Green Tea Drinking Research Articles

Determination of Ethanol Concentration in Kombucha Beverages: Single-Laboratory Validation of an Enzymatic Method, First Action Method 2019.08.

Kombucha is a fermented, lightly effervescent sweetened black or green tea drink. It is marketed as a functional beverage based on its proposed health benefits. Kombucha is produced by fermenting tea using a “symbiotic colony of bacteria and yeast” (SCOBY). Kombucha is marketed as a non-alcoholic beverage, however due to the production process employed, there is a high possibility that the Kombucha products will contain low levels of ethanol. Kombucha is sold in a raw and unpasteurized form and, if kept at temperatures above 4 °C, the possibility exists that it will continue to ferment, producing ethanol. This possibility of continued fermentation may lead to an increase in ethanol content from levels below 0.5%ABV at time of production to higher levels at time of consumption. Thus, there is a potential for levels rising to greater than 0.5%ABV, the threshold for certification as a non-alcoholic beverage. It is essential that Kombucha manufacturers have the capacity to accurately and quickly test for ethanol in their products. The Ethanol Assay Kit is an enzymatic test kit developed by Megazyme for the determination of ethanol in a variety of samples. The kit has been validated in a single laboratory for use with Kombucha fermented drinks, fruit juices, and low-alcohol beer samples. The commercially available Ethanol Assay Kit (Megazyme catalogue no. K-ETOH) contains all components required for the analysis. Quantification is based on the oxidation of ethanol to acetaldehyde by alcohol dehydrogenase and further oxidation of acetaldehyde by acetaldehyde dehydrogenase with conversion of NAD+ to NADH. The single laboratory validation (SLV) outlined in this document was performed on a sample set of eight different commercial Kombucha products purchased in Ireland, a set of five Cerilliant aqueous ethanol solutions, two BCR low-alcohol beer reference materials, two alcohol-free beer samples, and two fruit juice samples against SMPR 2016.001 (1). Parameters examined during the validation included Working range, Selectivity, Limit of Detection (LOD), Limit of Quantification (LOQ), Trueness (bias), Precision (reproducibility and repeatability), Robustness, and Stability. The Ethanol Assay is a robust, quick and easy method for the measurement of ethanol in Kombucha. Our data suggests this method is also reliable for similar matrices, such as low-alcohol beer and fruit juice. The assay meets all requirements set out in in AOAC SMPR 2016.001.

Correlation of major components and radical scavenging activity of commercial tea drinks in Taiwan

Correlation of major components with free radical scavenging activities of 27 commercial tea drinks prepared from green, Oolong, and black teas in Taiwan were investigated. Green tea drinks contained the highest level of total catechins including epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin (EC), epicatechin gallate (ECG), and gallocatechin gallate (GCG), while these components were low in black tea drinks and moderate in Oolong tea drinks. EGC and EGCG were the major catechins in the three types of tea drinks, and gallic acid showed the highest abundance in black tea drinks. Caffeine concentrations were comparable in the three types of tea drinks. All black tea drinks contained sugars, and sucrose was the main sweetener added. The scavenging abilities against l,l-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals were used to determine the antioxidant potential of tea drinks, and the ranked order of potency was green tea > Oolong tea > black tea. Total phenolics, total catechins, and EGC of tea drinks were positively and significantly (r > 0.8) correlated to the scavenging abilities against DPPH and ABTS radicals. Our results show that green tea drinks have higher free radical scavenging activity than black and Oolong tea drinks may be related to their high levels of total phenolics and catechins.

Alimentos com ação fotoprotetora : possível prevenção no câncer de pele?

