Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| in vitro chemopreventive activity of camellia sinensis, ilex paraguariensis and ardisia compressa tea extracts and selected polyphenols. | several herbal teas contain bioactive compounds that have been associated with a lower risk of chronic diseases including cancer. the aim of this study was to evaluate the chemopreventive activity of tea aqueous extracts and selected constituent pure polyphenols using a battery of in vitro marker systems relevant for the prevention of cancer. the effects of (-) epigallocatechin gallate (egcg), quercetin (q), gallic acid (ga), green tea (gt, camellia sinensis), ardisia tea (at, ardisia compressa) ... | 2004 | 15450404 |
| fluorides in groundwater, soil and infused black tea and the occurrence of dental fluorosis among school children of the gaza strip. | the purpose of this study was to determine the fluoride levels in water, soil and tea, and to identify the major fluoride minerals in soil that supply water with fluoride ions. another aim was to study the prevalence of dental fluorosis in permanent dentition of the school children of the gaza strip. monitoring of fluoride levels in 73 groundwater wells and 20 topsoil samples for the last three years revealed a general trend of increasing from north to south of the gaza strip. a linear regressio ... | 2004 | 15384727 |
| do leaf surface characteristics affect agrobacterium infection in tea [camellia sinensis (l.) o kuntze]? | the host range specificity of agrobacterium with five tea cultivars and an unrelated species (artemisia parviflora) having extreme surface characteristics was evaluated in the present study. the degree of agrobacterium infection in the five cultivars of tea was affected by leaf wetness, micro-morphology and surface chemistry. wettable leaf surfaces of tv1, upasi-9 and kangra jat showed higher rate (75%) of agrobacterium infection compared to upasi-10 and st-449, whereas non-wettable leaves of a. ... | 2004 | 15381852 |
| phenolic constituents and antioxidant activity of wendita calysina leaves (burrito), a folk paraguayan tea. | burrito tea originates from the leaves of wendita calysina, an indigenous paraguayan plant, which is commonly consumed in south america and in western countries. phytochemical investigation of this species has led to the isolation of 14 constituents, among them 2 new flavanonols, dihydroquercetagetin (1) and 3,5,6,7,4'-pentahydroxyflavanonol (2), in addition to several known methoxyflavones, methoxyflavonols, phenylethanoid glycosides, and benzoic acid derivatives (4-14). all structures were elu ... | 2004 | 15366833 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| octadecyl silica membrane disks modified with a new schiff's base for the preconcentration of lead and copper before their determination in water samples. | a simple and fast method for the extraction and determination of ppt level of pb2+ and cu2+ ions using octadecyl-bonded silica membrane disks modified by a new tetradentates schiffs base [bis(2,4-dimethoxy benzaldehyde) ethylen diimine](tdsb) and inductively coupled plasma atomic emission spectrometry is described. extraction efficiency, and influence of flow rate, ph, type and the least amount of acid for stripping of cu2+ and pb2+ from the modified disks and break through volume were evaluated ... | 2016 | 15279104 |
| analysis of catechin content of commercial green tea products. | tea (camellia sinensis) contains numerous polyphenolic flavonoid-derived compounds known as catechins, which have shown interesting protective activity against cancer and cardiovascular disease. numerous products based on tea are commercially available, many of which claim to contain specific amounts of the bioactive catechins. the catechin content of seven commercial green tea products (encapsulated extracts or tea bags) was quantified by hplc and, where possible, compared to that claimed on th ... | 2003 | 15277054 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| heavy metals in black tea samples produced in turkey. | 2004 | 15200002 | |
| lung cancer risk among nonsmoking women in relation to diet and physical activity. | to investigate the relationship between diet, physical activity, and the risk of lung cancer among female nonsmokers, and to compare it with female smokers in the same population, we conducted a case-control study. data collected by personal interviews from 419 cases and 1593 controls were analyzed using unconditional logistic regression. as expected, among 130 nonsmoking cases, adenocarcinoma was the predominant cell type (49.2%), followed by squamous cell (20.2%) and small cell cancers (10.5%) ... | 2004 | 15190423 |
| black tea increases coronary flow velocity reserve in healthy male subjects. | epidemiologic studies suggest that tea consumption decreases the risk for cardiovascular events. however, there has been no clinical report examining the effects of tea consumption on coronary circulation. the purpose of this study was to evaluate the effects of black tea on coronary flow velocity reserve (cfvr) using transthoracic doppler echocardiography (ttde). this was a double-blind crossover study of 10 healthy male volunteers conducted to compare the effects of black tea and caffeine on c ... | 2004 | 15165919 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [hepatotoxicity due to camelia sinensis]. | 2004 | 15153351 | |
