Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| an epidemiologic study of tongue lesions in 1901 iranian dental outpatients. | the aim of this study was to assess the frequency of nine tongue conditions and evaluate their relationship to oral hygiene status and personal habits in a northern iranian population. | 2008 | 18997919 |
| pcr differential display-based identification of regulator of g protein signaling 10 as the target gene in human colon cancer cells induced by black tea polyphenol theaflavin monogallate. | we have previously reported that black tea polyphenol theaflavin monogallate (tf-2) suppressed cox-2 and induced apoptosis in human colon cancer cells [lu, j.b., ho, c.-t., ghai, g., chen, k.y., 2000. differential effects of theaflavin monogallates on cell growth, apoptosis and cox-2 gene expression in cancerous versus normal cells. cancer res. 60, 6465-6471.]. we now extended the study by using pcr-based differential display to search for genes that were selectively induced by tf-2. here we rep ... | 2008 | 18992738 |
| black tea polyphenols modulate xenobiotic-metabolizing enzymes, oxidative stress and adduct formation in a rat hepatocarcinogenesis model. | the present study was designed to investigate the modulatory effects of black tea polyphenols (polyphenon-b) on phase i and phase ii xenobiotic-metabolizing enzymes and oxidative stress in a rat model of hepatocellular carcinoma (hcc). liver tumours induced in male sprague-dawley rats by dietary administration of rho-dimethylaminoazobenzene (dab) increased cytochrome p450 (total and cyp1a1, 1a2 and 2b isoforms), cytochrome b(5), cytochrome b(5) reductase, glutathione s-transferase (gst total and ... | 2008 | 18985486 |
| in vitro antioxidative potential of lactoferrin and black tea polyphenols and protective effects in vivo on carcinogen activation, dna damage, proliferation, invasion, and angiogenesis during experimental oral carcinogenesis. | the present study was designed to evaluate the in vitro antioxidant potential of bovine lactoferrin (blf) and black tea polyphenols [polyphenon-b (p-b)] as well as in vivo inhibitory effects on the development of 7,12-dimethylbenz[a]anthracene (dmba)-induced hamster buccal pouch (hbp) carcinomas. antioxidant activity was screened using a panel of assays including 1,1-diphenyl-2-picrylhydrazyl (dpph), 2,2'-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid) (abts), hydroxyl radical anion (oh*), su ... | 2008 | 18980016 |
| antiproliferative and antimicrobial activity of traditional kombucha and satureja montana l. kombucha. | to carry out a preliminary investigation of the biological activity of kombucha beverages from camellia sinensis l. (black tea) and satureja montana l. (winter savory tea), that have consuming acidity. | 2008 | 18979556 |
| column solid-phase extraction of nickel and silver in environmental samples prior to their flame atomic absorption spectrometric determinations. | a biosorption procedure for preconcentration-separation of nickel(ii) and silver(i) at trace levels on bacillus sphaericus-loaded chromosorb 106 (bslc106) has been presented in this work. the conditions like ph, amounts of microorganism, eluent type, etc. for the quantitative adsorption of the analyte ions on bscl106 column were investigated. the analyte ions were quantitatively recovered and desorbed at ph range of 6.0-7.0 and 10 ml of 1m hcl, respectively. the effects of various cationic and a ... | 2009 | 18977595 |
| paenibacillus camelliae sp. nov., isolated from fermented leaves of camellia sinensis. | a novel bacterium, strain blls-2(t) was isolated from pu'er tea. the isolate was gram-positive, endospore-forming motile rod that grew at 15 approximately 42 degrees c and ph 6.0 approximately 10.2. the dna g+c content was 48.3 mol%, the predominant isoprenoid quinone was mk-7, and the predominant cellular fatty acid was anteiso-c15:0 (54.2%) followed by c16:0 (15.5%) and iso-c16:0 (8.2%). the polar lipid pattern of blls-2(t) was characterized by the presence of diphosphatidylglycerol, phosphati ... | 2008 | 18974954 |
| influence of culture media and environmental factors on mycelial growth and sporulation of lasiodiplodia theobromae (pat.) griffon and maubl. | lasiodiplodia theobromae, a common tea (camellia sinensis) pathogen, usually does not sporulate or sporulates poorly in common media, which makes spore production difficult. in this study the effects of culture media, carbon source, nitrogen source, temperature, ph and light on mycelial growth and sporulation were evaluated. among several carbon sources tested, glucose and sucrose were found superior for growth. potassium nitrate supplemented media showed maximum growth amongst the tested inorga ... | 2008 | 18972700 |
| biosorption of heavy metals on aspergillus fumigatus immobilized diaion hp-2mg resin for their atomic absorption spectrometric determinations. | a solid phase extraction procedure based on biosorption of copper(ii), lead(ii), zinc(ii), iron(iii), nickel(ii) and cobalt(ii) ions on aspergillus fumigatus immobilized diaion hp-2mg has been investigated. the analytical conditions including amounts of a. fumigatus, eluent type, flow rates of sample and eluent solutions were examined. good recoveries were obtained to the spiked natural waters. the influences of the concomitant ions on the retentions of the analytes were also examined. the detec ... | 2006 | 18970890 |
| a study on the determination of chromium as chromate at a carbon paste electrode modified with surfactants. | a procedure for the determination of chromium is described based on synergistic pre-concentration of the chromate anion at a carbon paste electrode modified in situ with quarternary ammonium salts such as 1-ethoxycarbonylpentadecyltrimethylammonium bromide (septonex((r))), cetyltrimethylammonium bromide (ctab) or cetylpyridinium bromide (cpb). the proper electrochemical detection utilises the reduction cr(vi) --> cr(iii) performed in the differential pulse cathodic voltammetric mode. in discussi ... | 2004 | 18969679 |
| simultaneous determination of catechins, caffeine and gallic acids in green, oolong, black and pu-erh teas using hplc with a photodiode array detector. | a simple and fast hplc method using a photodiode array detector was developed for simultaneous determination of four major catechins, gallic acid and caffeine. after multiple extractions with aqueous methanol and acidic methanol solutions, tea extract was separated within 20 min using a methanol-acetate-water buffer gradient elution system on a c(18) column. the sample extraction data demonstrated that the single extraction used in the previous studies with aqueous acetonitrile or methanol is no ... | 2002 | 18968631 |
| classification of tea samples by their chemical composition using discriminant analysis. | multivariate analysis in combination with pattern recognition procedures has been applied to samples of green and black tea. discriminant analysis has been used for classification purposes. aqueous extract, polyphenols, amino acids, caffeine, theobromine and theophylline were used as chemical descriptors. | 1996 | 18966503 |
