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PubMed1998

Fluoride in tea--its dental significance: a review.

It has long been accepted that fluoride accumulates in the leaves of the tea plant. Camellia sinensis. In addition it is known that some of this fluoride is released into the infusion which is drunk as tea. The exact concentration of fluoride in a cup of tea and the effects of this fluoride have been the subject of many international studies. This review summarizes the main points of such studies which have been carried out in an attempt to establish the dental significance of fluoride in tea. The most popular teas in Ireland are not readily available in any other country and therefore, Irish data may not be assumed to be similar to those in the studies reviewed here. By identifying potential sources of high fluoride ingestion, recommendations can be made to reduce consumption from these sources in patients who may be at risk of dental fluorosis. In conclusion, it is recommended that a research project be carried out to analyse the fluoride levels released and the rates of the releases from teas available on the Irish market. Ireland has the highest per capita consumption of tea in the world.

Animals↗
PubMed1999

Green tea (Camellia sinensis) extract and its possible role in the prevention of cancer.

The American Cancer Society estimates that in the 1980s more than 4. 5 million Americans died of cancer. In addition, there were nearly nine million new cases and about 12 million people were under medical care for cancer. With cancer being the second most common cause of death in the United States population, the possibility that readily-available natural substances may be beneficial in the prevention of cancer warrants closer examination. A growing body of research has demonstrated green tea polyphenols to be powerful antioxidants with anticarcinogenic properties. These polyphenolic compounds, specifically the catechins epigallocatechin-3-gallate (EGCG), epigallocatechin (EGC), and epicatechin-3-gallate (ECG), which account for 30-40 percent of the extractable solids of green tea leaves, are believed to mediate many of the cancer chemopreventive effects. Mechanisms of action may include antioxidant and free-radical scavenging activity, and stimulation of detoxification systems through selective induction or modification of phase I and phase II metabolic enzymes. In addition, green tea may inhibit biochemical markers of tumor initiation and promotion, including the rate of cell replication and thus inhibition of the growth and development of neoplasms. Current studies are hopeful, as they show an inverse association between green tea consumption and cancer risk, supporting a possible chemopreventive effect of green tea. Based on the knowledge that green tea is inexpensive, non-toxic, and is a popular beverage consumed worldwide, clinical trials should be conducted to evaluate the in-vivo effectiveness of green tea polyphenols on the inhibition and chemopreventive treatment of cancer.

Catechin↗
PubMed2000

[Amounts of selected minerals in green and black teas].

The paper contains the results of 19 minerals (Ca, K, P, Na, Mg, Zn, Fe, Mn, Cu, F, Ni, Co, Cr, Li, Sr, Al, Cd, Hg, Pb) determined in green and black species of market teas. The examined minerals (except phosphorus, fluoride and mercury) were determined by ASA-method using air-acetylene flame (aluminium was determined in the nitrous oxide-acetylene flame). Mercury was determined by cold vapour method. The phosphorus and fluoride was determined by spectrophotometry methods (phosphorus in the form of phosphomolybdate blue and fluoride by use microdiffusion procedure where alizarin-fluoride complex was formed). It has been found that the examined teas are important source of potassium and low source of sodium, assuming a daily intake of 4 glasses of tea infusions. Tea drinking may be advantageous for hypertensive persons. The investigated teas are also important source of other examined minerals especially some microelements. The intake of the toxic metals with tea (Cd, Hg, Pb, Al) is low, from a centesimal to a few percent of the PTWI dose accepted by the FAO/WHO Experts. This paper presents also the first findings of the lithium and stronthium contents of examined tea species--whose physiological role still remains unknown.

Minerals↗
PubMed2000

[Antimicrobial effects of tea tree oil (Melaleuca alternifolia) on oral microorganisms].

