosphorus, 6.56 g of calcium and 8.92 mj metaboliz ... | 2005 | 16051080 |
| inhibitory effects of various beverages on ritodrine sulfation by recombinant human sulfotransferase isoforms sult1a1 and sult1a3. | ritodrine is known to undergo extensive presystemic sulfation in the intestinal mucosa, and its bioavailability is as low as 30%. accordingly, inhibition of intestinal sulfation may lead to an increase in the bioavailability of ritodrine. in this study, we aimed to investigate the activities of ritodrine sulfation by sult1a1, which is expressed predominantly in the liver, and sult1a3, which is expressed predominantly in the intestine, as well as the inhibitory effects of beverages on their activ ... | 2005 | 16078151 |
| synergistic antimicrobial activity of tea & antibiotics. | tea leaves are known for its antibacterial activity against many microorganisms. in this study we attempted to describe the synergistic antimicrobial activity of tea and antibiotics against enteropathogens. antimicrobial activity of boiled water tea extract and organic solvent extract were studied against salmonella typhimurium 1402/84, s. typhi, s. typhi ty2a, shigella dysenteriae, yersinia enterocolitica c770, and escherichia coli (epec p2 1265) determining minimum inhibitory concentration (mi ... | 2005 | 16106094 |
| protective effects of black tea extract on testosterone induced oxidative damage in prostate. | since ancient times, antipyretic, anti-inflammatory, antimicrobial and antioxidative properties of tea have been recognized. black tea (camellia sinensis) contains a variety of polyphenolic ingredients including the theaflavins (tf), thearubigins (tg) and catechins. components from black tea have been accounted to play an important role in scavenging free radicals generated by mutagens and carcinogens. androgens are the key factors in either the initiation or progression of prostate cancer (pca) ... | 2005 | 16112415 |
| hplc analysis of naturally occurring methylated catechins, 3' '- and 4' '-methyl-epigallocatechin gallate, in various fresh tea leaves and commercial teas and their potent inhibitory effects on inducible nitric oxide synthase in macrophages. | (-)-epigallocatechin-3-gallate (egcg), a major polyphenol of green tea, undergoes substantial biotransformation to species that includes the methylated compounds. recent studies have demonstrated that the methylated egcg has many biological activities. in this study, we have investigated the composition of the three o-methylated egcg derivatives, (-)-epigallocatechin-3-o-(3-o-methyl)gallate (3' '-me-egcg), (-)-epigallocatechin-3-o-(4-o-methyl)gallate (4' '-me-egcg) and (-)-4'-methyl epigallocate ... | 2005 | 16131108 |
| inhibitory effects of epigallocatechin gallate on compound 48/80-induced mast cell activation and passive cutaneous anaphylaxis. | epigallocatechin gallate (egcg) is a principle phenolic antioxidant found in a variety of plants, including green and black tea. the anti-allergic effect of egcg is unknown. the purpose of this study is to investigate the effects of egcg on compound 48/80-induced mast cell activation and passive cutaneous anaphylaxis. for this, the influences of egcg on the compound 48/80-induced cutaneous reaction were measured in vivo and the effects of egcg on the compound 48/80-induced mast cell activations ... | 2005 | 16155406 |
| novel treatments for obesity and osteoporosis: targeting apoptotic pathways in adipocytes. | obesity and osteoporosis have grave consequences for human health, quality of life, and even the efficiency of the labor force and economy. however, these pathologies share a common cell progenitor, revealing a surprising target for drug research and development. recent findings show that high adipocyte count in bone marrow is directly related to bone loss, as fat cells replace osteoblasts (or bone-forming cells). the objective of this review is to examine the importance of adipocyte apoptosis i ... | 2005 | 16178781 |
| effect of herbal polyphenols on atherogenic transcriptome. | the ancient indian system of medicine supports the antiatherogenic properties of some herbs. the crosstalk amongst the genes coding for ldlr, lxralpha, ppars (alpha,gamma), cd-36 and c-myc may be important in atherogenesis because these genes control lipid metabolism, cytokine production and cellular activity within the arterial wall. hence, we attempted for the first time to explore whether or not the polyphenols extracted from medicinal herbs had any effect on the transcription of these genes. ... | 2005 | 16180103 |