| new dibenzotropolone derivatives characterized from black tea using lc/ms/ms. | theaflavins and thearubigins are major pigments in black tea, and it is generally accepted that they are produced by oxidation of flavan-3-ols (catechins) during tea fermentation. in the course of studies on the oxidation mechanism of tea polyphenols, especially the formation of thearubigins, a method combining the enzymatic synthesis and lc/esi-ms/ms analysis was developed to search for new higher molecular weight polymers from black tea. three new dibenzotropolones, theadibenzotropolone a, b, ... | 2004 | 15142559 |
| 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 |
| hplc-msn analysis of phenolic compounds and purine alkaloids in green and black tea. | tea is a complex mixture containing a range of compounds from simple phenolics to complex thearubigins, many of which have well-recognized antioxidant properties. this paper describes the application of high-performance liquid chromatography-mass spectrometry (hplc-ms(n)) methods for the rapid and routine analysis of more than 30 phenolics in tea. green and black tea infusions were injected directly onto a reversed phase hplc column, and the phenolics eluted using two different mobile phase grad ... | 2004 | 15137818 |
| 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 |
| 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 |
| pigments in green tea leaves (camellia sinensis) suppress transformation of the aryl hydrocarbon receptor induced by dioxin. | environmental contaminants such as dioxins enter the body mainly through diet and cause various toxicities through transformation of the aryl hydrocarbon receptor (ahr). we previously reported that certain natural flavonoids at the dietary level suppress the ahr transformation induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (tcdd). in this study, we identified lutein and chlorophyll a and b from green tea leaves as the novel antagonists for ahr. these active compounds suppressed ahr transformatio ... | 2004 | 15113147 |
| analysis of theaflavins and thearubigins from black tea extract by maldi-tof mass spectrometry. | black tea contains two major groups of pigments, theaflavins (tfs) and thearubigins (trs). tfs contain a bis-flavan substituted 1,2-dihydroxy-3,4-benzotropolone moiety. unlike the tfs, trs have not yet been characterized. the chemical structure of the trs remains a mystery. the present paper reports our effort to study the structure of tfs and trs using delayed pulsed ion extraction of ions generated via the matrix-assisted laser desorption ionization (maldi) technique, on line with a linear tim ... | 2004 | 15113141 |
| modulation of tea and tea polyphenols on benzo(a)pyrene-induced dna damage in chang liver cells. | the protective effects of three tea extracts (green tea, gte; oolong tea, ote; and black tea, bte) and five tea polyphenols (epicatechin, ec; epicatechin gallate, ecg; epigallocatechin, egc; epigallocatechin gallate, egcg; and theaflavins, thfs) on benzo[a]pyrene (b[a]p)-induced dna damage in chang liver cells were evaluated using the comet assay. b[a]p-induced dna damage in chang liver cells was significantly (p < 0.05) inhibited by gte and ote at a concentration of 10 microg/ml and by bte at 2 ... | 2004 | 15104213 |
| 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 |
| effects of sweet and bitter gustatory stimuli in anorexia nervosa on eeg frequency spectra. | the possible differences in processing gustatory stimuli in anorexic patients compared to healthy control subjects was investigated by electrophysiological methods. the electroencephalogram (eeg) was recorded in outpatients treated with anorexia nervosa (an) and age-matched controls after exposure to sweet (milk chocolate) and bitter (black tea) taste stimuli. power spectrum analysis was performed on eeg epochs recorded in the above conditions. compared to controls a significantly higher percent ... | 2004 | 15094251 |
| 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 |
| 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 |
| development of methods to enhance extrinsic tooth discoloration for comparison of toothpastes. 2. two-product clinical study. | extrinsic staining of teeth is considered to be unsightly and a number of 'whitening' toothpastes have been formulated to inhibit or remove such tooth discoloration. the aim of this study was to compare the stain prevention of two toothpastes. | 2004 | 15058367 |
