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Thearubigins (TRs) are chemically ill-defined black tea pigments composed of numerous catechin oxidation products. TRs contain oligomeric components; however, the oligomerization mechanisms are poorly understood. The comparison of the 13C nuclear magnetic resonance (NMR) spectra of TRs with different molecular sizes suggested the participation of A-ring methine carbons in the oligomerization. Crushing fresh tea leaves with phloroglucinol, a mimic of the catechin A-rings, yielded the phloroglucinol adducts of the B-ring quinones of pyrogallol-type catechins and dehydrotheasinensins, indicating that intermolecular oxidative couplings between pyrogallol-type B-rings and A-rings are involved in the oligomerization. This is supported by the comparison of the 13C NMR spectra of the oligomers generated from the dehydrotheasinensins and epicatechin. Furthermore, the presence of the quinones or related structures in the catechin oligomers is shown by condensation with 1,2-phenylenediamine. The pyrogallol-type catechins account for approximately 70% of tea catechins; therefore, the B–A ring couplings of the pyrogallol-type catechins are important in the catechin oligomerization involved in TR production., Journal of agricultural and food chemistry, 71(41), pp.15319-15330; 2023

Pengaruh konsumsi teh hitam dan konsultasi gizi terhadap kadar glukosa darah penderita DM tipe 2 di rumah sakit umum provinsi Sulawesi Tenggara

Pengaruh konsumsi teh hitam dan konsultasi gizi terhadap kadar glukosa darah penderita DM tipe 2 di rumah sakit umum provinsi Sulawesi Tenggara

BACKGROUND People brew tea to drink an infusion that only contains 25% water-soluble constituents, leading to most of the insoluble materials being wasted. Tea powder could be drunk directly by mixing with water without producing any waste. Tea powder can also be used as a natural additive to improve the flavour and taste in beverages and foods. Much detailed information on the particle properties of tea powder is required with its increasing consumption. The aim of this study was to investigate the effects of particle size ranging from median diameter D-50 = 4.32 to 26.59 mu m on the composition, physical, rheological, and bioactive properties of black tea powder. RESULTS The results indicate that large powder sizes had high bulk density and flowability, whereas small powder sizes possessed good swelling ability and wettability. The contents of water extract, total polyphenols, crude fibre, catechins, and thearubigins reduced with a decrease in particle size. To change the particle size and concentration could adjust the elastic modulus and the viscous modulus of the black tea powder suspension. Moreover, black tea powder with small particle size could regulate blood lipids in a hyperlipidaemic rat model by lowering triacylglycerols and elevating high-density lipoprotein cholesterol, whereas large particles presented an advantage in reducing body weight. CONCLUSION Our investigation extended the knowledge of commercial black tea powder in composition, physical, rheological, and bioactive properties. These results lay the foundation for future exploration of the use of tea powder in the food industry. (c) 2022 Society of Chemical Industry

The formation of prostaglandin E2 (PGE2) is associated with adverse inflammatory effects. However, long-term treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) comes with risk of severe side effects. Therefore, alternative ways to inhibit PGE2 are warranted. We have investigated the effects of tea extracts and the polyphenols epigallocatechin gallate (EGCG) and quercetin on PGE2 formation, determined by immunoassay, and protein expression, determined by immunoblotting, of cytosolic phospholipase A2 (cPLA2), cyclooxygenase 2 (COX-2) and microsomal PGE synthase-1 (mPGES-1) in human monocytes. Green and black tea extracts, and with a lower potency, Rooibos tea extract, inhibited lipopolysaccharide (LPS) and calcium ionophore-induced PGE2 formation. In addition, all tea extracts inhibited the LPS-induced expression of mPGES-1, and the green and black tea extracts also inhibited, to a lesser extent, COX-2 expression. The tea extracts only marginally reduced cPLA2 expression and had no effect on COX-1 expression. EGCG, present in green and black tea, and quercetin, present in all three teas, also inhibited PGE2 formation and expression of mPGES-1, COX-2 and cPLA2. Cell-based and cell-free assays were also performed to evaluate direct effects on the enzymatic activity of COX and PGE synthases. Mainly, the cell-free assay demonstrated partial inhibition by the tea extracts and polyphenols. However, the inhibition required higher doses compared to the effects demonstrated on protein expression. In conclusion, green and black tea, and to a lesser extent Rooibos tea, are potent inhibitors of PGE2 formation in human monocytes, and mediate their effects by inhibiting the expression of the enzymes responsible for PGE2 formation, especially mPGES-1.

This study aims to determine the effect of adding Dutch eggplant juice on the characteristics of black tea drinks. This study used a completely randomized design (CRD) with 5 treatments and 3 replications. The data was analyzed statistically with the F test, if it was significantly different, it was continued with Duncan's new Multiple Range Test (DNMRT) at the level of 5%. The addition of Dutch eggplant juice was 6%, 8%, 10%, 12%, 14%. This study showed the effect of adding Dutch eggplant juice to vitamin C, PH, antioxidants, polyphenols, flavonoids, alkaloids, tannins, saponins and sensory analysis (color, aroma and taste). The best product was the product with treatment E (addition of 14% Dutch eggplant extract) with antioxidant characteristics of 77.67%, polyphenols 393.37 mg GAE/g, flavonoids 296.83 mg QE/g, vitamin C 168.96 mg/100g, pH 4, alkaloid (+), tannin (+), saponin (+), color 3.05, aroma 3.90 and taste 3.75.

This study aims to determine the effect of adding Dutch eggplant juice on the characteristics of black tea drinks. This study used a completely randomized design (CRD) with 5 treatments and 3 replications. The data was analyzed statistically with the F test, if it was significantly different, it was continued with Duncan's new Multiple Range Test (DNMRT) at the level of 5%. The addition of Dutch eggplant juice was 6%, 8%, 10%, 12%, 14%. This study showed the effect of adding Dutch eggplant juice to vitamin C, PH, antioxidants, polyphenols, flavonoids, alkaloids, tannins, saponins and sensory analysis (color, aroma and taste). The best product was the product with treatment E (addition of 14% Dutch eggplant extract) with antioxidant characteristics of 77.67%, polyphenols 393.37 mg GAE/g, flavonoids 296.83 mg QE/g, vitamin C 168.96 mg/100g, pH 4, alkaloid (+), tannin (+), saponin (+), color 3.05, aroma 3.90 and taste 3.75.