| differential growth suppression of human melanoma cells by tea (camellia sinensis) epicatechins (ecg, egc and egcg). | we previously reported that catechins of green tea have different antiproliferative effects on cell lines derived from gender-dependent cancers; epicatechin 3-gallate (ecg) had the strongest inhibitory effect. in the present study, we examined the effects of epigallocatechin (egc), epicatechin-gallate (ecg) and egc 3-gallate (egcg) on the viability, density, doubling time and cycle number of cell lines derived from melanoma metastasized to lymph nodes (mb-1133 and se-0154) or distant organs (ch- ... | 2009 | 18955299 |
| identification of green tea's (camellia sinensis (l.)) quality level according to measurement of main catechins and caffeine contents by hplc and support vector classification pattern recognition. | high performance liquid chromatography (hplc) was identified green tea's quality level by measurement of catechins and caffeine content. four grades of roast green teas were attempted in this work. five main catechins ((-)-epigallocatechin gallate (egcg), (-)-epigallocatechin (egc), (-)-epicatechin gallate (ecg), (-)-epicatechin (ec), and (+)-catechin (c)) and caffeine contents were measured simultaneously by hplc. as a new chemical pattern recognition, support vector classification (svc) was ap ... | 2008 | 18952392 |
| green tea (camellia sinensis) and cancer prevention: a systematic review of randomized trials and epidemiological studies. | green tea is one of the most popular beverages worldwide. this review summarizes the beneficial effects of green tea on cancer prevention. | 2008 | 18940008 |
| green tea protects rats against autoimmune arthritis by modulating disease-related immune events. | green tea, a product of the dried leaves of camellia sinensis, is the most widely consumed beverage in the world. the polyphenolic compounds from green tea (pgt) possess antiinflammatory properties. we investigated whether pgt can afford protection against autoimmune arthritis and also examined the immunological basis of this effect using the rat adjuvant arthritis (aa) model of human rheumatoid arthritis (ra). aa can be induced in lewis rats (rt.1(l)) by immunization with heat-killed mycobacter ... | 2008 | 18936206 |
| p-coumarate:coa ligase as a key gene in the yield of catechins in tea [camellia sinensis (l.) o. kuntze]. | tea is an important crop known for its beverage and antioxidant polyphenols -- catechins and its derivatives. catechins are synthesized through flavonoid (fl) pathway and stored in the vacuole. a metabolic flux for the operation of fl pathway is maintained through the supply of 4-coumaroyl-coa of phenylpropanoid pathway. 4-coumaroyl-coa is synthesized through the catalytic activity of p-coumarate:coa ligase (4cl) using 4-coumaric acid and acetyl-coa as the substrates. the present manuscript repo ... | 2009 | 18931865 |
| green and black tea extracts inhibit hmg-coa reductase and activate amp kinase to decrease cholesterol synthesis in hepatoma cells. | recent studies have demonstrated that green and black tea consumption can lower serum cholesterol in animals and in man, and suppression of hepatic cholesterol synthesis is suggested to contribute to this effect. to evaluate this hypothesis, we measured cholesterol synthesis in cultured rat hepatoma cells in the presence of green and black tea extracts and selected components. green and black tea decreased cholesterol synthesis by up to 55% and 78%, respectively, as measured by a 3-h incorporati ... | 2009 | 18926682 |
| standardized capsule of camellia sinensis lowers cardiovascular risk factors in a randomized, double-blind, placebo-controlled study. | previous studies examining the effect of tea drinking on cardiovascular health have produced mixed results due to their observational nature and qualitatively and quantitatively imprecise definitions of active tea components. the objective of this study was to determine if a standardized and defined decaffeinated green tea (camellia sinensis) product lowers blood pressure, serum lipids, oxidative stress, and markers of chronic inflammation. | 2009 | 18848434 |
| coffee, tea, and incident type 2 diabetes: the singapore chinese health study. | increasing coffee intake was inversely associated with risk of type 2 diabetes in populations of european descent; however, data from high-risk asian populations are lacking as are data on tea intake in general. | 2008 | 18842784 |
| screening of dhfr-binding drugs by maldi-tofms. | the class of antimetabolite chemotherapeutical agents has been used to treat cancers in humans for almost 50 years and gives significant results by binding dihydrofolate reductase (dhfr), a key enzyme in dna synthesis. therefore, finding new active compounds inhibiting dna synthesis through their binding to dhfr is of prime interest. the aim of this work is to describe a protocol designed to study the binding of compounds to dhfr. this screening protocol involves matrix-assisted laser desorption ... | 2008 | 18841351 |
| in vitro effects of tea polyphenols on redox metabolism, oxidative stress, and apoptosis in pc12 cells. | tea polyphenols, especially catechins, have been reported to be potent antioxidants and beneficial in oxidative stress-related diseases including cancer. numerous animal and cell culture models demonstrate anticancer effects of tea catechins. experimental and epidemiological evidence suggests the use of black tea polyphenols (btp), green tea catechins (especially epigallocatechin gallate [egcg]), and other polyphenols in preventing the progression of cancer both in animal and human populations. ... | 2008 | 18837911 |
| volatile components of camellia sinensis inhibit growth and biofilm formation of oral streptococci in vitro. | this study aimed to evaluate the efficacy of semi fermented and non fermented camellia sinensis extracts (black and green tea) and comparison between them against streptococcus mutans atcc 25175, s. mitis atcc 9811 and s. sanguis atcc 10556 that are responsible for dental caries and bacteremias following dental manipulations. minimum inhibitory concentrations of both tea extracts were assessed by well diffusion and broth dilution methods and examination of cell adherence (biofilm inhibitory conc ... | 2008 | 18817265 |
| quantitative assessment of metals in local brands of tea in pakistan. | in present study, mn, fe, zn, cu, co, pb, cr, ni and cd were analyzed by faas in green and black tea samples of locally available in the pakistani market. na and k were also determined by flame photometer. tea leaves can be the source of mineral components and trace elements, as well as some undesirable substances due to exposure to the environment. among the metals tested, k was the most abundant one followed by na, mn and fe. fortunately, toxic heavy metals, pb and cd, had the lowest contents ... | 2008 | 18817205 |
| tea polyphenols benefit vascular function. | tea, the most popular beverage worldwide, is consumed in three basic forms; green tea, black tea and oolong tea. tea contains over 4,000 chemicals some of which are bioactive. in recent years there has been a mounting interest in understanding the cardiovascular and metabolic benefits of polyphenolic flavonoids in tea, which can be used as a supplement among patients. diverse cardioprotective effects of consuming tea or tea polyphenols have been described on pathological conditions, e. g. hypert ... | 2008 | 18815738 |