Introdução: O câncer de pele é o mais frequente no Brasil e representa 30% de todos os tumores malignos registrados no país. Alguns compostos bioativos presentes nos alimentos como carotenóides (betacaroteno, licopeno), probióticos e ômega-3, extrato de própolis, podem auxiliar na proteção da pele contra os danos causados por raios ultravioleta. Material e método: Para atingir o objetivo foi realizada uma revisão bibliográfica para avaliar a ação fotoprotetora dos compostos bioativos, nas principais bases de dados em saúde Pubmed, Lilacs e Scielo, com palavras-chave: neoplasias cutâneas, dieta, fotoproteção, nos idiomas português e inglês, considerando o período de 2008 a 2019. Resultado: O uso de betacaroteno na fotoproteção mostrou-se eficaz, com suplementação diária entre 15 mg e 180 mg e protegeu a pele contra queimaduras solares. Extrato de tomate contendo licopeno conferiu proteção contra danos agudos à pele causados pela exposição solar à longo prazo. A suplementação de licopeno e luteína protegeu a pele contra danos à pele causados pela radiação solar. A ingestão diária da bebida polifenol chá verde por 12 semanas apresentou efeito fotoprotetor. Observou-se que substâncias não tóxicas consumidas na dieta como polifenóis em frutas, vegetais, vinho, chá e cafeína, ou disponíveis na forma oral de suplementos, podem aumentar a produção de ATP e inibir a produção de ROS ou diminui a produção de PGE2, causando redução dos danos induzidos pela luz solar em humanos e protegendo a pele por vários mecanismos potenciais. Extrato de própolis tem sido utilizado no preparo de alimentos e bebidas com a finalidade de melhorar ou prevenir o câncer, e a fruta romã pode exercer ação antiinflamatória, antiproliferativa e ter efeitos anti-tumorigênicos. Conclusão: Conforme os artigos estudados, o consumo dos compostos bioativos carotenoides como betacaroteno e licopeno, flavonóides, polifenóis, cafeína, ácidos graxos poli-insaturados ômega-3, vitamina E e minerais como o selênio, são estratégias eficientes na proteção da pele contra a radiação solar, diminuindo o risco do câncer de pele. Entretanto, mais estudos clínicos randomizados precisam ser realizados para confirmar seus efeitos e estabelecer doses adequadas para efeito fotoprotetor.

Effect of tea polyphenols on the oral and intravenous pharmacokinetics of ticagrelor in rats and its in vitro metabolism.

Green tea is widely consumed as a beverage and/or dietary supplement worldwide, resulting in the difficulty to avoid the comedication with ticagrelor for acute coronary syndrome (ACS) patients receiving antiplatelet therapy. This study was designed to investigate the effect of the most abundant content in green tea, tea polyphenols on the oral and intravenous pharmacokinetics of ticagrelor in rats and its in vitro metabolism. Rats were orally treated with either saline or tea polyphenol extracts (TPEs) dissolved in saline once daily for 6 consecutive days. On day 6, after the last dose of saline or TPE, ticagrelor was given to the rats orally or intravenously. Plasma samples were collected for pharmacokinetic analysis. Human liver and intestinal microsomes were then used to investigate the inhibition by TPE, as well as its major constituents on the metabolism of ticagrelor to its two metabolites, AR-C124910XX and AR-C133913XX. Apparent kinetic constants and inhibition potency (IC50 ) for each metabolic pathway of each compound were estimated. Oral study indicated that exposure of ticagrelor and AR-C124910XX was significantly decreased after TPE administration, while no significant differences were observed in pharmacokinetic parameters after intravenous administration of ticagrelor. TPE effectively inhibited the metabolism of ticagrelor in vitro, with epigallocatechin-3-gallate as the major constituent responsible for the observed inhibitory effects in human liver microsomes and intestinal microsomes (IC50 = 4.23±0.18µM). Caution should be taken for ACS patients receiving ticagrelor therapy with daily drinking of green tea. PRACTICAL APPLICATION: Potential interactions between tea polyphenols and ticagrelor were revealed for the first time. Results can provide suggestions for clinicians to optimize the dosing of ticagrelor while they are in the face of ACS patients receiving ticagrelor therapy, who also take green tea or its related products in their daily life.

The Effect of Different Doses of Green Tea Extract on Hematological and Biochemical Parameters in Adult Male Rats

This investigates the effects of various concentrations of continuous drinking of green tea in rats. (24) male rats are randomly categorized into four groups: control, which does not receive green tea, GTE5, GTE10 and GTE20 (receive 5g, 10g and 20g GTE, respectively). In hematological parameters analysis, there are no significant variation (p>0.05) in the RBC, MCHC and platelet among all groups. Furthermore, Control group presented a considerable decrease (p <0.05) in HB, HTC, MCV and MCH as compared with GTE5, GTE10 and GTE20. The biochemical analysis, control and GTE5 groups had high significant decrease (p<0.05) in glucose level as compared with GTE10 and GTE20 groups. Analysis of albumin and globulin, control and GTE5 groups had a significant decrease (p<0.05) higher than that of GTE10 and GTE20 groups. On the other hand, GTE20 group revealed a highly significant increase variation (p<0.05) in total protein than the control, GTE5 and GTE10 groups. In the control group showed a significant increase (p <0.05) in values of AST, ALT and ALK as compared with other groups. Therefore, it is recommended that using green tea for a long period leads to inhibition of the free oxygen radical damages in the liver and erythrocyte.