Проблема контроля подлинности пищевых продуктов является актуальной как с теоретической, так и практической точки зрения. По отношению к идентификации продукции применяются различные подходы, например, поиск веществ-маркеров и методы распознавания образов. Последний рассматривает профили различной природы как единую характеристическую особенность продукта, что позволяет получать классификационную модель объектов. Другой способ сравнения профилей – построение и визуальное сравнение лепестковых диаграмм. Данная работа направлена на изучение электрофоретического профиля черного чая и выявление характеристик, позволяющих классифицировать чай по географическому происхождению, не учитывая технологию его изготовления. Проведена апробация методики определения кофеина, катехина, эпигаллокатехин галлата, эпикатехина и галловой кислоты в экстрактах чая методом мицеллярной электрокинетической хроматографии. Установлен диапазон линейности определения, который для всех изучаемых компонентов составляет 0.5-200 мкг/см3, погрешность определения аналитов не превышает 15 %, стандартное отклонение величины площади пиков на электрофореграмме менее 10 %. Изучение электрофоретических профилей экстрактов черного чая различного происхождения позволило выявить девять характеристических пиков, которые удовлетворительно воспроизводятся, разрешены и присутствуют во всех образцах. Сформирован массив данных на основе площадей характеристических пиков электрофореграмм, зарегистрированных для экстрактов ассамского, цейлонского и «оригинального» краснодарского чая. Для нивелирования влияния разброса значений площадей характеристических пиков проведено их соотнесение друг к другу. Применение к матрице данных, включающих соотношения площадей характеристических пиков, дисперсионного анализа с последующей обработкой его результатов методом главных компонент, позволило установить соотношения, оказывающие наибольшее влияние на отнесение образца к группе чая соответствующего происхождения На основе выбранн, The problem of food authenticity control is relevant from both a theoretical and a practical point of view. Various approaches are applied to product identification, for example, the search for marker substances and pattern recognition methods. The latter considers profiles of various nature as a single characteristic feature of the product, which allows one to obtain a classification model of objects. Another way to compare profiles is to build and visually compare the petal diagrams. This paper is aimed at studying the electrophoretic profile of black tea and identifying characteristics which make it possible to classify tea according to the geographical origin, without considering the technology of its manufacture. The methodology for the determination of caffeine, catechin, epigallocatechin gallate, epicatechin and gallic acid in tea extracts was tested by micellar electrokinetic chromatography method. The range of determination linearity was established and amounted to 0.5-200 μg / ml for all the components under study, the error in the analytes determination did not exceed 15%, the standard deviation of the peak area on the electrophoregram was less than 10%. We have examined the electrophoretic profiles of black tea extracts of various origins and observed nine characteristic peaks that were satisfactorily reproduced, were legal, and were present in all the samples. An array of data was generated based on the characteristic peaks areas on the electrophoregrams recorded for extracts of Assamese, Ceylon and “original” Krasnodar tea. To level the influence of values spread of the characteristic peaks areas, they were related to each other. The application to the matrix of data, which included the ratio of the characteristic peak areas, of the variance analysis with subsequent processing of its results using the principal component method, made it possible to establish the ratios most influencing the sample reference to a certain tea group. Based on the selected

Black tea like other food crops is prone to mercury ion (Hg2+) contamination right from cultivation to industrial processing. Due to the dangerous health effects posed even in trace contents, sensitive detection and quantification sensors are required. This study employed the surface-enhanced Raman scattering (SERS) enhancement property of 4-aminothiophenol (4-ATP) as a signal turn off approach functionalized on Ag-Au alloyed nanopartide to firstly detect Hg2+ in standard solutions and spiked tea samples. Different chemometric algorithms were applied on the acquired SERS and inductively coupled plasma-mass spectrometry (ICP-MS) chemical reference data to select effective wavelengths and spectral variables in order to develop models to predict the Hg2+. Results indicated that Ag-Au/4-ATP SERS sensor combined with ant colony optimization partial least squares (ACO-PLS) exhibited the best correlation efficient and minimum errors for Hg2+ standard solutions (R-c = 0.984, R-p = 0.974, RMSEC = 0.157 mu g/mL, RMSEP = 0.211 mu g/mL) and spiked tea samples (R-c = 0.979, R-p = 0.963, RMSEC = 0.181 mu g/g and RMSEP = 0210 mu g/g). The limit of detection of the proposed sensor was 4.12 x 10(-7) mu g/mL for Hg2+ standard solutions and 2.83 x 10(-5) mu g/g for Hg2+ spiked tea samples. High stability and reproducibility with relative standard deviation of 1.14% and 0.84% were detected. The potent strong relationship between the SERS sensor and the chemical reference method encourages the application of the developed chemometrics coupled SERS system for future monitoring and evaluation of Hg2+ in tea.

During black tea production, catechins and their galloyl esters are enzymatically oxidized to generate a complex mixture of black tea polyphenols. The role of galloyl ester groups in this process has yet to be determined. Enzymatic oxidation of epicatechin 3-O-gallate (1) yielded two new oxidation products, theaflavate C and bistheaflavate A, along with theaflavate A (2), a known dimer of 1 generated by coupling of the B-ring with the galloyl group. Theaflavate C is a trimer of 1 and possesses two benzotropolone moieties generated by the oxidative coupling of the galloyl groups with the catechol B-rings. Bistheaflavate A was found to be a tetramer produced by intermolecular coupling of two benzotropolone moieties of 2. From the structures of the products, it was deduced that oxidative coupling of galloyl groups resulted in extension of the molecular size of the products in catechin oxidation., identifier:Chemical & Pharmaceutical Bulletin v.55(12) p.1768-1772, 2007