The essential oil of Melaleuca alternifolia (tea tree oil) exhibits antimicrobial activity against a wide range of Gram-positive and Gram-negative bacteria, yeasts and fungi. In this study the bacteriostatic and bacteriocidal/fungicidal activity of a tea tree oil solution, of a new tea tree oil (Tebodont) and the respective placebo-gel, of a chlorhexidindigluconate-solution and of PlakOut was tested in vitro against ten different oral microorganisms. Minimum inhibitory concentrations were in the range from 0.0293% to 1.25% for the tea tree oil solution and from 0.0082% to 1.25% for the tea tree oil gel. The values for minimum bacteriocidal/fungicidal concentrations were in the range from 0.0521% to 2.5% for the tea tree oil solution and from <0.0098% to 3.33% for the tea tree oil gel. The most susceptible microorganisms were Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, and Porphyromonas gingivalis, whereas Streptococcus mutans and Prevotella intermedia were the least susceptible ones. Both for the chlorhexidindigluconate solution and for PlakOut the values for the minimal inhibitory concentration and for the minimal cidal concentration were between <0.0002% and 0.0125%.

Anti-Infective Agents, Local↗
PubMed1999

[Origin of the word tea, and its extension to designate different hot infused drinks].

Currently, the word tea applies to the teatree and to the vegetal material, as well as to the infused drink itself. During the VIth century, the chinese language and writing become specific when they designate the teatree with the word -cha-. However, this word is likewise used to designate different hot infused drinks. When imported from China to Europe during the XVIIth century, its consumption spreads rapidly among town people. Used by the Chinese traders operating in the Fou-Kien area, the vulgar word -te- set up in Great Britain, the Netherlands, Germany and France, from which issue tea, Tee and the . At a time when the physicians consider the consumption of hot infused drinks as jeopardizing the stomach, their common use becomes largely widespread during the XVIIIth century with several types of medicinal herbs often named tea, as the Swiss tea (labiateae), the tea of Europe (veronica) and for example the lime tea. The use of China tea influenced the habits of European people.

Beverages↗
PubMed2000

[The effects of tea polyphenols on the adherence of cariogenic bacterium to the salivary acquired pellicle in vitro].

OBJECTIVE: It has been proved that tea polyphenols (TP) can inhibit the sucrose-dependent adherence of oral cariogenic bacterium to the tooth surface. This study is carried on to investigate the effects of tea polyphenols on the preliminary adherence of main cariogenic bacterium to salivary acquired pellicle and reveal the anticarious mechanisms of tea polyphenols further. METHODS: The hydroxyapatites were coated by saliva to form S-HA, an in-vitro model of experimental pellicle. Streptococcus mutans 3a3 and Actinomyces viscosus ATCC 19246 were chosen as the main cariogenic bacterium, and the microorganisms were radiolabelled by growing them in TPY culture medium supplemented with 3H-thymidine. Tea polyphenols solution was prepared, the concentrations of which were 0.5, 1.0, 2.0 and 4.0 mg/ml respectively. Two parts of inhibited adherence tests were done with TP-treated S-HA or TP-treated bacterium. In the first one, S-HA was immerged into the TP solution of different concentrations for 1 h before the attachment of bacterium. In the other, the bacterium were mixed with the TP solution for 1 h and then centrifuged and washed before bound to S-HA. The whole process was carried on in KCl buffer solution. The number of 3H-thymidine-labelled bacterium which attached to S-HA were determined by scintillation counting. RESULTS: In both the two parts of this study, tea polyphenols solution, the concentrations of which were changed from 1.0 to 4.0 mg/ml, could decrease the number of S. mutans 3a3 and A. viscosus ATCC 19246, and the inhibition rates rose with the increase of the concentrations of TP solution. But the inhibitory effects of 0.5 mg/ml TP solution were inconsistent in different tests. The results showed that 1.0-4.0 mg/ml TP solution could inhibit the attachments of S. mutans and A. viscosus to S-HA effectively. The inhibitory functions of tea polyphenols were so obvious that in some experiments, while the concentrations of TP solution were changed from 2.0 to 4.0 mg/ml, the number of 3H-thymidine-labelled bacterium which attached to S-HA was even less than that of the same bacterium which attached to naked HA. CONCLUSION: Tea polyphenols can inhibit the preliminary adherence of Streptococcus mutans and Actinomyces viscosus to S-HA effectively. TP may prevent enamel from caries by decreasing the adherence of main cariogenic bacterium to salivary acquired pellicle.