| determination of ni (ii) in beverages without any sample pretreatment by adsorptive stripping chronopotentiometry (adscp). | the purpose of this paper was to use adsorptive stripping chronopotentiometry for the determination of ni (ii) in worldwide consumed beverages without any sample pretreatment, using dimethilglyoxime (dmg) as complexing agent and a glassy carbon mercury film electrode as the working electrode. ni (dmg)2 complex is adsorbed onto the mercury film at an electrolysis potential of -500 mv for 60 s and then reduced by a -5 microa constant cathodic current. the sensitivity of the method was studied for ... | 2004 | 15053517 |
| 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 |
| reaction of iron(iii) with theaflavin: complexation and oxidative products. | theaflavins are a family of compounds, whose chemistry has been sparsely investigated. they can comprise up to 40% the dry weight of black tea. they are known to chelate metals, however very little knowledge exists on the mechanisms involved. there is some correlation between both of these areas in that following degradation of the iron theaflavin complex, subsequent redox reactions may lead to the formation of similar products on both occasions. the interaction of iron(iii) with theaflavin at p ... | 2004 | 15041246 |
| [determination of low-level pesticide residues in agricultural products by ion-trap gc/ms/ms]. | the objective of this study was to elucidate the utility of ion-trap gc/ms/ms for the analysis of pesticides in extracted matrices from various agricultural products. identification and quantitative analysis of pesticides in matrices were performed by quadrupole gc/ms and ion-trap gc/ms/ms. chlorpyrifos was added to the matrix of spinach, soybean in the pod or corn, and aldrin, dieldrin, endrin, alpha-bhc, beta-bhc, gamma-bhc, delta-bhc, p,p'-ddd, p,p'-dde, o,p'-ddt and p,p'-ddt were added to ea ... | 2003 | 15038113 |
| 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 |
| 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 |
| 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 |
| a clinical study to assess the ability of a powered toothbrush to remove chlorhexidine/tea dental stain. | a single-center, single-blind, two-way crossover study was performed to compare the effects of an electric powered toothbrush with a conventional manual toothbrush at removing chlorhexidine/tea tooth staining. | 2004 | 15016033 |
| role of hydrogen peroxide in bactericidal action of catechin. | catechin (epicatechin (ec), epicatechin gallate (ecg), epigallocatechin (egc) and epigallocatechin gallate (egcg)), which occur in green tea and black tea, possess strong bactericidal action. we observed a reactive oxygen species that was generated from the catechins as the active mechanism: and this reactive oxygen was identified. egcg reacted with the dissolved oxygen in aqueous solution, resulting in the generation of hydrogen peroxide. hydrogen peroxide production derived from egcg rose with ... | 2004 | 14993788 |
| caffeine synthase and related methyltransferases in plants. | caffeine (1,3,7-trimethylxanthine) is a purine alkaloid present in high concentrations in tea and coffee and it is also found in a number of beverages such as coca cola. it is necessary to elucidate the caffeine biosynthetic pathway and to clone the genes related to the production of caffeine not only to determine the metabolism of the purine alkaloid but also to control the content of caffeine in tea and coffee. the available data support the operation of a xanthosine-->7-methylxanthosine-->7-m ... | 2004 | 14977590 |
| effect of a 4-month tea intervention on oxidative dna damage among heavy smokers: role of glutathione s-transferase genotypes. | glutathione s-transferase (gst), a member of the phase ii group of xenobiotic metabolizing enzymes, has been intensively studied at the levels of phenotype and genotype. the gst mu 1 (gstm1) and gst theta 1 (gstt1) genes have a null-allele variant in which the entire gene is absent. the null genotype for both enzymes has been associated with many different types of tumors. the aim of this study was to determine the possible differences in increased oxidative stress susceptibility to smoking with ... | 2004 | 14973088 |
| 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 |
| 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 |
| 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 |
| 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 |
| fluoride and aluminum in teas and tea-based beverages. | to evaluate fluoride and aluminum concentration in herbal, black, ready-to-drink, and imported teas available in brazil considering the risks fluoride and aluminum pose to oral and general health, respectively. | 2004 | 14963548 |
| [acute hepatitis due to exolise, a camellia sinensis-derived drug]. | 2003 | 14770123 | |
| comparative study of the growth-inhibitory and apoptosis-inducing activities of black tea theaflavins and green tea catechin on murine myeloid leukemia cells. | among the black tea polyphenols, theaflavins are generally considered to be the more effective components for the inhibition of carcinogenesis. in this study, we attempted to compare the growth-inhibitory and apoptosis-inducing activities of the four black tea theaflavins (tf-1, tf-2a, tf-2b and tf-3) with the major green tea catechin epigallocatechin-3-gallate (egcg) on the murine myeloid leukemia wehi-3b jcs cells. all the four black tea theaflavins were shown to exert potent anti-proliferativ ... | 2004 | 14767581 |