This review will discuss recent progress in the chemistry of secondary polyphenols produced during food processing. The production mechanism of the secondary polyphenols in black tea, whisky, cinnamon, and persimmon fruits will be introduced. In the process of black tea production, tea leaf catechins are enzymatically oxidized to yield a complex mixture of oxidation products, including theaflavins and thearubigins. Despite the importance of the beverage, most of the chemical constituents have not yet been confirmed due to the complexity of the mixture. However, the reaction mechanisms at the initial stages of catechin oxidation are explained by simple quinone-phenol coupling reactions. In vitro model experiments indicated the presence of interesting regio- and stereoselective reactions. Recent results on the reaction mechanisms will be introduced. During the aging of whisky in oak wood barrels, ellagitannins originating from oak wood are oxidized and react with ethanol to give characteristic secondary ellagitannins. The major part of the cinnamon procyanidins is polymerized by copolymerization with cinnamaldehyde. In addition, anthocyanidin structural units are generated in the polymer molecules by oxidation which accounts for the reddish coloration of the cinnamon extract. This reaction is related to the insolubilization of proanthocyanidins in persimmon fruits by condensation with acetaldehyde. In addition to oxidation, the reaction of polyphenols with aldehydes may be important in food processing., identifier:International journal of molecular sciences, 11(1), pp.14-40; 2010

This study was to examine the formation of advanced glycation end-products (AGEs) in black tea during drying process at 90, 120, and 150 degrees C for 1 h. Nine AGEs including N epsilon-(carboxyethyl)-L-lysine (CEL), N epsilon-(carboxymethyl)-L-lysine (CML), three isomers of methylglyoxal-hydroimidazolones (MG-Hs), three isomers of glyoxal-hydroimidazolones (GO-Hs), and argpyrimidine were quantified by using HPLC-MS/MS with isotope-labelled internal standard. Results showed that each AGE during the drying process of 150 degrees C was significantly higher (p < 0.05) than at 90 and 120 degrees C, and argpyrimidine was only found in the treatment of 150 degrees C. MG-H1/3 was first quantified as the major AGE during drying at 120- 150 degrees C, the content respectively reached to (39.66 +/- 2.61) mu g/g and (58.88 +/- 1.76) mu g/g after 1 h drying, where CML content only had (19.86 +/- 1.02) mu g/g and (23.71 +/- 1.40) mu g/g. This study indicated that arginine derived-AGEs are the key components of black tea AGEs., Errata: Zhang W., Zhang B., Ye Y., Zhu H. Corrigendum to “Methylglyoxal-hydroimidazolones (MG-Hs) instead of Nɛ-(carboxymethyl)-l-lysine (CML) is the major advanced glycation end-product during drying process in black tea” [Food Chem. 333 (2020) 127499]. Food Chem. 2020;333:127499. DOI: 10.1016/j.foodchem.2021.129326

Objective To examine the possible relationship between tea consumption and risk of gastric cancer (GC) among Japanese men and women included in a large Japanese population-based study titled the Japan Collaborative Cohort (JACC) Study. Design Prospective cohort study. Setting A population-based cohort included subjects who were recruited from 24 areas of JACC Study, in which data regarding the incidence of cancer were available. Participants 63 848 participants (26 025 men and 37 823 women), aged 40-79, were included in the analyses and underwent follow-up (median 13.3 years) prospectively in research on cancer incidence. Primary and secondary outcome measures The primary outcome variable was the risk of GC according to the frequency intakes of total tea, green tea, black tea and oolong tea. The adjusted HRs for the risk of GC associated with tea consumption were calculated using the Cox proportional hazards model. Results 1494 cases of GC were detected (960 men and 534 women) during the follow-up period. The multivariable-adjusted HRs for the risk of GC in the highest versus lowest quintiles of total tea intake were 1.05 (0.83-1.33); p trend=0.50 in men, and 0.82 (0.60-1.12); p trend=0.45 in women. There was no association found between the consumption of green tea, black tea or oolong tea with the risk for GC in either gender. Conclusions In this large community-based prospective cohort study, tea consumption was not associated with the risk of GC in either gender.

Objective To examine the possible relationship between tea consumption and risk of gastric cancer (GC) among Japanese men and women included in a large Japanese population-based study titled the Japan Collaborative Cohort (JACC) Study. Design Prospective cohort study. Setting A population-based cohort included subjects who were recruited from 24 areas of JACC Study, in which data regarding the incidence of cancer were available. Participants 63 848 participants (26 025 men and 37 823 women), aged 40-79, were included in the analyses and underwent follow-up (median 13.3 years) prospectively in research on cancer incidence. Primary and secondary outcome measures The primary outcome variable was the risk of GC according to the frequency intakes of total tea, green tea, black tea and oolong tea. The adjusted HRs for the risk of GC associated with tea consumption were calculated using the Cox proportional hazards model. Results 1494 cases of GC were detected (960 men and 534 women) during the follow-up period. The multivariable-adjusted HRs for the risk of GC in the highest versus lowest quintiles of total tea intake were 1.05 (0.83-1.33); p trend=0.50 in men, and 0.82 (0.60-1.12); p trend=0.45 in women. There was no association found between the consumption of green tea, black tea or oolong tea with the risk for GC in either gender. Conclusions In this large community-based prospective cohort study, tea consumption was not associated with the risk of GC in either gender.

Theaflavins (TFs) are derived from black tea, an important source of dietary polyphenols. Although the potential interactions between dietary polyphenols and drugs have been demonstrated through in vitro and in vivo studies, little information is available concerning the influence of TFs on drug disposition. Organic anion transporting polypeptide 2B1 (OATP2B1) is expressed in human enterocytes and plays a role in the intestinal absorption of numerous drugs. The current study evaluated the effects of black tea extracts on the pharmacokinetics of rosuvastatin in rats, and investigated the effect of four major TFs (theaflavin, theaflavin-3-gallate, theaflavin-3 '-gallate and theaflavin-3,3 '-digallate) on the transport activity of OATP2B1. Black tea extracts significantly decreased the maximum plasma concentration (C-max) and area under the plasma concentration-time curve (AUC(0)-(8)) of rosuvastatin by 48% and 37%, respectively (p < 0.001 and p < 0.01, respectively). Moreover, OATP2B1-mediated rosuvastatin and estrone-3-sulfate uptake was significantly reduced in the presence of TFs. A kinetic study revealed that the uptake efficiency (in terms of V-max/K-m) of rosuvastatin was decreased following treatment with TFs. Black tea extracts also reduced OATP2B1-mediated rosuvastatin uptake. These results suggest that black tea reduces the plasma concentrations of rosuvastatin by inhibiting the intestinal OATP2B1-mediated transport of rosuvastatin.