| characterisation of lysozyme activity in the in situ pellicle using a fluorimetric assay. | lysozyme is among the most protective enzymes in the pellicle layer. the aim of the present study was to establish a precise fluorimetric assay for determination and characterisation of lysozyme activity immobilised in the initial in situ formed pellicle. for in situ pellicle formation, bovine enamel slabs were fixed on maxillary splints and carried by six subjects for different times (3, 30 min) on buccal and palatal sites. the enzymatic assay was based on hydrolysis of cell walls from micrococ ... | 2009 | 18810509 |
| high level of genetic diversity among the selected accessions of tea (camellia sinensis) from abandoned tea gardens in western himalaya. | to revive cultivation of the tea unique to the western himalayan region, it is important to evaluate the seed-derived bushes available in the area's abandoned gardens. this study used quantitative leaf characters, catechin content, and aflp markers to assess these china cultivar type bushes. compared with other china cultivar germplasm, these accessions showed a higher level of diversity among themselves. among the quantitative morphological characters, leaf length is important in distinguishing ... | 2008 | 18784998 |
| preservation of kombucha tea-effect of temperature on tea components and free radical scavenging properties. | kombucha tea is sugared black tea fermented with a consortium of acetic acid bacteria and yeasts (tea fungus) for 14 days. the tea tastes slightly sweet and acidic. the formation of tea fungal biofilms during storage is a big problem when kombucha tea is being stored and commercialized. various thermal treatments have been tried for long-term storage of kombucha tea. the present study revealed the influence of heat on the biochemical constituents and the free radical scavenging properties of kom ... | 2008 | 18781766 |
| antibacterial effects of green tea polyphenols on clinical isolates of methicillin-resistant staphylococcus aureus. | the antibacterial effects of tea polyphenols (tpp) extracted from korean green tea (camellia sinensis) against clinical isolates of methicillin-resistant staphylococcus aureus (mrsa) were evaluated. characterization of the minimal inhibitory concentration (mic) of oxacillin for 30 s. aureus strains isolated from patients treated with oxacillin identified 13 strains with an oxacillin mic >or= 4 microg/ml as methicillin-resistant staphylococcus aureus (mrsa) (range: 8 to 512 microg/ml), while 17 s ... | 2008 | 18781360 |
| total polyphenol content and antioxidant capacity of commercially available tea (camellia sinensis) in argentina. | tea, camellia sinensis (l.) o. kuntze (theaceae) is cultivated in argentina in the northeastern region (provinces of misiones and corrientes), between 26 degrees and 28 degrees south latitude, the southernmost area of the world where tea is cultivated. the objective of this work was to determine the total polyphenol content and the in vitro antioxidant capacity of green and black tea cultivated and industrialized in argentina. twelve samples of eight brands were analyzed. the total polyphenol co ... | 2008 | 18778031 |
| efficacy and safety of chinese black tea (pu-ehr) extract in healthy and hypercholesterolemic subjects. | water-extracted chinese black tea (pu-ehr) exerts a precipitating effect on mixed bile salt micelles in foods. the amount of black tea extract (bte) effective for hypercholesterolemia (hc) was examined in humans. | 2008 | 18769024 |
| medicinal flowers. xxii. structures of chakasaponins v and vi, chakanoside i, and chakaflavonoside a from flower buds of chinese tea plant (camellia sinensis). | two acylated oleanane-type triterpene oligoglycosides, chakasaponins v and vi, an aromatic glycoside, chakanoside i, and an acylated flavonol oligoglycoside, chakaflavonoside a, were isolated from the flower buds of chinese tea plant [camellia sinensis (l.) o. kuntze]. the chemical structures of those new glycosides were elucidated on the basis of chemical and physicochemical evidence. | 2008 | 18758105 |
| a population-based, case-control study of green tea consumption and leukemia risk in southwestern taiwan. | this study investigated the association between green tea consumption and leukemia. | 2009 | 18752033 |
| characterization of cellulose production by a gluconacetobacter xylinus strain from kombucha. | the aims of this work were to characterize and improve cellulose production by a gluconoacetobacter xylinus strain isolated from kombucha and determine the purity and some structural features of the cellulose from this strain. cellulose yield in tea medium with both black tea and green tea and in hestrin and schramm (hs) medium under both static and agitated cultures was compared. in the tea medium, the highest cellulose yield was obtained with green tea (approximately 0.20 g/l) rather than blac ... | 2008 | 18704575 |
| new phenolic components and chromatographic profiles of green and fermented teas. | a standardized profiling method based on liquid chromatography with diode array and electrospray ionization mass spectrometric detection (lc-dad-esi/ms) was applied to establish the phenolic profiles of 41 green teas and 25 fermented teas. more than 96 phenolic compounds were identified that allowed the teas to be organized into five groups. epigallocatechin gallate (egcg) was the major phenolic component of green tea made from mature leaves (group 2), while green tea made from the younger buds ... | 2008 | 18686968 |
| selective effects of tea extract and its phenolic compounds on human peripheral blood mononuclear cell cytokine secretions. | the effects of black tea extract (bte) and some of its pure phenolics on human peripheral blood mononuclear cell (pbmc) cytokine secretion were examined in vitro. | 2009 | 18686109 |
| the effects of sour tea (hibiscus sabdariffa) on hypertension in patients with type ii diabetes. | to compare the antihypertensive effectiveness of sour tea (st; hibiscus sabdariffa) with black tea (bt) infusion in diabetic patients, this double-blind randomized controlled trial was carried out. sixty diabetic patients with mild hypertension, without taking antihypertensive or antihyperlipidaemic medicines, were recruited in the study. the patients were randomly allocated to the st and bt groups and instructed to drink st and bt infusions two times a day for 1 month. their blood pressure (bp) ... | 2009 | 18685605 |
| effect of genistein on the bioavailability and intestinal cancer chemopreventive activity of (-)-epigallocatechin-3-gallate. | the green tea (camellia sinensis) catechin, (-)-epigallocatechin-3-gallate (egcg), has shown cancer-preventive activity in animal models. previously, we have reported the bioavailability of egcg in rats and mice. here, we report that cotreatment of ht-29 human colon cancer cells with genistein (from soy) increased cytosolic egcg by 2- to 5-fold compared with treatment with egcg only. inclusion of genistein, at non-cytotoxic concentrations, increased the growth inhibitory effects of egcg against ... | 2008 | 18684728 |