Electroencephalographical investigation of drinking green tea to the human brain

Background: Nowadays green tea has become one of the most popular drinks all over the world. Evidences suggest that green tea become second most consumer following regular drinking water. Green tea contains Theanine, an amino acid primarily found in green tea and black tea. The content is generally found 1-2% of dried tea or around 60 milligrams per 200 milliliters of tea drink. In particular, this substance is found in the form of L-theanine that can be absorbed to the blood system and then to the brain within 30 minutes, which causes relaxation and reducing stress.&#x0D; Aims and Objective: The objective was to examine the effect of green tea consumption on electroencephalographic (EEG) activities.&#x0D; Materials and Methods: This study was an experimental design. The participants were twelve Thai healthy, aged between 21-55 years old. During the experiment, all participants were asked to drink green tea every 10 minutes.&#x0D; Results: The influence to brainwave and attentive process were tested by experimental design. The study indicated that alpha brainwave was shown after drinking green tea. Frequency of alpha brainwave along cumulative drinking of green tea was shown significantly since the 10th minute. However, spectrum of the alpha brainwave changed significantly after drinking green tea, after 30th minutes.&#x0D; Conclusion: The benefit of this study was to provide the guideline for planning and campaigning green tea consumption for the purpose of stress reduction resulting in relaxation.

The effect of pressure on the kinetics of polyphenolics degradation – Implications to hyperbaric storage using Epigallocatechin-gallate as a model

Understanding reaction kinetics at elevated pressures is of importance for the development of pressure-based technologies and especially for hyperbaric storage (HS), a potential alternative for the energy-consuming refrigeration. The effect of pressure on degradation kinetics of a polyphenol, Epigallocatechin-gallate (EGCG), was explored at pressures up to 200 MPa (HS levels) for several hours, with and without fructose. In a baroresistant buffer, pressure enhanced EGCG degradation, due to a negative activation volume, while in phosphate buffer the pH decreased (as is also expected to occur in many foods) resulting in a superposition of accelerating and protective effects. A previously undescribed protective, pressure-level dependent, effect of fructose was identified. Novel in situ spectroscopy and HPLC analysis revealed that in addition to the effect on EGCG degradation rate, pressure also modifies the ratios between the numerous degradation products, likely due to a varying effect on the different steps involved in the degradation pathway. Industrial relevanceThe effect of pressure on reaction kinetics in food systems can be of great importance in processing conditions combining thermal and high pressure, and critical for the emerging concept of hyperbaric storage, where the food is exposed to high pressures for long duration of time, allowing a plethora of reactions to take place, all varyingly affected by pressure. Yet the effects of pressure on kinetics are often overlooked. Polyphenolic compounds are a large group of molecules responsible for both sensorial and health-promoting functionality in plant-based foods. Those compounds are known to undergo degradation by several mechanisms during processing and storage and their successful conservation is often considered of significant industrial importance. The presented work provides fundamental information regarding the effects of pressure on the kinetics of EGCG (Epigallocatechin-gallate) degradation, as a model for relatively unstable, polyphenolic compound, (taking into account pressure-induced pH shifts, and the presence of co-solutes). EGCG is also of specific importance in many products where it naturally occurs (green tea drinks etc.) and where it is externally added as a valuable supplement.

Green tea consumption and risk of hematologic neoplasms: the Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC Study).