Theaflavins (TFs) are derived from black tea, an important source of dietary polyphenols. Although the potential interactions between dietary polyphenols and drugs have been demonstrated through in vitro and in vivo studies, little information is available concerning the influence of TFs on drug disposition. Organic anion transporting polypeptide 2B1 (OATP2B1) is expressed in human enterocytes and plays a role in the intestinal absorption of numerous drugs. The current study evaluated the effects of black tea extracts on the pharmacokinetics of rosuvastatin in rats, and investigated the effect of four major TFs (theaflavin, theaflavin-3-gallate, theaflavin-3 '-gallate and theaflavin-3,3 '-digallate) on the transport activity of OATP2B1. Black tea extracts significantly decreased the maximum plasma concentration (C-max) and area under the plasma concentration-time curve (AUC(0)-(8)) of rosuvastatin by 48% and 37%, respectively (p < 0.001 and p < 0.01, respectively). Moreover, OATP2B1-mediated rosuvastatin and estrone-3-sulfate uptake was significantly reduced in the presence of TFs. A kinetic study revealed that the uptake efficiency (in terms of V-max/K-m) of rosuvastatin was decreased following treatment with TFs. Black tea extracts also reduced OATP2B1-mediated rosuvastatin uptake. These results suggest that black tea reduces the plasma concentrations of rosuvastatin by inhibiting the intestinal OATP2B1-mediated transport of rosuvastatin.

Theaflavins (TFs) are derived from black tea, an important source of dietary polyphenols. Although the potential interactions between dietary polyphenols and drugs have been demonstrated through in vitro and in vivo studies, little information is available concerning the influence of TFs on drug disposition. Organic anion transporting polypeptide 2B1 (OATP2B1) is expressed in human enterocytes and plays a role in the intestinal absorption of numerous drugs. The current study evaluated the effects of black tea extracts on the pharmacokinetics of rosuvastatin in rats, and investigated the effect of four major TFs (theaflavin, theaflavin-3-gallate, theaflavin-3 '-gallate and theaflavin-3,3 '-digallate) on the transport activity of OATP2B1. Black tea extracts significantly decreased the maximum plasma concentration (C-max) and area under the plasma concentration-time curve (AUC(0)-(8)) of rosuvastatin by 48% and 37%, respectively (p < 0.001 and p < 0.01, respectively). Moreover, OATP2B1-mediated rosuvastatin and estrone-3-sulfate uptake was significantly reduced in the presence of TFs. A kinetic study revealed that the uptake efficiency (in terms of V-max/K-m) of rosuvastatin was decreased following treatment with TFs. Black tea extracts also reduced OATP2B1-mediated rosuvastatin uptake. These results suggest that black tea reduces the plasma concentrations of rosuvastatin by inhibiting the intestinal OATP2B1-mediated transport of rosuvastatin.

Background: Coffee consumption in relation to female hormone-related cancers has been investigated but meta-analyses regarding breast and ovarian cancer include studies published up to 2012 with inconsistent results for ovarian cancer.Methods: We conducted two updated meta-analyses of studies published up to June 2016 to quantify the association of coffee intake with breast and ovarian cancer risk with random effects models. We used the dataset developed by the International Agency for Research on Cancer Working Group for Monograph 116 meeting (May 2016). We additionally performed a PubMed search in June 2016.Results: Summary relative risks (RRs) (95% confidence intervals (CI)) for the study-specific highest vs. lowest coffee consumption were for breast and ovarian cancer respectively: 0.97 (0.93-1.00, I-2 5.5%, 40 studies, 76,728 cases) and 1.03 (0.93-1.14, I-2 31.9%, 31 studies, 13,111 cases). For decaffeinated coffee the corresponding RRs were: 1.00 (0.93-1.08, I-2 32.2%, 13 studies) and 0.83 (0.71-0.96, I-2 about 0%, 9 studies). The association of coffee with ovarian cancer risk was higher among publications before (RR=1.37, 1.12-1.69) compared to after 2000 (RR=0.96, 0.86-1.06).Conclusion: Our meta-analyses provide strong, quantitative evidence that coffee consumption is not related to breast cancer risk and appears to be unrelated to ovarian cancer risk.

Fermentation process directly determines the product quality of black tea. This work aimed to develop a rapid method for detecting the degree of fermentation of black tea based on electrical properties of tea leaves. An LCR meter employed to identify 11 electrical parameters of tea leaves during the fermentation process, and the content of catechins and tea pigments in tea leaves were measured by using HPLC and UV-Vis spectrometer, respectively. Principal component analysis and hierarchical clustering analysis applied to divide samples into different groups in the degree of fermentation. Correlation analysis used to characterize the responding strength of electrical parameters on the variation of catechins and pigments. Finally, multilayer perceptron, random forest, and support vector machine algorithm used to build discrimination models of fermentation degree, and the average accuracy rate on the testing set reached to 88.90%, 100%, and 76.92%, respectively.