| topographic and radiographic profile assessment of dental erosion. part iii: effect of green and black tea on human dentition. | this study compared green and black tea to soda and orange juice in terms of their erosive effect on the human dentition. vinegar and water were used as active and passive control fluids. an accelerated in vitro test was used to monitor how short- and long-term exposure to these fluids affected the topography and morphology of the coronal segments of the human dentition. this 20-week test was conducted under controlled conditions, independent of the influencing factors of the oral environment. t ... | 2008 | 18683403 |
| proteome analysis of tea pollen (camellia sinensis) under different storage conditions. | the protein complement of tea pollen collecting from tea tree (camellia sinensis) was compared under different storage conditions. protein was partially identified using a combination of the 2d-page, maldi-tof/ms, mascot, and xproteo search engine. two hundred and sixty-nine and 396 proteins were detected in pollen stored at room temperature (rt) and -20 degrees c, respectively. forty-three of the identified proteins were assigned to defense-related functions, energy metabolism, cytoskeleton, nu ... | 2008 | 18680303 |
| [chemical studies on plant polyphenols and formation of black tea polyphenols]. | recent biological and pharmacological studies strongly suggested that plant polyphenols in foods, beverages and crude drugs have various health benefits. however, still there are chemically uncharacterized polyphenols, especially those with large molecular weights. the typical example is black tea polyphenols. four tea catechins of fresh tea leaves are enzymatically oxidized in tea fermentation process of black tea manufacture to give a complex mixture of the oxidation products. despite many eff ... | 2008 | 18670177 |
| cloning of two cdnas encoding a family of atp sulfurylase from camellia sinensis related to selenium or sulfur metabolism and functional expression in escherichia coli. | atp sulfurylase, the first enzyme in the sulfate assimilation pathway of plants, catalyzes the formation of adenosine phosphosulfate from atp and sulfate. here we report the cloning of two cdnas encoding atp sulfurylase (aps1 and aps2) from camellia sinensis. they were isolated by rt-pcr and race-pcr reactions. the expression of aps1 and aps2 are correlated with the presence of atp sulfurylase enzyme activity in cell extracts. aps1 is a 1415-bp cdna with an open reading frame predicted to encode ... | 2008 | 18657428 |
| determination of theanine, gaba, and other amino acids in green, oolong, black, and pu-erh teas with dabsylation and high-performance liquid chromatography. | dabsyl chloride (dimethylaminoazobenzene sulfonyl chloride), a useful chromophoric labeling reagent for amino acids and amines, was developed in this laboratory in 1975. although several methods have been developed to determine various types of amino acids, a quick and easy method of determining theanine, gaba, and other amino acids has not been developed in one hplc system. in this paper are analyzed the free amino acid contents of theanine and gaba in different teas (green tea, black tea, oolo ... | 2008 | 18652476 |
| beverage consumption and the prevalence of tooth loss in pregnant japanese women: the osaka maternal and child health study. | recently, there has been growing interest in the impact of beverage consumption on dental health because changes have occurred in the types and quantities of beverage consumed. this cross-sectional study investigated the relationship between consumption frequencies of various beverages and the prevalence of tooth loss among young adult women. study subjects were 1002 pregnant japanese women. tooth loss was defined as previous extraction of one or more teeth. dietary habits were evaluated by a va ... | 2008 | 18646593 |
| [mechanism study of tea pigment on the selective against the colony growth of preneoplastic and normal syrian hamster embryo cells]. | to use co-cultures of she normal and preneoplastic cells in order to study the chemopreventive effects of doses of tea pigment (tp) from black tea on growth, proliferation, apoptosis and related regulation gene expression of normal and preneoplastic she cells. | 2008 | 18646525 |
| effect of black tea in diethylnitrosamine-induced esophageal carcinogenesis in mice. | to evaluate the effect of black tea on esophageal carcinogenesis induced by the oral administration of diethylnitrosamine (den). | 2008 | 18641802 |
| green tea consumption is associated with decreased dna damage among gstm1-positive smokers regardless of their hogg1 genotype. | the levels of tobacco-related dna adducts in human tissues reflect a dynamic process that is dependent on the intensity and time of exposure to tobacco smoke, the metabolic balance between activation of detoxification mechanisms, and the removal of adducts by dna repair and/or cell turnover. urinary 8-hydroxydeoxyguanosine (8-ohdg) is probably 1 of the most abundant dna lesions formed during oxidative stress and is proposed as a sensitive biomarker of the overall oxidative dna damage and repair. ... | 2008 | 18641208 |
| a review of the epidemiological evidence on tea, flavonoids, and lung cancer. | tea and its main bioactive ingredients, the flavonoids, have been associated with human cancer for several decades. in this article, an overview is provided of observational epidemiological studies of lung cancer incidence in relation to intake of green tea, black tea, flavonols/flavones, and catechins. a pubmed search was conducted in september 2007. articles were selected if they provided risk ratios (relative risk or odds ratio) for lung cancer and were of observational design (cohort, case-c ... | 2008 | 18641207 |
| nongallated compared with gallated flavan-3-ols in green and black tea are more bioavailable. | green tea and black tea (bt) contain gallated [(-)-epigallocatechin-3-gallate (egcg), (-)-epicatechin-3-gallate] and nongallated [(-)-epicatechin, (-)-epigallocatechin (egc)] tea polyphenols (pp). during bt production, pp undergo oxidation and form larger polymers such as theaflavins (the) and thearubigins, which contribute to the health benefit of bt. this article gives an overview of the role of chemical characteristics and endogenous metabolism of tea pp and their bioavailability in humans an ... | 2008 | 18641202 |
| in vitro assessment of the effectiveness of whitening dentifrices for the removal of extrinsic tooth stains. | this in vitro study evaluated the effectiveness of whitening dentifrices for the removal of extrinsic tooth stains. twenty dental blocks (4 x 4 mm), including enamel and dentine, removed from freshly extracted bovine incisors, were randomly divided into 4 groups: g1--distilled water, g2--colgate, g3--crest extra whitening and g4--rapid white. in all specimens, the dentin was covered with colorless nail polish, and the enamel was left exposed. next, the specimens were immersed in a solution of bl ... | 2008 | 18622478 |