Actinomyces viscosus↗
PubMed2000

[The effects of tea polyphenols on the adherence of cariogenic bacterium to the collagen in vitro].

OBJECTIVE: In the first phase of our study, it has been proved that tea polyphenols (TP) can inhibit the preliminary adherence of oral cariogenic bacterium to salivary acquired pellicle. This study is carried on to investigate the effects of tea polyphenols on the preliminary adherence of main cariogenic bacterium to collagen I and reveal the anticarious mechanisms of tea polyphenols further. METHODS: Tea polyphenols solution was prepared firstly, the concentrations of which were 0.5, 1.0, 2.0 and 4.0 mg/ml. An in-vitro model of experimental pellicle(C-HA) was formed by immerging the hydroxyapatites in 250 micrograms/ml collagen I solution for 1 h. Streptococcus mutans 3a3, Actinomyces viscosus ATCC 19246 and Lactobacillus ATCC 4546 were chosen as the main cariogenic bacterium and radiolabelled by growing them in TPY culture medium supplemented with 3H-thymidine. Two parts of inhibited adherence tests were done with TP-treated C-HA or TP-treated bacterium respectively. In the first one, C-HA was immerged into the TP solution of different concentrations for 1 h before the attachment of bacterium. In the other, the bacterium were mixed with the TP solution for 1 h and then centrifuged and washed before bound to C-HA. KCl buffer solution provided a steady condition to the whole process. Finally, the number of 3H-thymidine-labelled bacterium which attached to C-HA were determined by scintillation counting. RESULTS: In both the two parts of this study, tea polyphenols solution, the concentrations of which were changed from 1.0 to 4.0 mg/ml could inhibit the attachments of S. mutans 3a3, A. viscosus ATCC 19246 and Lactobacillus ATCC 4546 to C-HA effectively, and the inhibition rates rose with the increase of the concentrations of TP solution. But the inhibitory effects of 0.5 mg/ml TP solution were inconsistent in different tests. The inhibitory functions of tea polyphenols were so prominent that in some experiments, while the concentrations of TP solution were higher than 2.0 mg/ml, the number of 3H-thymidine-labelled bacterium which attached to C-HA was even less than that of the same bacterium which attached to naked HA. These results showed that TP had the remarkable inhibitory efficiency on the attachments of S. mutans, A. viscosus and Lactobacillus to C-HA. CONCLUSION: Tea polyphenols can inhibit the preliminary adherence of Streptococcus mutans, Actinomyces viscosus and Lactobacillus to C-HA effectively. TP may prevent dentine from caries by decreasing the adherence of main cariogenic bacterium to collagen.

Actinomyces viscosus↗
PubMed2003

Signal transduction pathways: targets for green and black tea polyphenols.

Tea is one of the most popular beverages consumed in the world and has been demonstrated to have anti-cancer activity in animal models. Research findings suggest that the polyphenolic compounds, (-)-epigallocatechin-3-gallate found primarily in green tea, and theaflavin-3,3'-digallate, a major component of black tea, are the two most effective anti-cancer factors found in tea. Several mechanisms to explain the chemopreventive effects of tea have been presented but others and we suggest that tea components target specific cell-signaling pathways responsible for regulating cellular proliferation or apoptosis. These pathways include signal transduction pathways leading to activator protein-1 (AP-1) and/or nuclear factor kappa B (NF-kappaB). AP-1 and NF-kappaB are transcription factors that are known to be extremely important in tumor promoterinduced cell transformation and tumor promotion, and both are influenced differentially by the MAP kinase pathways. The purpose of this brief review is to present recent research data from other and our laboratory focusing on the tea-induced cellular signal transduction events associated with the MAP kinase, AP-1, and NF-kappaB pathways.

Animals↗
PubMed2003

Inhibitory effect of tea polyphenols on renal cell apoptosis in rat test subjects suffering from cyclosporine-induced chronic nephrotoxicity.