BackgroundAccumulating evidence supports the neuroprotective effects of bioactive compounds from tea leaves. There are limited data from black tea consumption populations.ObjectiveTo determine whether black tea consumption is associated with cognitive decline among older men.MethodsWe chose to study the association between black tea consumption and cognition using data from the Osteoporotic Fractures in Men (MrOS) cohort, which collected information on tea consumption at baseline and has repeatedly assessed cognitive function in 3,844 men aged 65+ years (mean = 72.4 years). We defined tea drinkers as those who drank black tea at least once per week and further grouped them into weekly drinkers and daily drinkers. Cognitive function was assessed at baseline and approximately 7 years later using the Modified Mini-Mental State Examination (3MSE). Multivariable logistic regression and linear regression models were constructed to assess the association between black tea consumption and risk of fast cognitive decline as a binary variable and change in 3MSE scores as continuous variable. Fast cognitive decline was defined as decline in 3MSE >1.5 standard deviation of mean change score. Models were adjusted for age, education level, and baseline cognitive scores.ResultsWeekly and daily black tea drinkers were 24.8% and 12.4% of the study cohort, respectively. Fast cognitive decline occurred in 243 (6.3%) participants. Tea consumption was not associated with risk of cognitive decline, nor was tea associated with cognitive decline measured by absolute change in 3MSE scores.ConclusionsThere was no association of black tea consumption and cognitive decline among older men in the US.

BackgroundAccumulating evidence supports the neuroprotective effects of bioactive compounds from tea leaves. There are limited data from black tea consumption populations.ObjectiveTo determine whether black tea consumption is associated with cognitive decline among older men.MethodsWe chose to study the association between black tea consumption and cognition using data from the Osteoporotic Fractures in Men (MrOS) cohort, which collected information on tea consumption at baseline and has repeatedly assessed cognitive function in 3,844 men aged 65+ years (mean = 72.4 years). We defined tea drinkers as those who drank black tea at least once per week and further grouped them into weekly drinkers and daily drinkers. Cognitive function was assessed at baseline and approximately 7 years later using the Modified Mini-Mental State Examination (3MSE). Multivariable logistic regression and linear regression models were constructed to assess the association between black tea consumption and risk of fast cognitive decline as a binary variable and change in 3MSE scores as continuous variable. Fast cognitive decline was defined as decline in 3MSE >1.5 standard deviation of mean change score. Models were adjusted for age, education level, and baseline cognitive scores.ResultsWeekly and daily black tea drinkers were 24.8% and 12.4% of the study cohort, respectively. Fast cognitive decline occurred in 243 (6.3%) participants. Tea consumption was not associated with risk of cognitive decline, nor was tea associated with cognitive decline measured by absolute change in 3MSE scores.ConclusionsThere was no association of black tea consumption and cognitive decline among older men in the US.

Following an application from Unilever NV, submitted for authorisation of a health claim pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of Ireland, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to black tea and improvement of attention. The scope of the application was proposed to fall under a health claim based on newly developed scientific evidence. The food proposed by the applicant as the subject of the health claim is black tea. The Panel considers that black tea characterised by its content of tea solids, caffeine and L-theanine, which is the subject of the health claim, is sufficiently characterised in relation to the claimed effect. The claimed effect proposed by the applicant is ‘improves attention’. The Panel considers that improvement of attention is a beneficial physiological effect. Three human intervention studies provided by the applicant show an effect of black tea on attention under the conditions of used proposed by the applicant. The applicant proposed that the claimed effect depends on the concerted action of two substances, caffeine and L-theanine, both of which are present in black tea. The Panel considers that the effect of black tea on attention observed in the three human intervention studies provided by the applicant can be explained by its caffeine content. The Panel concludes that a cause and effect relationship has been established between the consumption of black tea and improvement of attention. The Panel considers that the effect of black tea on attention can be explained by its caffeine content. The following wording reflects the scientific evidence: ‘Owing to its caffeine content, black tea improves attention’. In order to obtain the claimed effect, 2–3 servings of black tea providing at least 75 mg of caffeine in total should be consumed within 90 min.

Following an application from Unilever NV, submitted for authorisation of a health claim pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of Ireland, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to black tea and improvement of attention. The scope of the application was proposed to fall under a health claim based on newly developed scientific evidence. The food proposed by the applicant as the subject of the health claim is black tea. The Panel considers that black tea characterised by its content of tea solids, caffeine and L-theanine, which is the subject of the health claim, is sufficiently characterised in relation to the claimed effect. The claimed effect proposed by the applicant is ‘improves attention’. The Panel considers that improvement of attention is a beneficial physiological effect. Three human intervention studies provided by the applicant show an effect of black tea on attention under the conditions of used proposed by the applicant. The applicant proposed that the claimed effect depends on the concerted action of two substances, caffeine and L-theanine, both of which are present in black tea. The Panel considers that the effect of black tea on attention observed in the three human intervention studies provided by the applicant can be explained by its caffeine content. The Panel concludes that a cause and effect relationship has been established between the consumption of black tea and improvement of attention. The Panel considers that the effect of black tea on attention can be explained by its caffeine content. The following wording reflects the scientific evidence: ‘Owing to its caffeine content, black tea improves attention’. In order to obtain the claimed effect, 2–3 servings of black tea providing at least 75 mg of caffeine in total should be consumed within 90 min.

Objectives The health benefits of ‘drinking at least 8 glasses of water a day” in healthy individuals are largely unproven. We aimed to examine the relationship between total fluid and the sources of fluid consumption, risk of rapid renal decline, cardiovascular disease (CVD) mortality and all-cause mortality in elderly women. Design, setting and participants We conducted a longitudinal analysis of a population-based cohort study of 1055 women aged ≥70 years residing in Australia. Main outcome measures The associations between total daily fluid intake (defined as total volume of beverage excluding alcohol and milk) and the types of fluid (water, black tea, coffee, milk and other fluids) measured as cups per day and rapid renal decline, CVD and all-cause mortality were assessed using adjusted logistic and Cox regression analyses. Results Over a follow-up period of 10 years, 70 (6.6%) experienced rapid renal decline and 362 (34.4%) died, of which 142 (13.5%) deaths were attributed to CVD. The median (IQR) intake of total fluid was 10.4 (8.5–12.5) cups per day, with water (median (IQR) 4 (2–6) cups per day) and black tea (median (IQR) 3 (1–4) cups per day) being the most frequent type of fluid consumed. Every cup per day higher intake of black tea was associated with adjusted HRs of 0.90 (95% CI 0.81 to 0.99) and 0.92 (95% CI 0.86 to 0.98) for CVD mortality and all-cause mortality, respectively. There were no associations between black tea intake and rapid renal decline, or between the quantity or type of other fluids, including water intake, and any clinical outcomes. Conclusions Habitual higher intake of black tea may potentially improve long-term health outcomes, independent of treating traditional CVD risk factors, but validation of our study findings is essential.