Experimental studies suggested that green tea may have an anticancer effect on hematologic neoplasms. However, few prospective studies have been conducted. A total of 65,042 individuals aged 40-79years participated in this study and completed a self-administered questionnaire about their lifestyle and medical history at baseline (1988-1990). Of these, 52,462 individuals living in 24 communities with information on incident hematologic neoplasms available in the cancer registry, who did not have a history of cancer and provided valid information on frequency of green tea consumption, were followed through 2009. Hazard ratios (HRs) and 95% confidence intervals (CIs) for the incidence of hematologic neoplasms according to green tea consumption were analyzed. The incidence of hematologic neoplasms during a median follow-up of 13.3years was 323. Compared with the never-drinkers of green tea, the multivariate HRs and 95% CIs for total hematologic neoplasms in green tea drinkers of ≤ 2 cups/day, 3-4 cups/day, and ≥ 5 cups/day were 0.65 (0.42-1.00), 0.73 (0.47-1.13), and 0.63 (0.42-0.96), respectively. The association was more prominent for acute myeloid leukemias and follicular lymphomas. The present cohort study suggests a protective effect of green tea against hematologic neoplasms, especially acute myeloid leukemias.

PERBANDINGAN MENGONSUMSI BERBAGAI JENIS MINUMAN BERKAFEIN (KOPI, TEH HIJAU, DAN MINUMAN BERENERGI) TERHADAP WAKTU REAKSI

Generally, the aim of this research to know the comparison of caffeine drinks through the result of reaction time after consumption coffee, green tea, and energy drink by the same amount of caffeine. The way to gather the data is using purposive sampling, the population that chosen by researcher is 10 respondents college students of Ilmu Keolahragaan batch 2016. For data analysis, using SPSS 21 program for windows and Statistical calculation that used is One-Way ANOVA continues with Post Hoc Tukey. The average of result from time reaction on Speed Anticipation Reaction is 1.263 (placebo), 1,257 (green tea), 1.271 (energy drink), and 1.358 (black coffee). For Body Reaction Time Test (visual) shows the average around 1.239 (placebo), 0.245 (green tea), 0.257 (green tea), and 0.244 (black coffee). While on Whole Body Reaction Time Test (auditory) shows the average0.239 (placebo), 0.239 (green tea), 0.274 (energy drink), and 0.263 (black coffee). The signification value from three time reaction test are (Speed Anticipation Reaction Sig. 0.706 &gt; 0.05, Whole Body Reaction (visual) Sig. 0.877 &gt; 0.05, and Whole Body Reaction (auditory) Sig. 0.348 &gt; 0.05) all of the result above 0.05. Hence, it can be conclude there is no significantly difference through time reaction result after consumption kind of caffeine drinks with the same concentration.

Genetic polymorphism of catechol-O-methyltransferase modulates the association of green tea consumption and lung cancer.

Tea polyphenols are strong antioxidants, which can be rapidly O-methylated by catechol-O-methyltransferase (COMT). Thus, it is possible that the genetic polymorphism of COMT can modulate the association of green tea consumption and lung cancer. Here, we designed a case-control study to evaluate the combined effect of green tea consumption and COMT genotypes on the risk of lung cancer. A total of 237 lung cancer patients and 474 healthy controls were recruited. Questionnaires were administered to obtain demographic data, smoking status, green tea consumption, fruits and vegetables intake, exposure to cooking fumes, and family history of lung cancer. Genotypes for COMT were identified by PCR. Smoking, green tea consumption, exposure to cooking fumes, and family history of lung cancer were associated with the development of lung cancer. When green tea drinkers carrying COMT HL/LL genotypes were selected as the reference group, drinkers carrying the COMT HH genotype had a higher risk for the development of lung cancer (odds ratio: 1.97, 95% confidence interval: 0.99-3.91). Among the current and ever smokers, the elevated risk for lung cancer was more apparent in green tea drinkers carrying the COMT HH genotype compared with green tea drinkers carrying COMT HL/LL genotypes (odds ratio: 5.84, 95% confidence interval: 1.75-19.45). Green tea drinkers with greater activity of the COMT genotype, whereby polyphenols are effectively excluded, will gain fewer protective benefits against lung cancer development.

Soy and tea intake on cervical cancer risk: the Singapore Chinese Health Study.