| a preconcentration system for determination of copper and nickel in water and food samples employing flame atomic absorption spectrometry. | a separation/preconcentration procedure using solid phase extraction has been proposed for the flame atomic absorption spectrometric determination of copper and nickel at trace level in food samples. the solid phase is dowex optipore sd-2 resin contained on a minicolumn, where analyte ions are sorbed as 5-methyl-4-(2-thiazolylazo) resorcinol chelates. after elution using 1 mol l(-1) nitric acid solution, the analytes are determinate employing flame atomic absorption spectrometry. the optimizatio ... | 2009 | 18620809 |
| flavonoids, flavonoid-rich foods, and cardiovascular risk: a meta-analysis of randomized controlled trials. | the beneficial effects of flavonoid consumption on cardiovascular risk are supported by mechanistic and epidemiologic evidence. | 2008 | 18614722 |
| an early gene of the flavonoid pathway, flavanone 3-hydroxylase, exhibits a positive relationship with the concentration of catechins in tea (camellia sinensis). | tea (camellia sinensis (l.) o. kuntze) leaves are a major source of flavonoids that mainly belong to the flavan 3-ols or catechins. apart from being responsible for tea quality, these compounds have medicinal properties. flavanone 3-hydroxylase (f3h) is an abundant enzyme in tea leaves that catalyzes the stereospecific hydroxylation of (2s)-naringenin to form (2r,3r)-dihydrokaempferol. we report a full-length cdna sequence of f3h from tea (csf3h accession no. ay641730). csf3h comprised 1365 bp w ... | 2008 | 18595847 |
| a physiological model of tea-induced astringency. | the mechanism by which solutions containing polyphenols are perceived as astringent is not clearly understood. salivary proline-rich proteins and histatins are products of salivary glands and rapidly bind polyphenols - thought to be the main astringent compound in such as tea and wine. however it is unclear how this interaction leads to the altered oral mouthfeel known as astringency which is characterised by a dry, puckered feeling all around the mouth. to determine the role of saliva in the pe ... | 2008 | 18590751 |
| [toxic hepatitis due to camellia sinensis]. | 2016 | 18570823 | |
| extract of black tea (pu-ehr) inhibits postprandial rise in serum cholesterol in mice, and with long term use reduces serum cholesterol and low density lipoprotein levels and renal fat weight in rats. | a water-soluble extract of a traditional chinese fermented black tea, pu-ehr, decomposes bile acid cholesterol micelles. this black tea extract (bte) was studied to see if it could decrease the postprandial elevation of blood cholesterol levels after a single administration in ddy mice. it was found that bte (0.3 g/kg) significantly decreased the postprandial rise in blood cholesterol levels after oral administration of cholesterol (130 mg/kg). a non-fermented tea (i.e. green tea) extract did no ... | 2008 | 18570239 |
| effect of black tea brew of camellia sinensis on sexual competence of male rats. | in sri lankan traditional medicine black tea brew (btb) of camellia sinensis (l.) o. kuntze (theaceae) is claimed to have male sexual stimulant activity. as this claim is not scientifically tested and proven, this study was undertaken to evaluate the effects of btb on male sexual competence. | 2008 | 18565706 |
| influence of green and black tea on folic acid pharmacokinetics in healthy volunteers: potential risk of diminished folic acid bioavailability. | previous in vitro studies using caco-2 cell monolayers suggested a possible interaction between green and black tea and folic acid at the level of intestinal absorption. the main purpose of the present study was to investigate a possible pharmacokinetic interaction between tea and folic acid in healthy volunteers. in an open-labeled randomized cross-over study, the pharmacokinetic interaction between tea and folic acid (0.4 mg and 5 mg) was investigated in healthy volunteers. water was used as t ... | 2008 | 18551467 |
| pretreatment with black tea polyphenols modulates xenobiotic-metabolizing enzymes in an experimental oral carcinogenesis model. | the objective of this study was to evaluate the chemopreventive potential of the black tea polyphenols polyphenon-b and btf-35 during the preinitiation phase of 7,12-dimethylbenz[a]anthracene (dmba)-induced hamster buccal pouch (hbp) carcinogenesis. hamsters were divided into six groups. animals in groups 2 and 3 received diet containing polyphenon-b and btf-35, respectively, 4 weeks before carcinogen administration when they were 6 weeks of age and continued until the final exposure to carcinog ... | 2008 | 18543609 |
| expression of caffeine biosynthesis genes in tea (camellia sinensis). | using semi-quantitative reverse transcription-pcr, we studied the expression of genes encoding caffeine synthase (tcs1), inosine-5'-monophosphate dehydrogenase (tidh), s-adenosyl-l-methionine synthase (sams), phenylalanine ammonia-lyase (pal) and alpha-tubulin (tua1) in young and mature leaves, stems and roots of 4-month-old tea seedlings and young and old tea tissue cultures. the amounts of transcripts of tcs1 were much higher in young leaves than in other parts of the plant. expression of tidh ... | 2013 | 18533472 |
| the acute effect of green tea consumption on endothelial function in healthy individuals. | tea consumption is associated with decreased cardiovascular risk. flow-mediated dilatation (fmd) of the brachial artery is related to coronary endothelial function and it is an independent predictor of cardiovascular risk. black tea has a beneficial effect on endothelial function; the effect, however, of green tea on brachial artery reactivity has not been defined yet. | 2008 | 18525384 |
| structural determination and dpph radical-scavenging activity of two acylated flavonoid tetraglycosides in oolong tea (camellia sinensis). | two major acylated flavonoid tetraglycosides were isolated from the methanol extract of oolong tea. their structures were elucidated by spectroscopic methods as quercetin 3-o-[2(g)-(e)-coumaroyl-3(g)-o-beta-d-glucosyl-3(r)-o-beta-d-glucosylrutinoside] (1) and kaempferol 3-o-[2(g)-(e)-coumaroyl-3(g)-o-beta-d-glucosyl-3(r)-o-beta-d-glucosylrutinoside] (2). compounds 1 and 2 exhibited scavenging activity against dpph radical with ec(50) values of 30.5 and 487.2 microm, respectively. | 2008 | 18520094 |
| evaluation of black tea gel and its protection potential against uv. | in this study, aqueous and alcoholic extracts of black tea were obtained. the black tea extracts were tested in vitro for their ultraviolet (uv) absorption profile. it was found that both extracts showed uv absorption and followed the same path based on the wavelength. aqueous extract showed a stronger absorptivity per weight basis than the alcoholic extract of black tea. a peak was obtained between 250 and 300 nm. after 300 nm, uv absorption decreased fast towards 400 nm with a low absorptivity ... | 2007 | 18489382 |