| floratheasaponins a-c, acylated oleanane-type triterpene oligoglycosides with anti-hyperlipidemic activities from flowers of the tea plant (camellia sinensis). | the methanolic extract and its n-butanol-soluble fraction from the flowers of the tea plant (camellia sinensis) were found to suppress serum triglyceride elevation in olive oil-treated mice. from the n-butanol-soluble fraction, three new acylated oleanane-type triterpene oligoglycosides, floratheasaponins a-c (1-3), were isolated together with several flavonol glycosides and catechins. the structures of 1-3 were elucidated on the basis of chemical and physicochemical evidence as 21-o-angeloyl-22 ... | 2005 | 16180814 |
| oxidative deamination of benzylamine and lysine residue in bovine serum albumin by green tea, black tea, and coffee. | oxidative deamination by various polyphenolic compounds is presumed to be due to the oxidative conversion of polyphenols to the corresponding quinones through autoxidation. here we examined the oxidative deamination by the polyphenol-rich beverages green tea, black tea, and coffee at a physiological ph and temperature. green tea, black tea, and coffee extracts oxidatively deaminated benzylamine and the lysine residues of bovine serum albumin to benzaldehyde and alpha-aminoadipic delta-semialdehy ... | 2005 | 16190665 |
| modulation of mpp+ uptake by tea and some of its components in caco-2 cells. | the entry of most xeno/endobiotics into the organism is limited by their intestinal absorption. the interference of certain foods with the therapeutic efficacy of drugs or with chemical toxicity is becoming evident and growing attention is being given to these subjects. the aim of this work was to study the effect of green tea (gt) and black tea (bt), as well as some of their components, on the transport of organic cation molecules. for this purpose, 3h-mpp+ (radiolabeled 1-methyl-4-phenylpyridi ... | 2005 | 16193318 |
| cytotoxic and apoptogenic effect of tea (camellia sinensis var. assamica) root extract (tre) and two of its steroidal saponins ts1 and ts2 on human leukemic cell lines k562 and u937 and on cells of cml and all patients. | the anticancer activity of di- and tri-terpenes and other polyphenolic compounds present in tea is already reported. we evaluated the cytotoxic and apoptogenic effect of tea root extract (tre) and two of its steroidal saponins named as ts1 and ts2, on human cell lines and on cells from leukemic patients. it was found that tre, ts1 and ts2 significantly decreased cell count and that tre caused apoptosis, as confirmed morphologically by confocal microscopy and by flow-cytometric analysis using ann ... | 2006 | 16197994 |
| hepatoprotective effect of green tea (camellia sinensis) extract against tamoxifen-induced liver injury in rats. | tamoxifen citrate (tam), is widely used for treatment of breast cancer. it showed a degree of hepatic carcinogenesis. the purpose of this study was to elucidate the antioxidant capacity of green tea (camellia sinensis) extract (gte) against tam-induced liver injury. a model of liver injury in female rats was done by intraperitoneal injection of tam in a dose of 45mg kg(-1) day(-1), i.p. for 7 successive days. gte in the concentration of 1.5 %, was orally administered 4 days prior and 14 days aft ... | 2005 | 16202236 |
| dose-dependent levels of epigallocatechin-3-gallate in human colon cancer cells and mouse plasma and tissues. | epigallocatechin-3-gallate (egcg; molecular formula: c22h18011)is the most abundant catechin in green tea (camellia sinensis theaceae). both egcg and green tea have been shown to have cancer-preventive activity in a number of animal models, and numerous mechanisms have been proposed based on studies with human cell lines. egcg has been shown to undergo extensive biotransformation to yield methylated and glucuronidated metabolites in mice, rats, and humans. in the present study, we determined the ... | 2006 | 16204466 |
| keemun black tea extract contains potent fatty acid synthase inhibitors and reduces food intake and body weight of rats via oral administration. | the inhibitory effects of a black tea extract on fatty acid synthase were measured through inhibition kinetics. the keemun black tea extract showed more potent inhibitory activity on fatty acid synthase than green tea extract. additionally, the inhibitory ability of the black tea extract depended on the extracting solvent and the conditions used. only 10-23% of the inhibitory activity from the black tea was extracted by the general method of boiling with water. the results suggested that the mai ... | 2005 | 16206829 |