| 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 |
| 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 |
| 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 |
| 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 |
| delivery of tea polyphenols to the oral cavity by green tea leaves and black tea extract. | catechins and theaflavins, polyphenolic compounds derived from tea (camellia sinensis, fam. theaceae), have been reported to have a wide range of biological activities including prevention of tooth decay and oral cancer. the present study was undertaken to determine the usefulness of green tea leaves and black tea extract for the delivery of catechins and theaflavins to the oral cavity. after holding either green tea leaves (2 g) or brewed black tea (2 g of black tea leaves in 100 ml) in the mou ... | 2004 | 14744744 |
| 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 |
| tissue distribution and intracellular localization of catechins in tea leaves. | we investigated the leaf tissue and cellular morphology of tea (camellia sinensis). osmiophilic material, presumably catechins, was present in mesophyll cells, but not in epidermal cells. electron microscopy showed that catechins were localized to restricted regions within the central vacuoles. in addition, two kinds of small vacuoles of 0.5-3 microm were present in mesophyll cells. one vacuole had catechins within its whole lumen, while the other had an electron-lucent lumen. we found fusion pr ... | 2003 | 14730155 |
| production of hydrogen peroxide by polyphenols and polyphenol-rich beverages under quasi-physiological conditions. | to investigate the ability of the production of h(2)o(2) by polyphenols, we incubated various phenolic compounds and natural polyphenols under a quasi-physiological ph and temperature (ph 7.4, 37 degrees c), and then measured the formation of h(2)o(2) by the ferrous ion oxidation-xylenol orange assay. pyrocatechol, hydroquinone, pyrogallol, 1,2,4-benzenetriol, and polyphenols such as catechins yielded a significant amount of h(2)o(2). we also examined the effects of a metal chelator, ph, and o(2 ... | 2003 | 14730143 |
| impact of tea drinking on iron status in the uk: a review. | the aims of this review are (1) to evaluate the literature on the likely impact of tea drinking on the iron status of different groups within the uk population and (2) to formulate targeted and evidence based advice on tea drinking in the context of iron nutrition in different groups of people. | 2004 | 14718031 |
| 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 |
| 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 |
| 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 |
| 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 |
| foods and beverages in relation to urothelial cancer: case-control study in japan. | the roles of several foods and beverages in the development of bladder cancer remain unclear. | 2004 | 14678179 |
| influence of milk on the antimutagenic potential of green and black teas. | the objective of this study was to evaluate whether addition of milk to green, black and decaffeinated black teas alters their antimutagenic activity. | 2016 | 14666689 |
| 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 |
| 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 |
| unfermented rooibos tea: quantitative characterization of flavonoids by hplc-uv and determination of the total antioxidant activity. | unfermented rooibos originates from the leaves and the stems of the indigenous south african plant, aspalathus linearis, and it has been reported to have a higher content of flavonoids compared to that of fermented rooibos. the hplc/uv method developed in our laboratory for the analysis of the fermented rooibos was applied to the quantitative characterization of the major flavonoids present in the unfermented rooibos. main compounds determined were aspalathin (49.92 +/- 0.80 mg/g), isoorientin ( ... | 2003 | 14640601 |
| antioxidative activities of volatile extracts from green tea, oolong tea, and black tea. | antioxidative activities of volatile extracts from six teas (one green tea, one oolong tea, one roasted green tea, and three black teas) were investigated using an aldehyde/carboxylic acid assay and a conjugated diene assay. the samples were tested at levels of 20, 50, 100, and 200 micrograms/ml of dichloromethane. the results obtained from the two assays were consistent. all extracts except roasted green tea exhibited dose-dependent inhibitory activity in the aldehyde/carboxylic acid assay. a v ... | 2003 | 14640590 |
| cocoa has more phenolic phytochemicals and a higher antioxidant capacity than teas and red wine. | black tea, green tea, red wine, and cocoa are high in phenolic phytochemicals, among which theaflavin, epigallocatechin gallate, resveratrol, and procyanidin, respectively, have been extensively investigated due to their possible role as chemopreventive agents based on their antioxidant capacities. the present study compared the phenolic and flavonoid contents and total antioxidant capacities of cocoa, black tea, green tea, and red wine. cocoa contained much higher levels of total phenolics (611 ... | 2003 | 14640573 |