| epigallocatechin gallate improves serum lipid profile and erythrocyte and cardiac tissue antioxidant parameters in wistar rats fed an atherogenic diet. | oxidative stress is believed to contribute to the pathogenesis of hypercholesterolaemic atherosclerosis; hence, various antioxidant compounds are being evaluated for potential anti-atherogenic effects. the present study assessed the efficacy of epigallocatechin gallate (egcg), an antioxidant component of the plant camellia sinensis, in improving serum lipid profile and antioxidant parameters in erythrocytes and cardiac tissue in rats fed an atherogenic diet. in male albino wistar rats fed an ath ... | 2008 | 18485145 |
| safety of green tea extracts : a systematic review by the us pharmacopeia. | green tea [camellia sinensis (l.) kuntze] is the fourth most commonly used dietary supplement in the us. recently, regulatory agencies in france and spain suspended market authorization of a weight-loss product containing green tea extract because of hepatotoxicity concerns. this was followed by publication of adverse event case reports involving green tea products. in response, the us pharmacopeia (usp) dietary supplement information expert committee (dsi ec) systematically reviewed the safety ... | 2008 | 18484782 |
| shoot epicatechin and epigallocatechin contents respond to water stress in tea [camellia sinensis (l.) o. kuntze]. | an experiment was conducted to determine the association of tea catechins to water stress in tea, with the objective of determining their suitability as indicators for predicting drought tolerance in tea (camellia sinensis). the study consisted of six tea clones (bbk 35, trfk 6/8, trfk 76/1, trfk 395/2, trfk 31/30, and trfk 311/287) and four levels of soil water content (38, 30, 22, and 14% v/v), which were arranged in a complete randomized design and replicated 3 times. the treatments were main ... | 2008 | 18460799 |
| different types of tea products attenuate inflammation induced in trypanosoma brucei infected mice. | an in vivo study was carried out to determine the effect of different types of kenyan tea extracts on male swiss albino mice infected with trypanosoma brucei brucei isolate ketri 2710. the isolate produced a similar clinical picture after a pre-patent period of 5 days post-infection (dpi). parasitemia levels in the untreated mice and those given different teas developed exponentially at similar rates reaching similar densities at the peak of parasitemia 8 dpi. between 9 and 13 dpi parasitemia de ... | 2008 | 18456544 |
| association between soy and green tea (camellia sinensis) diminishes hypercholesterolemia and increases total plasma antioxidant potential in dyslipidemic subjects. | to evaluate the hypolipemic and antioxidant effects of soy and green tea alone and/or in association in dyslipidemic subjects. | 2008 | 18455656 |
| cloning and differential expression of qm like protein homologue from tea [camellia sinensis (l.) o. kuntze]. | the qm like protein gene encodes for ribosomal protein l10, which is implicated in tumor suppression, transcription factor regulation, and ribosome stability in yeast and mammals. present study describes cloning of a full-length qm cdna (csqm) from tea leaves using differential display of mrna followed by rapid amplification of cdna ends. expression of csqm was studied in leaves of different stages of development and under various external cues. csqm contained an open reading frame of 651 bases, ... | 2009 | 18454353 |
| contribution of p53-mediated bax transactivation in theaflavin-induced mammary epithelial carcinoma cell apoptosis. | theaflavins, the bioactive flavonoids of black tea, have been demonstrated to inhibit proliferation and induce apoptosis in a variety of cancer cells. however, the contribution of p53 in mammary epithelial carcinoma cell apoptosis by theaflavins remains unclear. it has been reported that p53 triggers apoptosis by inducing mitochondrial outer membrane permeabilization through transcription-dependent and -independent mechanisms. using wild-type and mutant p53-expressing as well as p53-null cells w ... | 2008 | 18454316 |
| pharmacological studies on indian black tea (leaf variety) in acute and chronic inflammatory conditions. | infusions of indian black tea (bti), when administered orally, produced significant inhibition of rat paw oedema, induced with carrageenin (pre and post treatment) and arachidonic acid. bti was also found to inhibit peritoneal capillary permeability and caused a marked reduction of lipopolysaccharide induced pge(2) generation. in these models, the observed antioedema effect was similar to that of bw755c (a dual inhibitor of cyclooxygenase and 5-lipoxygenase enzymes). bti was found to scavenge su ... | 2008 | 18446842 |
| quality assessment and quantitative analysis of flavonoids from tea samples of different origins by hplc-dad-esi-ms. | components of green tea ( camellia sinensis) have been of considerable interest in recent years because of their potential utility as pharmaceutical agents, particularly for their antioxidant and anticarcinogenic activity. responding to the increasing scientific validation of numerous health benefits of tea, a comprehensive approach was adopted to carry out analysis for the quality assessment of flavonoids in tea samples of different origins. for this purpose, extraction, separation, and mass sp ... | 2008 | 18442252 |
| preparative isolation and purification of theaflavins and catechins by high-speed countercurrent chromatography. | high-speed countercurrent chromatography (hsccc) has been applied for the separation of theaflavins and catechins. the hsccc run was carried out with a two-phase solvent system composed of hexane-ethyl acetate-methanol-water-acetic acid (1:5:1:5:0.25, v/v) by eluting the lower aqueous phase at 2 ml/min at 700 rpm. the results indicated that pure theaflavin, theaflavins-3-gallate, theaflavins-3'-gallate and theaflavin-3,3'-digallate could be obtained from crude theaflavins sample and black tea. t ... | 2008 | 18436487 |
| potential anthelmintics: polyphenols from the tea plant camellia sinensis l. are lethally toxic to caenorhabditis elegans. | a novel gallate of tannin, (-)-epigallocatechin-(2 beta-->o-->7',4 beta-->8')-epicatechin-3'-o-gallate (8), together with (-)-epicatechin-3-o-gallate (4), (-)-epigallocatechin (5), (-)-epigallocatechin-3-o-gallate (6), and (+)-gallocatechin-(4 alpha-->8')-epigallocatechin (7), were isolated from the tea plant camellia sinensis (l.) o. kuntze var. sinensis (cv., yabukita). the structure of 8, including stereochemistry, was elucidated by spectroscopic methods and hydrolysis. the compounds, along w ... | 2008 | 18404315 |
| iron absorption in young indian women: the interaction of iron status with the influence of tea and ascorbic acid. | ascorbic acid (aa) enhances and tea inhibits iron absorption. it is unclear whether iron status influences the magnitude of this effect. | 2008 | 18400710 |