| arsenic removal from groundwater by pretreated waste tea fungal biomass. | arsenic contamination in ground water poses a serious threat on human health. the tea fungus, a waste produced during black tea fermentation has been examined for its capacity to sequester the metal ions from ground water samples. autoclaved tea fungal mat and autoclaving followed by fecl3 pretreated tea fungal mat were exploited for removal of as(iii), as(v) and fe(ii) from ground water sample collected from kolkata, west bengal, india. the biosorption rate tends to increase with the increase i ... | 2006 | 16216732 |
| antifungal activity of plant extracts against arthrinium sacchari and chaetomium funicola. | various plant extracts were examined for antifungal activity with the objective of improving the commercial sterility of aseptically filled tea beverage products in pet bottles. when the hot water extract and the methanol extract of 29 samples were measured for their antifungal activity against arthrinium sacchari m001 and chaetomium funicola m002 strains, five samples, acer nikoense, glycyrrhiza glabra, lagerstroemia speciosa, psidium guajava and thea sinensis, showed high activity. of these, t ... | 2000 | 16232887 |
| camellia sinensis: historical perspectives and future prospects. | as the source of brewed tea preparations, camellia sinensis has operated for centuries at the interface of agriculture, politics, and biology. the purpose of this review is to present an inter-disciplinary survey of issues surrounding cultivation, processing, and consumption of the tea plant. particular attention is given to the biologic effects of tea: first, assessing at the level of human physiology its value as a chemopreventive and chemotherapeutic agent; second, examining effects of produc ... | 2005 | 16236672 |
| flavor characteristics of lapsang souchong and smoked lapsang souchong, a special chinese black tea with pine smoking process. | the major volatile constituents of lapsang souchong, smoked lapsang souchong, and smoked souchong, a group of special black teas in china, were analyzed with gc and gc-ms analyses. forty-nine constituents were identified. longifolene and alpha-terpineol were the most abundant compounds in the aroma. due to its special production process, the compounds longifolene, longicyclene, guaiacol, 4-methylguaiacol, 4-ethylguaiacol, etc., were identified only in this kind of black tea. the aroma constituen ... | 2005 | 16248572 |
| induction of apoptosis in human leukemia cells by black tea and its polyphenol theaflavin. | treatment of human leukemic cell lines hl-60 and k-562 with extracts of green and black tea and their polyphenols epigallocatechin gallate and theaflavins, respectively, showed a dose dependent inhibition of growth as a result of cytotoxicity and suppression of cell proliferation. based on the ic50 values obtained from cytotoxicity data it was clearly evident that black tea was as efficient as green tea. analysis of polyphenol contents of tea extracts revealed that not only epigallocatechin gall ... | 2005 | 16253767 |
| [rapd analysis on genetic diversity of the preconcentrated core germplasms of camellia sinensis in china]. | the study was to evaluate the genetic diversity of 69 tea cultivars of the preconcentrated core germplasms of camellia sinensis in china by the random amplified polymorphic dna (rapd). among 50 arbitrary primers, 32 primers could generate enough amplified bands for all the strains in this study. among a total of 348 bands observed, 328 (94.3%)bands were polymorphic in the 69 cultivars tested except additional 20 cultivars. genetic distances between the cultivars varied from 0.223 to 0.723. the s ... | 2005 | 16257906 |
| oral administration of a decaffeinated green tea (camellia sinensis) extract did not alter urinary 8-epi-prostaglandin f(2 alpha), a biomarker for in-vivo lipid peroxidation. | oxidative stress is involved in the pathogenesis of numerous chronic human diseases. the objective of this study was to determine whether administration of a decaffeinated green tea extract providing 844 mg flavonoids daily reduced the urinary excretion of 8-epi-prostaglandin f(2 alpha) (8-epi-pgf(2 alpha)), a product of lipid peroxidation in cellular membranes and of low-density lipoprotein (ldl). nine healthy male and female subjects were studied at baseline and after 14 days of green tea supp ... | 2005 | 16259767 |