| inhibition of caffeine biosynthesis in tea (camellia sinensis) and coffee (coffea arabica) plants by ribavirin. | the effects of ribavirin, an inhibitor of inosine-5'-monophosphate (imp) dehydrogenase, on [8-(14)c]inosine metabolism in tea leaves, coffee leaves and coffee fruits were investigated. incorporation of radioactivity from [8-(14)c]inosine into purine alkaloids, such as theobromine and caffeine, guanine residues of rna, and co(2) was reduced by ribavirin, while incorporation into nucleotides, including imp and adenine residues of rna, was increased. the results indicate that inhibition of imp dehy ... | 2003 | 14623114 |
| [liver toxicity of camellia sinensis dried etanolic extract]. | 2003 | 14622530 | |
| 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 |
| 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 |
| 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 |
| 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 |
| molecular detection of cashew husk (anacardium occidentale) adulteration in market samples of dry tea (camellia sinensis). | species-specific pcr primers were developed from intergenic spacer regions of 5s ribosomal rna genes and used successfully in the detection of adulteration of cashew husk (anacardium occidentale l.) in tea [camellia sinensis (l.) o. kuntze] samples. this is the first report of detecting adulteration in tea using molecular tools. application of this approach in detecting adulteration of other biological materials in tea, medicinal herbs and the composition of admixtures of ayurvedic herbs has bee ... | 2003 | 14598225 |
| effective use of tea to limit dietary iron available to starlings (sturnus vulgaris). | wild-caught starlings (sturnus vulgaris) were fed an iron-enriched diet, with or without supplemental black tea leaves, to determine whether tea-derived tannins would prevent intestinal iron absorption. hepatic biopsies were obtained to determine hepatic iron concentrations by atomic absorption spectroscopy. hepatic iron concentrations increased significantly (p = 0.04) in 21 birds that consumed only the iron-enriched diet for 6 mo but not in the 20 birds that consumed the iron-enriched diet wit ... | 2003 | 14582799 |
| [antioxidant activities of green and black teas determined by the cumene hydroperoxide/hemoglobin.methylene blue method]. | antioxidant activity in tea was measured by the new cumene hydroperoxide/hemoglobin.methylene blue(chp/hb.mb) method developed in our laboratory. using the chp/hb.mb method, we investigated the activities of polyphenols(11 varieties) in order to determine their reactivity on chp. according to the chp/hb.mb method, an increase in the number of hydroxyl groups in polyphenols induced high antioxidant activity. we found that this method was capable of measuring the antioxidant activity of polyphenol ... | 2003 | 14560653 |
| 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 |
| fermentation characteristics of some assamica clones and process optimization of black tea manufacturing. | changes in the specific activities of polyphenol oxidase (ppo), peroxidase (pod), and protease and in the relative amounts of flavan-3-ols for eight genetically derived cultivated teas at various stages of leaf maturity and in four succescive seasons were examined. a series of investigations were carried out to study the cross-reactivity of complex polyphenols and ppo-generated orange-yellow theaflavins, as well as of pod oxidized substrates, producing brown so-called thearubigins during ferment ... | 2003 | 14558781 |
| the epidemiology of tea consumption and colorectal cancer incidence. | this manuscript provides a brief synopsis of 30 studies aimed at examining tea consumption as a factor in the incidence of colon and rectal cancers. the 30 papers examine populations in 12 countries and provide data on consumption of both black and green tea. these studies do not provide consistent evidence to support the theory from animal studies and basic research that tea is a potent chemopreventive agent. details of the studies are presented, and the potential impact of measurement error, p ... | 2003 | 14519831 |
| effect of increased tea consumption on oxidative dna damage among smokers: a randomized controlled study. | tea drinking has been associated with decreased occurrence of cancer and heart disease. one potential mechanism for these findings is the strong antioxidant effect of tea polyphenols. a phase ii randomized controlled tea intervention trial was designed to study the effect of high consumption (4 cups/d) of decaffeinated green or black tea on oxidative dna damage as measured by urinary 8-hydroxydeoxyguanosine (8-ohdg) among smokers over a 4-mo period. a total of 143 heavy smokers, aged 18-79 y, we ... | 2003 | 14519830 |