| evaluation of toxicity of green tea catechins with 90-day dietary administration to f344 rats. | green tea catechins (gtc), polyphenols extracted from the stalks and leaves of camellia sinensis, are found in the different types of tea beverages and as antioxidant additives to many foods, snacks, fats and fatty oils. as a part of their safety assessment, subchronic toxicity was investigated in male and female f344 rats with dietary administration at concentrations of 0 (control), 0.3%, 1.25% and 5.0% for 90 days. the average daily intakes of gtc in each group were 180, 764 and 3525mg/kg body ... | 2008 | 18400353 |
| polymeric black tea polyphenols inhibit mouse skin chemical carcinogenesis by decreasing cell proliferation. | the aim of this study was to investigate the antitumour promoting effects and possible mechanisms of action of the most abundant polymeric black tea polyphenols (pbps 1-5) or thearubigins, in vivo. | 2008 | 18400024 |
| nutritional risk factors for the development of hypertension in diabetic patients. | the aim of this cross-sectional study was to determine the significant limitations, sensitivity, specificity, partial correlations, and odds ratios of nutrient intake in patients with and without hypertension with type 2 diabetes mellitus. diabetic patients (n=220) with clinical diagnosis of hypertension and diabetic patients (n=230) without hypertension were included in this study. the questionnaire form included a list of 65 food items formed from five main food groups (grain, meat and alterna ... | 2009 | 18394930 |
| a mixture of extracts of black and green teas and mulberry leaf did not reduce weight gain in rats fed a high-fat diet. | tea extracts are used in many over-the-counter preparations claiming to promote weight loss. the rationale for this usage includes reports that green tea extract increases thermogenesis, and extracts of green and black tea and mulberry leaf inhibit the digestion/absorption of carbohydrate and fat. the investigators in this study tested the potential of increasing doses of a mixture of three extracts (50-percent black tea, 20-percent green tea, and 30-percent mulberry) to induce weight loss, stea ... | 2008 | 18377102 |
| levels of selected heavy metals in black tea varieties consumed in saudi arabia. | the metal contents (fe, cu, zn, mn, cr, pb, ni, cd, co) of 17 black tea samples were analyzed by using inductively coupled plasma atomic emission spectroscopy (icp-aes). among the investigated metals mn was the highest (1,071.7 microg/g), whereas pb showed minimum levels (0.30 microg/g). iron was the second highest element found in black tea samples. lowest pb concentration (0.30 microg/g) was found in abu jabal tea; whereas maximum (2.2 microg/g) was found in manasul tea. lowest cd concentratio ... | 2008 | 18373271 |
| characteristics of catechin- and theaflavin-mediated cardioprotection. | catechins and theaflavins-the main polyphenolic substances of green and black tea, respectively-exert a plethora of beneficial effects on the cardiovascular system. in a model of h(2)o(2)-mediated oxidative stress, we investigated the effects of epigallocatechin-3-gallate (egcg) and theaflavin-3,3'-digallate (tf3) on neonatal rat cardiomyocytes. pretreatment with egcg or tf3 1 hr prior to induction of oxidative stress by h(2)o(2) effectively protected cardiac myocytes as determined by measuring ... | 2008 | 18367631 |
| polymeric black tea polyphenols induce phase ii enzymes via nrf2 in mouse liver and lungs. | among tea polyphenols, the anti-initiating properties of polymeric black tea polyphenols (pbps), the most abundant polyphenols in black tea, are poorly elucidated. hence, this study was undertaken to investigate the effects of pbp extract on the induction of phase ii enzymes. pbp extract induced transcriptional up-regulation of phase ii enzymes in liver and lungs by increasing nrf2-mediated antioxidant-responsive element (are) binding. pbp extract did not alter nrf2 or keap1 at the transcription ... | 2008 | 18358244 |
| coffee, tea, colas, and risk of epithelial ovarian cancer. | associations of coffee, tea, and other caffeinated beverages with ovarian cancer risk remain uncertain. in a population-based study in washington state, 781 women with epithelial ovarian cancer diagnosed in 2002 to 2005 and 1,263 controls completed self-administered questionnaires detailing consumption of caffeinated and noncaffeinated coffee, teas, and colas and in-person interviews regarding reproductive and hormonal exposures. we assessed risk associated with coffee, tea, and cola drinking an ... | 2008 | 18349292 |
| a case-control study of lifestyle and lung cancer associations by histological types. | the objective of the study was to investigate the contribution of dietary factors and physical exercise to the variation in the risk of lung cancer and its major histological types among men and women in the czech republic, and reveal interactions between smoking and diet/physical exercise, if any. in a hospital based case-control study, data collected by in-person interviews from 1096 microscopically confirmed lung cancer cases (587 women, 509 men) and 2966 controls were analyzed using uncondit ... | 2008 | 18348651 |
| theaflavin-3-gallate and theaflavin-3'-gallate, polyphenols in black tea with prooxidant properties. | this study compared the in vitro responses of human gingival fibroblasts and of carcinoma cells derived from the tongue to theaflavin-3-gallate (tf-2a) and theaflavin-3'-gallate (tf-2b), polyphenols in black tea. the antiproliferative and cytotoxic effects of the theaflavin monomers were more pronounced to the carcinoma, than to the normal, cells. in phosphate buffer at ph 7.4, the theaflavins generated hydrogen peroxide and the superoxide anion, suggesting that their mode of toxicity may be due ... | 2008 | 18346048 |
| an exposure and risk assessment for fluoride and trace metals in black tea. | exposure and associated health risks for fluoride and trace metals in black tea were estimated. fifty participants were randomly recruited to supply samples from the tea that they drink, and self-administer a questionnaire that inquired about personal characteristics and daily tea intake. analyzed trace metals included aluminum, arsenic, barium, cadmium, cobalt, chromium, copper, manganese, nickel, strontium, and zinc. fluoride and four metals (al, cr, mn, ni) were detected in all samples while ... | 2008 | 18329795 |
| polymer-like polyphenols of black tea and their lipase and amylase inhibitory activities. | lipase and amylase inhibitory activities of black tea were examined. after solvent partitioning of a black tea extract with the ethyl acetate and n-butanol, the two soluble fractions showed comparable inhibitory activities. activity in the ethyl acetate fraction was mainly attributable to polyphenols with low-molecular weights, such as theaflavin gallates. on the other hand, the active substance in the n-butanol layer was ascertained to be a polymer-like substance. 1h- and 13c-nmr spectra showed ... | 2008 | 18310934 |
| element composition of tea leaves and tea infusions and its impact on health. | tea infusion is the most frequently consumed beverage worldwide next to water, with about 20 billion cups consumed daily. in taiwan, daily consumption averages 2.5 cups of tea infusion per person. many studies have concluded that tea has numerous beneficial effects on health. however, some undesirable trace elements, such as arsenic, chromium, cadmium, lead, etc., are a concern. this study has three aims: (1) to measure the concentrations of arsenic and heavy metal elements, such as chromium, ca ... | 2008 | 18309449 |