| in vitro and in vivo antimicrobial action of tea: the commonest beverage of asia. | the methanolic extract of leaves of camellia sinensis (l) o. kuntze was screened for antimicrobial property against 111 bacteria comprising 2 genera of gram positive and 7 genera of gram negative bacteria. most of these strains were inhibited by the compound at 10-50 microg/ml level and few strains were sensitive even at lower concentrations (5 microg/ml). the bacteria could be arranged in the decreasing order of sensitivity towards the compound in the following manner: staphylococcus aureus, vi ... | 2005 | 16272702 |
| aqueous extract of black tea (camellia sinensis) prevents ethanol+cholecystokinin-induced pancreatitis in a rat model. | black tea extract (bte), a phytocompound has been attributed with a plethora of health-promoting actions. we have previously demonstrated that bte inhibits chronic hepatitis in a rat model induced with high-fat and ethanol (etoh). this study reports that bte prevents altered pancreatic acinar cell functions, oxidative stress, inflammatory changes and dna damage in the etoh+cholecystokinin (cck)-induced model of pancreatitis. the etoh+cck model rats were administered with bte, and were examined t ... | 2006 | 16289561 |
| in vitro cytotoxicity of a theaflavin mixture from black tea to malignant, immortalized, and normal cells from the human oral cavity. | the growth inhibitory effects of a theaflavin mixture from black tea were more pronounced to malignant (cal27; hsc-2; hsg1) and immortalized (s-g; gt1) cells than to normal (hgf-2) cells from the human oral cavity. studies with malignant carcinoma cal27 cells and immortalized gt1 fibroblasts showed that cytotoxicity of the theaflavin mixture was enhanced as the exposure time was increased, with the tumor cal27 cells more sensitive than the gt1 cells. hydrogen peroxide (h(2)o(2)) was detected in ... | 2006 | 16297594 |
| anticlastogenic effects of black tea polyphenols theaflavins and thearubigins in human lymphocytes in vitro. | black tea accounts for nearly 80% of total world tea production. it contains dimeric flavanols and polymeric polyphenols known as theaflavins (tf) and thearubigins (tr). tr is exclusively present in black tea. on the basis of our previous potent antimutagenic and anticlastogenic effects of tf and tr in vitro in bacterial system and in vivo in mouse bone marrow cells, we have decided to extend our study in human cells in vitro. this study investigated the anticlastogenic effects of black tea poly ... | 2006 | 16314069 |
| effect of polymeric black tea polyphenols on benzo(a)pyrene [b(a)p]-induced cytochrome p4501a1 and 1a2 in mice. | the chemopreventive activity of green tea polyphenols (gtps) is, in part, due to modulation of cytochrome p450s (cyps). to investigate the enzyme modulatory properties of major black tea polyphenols, the effect of decaffeinated black tea extract (dbte) or polymeric black tea polyphenol (pbp) mix was studied on cyp1a1 and cyp1a2 in mouse tissues. animals receiving 2.5% dbte or 1% pbp mix or drinking water (15 days) were challenged with single oral benzo(a)pyrene (b(a)p) (1 mg/mouse) treatment on ... | 2005 | 16316927 |
| a clinical study: melaleuca, manuka, calendula and green tea mouth rinse. | a novel mouthrinse (ind 61,164) containing essential oils and extracts from four plant species (melaleuca alternifolia, leptospermum scoparium, calendula officinalis and camellia sinensis) were tested. this study aimed to evaluate the safety, palatability and preliminary efficacy of the rinse. fifteen subjects completed the phase i safety study. seventeen subjects completed the phase ii randomized placebo-controlled study. plaque was collected, gingival and plaque indices were recorded (baseline ... | 2005 | 16317652 |
| bioactive saponins and glycosides. xxiii. triterpene saponins with gastroprotective effect from the seeds of camellia sinensis--theasaponins e3, e4, e5, e6, and e7. | the saponin fraction from the seeds of the tea plant [camellia sinensis (l.) o. kuntze (theaceae)] was found to exhibit potent protective effects on ethanol- and indomethacin-induced gastric mucosal lesions in rats. five new triterpene saponins, theasaponins e3 (1), e4 (2), e5 (3), e6 (4), and e7 (5), were isolated together with 11 known saponins from the saponin fraction. the chemical structures of 1-5 were elucidated on the basis of chemical and physicochemical evidence. among the isolated sap ... | 2005 | 16327189 |