Soy isoflavones and tea catechins have immunomodulating and chemopreventive properties relevant for cervical carcinogenesis; however, there are limited epidemiologic data on the relationship of soy and tea consumption with cervical cancer risk. The aim of our study was to examine effects of soy and tea intake on cervical cancer risk among Singapore Chinese women. The association between intake of soy and tea drinking and cervical cancer risk was investigated in a prospective, population-based cohort of 30,744 Chinese women in Singapore with an average 16.7years of follow-up and 312 incident cervical cancer cases. Multivariable proportional hazard models were used to estimate hazard ratio (HR) and 95% confidence interval (CI) of cervical cancer associated with intake levels of soy and tea. High intake of soy alone was associated with a statistically borderline significant 20% reduced risk of cervical cancer (HR 0.80, 95% CI 0.61, 1.05) while green tea alone was not (HR 0.97, 95% CI: 0.76, 1.22). In stratified analysis, high intake of soy was associated with a statistically significant decrease in cervical cancer risk among green tea drinkers (HR 0.43; 95% CI 0.28, 0.69) but not among non-drinkers of green tea. The difference in the soy-cervical cancer risk association between green tea drinkers and non-drinkers was statistically significant (p for interaction = 0.004). This inverse association between soy intake and cervical cancer risk remained after further adjustment for human papillomavirus serostatus. Black tea consumption was not associated with cervical cancer risk. These findings suggest that a protective effect of soy against cervical cancer development may depend on green tea constituents.

AUDIT OPERASIONAL PEMASARAN TERHADAP PERSPEKTIF KEPUASAN PELANGGAN ATAS PRODUK NU GREEN TEA PT ABC PRESIDENT INDONESIA

The purpose of this research is to find out customer satisfaction of Nu Green Tea drinks through marketing programs and marketing budgets. As Marketing operational audit can use not only financial data as a key performance indicator. Data obtained by distributing questionnaires to several customers, namely traditional shops or agents that have been determined. The analysis used descriptive analysis method with describe quantitative analysis approach or describe the object of research to find out how effective and efficient the marketing program is on the marketing budget. Among of the results show that Marketing programs and marketing budgets simultaneously have a positive and significant impact on customer satisfaction . Marketing programs are influenced by the existence of programs that include the development of human resources on the internal part, including marketing training. Marketing training, among the others, is to improve quality in order to improve the best sales performance by selling effectively and productively. Identifying the target market will help in developing an effective marketing strategy. Introducing products to consumers, promoting consistently, continuously, and in creative ways. Internet marketing is one of marketing strategy that is very effective, knowing the tastes of customers and customer needs by placing on social networking sites.

Assessment of the tear film in normal eye subjects after consumption of a single dose of hot peppermint drink.

Objective: To test the effect of a single dose of hot peppermint consumption on the tear film in normal eye subjects.Methods: Thirty healthy male subjects aged 18–39 years (23.20±2.17 years) were enrolled. Also, an age-matched control group of 30 male subjects (19–39 years, 23.50±0.70 years) was enrolled to test the effect of the hot water. Tear meniscus height (TMH), noninvasive tear breakup time (NITBUT), and tear ferning (TF) tests were performed for each patient 30 mins before and 60 mins after they drank hot peppermint.Results: Mean TMH measurements were higher postintervention (0.32±0.07) than preintervention (0.27±0.04 mm). Similarly, mean TF grades were significantly higher (2.07±1.20) postintervention than preintervention (0.84±0.71). By contrast, mean NITBUT was lower postintervention than preintervention (11.57±3.17 and 15.84±3.36, respectively). TMH measurements increased in 90% of the subjects. Conversely, NITBUT decreased in 96.7% of the subjects. For the control group that tests the effect of drinking hot water, the scores did not differ significantly in the three tests pre- and postintervention (P˂0.05). TF grades increased in 93.3% of the subjects, postintervention.Conclusion: Tear film quality decreases significantly after peppermint beverage consumption. A similar observation has been made on the consumption of hot green tea drink.

Daily Green Tea Infusions in Hypercalciuric Renal Stone Patients: No Evidence for Increased Stone Risk Factors or Oxalate-Dependent Stones.

Green tea is widely used as a ‘’healthy’’ beverage due to its high level of antioxidant polyphenol compounds. However tea is also known to contain significant amount of oxalate. The objective was to determine, in a cross-sectional observational study among a population of 273 hypercalciuric stone-formers referred to our center for metabolic evaluation, whether daily green tea drinkers (n = 41) experienced increased stone risk factors (especially for oxalate) compared to non-drinkers. Stone risk factors and stone composition were analyzed according to green tea status and sex. In 24-h urine collection, the comparison between green tea drinkers and non-drinkers showed no difference for stone risk factors such as urine oxalate, calcium, urate, citrate, and pH. In females, the prevalence of calcium oxalate dihydrate (COD) and calcium phosphate stones, assessed by infrared analysis (IRS) was similar between green tea drinkers and non-drinkers, whereas prevalence of calcium oxalate monohydrate (COM) stones was strikingly decreased in green tea drinkers (0% vs. 42%, p = 0.04), with data in accordance with a decreased oxalate supersaturation index. In males, stone composition and supersaturation indexes were similar between the two groups. Our data show no evidence for increased stone risk factors or oxalate-dependent stones in daily green tea drinkers.