Objectives: The health benefits of ‘drinking at least 8 glasses of water a day” in healthy individuals are largely unproven. We aimed to examine the relationship between total fluid and the sources of fluid consumption, risk of rapid renal decline, cardiovascular disease (CVD) mortality and all-cause mortality in elderly women. Design, setting and participants: We conducted a longitudinal analysis of a population-based cohort study of 1055 women aged ≥70 years residing in Australia. Main outcome measures The associations between total daily fluid intake (defined as total volume of beverage excluding alcohol and milk) and the types of fluid (water, black tea, coffee, milk and other fluids) measured as cups per day and rapid renal decline, CVD and all-cause mortality were assessed using adjusted logistic and Cox regression analyses. Results: Over a follow-up period of 10 years, 70 (6.6%) experienced rapid renal decline and 362 (34.4%) died, of which 142 (13.5%) deaths were attributed to CVD. The median (IQR) intake of total fluid was 10.4 (8.5–12.5) cups per day, with water (median (IQR) 4 (2–6) cups per day) and black tea (median (IQR) 3 (1–4) cups per day) being the most frequent type of fluid consumed. Every cup per day higher intake of black tea was associated with adjusted HRs of 0.90 (95% CI 0.81 to 0.99) and 0.92 (95% CI 0.86 to 0.98) for CVD mortality and all-cause mortality, respectively. There were no associations between black tea intake and rapid renal decline, or between the quantity or type of other fluids, including water intake, and any clinical outcomes. Conclusions: Habitual higher intake of black tea may potentially improve long-term health outcomes, independent of treating traditional CVD risk factors, but validation of our study findings is essential.

The influence of daily consumption of some common beverages on the development of cataract in rats was investigated. Total phenol content was determined in the beverages and an oral standardized dose of total phenols from each beverage was given to the treated rats. Weaned male albino rats were used and divided into five groups (n=7). Rats were fed Ain 93G and administered the standardized dose of instant coffee, black tea and hibiscus beverages for 30 days. On day 14 all rats were injected with a single dose of sodium selenite (Na2SeO3) 15 µmol/kg bodyweight, except the control groups NC (negative control, did not receive Na2SeO3) and PC (positive control, was already injected on day 1 of the study). The rats were continued on Ain 93G and the standardized dose for another 16 days. Positive control rats were used. Total phenols were 210, 40, and 44 mg/g dry weight gallic acid equivalent in black coffee, black tea, and hibiscus, respectively. Decreased levels (statistically significant P<0.05) of malondialdehyde, total nitric oxide, Ca-ATPase, tumor necrosis factor-alpha, interleukin-1beta, superoxide dismutase, and conversely, increased levels (statistically significant P<0.05) of total protein, reduced glutathione, catalase were found in the lenses of the coffee group compared to PC. There are co-phenol substances in the instant black coffee that promoted coffee to be the most effective beverage., Der Einfluss des täglichen Konsums einiger üblicher Getränke auf die Entwicklung einer Katarakt wurde in Ratten untersucht. Der Gesamtphenolgehalt der Getränke wurde bestimmt und eine standardisierte Menge an Gesamtphenol jedes Getränks wurde an die Ratten verfüttert. Abgestillte Albinoratten wurden in 5 Gruppen (n=7) aufgeteilt, die alle mit Ain93G gefüttert wurden. Über 30 Tage erhielten die behandelten Ratten eine festgelegte Standarddosis an Instant-Kaffee, schwarzem Tee bzw. eine Hibiskuszubereitung. Am 14. Tag wurde den Ratten eine Dosis Natriumselenit (15 µmol/kg Körpergewicht) gespritzt, ausgenommen die negative Kontrollgruppe, die kein Selenit bekam, und die positive Kontrollgruppe, die bereits am 1. Tag der Studie die Selenitinjektion erhielt. Die Ratten wurden weitere 16 Tage mit Ain93G gefüttert und erhielten die festgelegte Menge an Kaffee, Tee bzw. Hibiscus. Die Gsamtphenolgehalte von Kaffee, schwarzem Tee bzw. Hibiskus waren jeweils 210, 40 und 44 mg/g Trockengewicht Gallussäure-Äquivalente. In den Linsen der Kaffee-Gruppe wurden im Vergleich zur positiven Kontrollgruppe verminderte Gehalte an Malondialdehyd, Gesamt-Stickstoffoxid, Calcium-ATPase, Tumornekrosefaktor-alpha, Interleukin-1beta und Superoxiddismutase gemessen, andererseits erhöhte Gehalte ( p<0,05) an Gesamtprotein, reduziertem Glutathion und Katalase. Co-Phenol-Substanzen im schwarzen Instant-Kaffee bewirken, dass Kaffee als wirksamstes Nahrungsmittel gegen die Entstehung der Katarakt bei Ratten angesehen werden kann.