| changing diversity of hymenopteran parasitoids from organically and conventionally managed tea-ecosystem of north bengal, india. | tea, camellia sinensis (l.) o. kuntze, is grown conventionally (application of chemical fertilizer and pesticides) as well as organically in darjeeling hills and adjoining plains. studies on parasitic hymenoptera gain relevance due to their effective role as biocontrol agents for maintenance of ecological balance and as biological indicators of health of tea agro-ecosystem. diversity of the hymenopterans was studied using shannon-weaver index (1963) both at morphospecies and family levels. the a ... | 2005 | 16334289 |
| safety studies on epigallocatechin gallate (egcg) preparations. part 1: genotoxicity. | public interest in green tea has grown recently due to the potential health benefits from its consumption. epigallocatechin gallate (egcg), a principal polyphenolic component of green tea, is considered key to these healthful qualities. although numerous studies have evaluated the anti-cancer effects of green tea and egcg, few have examined the safety of egcg consumption. the genotoxic potential of a concentrated egcg preparation was tested in salmonella and l5178y tk+/- mouse lymphoma cell assa ... | 2006 | 16364532 |
| of the major phenolic acids formed during human microbial fermentation of tea, citrus, and soy flavonoid supplements, only 3,4-dihydroxyphenylacetic acid has antiproliferative activity. | dietary flavonoids are poorly absorbed from the gastrointestinal tract. colonic bacteria convert flavonoids into smaller phenolic acids (pa), which can be absorbed into the circulation and may contribute to the chemopreventive activity of the parent compounds. the purpose of our study was to determine whether flavonoids from green and black tea (gt, bt), citrus fruit with rutin (cf+r) and soy (s) supplements exposed to the same conditions in a dynamic in vitro model of the colon (tim-2) will for ... | 2006 | 16365058 |
| inhibition of cwr22rnu1 tumor growth and psa secretion in athymic nude mice by green and black teas. | cancer of the prostate gland (cap), the most common invasive malignancy and a major cause of cancer related deaths in male population in the usa, is an ideal candidate disease for chemoprevention because it is typically detected in elderly population with a relatively slower rate of growth and progression. many dietary phytochemicals are showing promising chemopreventive effects, at-least in pre-clinical models of cap. our published data in cell culture and animal studies, supported by the work ... | 2006 | 16387739 |
| inhibition of angiotensin converting enzyme activity by flavanol-rich foods. | angiotensin converting enzyme (ace) activity was evaluated in the presence of flavanol-rich foods, i.e., wines, chocolates, and teas, and of purified flavonoids. all foods assayed inhibited ace activity, red wines being more effective than white wine, and green tea more effective than black tea. the inhibition of ace activity was associated with both phenolic and flavanol content in the foods. when isolated polyphenols were assayed, procyanidins (dimer and hexamer) and epigallocatechin significa ... | 2006 | 16390204 |
| maximum residue limit and risk assessment of spiromesifen (bay bsn 2060; oberon 240sc) on tea (camellia sinensis (l) o' kuntze). | | 2005 | 16400559 |
| inhibitory effects of black tea theaflavin derivatives on 12-o-tetradecanoylphorbol-13-acetate-induced inflammation and arachidonic acid metabolism in mouse ears. | tea has been shown to possess several health beneficial properties primarily due to its polyphenolic content. the major polyphenolic compounds in black tea leaves are theaflavins (tfs) formed by oxidative coupling of catechins in tea leaves during its processing. in this paper, we report the characterization of 12-o-tetradecanoylphorbol-13-acetate (tpa)-induced mouse ear inflammatory model and the inhibitory effects of major black tea tfs derivatives on this inflammation. in addition, the effect ... | 2006 | 16404705 |
| neuroprotective effects of green and black teas and their catechin gallate esters against beta-amyloid-induced toxicity. | teas represent a large family of plants containing high amounts of polyphenols that may confer health benefits in various diseases. recently, it has been hypothesized that tea consumption may also reduce the risk of age-related neurodegenerative pathologies. considering the deleterious role of beta-amyloid (abeta) in the aetiology of alzheimer's disease (ad), we investigated green and black tea extracts and flavan-3-ols (present as monomers and dimers in green and black forms, respectively) agai ... | 2006 | 16420415 |