OBJECTIVE: To investigate the inhibitory effect of tea polyphenols on renal cell apoptosis in rat test subjects suffering from cyclosporine A (CsA)-induced chronic nephrotoxicity. METHODS: Four groups of rats with CsA-induced chronic nephrotoxicity were respectively treated with vehicle olive oil, tea polyphenols, CsA and tea polyphenols plus CsA. At the end of the 28th day of treatment, 24 hours urine and blood samples were obtained, and the animals were then sacrificed. The serum and urine samples were analysed for creatinine clearance, and kidney tissue was used for pathologic analysis of renal tubular injury and interstitial fibrosis. The TUNEL assay, apoptosis-related enzyme caspase-3 mRNA detected by RT-PCR, and its enzymatic activity were analysed for the possible detections of cell apoptosis. RESULTS: CsA-treated rats displayed increased apoptosis of the tubular and interstitial cells, in comparison with vehicle-treated controls (18.3 +/- 4.6 vs 4.8 +/- 1.3 cells/mm(2), P < 0.05). In comparison with animals treated by CsA, animals treated with CsA plus tea polyphenols demonstrated significantly improved levels of creatinine clearance (0.12 +/- 0.03 vs 0.22 +/- 0.02 ml.min(-1).100 g(-1) body weight, P < 0.05), tubular injury (2.29 +/- 0.43 vs 1.42 +/- 0.26, P < 0.05), and interstitial fibrosis (2.83 +/- 0.20 vs 1.46 +/- 0.19, P < 0.05), and showed a statistically significant decrease in tubular and interstitial cell apoptosis (18.3 +/- 4.6 vs 7.7 +/- 2.1 cells/mm(2), P < 0.05). The expression of caspase-3 mRNA and caspase-3 activity was significantly higher in the CsA-treated group than that of the CsA plus tea polyphenols (TP)-treated group (P < 0.05). CONCLUSION: These results suggested that tea polyphenols significantly inhibits apoptosis of the tubular and interstitial cells in rats with cyclosporine-induced chronic nephrotoxicity, and that tea polyphenols may be useful to prevent CsA-associated kidney toxicity.

Animals↗
PubMed2003

[Studies on cancer chemoprevention by tea pigments].

The present study was to investigate the chemopreventive effects of tea pigments. In vitro study showed that tea pigments induced QR activity and GST activity in Hep G2 cells. Three animal models were used to observe the preventive effects of tea pigments on liver cancer, colorectal cancer and oral cancer. Oral administration of 0.1% tea pigments increased GST activity in rat liver by 18%, and this increase was accompanied by the significant increase of GST 1-1, 1-2, and 3-3 protein expression in rat liver. Tea pigments inhibited the proliferating cell nuclear antigen labeling index (PCNA-LI), the expression of Bcl-2 protein and ras-p21 protein, and induced the expression of Bax protein in rat colorectal cancer. PCNA-LI, silver-stained nucleolar organizer regions (AgNOR) and epidermal growth factor receptor (EGFR) expression were also inhibited by tea pigments in hamster oral cancer. Our results suggested that tea pigments had chemopreventive effects on cancer, and the anti-cancer properties may be due to the activation of detoxifying enzymes such as QR and GST, the inhibition of cell proliferation and the induction of apoptosis.

Animals↗
PubMed2004

cDNA microarray analysis of endothelial cells in response to green tea reveals a suppressive phenotype.