A rapid screening color test for glyphosate using dabsyl derivatization

Glyphosate is the most common herbicide in the world, and involved in many poisoning cases. However, the analysis of glyphosate has been difficult because of its high polarity and zwitterionic structure, and no simple screening tests for glyphosate have been known. The purpose of this study was to develop a rapid screening test for glyphosate. Glyphosate was visualized through a color change induced by dabsyl derivatization, and the derivatized glyphosate was trapped on the surface of zirconia-coated silica particles by specific chemical interaction between a phosphonate group of glyphosate and the zirconia surface. The presence of glyphosate was indicated by the color change of zirconia surface, which was easily noticed by the naked eye. The developed method was applied to biological samples (urine and serum), beverage samples (green tea and cola drink), and soil samples. No false positive was observed and the detection limit was 100 μg/mL for the biological samples and 800 μg/mL for the beverage samples. A simple screening method for glyphosate based on a color test was established. The method is rapid and requires less than 30 μL of samples. The sensitivity was sufficient for most cases of moderate to severe poisoning.

PENGARUH KOMPOSISI HERBAL DALAM MINUMAN TEH HIJAU GAMBUNG HERBAL TERHADAP HAMBATAN α-GLUKOSIDASE

The aim of this study is to make a formula of green tea that is enriched by other herbs. Green tea drinks are made using the basic ingredients of gambung (THG) green tea enriched with sapodilla leaves ( Manilkara zapota (Aw) bay leaves ( Syzygium polyanthum (Am), Artocarpus communis (Un) breadfruit leaves, and cinnamon leaves ( Cinnamomum verum (K)). The composition of gambung herbal green tea is made by reference to the antidiabetic activity of each herb. All the samples were tested for inhibition of α-glucosidase enzymes and toxicity using the lethality test method for brine shrimp. All samples showed good inhibition of the α-glucosidase enzyme barriers of gamboeng green tea (THG) 82.05%, sapodilla leaves (Aw) 97.81%, breadfruit leaves (Un) 73.34%, bay leaves (Am) 93.80%, cinnamon leaves (K) 91.24 %. The inhibition value of α-glucoside enzymes in the formulation of gamboeng herbal green tea drinks: 96.203% (GKUn) is higher when compared to the GKAm formula (94.78%) and GKAw (62.487%).

Green tea intake and risk of incident kidney stones: Prospective cohort studies in middle-aged and elderly Chinese individuals.

To investigate the association between green tea intake and incident stones in two large prospective cohorts. We examined self-reported incident kidney stone risk in the Shanghai Men's Health Study (n=58054; baseline age 40-74years) and the Shanghai Women's Health Study (n=69166; baseline age 40-70years). Information on the stone history and tea intake was collected by in-person surveys. Multivariable Cox proportional hazards models were adjusted for baseline demographic variables, medical history and dietary intakes including non-tea oxalate from a validated food frequency questionnaire. During 319211 and 696950 person-years of follow up, respectively, 1202 men and 1451 women reported incident stones. Approximately two-thirds of men and one-quarter of women were tea drinkers at baseline, of whom green tea was the primary type consumed (95% in men, 88% in women). Tea drinkers (men: hazard ratio 0.78, 95% confidence interval 0.69-0.88; women: hazard ratio 0.8, 95% confidence interval 0.77-0.98) and specifically green tea drinkers (men: hazard ratio 0.78, 95% confidence interval 0.69-0.88; women: hazard ratio 0.84, 95% confidence interval 0.74-0.95) had lower incident risk than never/former drinkers. Compared with never/former drinkers, a stronger dose-response trend was observed for the amount of dried tea leaf consumed/month by men (hazard ratiohighest category 0.67, 95% confidence interval 0.56-0.80, Ptrend <0.001) than by women (hazard ratiohighest category 0.87, 95% confidence interval 0.70-1.08, Ptrend =0.041). Green tea intake is associated with a lower risk of incident kidney stones, and the benefit is observed more strongly among men.