Катехины, входящие в состав чая, проявляют биологическую активность, обуславливая его антиоксидантные, антиканцерогенные и антимутагенные свойства. Содержания катехинов и других индивидуальных соединений в чайном экстракте находят хроматографическим методом (ВЭЖХ) или методом капиллярного электрофореза (КЭ). Учитывая состав чая, экстрагируемость, устойчивость и биологическую активность его компонентов, а также возможность их раздельного определения, в качестве индикаторных соединений выбрали катехин (КТ), эпикатехин (ЭКТ), галловую кислоту (ГК) и кофеин (КФ). Эти соединения экстрагировали горячей водой, разделяли в режиме градиентного элюирования и определяли методом ВЭЖХ с диодно-матричным детектором в УФ-области. Прямое количественное определение КТ и ЭКТ при 210 нм, а ГК и КФ при 270 нм возможно, если содержания аналитов в экстракте выше 1 мкг/мл. Методика обеспечивает полное разделение аналитов, отсутствие влияния посторонних веществ и прецизионность результатов ( s r < 7 %). Длительность анализа одной пробы около 1.5 ч. Правильность результатов подтверждена методом «введено-найдено». Полученные данные согласуются с результатами анализа тех же проб методом КЭ. По разработанной методике проанализированы экстракты 42 образцов черного чая (14 торговых наименований, различающихся по типу чайного растения). Для всех образцов найденные содержания аналитов снижаются в ряду КФ > ГК > ЭКТ > КТ. Усредненные содержания «макрокомпонентов» (КФ и ГК) в экстрактах из разных образцов довольно близки. Значительно сильнее (в 4-5 раз) различаются содержания «микрокомпонентов» (ЭКТ, а также КТ), что нельзя объяснить случайными погрешностями анализа. Содержания КТ и ЭКТ в разных образцах достоверно закоррелированы. Сильно меняющееся от образцу к образцу содержание ЭКТ (или КТ) в экстракте может быть новым показателем качества черного чая, более информативным, чем обычно применяемые интегральные показатели. Охарактеризованы значимость полученных результатов и п, Catechins, contained in tea, exhibit biological activity with its antioxidant, anticarcinogenic and antimutagenic properties. Catechins and other individual substances contained in the tea extract can be detected using the chromatographic method (HPLC) or the capillary electrophoresis (CE). Taking into account the composition of the tea, the extractability, stability and biological activity of its components, and the opportunity of their simultaneous determination, Catechin (CT), Epicatechin (ECT), Gallic acid (GC) and caffeine (CF) were chosen as the indicator substances. These substances were extracted with hot water, separated in gradient elution conditions and determined by diode-array detector in UV-spectra. Direct quantitative determination of CT and ECT at 210 nm, GC and CF at 270 nm is possible if the analyte content in the extract is above 1 µg/ml. The developed method provides a complete separation of analytes, absence of foreign substances influences and the precision of the results ( s r < 7 %). The duration of the analysis of one sample was about 1.5 hours. The accuracy of the results was confirmed by the "added-found" method. The resulting data is consistent with the results of the analysis of the same samples by CE. According to the developed method the extracts of 14 black tea samples, which differed according to the type of tea plants and trade names, were analyzed. For all samples the analytes’ contents found reduced in a CF > GC > ECT > CT sequence. The average content of “macrocomponents” (GC and CF) in the extracts of different samples was rather close. The content of “microcomponents” (ECT, as well CT) differed significantly more (4-5 times), and this cannot be explained by the random errors in the analysis. The content of CT and ECT in different samples was correlated. The greatly varying ECT (or CT) content in the extract from one sample to the other may be a new indicator of the quality of black tea and more informativ

BackgroundThere is limited research examining beverage habits, one of the most habitual dietary behaviors, with mortality risk.ObjectiveThis study examined the association between coffee, black and green tea, sugar-sweetened beverages (soft drinks and juice), and alcohol and all-cause and cause-specific mortality.MethodsA prospective data analysis was conducted with the use of the Singapore Chinese Health Study, including 52,584 Chinese men and women (aged 45-74 y) free of diabetes, cardiovascular disease (CVD), and cancer at baseline (1993-1998) and followed through 2011 with 10,029 deaths. Beverages were examined with all-cause and cause-specific (cancer, CVD, and respiratory disease) mortality risk with the use of Cox proportional hazards regression.ResultsThe associations between coffee, black tea, and alcohol intake and all-cause mortality were modified by smoking status. Among never-smokers there was an inverse dose-response association between higher amounts of coffee and black tea intake and all-cause, respiratory-related, and CVD mortality (black tea only). The fully adjusted HRs for all-cause mortality for coffee for <1/d, 1/d, and ≥2/d relative to no coffee intake were 0.89, 0.86, and 0.83, respectively (P-trend = 0.0003). For the same black tea categories the HRs were 0.95, 0.90, and 0.72, respectively (P-trend = 0.0005). Among ever-smokers there was no association between coffee or black tea and the outcomes. Relative to no alcohol, light to moderate intake was inversely associated with all-cause mortality (HR: 0.87; 95% CI: 0.79, 0.96) in never-smokers with a similar magnitude of association in ever-smokers. There was no association between heavy alcohol intake and all-cause mortality in never-smokers and a strong positive association in ever-smokers (HR: 1.56; 95% CI: 1.40, 1.74). Green tea and sugar-sweetened beverages were not associated with all-cause or cause-specific mortality.ConclusionsHigher coffee and black tea intake was inversely associa

BackgroundThere is limited research examining beverage habits, one of the most habitual dietary behaviors, with mortality risk.ObjectiveThis study examined the association between coffee, black and green tea, sugar-sweetened beverages (soft drinks and juice), and alcohol and all-cause and cause-specific mortality.MethodsA prospective data analysis was conducted with the use of the Singapore Chinese Health Study, including 52,584 Chinese men and women (aged 45-74 y) free of diabetes, cardiovascular disease (CVD), and cancer at baseline (1993-1998) and followed through 2011 with 10,029 deaths. Beverages were examined with all-cause and cause-specific (cancer, CVD, and respiratory disease) mortality risk with the use of Cox proportional hazards regression.ResultsThe associations between coffee, black tea, and alcohol intake and all-cause mortality were modified by smoking status. Among never-smokers there was an inverse dose-response association between higher amounts of coffee and black tea intake and all-cause, respiratory-related, and CVD mortality (black tea only). The fully adjusted HRs for all-cause mortality for coffee for <1/d, 1/d, and ≥2/d relative to no coffee intake were 0.89, 0.86, and 0.83, respectively (P-trend = 0.0003). For the same black tea categories the HRs were 0.95, 0.90, and 0.72, respectively (P-trend = 0.0005). Among ever-smokers there was no association between coffee or black tea and the outcomes. Relative to no alcohol, light to moderate intake was inversely associated with all-cause mortality (HR: 0.87; 95% CI: 0.79, 0.96) in never-smokers with a similar magnitude of association in ever-smokers. There was no association between heavy alcohol intake and all-cause mortality in never-smokers and a strong positive association in ever-smokers (HR: 1.56; 95% CI: 1.40, 1.74). Green tea and sugar-sweetened beverages were not associated with all-cause or cause-specific mortality.ConclusionsHigher coffee and black tea intake was inversely associa