Green tea may prevent cancer, partially by inhibiting tumor angiogenesis. Our previous studies showed that green tea extract was effective in inhibiting breast cancer and endothelial cell proliferation in vitro, and suppressed xenograft size and decreased the tumor vessel density in vivo. Here, we set out to further investigate the molecular mechanisms of this observed angiogenesis suppression. We utilized cDNA microarray technology to profile the global changes in endothelial cellular gene expression in response to green tea. HUVEC (human umbilical vein endothelial cells) were exposed in vitro to green tea for either 6 or 48 h. Only statistically significantly differentially expressed genes were analyzed. Gene profiling demonstrated a global down-regulation of multiple genes involved in endothelial cell growth, signal transduction and oxidation, accompanied by up-regulation of several apoptotic genes. We validated these observations by showing positive correlations with biological assays of cellular proliferation, cell cycle, and apoptosis. The anti-oxidant characteristics of green tea and its metabolites were confirmed in the ORAC (oxygen radical absorbance capacity) assay. cDNA microarray revealed that green tea has an overall suppressive effect on multiple pathways in endothelial cells. This study contributes to the comprehensive analysis of the molecular effects of green tea on endothelial cells, and provides insight into genes that may be important in chemoprevention.

Apoptosis↗
PubMed2004

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, B. licheniformis was used for further studies. Tea plants were sprayed with a suspension of B. licheniformis at a dilution of 5 x 10(8) CFU/ml containing 0.1% Tween 80 as surfactant. In situ lowering of caffeine from tea leaves was evident without affecting the quality of the other tea components. Further, there was no change in the morphological and physiological characteristics as well. It is suggested that spraying of B. licheniformis may be useful in yielding decaffeinated tea with good flavour and aroma.

Bacillus↗
PubMed2004

Effects of tea polyphenols on hepatic fibrosis in rats with alcoholic liver disease.

BACKGROUND: As an anti-oxidation agent, tea polyphenols may have the effect of anti-fibrosis. This study was designed to observe the effect of tea polyphenols on hepatic fibrosis in rats with alcoholic liver disease and to explore the related mechanisms. METHODS: Sixty healthy Sprague-Dawley rats were divided randomly into normal control group, single alcohol group, and three alcohol groups given different doses of tea polyphenols. Alcohol or isovolumic normal saline and corresponding doses of tea polyphenols were given daily to the rats separately. The rats were sacrificed at the end of the 24th week. Masson staining was performed to observe liver fibrosis, serum endotoxin, and oxidant and anti-oxidant activity. RESULTS: Hepatic fibrosis was less severe in the rats of the alcohol groups given tea polyphenols than in the single alcohol group. Tea polyphenols increased the serum anti-oxidant capacity and decreased the endotoxin level. CONCLUSION: Tea polyphenols show anti-fibrosis effect in rats with alcoholic liver disease, and the mechanism may be related to the clearance of overall oxidant and decrease of the endotoxin level.

Animals↗
PubMed2005

[Tea and coffee consumption among Russian population].

Aim of present study was the getting data on black and green tea and coffee consumption among Russian population in 1995-2003. The consumption of beverages tea and coffee was estimated by 24-hour recall of dietary intake in course of Russian Longitudinal monitoring surveys of economics and health. About 82% of population have consumed the black tea and only 2.2%--the green tea. Mean daily black and green tea intake among all population were 446 ml and 10 ml, correspondingly. The prevalence of black tea consumption was decreased and green tea and coffee consumption were increased from 1995 to 2003.

Adolescent↗
PubMed2005

[Effect of tea polyphenols on oxidative metabolism of polymorphonuclear neutrophils in healthy and obese people].

UNLABELLED: Obese people are at high risk for developing diabetes, dyslipidemia, hypertension, and cardiovascular diseases, which lead to an increased risk of mortality. Evidence for the potential role of oxidative stress in various diseases and pathophysiological processes suggests that the dietary intake and the therapeutic use of antioxidants may have positive health effects. The aim of the study was: 1) to investigate the ability of the major tea polyphenols: (-)-epigallocatechin gallate (EGCG), theaflavins (TF) and gallic acid (GA) to protect in vitro human neutrophils from oxidative damage induced by phorbol myristate acetate (PMA), 2) estimation the level of reactive oxygen species (ROS) production in obese patient depending on the red tea Pu-Erh drinking, 3) estimation inflammatory marker: CRP. MATERIAL AND METHODS: We tested 14 obese patients (aged 45+/-12 years, women, BMI=34+/-5.1 kg/m2). The inclusion criteria were based on physical examination, BMI, WHR, and the body composition examination based on bioimpedance method. PMA were isolated and oxidant production, in response to 1 microg/ml PMA, was characterized by the production of hydrogen peroxide, nitric oxide and chemiluminescence intensity. CRP level was assayed by the immunoturbidimetric test in serum. Control group consisted of healthy blood donors. RESULTS: Women consuming red tea revealed alteration in reactive oxygen species generation; the relative decrease of RFT was greater after 5 months than that after 1 month of treatment. A decrease in ROS generation after red tea consumption was accompanied by the decrease of ROS in response to tested compounds in normal cells. EGCG and TF showed similar potency in antioxidative activities. Tea polyphenols were not found to modulate CRP level in obese women. CONCLUSIONS: Tea may thus represent an important source of dietary antioxidants; there is need for more detailed studies to improve our understanding of the role of tea in reducing risk of major disease states.