Achievable Central Nervous System Concentrations of the Green Tea Catechin EGCG Induce Stress in Glioblastoma Cells in Vitro

The polyphenolic compounds present in green tea are preventative against cancer in several animal tumor models. However, direct cytotoxic effects on cancer cells have also been reported. In order to determine whether drinking of green tea has chemopreventive or cytotoxic effects on brain cancer cells, we investigated the effect of the major green tea polyphenol EGCG as a pure substance and as tea extract dietary supplement on primary human glioblastoma cell cultures at the CNS-achievable concentration of 100 nM reported in the literature. We compared this with the effect of the cytotoxic concentration of 500 μM determined to be specific for the investigated primary glioblastoma cultures. After treatment with 500 µM EGCG, strong induction of autophagy and apoptosis was observed. Under treatment with 100 nM EGCG, glioblastoma cells proliferated over the entire observation period of 6 days without any detectable signs of cell death. Only within the first 12 h of treatment was increased accumulation of autophagic vacuoles and increased reactive oxygen species production as a stress response demonstrated. Mild forms of stress, such as treatment with 100 nM EGCG, activate different endogenous repair mechanisms to protect cells. Our data imply that drinking of green tea may have chemopreventive effects, but no direct cytotoxic properties.

Green tea consumption and risk of type 2 diabetes in Chinese adults: the Shanghai Women's Health Study and the Shanghai Men's Health Study.

Epidemiological evidence on the association between tea consumption and the risk of type 2 diabetes (T2D) is inconsistent. This study prospectively investigated whether green tea drinking affects the risk of T2D. This study included participants from the Shanghai Women's Health Study (N = 67058) and the Shanghai Men's Health Study (N = 52315) without diabetes at study enrolment. Details of tea consumption, including types and amounts, were collected at the baseline and follow-up survey. Incident T2D was identified through follow-up surveys. Plasma level of caffeine metabolite was measured in a nested case-control study involving 592 diabetes case-control pairs. Cox regression analysis, with tea drinking as a time-dependent variable and covariates adjusted for by a propensity score, was applied to estimate the hazard ratio (HR) and 95% confidence interval (CI) for T2D risk. Logistic regression analysis was applied to evaluate the association between caffeine metabolites and T2D risk. Current green tea drinkers had an increased risk of T2D compared with non-current drinkers [HR = 1.20 (95% CI = 1.14-1.27)], and a dose-response relationship was observed for duration of drinking tea and the amount of tea consumed [P for trend <0.001]. The increased risk associated with green tea drinking was observed in both women and men, across the entire period of follow-up, with HR (95% CI) of 1.08 (0.97-1.19) within 5 years of follow-up, 1.22 (1.12-1.32) during the period of 5-10 years of follow-up and 1.16 (1.03-1.30) after 10 years of follow-up. This association did not vary significantly by body mass index, waist-to-hip circumference ratio or smoking status. Plasma level of caffeine was also associated with increased diabetes risk (P = 0.03), confirming the results based on self-reported tea drinking. Green tea drinking was associated with an increased risk of T2D in Chinese adults. The mechanisms underlying the association need to be elucidated.

Solid-Contact Potentiometric Sensors and Multisensors Based on Polyaniline and Thiacalixarene Receptors for the Analysis of Some Beverages and Alcoholic Drinks.

Electronic tongue is a sensor array that aims to discriminate and analyze complex media like food and beverages on the base of chemometrics approaches for data mining and pattern recognition. In this review, the concept of electronic tongue comprising of solid-contact potentiometric sensors with polyaniline and thacalix[4]arene derivatives is described. The electrochemical reactions of polyaniline as a background of solid-contact sensors and the characteristics of thiacalixarenes and pillararenes as neutral ionophores are briefly considered. The electronic tongue systems described were successfully applied for assessment of fruit juices, green tea, beer, and alcoholic drinks They were classified in accordance with the origination, brands and styles. Variation of the sensor response resulted from the reactions between Fe(III) ions added and sample components, i.e., antioxidants and complexing agents. The use of principal component analysis and discriminant analysis is shown for multisensor signal treatment and visualization. The discrimination conditions can be optimized by variation of the ionophores, Fe(III) concentration, and sample dilution. The results obtained were compared with other electronic tongue systems reported for the same subjects.