| the influence of different food and drink on tics in tourette syndrome. | tourette syndrome (ts) is characterized by waxing and waning motor and vocal tics. because standard medication often remains unsatisfactory, many patients seek alternative medicine. the aim of this study was to increase experience about the influence of food and drinks in ts. | 2008 | 18307557 |
| methylglyoxal: its presence and potential scavengers. | hyperglycemia is the most important factor for the onset and progress of diabetic complications. a growing body of evidence indicates that the increase in reactive carbonyl intermediates such as methylglyoxal (mg) is a consequence of hyperglycemia in diabetes. several studies have shown that higher levels of mg are present in diabetic patients' plasma compared to non-diabetics. glyoxal (go) and mg, the two major alpha-dicarbonyl compounds found in humans, are very reactive and lead to nonenzymat ... | 2008 | 18296351 |
| l-theanine, a natural constituent in tea, and its effect on mental state. | tea is the most widely consumed beverage in the world after water. tea is known to be a rich source of flavonoid antioxidants. however tea also contains a unique amino acid, l-theanine that may modulate aspects of brain function in humans. evidence from human electroencephalograph (eeg) studies show that it has a direct effect on the brain (juneja et al. trends in food science & tech 1999;10;199-204). l-theanine significantly increases activity in the alpha frequency band which indicates that it ... | 2008 | 18296328 |
| association between consumption of black tea and iron status in adult africans in the north west province: the thusa study. | the association between black tea consumption and iron status was investigated in a sample of african adults participating in the cross-sectional thusa (transition and health during urbanization of south africans) study in the north west province, south africa. data were analysed from 1605 apparently healthy adults aged 15-65 years by demographic and ffq, anthropometric measurements and biochemical analyses. the main outcome measures were hb and serum ferritin concentrations. no associations wer ... | 2008 | 18275622 |
| combination chemoprevention of hamster buccal pouch carcinogenesis by bovine milk lactoferrin and black tea polyphenols. | combination chemoprevention is a promising approach for oral cancer prevention. the authors evaluated the combined chemopreventive effects of bovine milk lactoferrin (blf) and black tea polyphenols (polyphenon-b) in a clinically relevant in vivo model of 7,12-dimethylbenz[a]anthracene (dmba)-induced hamster buccal pouch (hbp) carcinogenesis. although dietary administration of blf and polyphenon-b alone significantly reduced the tumor incidence, combined administration of blf and polyphenon-b was ... | 2008 | 18259952 |
| immobilized proanthocyanidins for the capture of bacterial lipopolysaccharides. | proanthocyanidins (pacs) are an abundant class of compounds found in a variety of plant materials. here we demonstrate the application of these materials as capture molecules for the removal of bacterial lipopolysaccharide (lps) from solution. pacs from whole cranberries, grape juice, black tea, and cranberry juice were purified and immobilized onto thiol-activated sepharose beads. this material was used in pull-down type assays for the capture of lps. the binding of lps by pacs has been shown t ... | 2008 | 18257561 |
| gas chromatographic method for the determination of hexaconazole residues in black tea. | a highly reliable, quantitative and sensitive analytical method for determining the residues of the fungicide, hexaconazole in black tea is described. the proposed method is based on liquid-liquid extraction followed by gas chromatographic determination, using nitrogen phosphorus detector (gc-npd) for the identification and quantitation of hexaconazole. the most appropriate solvent mixture for extracting hexaconazole residues from black tea was n-hexane:acetone at 1:1 (v/v). the extract was clea ... | 2008 | 18257139 |
| expression and biochemical characterization of beta-primeverosidase and application of beta-primeverosylamidine to affinity purification. | beta-primeverosidase (pd) is a family 1 glycosidase catalyzing the hydrolysis of beta-primeverosides (6-o-beta-d-xylopyranosyl-beta-d-glucopyranosides) to release a disaccharide primeverose. to investigate how pd recognizes the disaccharide moiety of beta-primeverosides, the recombinant pd was expressed by a baculovirus-insect cell system. the recombinant pd was secreted from high five cells and was properly modified with n-glycosylation and correct cleavage at the n-terminal signal peptide. the ... | 2008 | 18256510 |
| theaflavin-3,3'-digallate, a component of black tea: an inducer of oxidative stress and apoptosis. | treatment of human oral squamous carcinoma hsc-2 cells and normal gn46 fibroblasts with theaflavin-3,3'-digallate (tf-3), a polyphenol in black tea, showed a concentration and time dependent inhibition of growth, with the tumor cells more sensitive than the fibroblasts. in buffer and in cell culture medium, tf-3 generated reactive oxygen species, with lower levels detected in buffer amended with catalase and superoxide dismutase, indicating the generation of hydrogen peroxide and superoxide, res ... | 2008 | 18248951 |
| the association between personal habits and bladder cancer in turkey. | in this study, we analyzed the effect of turkish coffee and black tea consumption, alcohol intake and smoking on bladder cancer. | 2008 | 18247151 |
| simple and rapid uv spectrophotometry of caffeine in tea coupled with sample pre-treatment using a cartridge column filled with polyvinylpolypyrrolidone (pvpp). | we have applied a sample pre-treatment method with a cartridge column filled with polyvinylpolypyrrolidone (pvpp) to the effective removal of polyphenols and simple uv spectrophotometry of caffeine in tea. the absorption maximum length (lambda(max)) for caffeine was close to those for tea catechins in aqueous 1% acetic acid; therefore, the uv spectrum of a non-treated green tea sample had a large absorption wave. in contrast, the absorbance of the green tea sample was gradually reduced by pvpp c ... | 2008 | 18239305 |
| immunostimulating activity of a crude polysaccharide derived from green tea (camellia sinensis) extract. | green tea extract is well-known to reduce the risk of a variety of diseases. here, we investigated the immunostimulating activity of tea polysaccharide (tps), one of the main components in green tea extract. the water extracts from mature or immature tea leaves were precipitated by using ethanol at room temperature. the sediment was washed with ethanol and acetone alternately and then dried. we used the phagocytic activity of macrophage-like cells as an indicator of immune function activation. c ... | 2008 | 18232634 |