Adult↗
PubMed2005

The effect of green tea on the activity of aldehyde dehydrogenase (ALDH) in the liver of rats during chronic ethanol consumption.

PURPOSE: Alterations in the redox state during chronic ethanol consumption are associated with the oxidation of ethanol via alcohol and aldehyde dehydrogenase. Among various antioxidants present in food, strong antioxidative effects have been attributed to polyphenols of green tea. The aim of the present study was to investigate the effect of green tea consumption during chronic ethanol intake on the activity of aldehyde dehydrogenase in the liver of rats during maturation and aging. MATERIALS AND METHODS: The activity of ALDH was measured in the livers of rats aged 2 (young), 12 (adult) and 24 months (old). The rats were fed with a control liquid Lieber DeCarli diet, control liquid diet containing green tea (3 g/l), ethanol liquid diet (with increasing ethanol dose from 2.3% to 7%) and ethanol liquid diet containing green tea. RESULTS: Chronic ethanol consumption significantly increased the liver ALDH activity in young and adult rats but decreased this activity in old animals. The drinking of green tea did not alter ALDH activity in ethanol-consuming rats. Drinking green tea alone significantly increased ALDH activity in young and adult rats but did not alter this activity in old rats. CONCLUSIONS: These results demonstrate that green tea administered during chronic ethanol consumption does not prevent the changes in the hepatic ALDH activity in the rats at each age.

Aldehyde Dehydrogenase↗
PubMed2005

[Analysis of 23 mineral elements in tea samples collected from China and Japan by using ICP-AES and ICP-MS combined with a closed decomposition].

After a closed decomposition, the concentrations of Al, Ba, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, La, Mg, Mn, Na, Ni, Pb, Rb, Sb, Sr, Th, U, Y and Zn in thirteen Chinese tea samples and six Japanese tea samples were analysed by using ICP-AES and ICP-MS, a tea standard reference material (GBW07605) was used to verify the accuracy and the precision of analytical method. It was demonstrated that a closed decomposition can help to get good results for the concentrations of mineral elements in tea samples. Compared with those in Japanese tea samples, the concentrations of Cd, Co, Cr, Cs, Fe, Pb, Rb, Sb, Th, U and Zn in Chinese tea samples are significantly high, which means the atmosphere in China is contaminated by heavy metal particles more severely than that in Japan. Moreover, it was found that the concentrations of many mineral elements in tea samples correlate each other.

China↗
PubMed2006

[Study on the identification of tea using near infrared reflectance spectroscopy].

A rapid tea identification method by near infrared spectroscopy coupled with pattern recognition based on principal components analysis and Mahalanobis' distance technique was proposed. Four famous brand teas in China were studied, including Longjing tea, Biluochun tea, Maofeng tea and Tieguanyin tea in the experiment. In the spectral region between 6 500 and 5 300 cm(-1), through preprocessing method of MSC (multiplicative scatter comection), the prediction model was built. The result showed that the model was the best with 8 principal component factors. The rates of identification in calibration set samples and prediction set samples were 98.75% and 95%, respectively. A new idea about quick and precise identification of tea was offered.

Algorithms↗