BackgroundThere is limited research examining beverage habits, one of the most habitual dietary behaviors, with mortality risk.ObjectiveThis study examined the association between coffee, black and green tea, sugar-sweetened beverages (soft drinks and juice), and alcohol and all-cause and cause-specific mortality.MethodsA prospective data analysis was conducted with the use of the Singapore Chinese Health Study, including 52,584 Chinese men and women (aged 45-74 y) free of diabetes, cardiovascular disease (CVD), and cancer at baseline (1993-1998) and followed through 2011 with 10,029 deaths. Beverages were examined with all-cause and cause-specific (cancer, CVD, and respiratory disease) mortality risk with the use of Cox proportional hazards regression.ResultsThe associations between coffee, black tea, and alcohol intake and all-cause mortality were modified by smoking status. Among never-smokers there was an inverse dose-response association between higher amounts of coffee and black tea intake and all-cause, respiratory-related, and CVD mortality (black tea only). The fully adjusted HRs for all-cause mortality for coffee for <1/d, 1/d, and ≥2/d relative to no coffee intake were 0.89, 0.86, and 0.83, respectively (P-trend = 0.0003). For the same black tea categories the HRs were 0.95, 0.90, and 0.72, respectively (P-trend = 0.0005). Among ever-smokers there was no association between coffee or black tea and the outcomes. Relative to no alcohol, light to moderate intake was inversely associated with all-cause mortality (HR: 0.87; 95% CI: 0.79, 0.96) in never-smokers with a similar magnitude of association in ever-smokers. There was no association between heavy alcohol intake and all-cause mortality in never-smokers and a strong positive association in ever-smokers (HR: 1.56; 95% CI: 1.40, 1.74). Green tea and sugar-sweetened beverages were not associated with all-cause or cause-specific mortality.ConclusionsHigher coffee and black tea intake was inversely associa

A large number of black tea polyphenols remain uncharacterized because of the complexity of catechin oxidation reactions that occur during tea fermentation. In the course of our studies on black tea polyphenols, we examined the enzymatic degradation of theaflavins, which are black tea pigments having a benzotropolone chromophore. Oxidation of theaflavin with peroxidase afforded a new product named theacoumarin A together with known pigment theanaphthoquinone. The structure of the new compound was determined by spectroscopic examination and a production mechanism via theanaphthoquinone is proposed., Tetrahedron Letters, 56(36), pp.5099-5102; 2015

In our previous chemical study of the production mechanism of black tea polyphenols, we demonstrated that Japanese pear fruit homogenate oxidizes green tea catechins bearing pyrogallol-type and catechol-type B-rings to produce theaflavins and dehydrotheasinensins. In contrast, unripe fruit homogenate of Citrus unshiu selectively oxidizes pyrogallol-type catechins to yield only dehydrotheasinensins. The difference in the selectivity of the two homogenates is probably related to the lower redox potential of pyrogallol-type catechins. The oxidation of epigallocatechin with C. unshiu homogenate gave two new compounds, including an ethanol adduct of an oolongtheanin precursor and epigallocatechin 4′-O-rutinoside, together with theasinensin C, dehydrotheasinensin E, and desgalloyl oolongtheanin. The structure of desgalloyl oolongtheanin should be revised based on the spectroscopic and computational data collected in the current study, and a mechanism responsible for the production of oolongtheanins is also proposed., Tetrahedron, 71(17), pp.2540-2548; 2015

To understand the structures of uncharacterized black tea polyphenols, the oxidation products of (-)-epigallocatechin were investigated. Enzymatic oxidation and subsequent heating of the reaction mixture afforded four new oxidation products (6, and 9-11) along with theasinensins C (4) and E (5), dehydrotheasinensin E (12), epitheaflagallin, hydroxytheaflavin, and desgalloyl oolongtheanin. The structures of the new compounds were determined chemically and spectroscopically. Isotheasinensin E (6) is a C-2 epimer of 5, and compounds 9 and 10 are oxidation products of 12. Another new compound, 11, is a yellow pigment and presumed to be a degradation product of proepitheaflagallin. The results disclosed new oxidation mechanisms that occur during black tea production., Tetrahedron, 69(42), pp.8952-8958; 2013

Background In previous meta-analyses, tea consumption has been associated with lower incidence of type 2 diabetes. It is unclear, however, if tea is associated inversely over the entire range of intake. Therefore, we investigated the association between tea consumption and incidence of type 2 diabetes in a European population. Methodology/Principal Findings The EPIC-InterAct case-cohort study was conducted in 26 centers in 8 European countries and consists of a total of 12,403 incident type 2 diabetes cases and a stratified subcohort of 16,835 individuals from a total cohort of 340,234 participants with 3.99 million person-years of follow-up. Country-specific Hazard Ratios (HR) for incidence of type 2 diabetes were obtained after adjustment for lifestyle and dietary factors using a Cox regression adapted for a case-cohort design. Subsequently, country-specific HR were combined using a random effects meta-analysis. Tea consumption was studied as categorical variable (0, >0

The present project was conducted with the objective of evaluation the content of the following catechins, epigallocatechin-3-gallate (EGCG), epigalocatechin (EGC), epicatechin (EC), catechin (C) and catechin gallate (CG), in the tea cultivar CH 14 INTA, CH 112 INTA, CH 318 INTA, CH 410 INTA and CH 732 INTA elaborated as black tea, during three harvest times. A system of water extraction was used and the determination was made by high performance liquid chromatography (HPLC), with isocratic elution. The catechin contents were analyzed by analisis of variance (P < 0.05), the differences were studied among cultivars and the population control, times and interactions. The means were compared among cultivars and the population control by Multiple Range Test (P < 0.05). The obtained results allow to establish the following conclusions. The total average content of all the analyzed catechins, reaching at 1.53 of dry matter (%). EGCG was the catechins with higher concentration, reaching at an average of 1.10% ± 0.13, not registering significant differences among cultivars. EGC reached a second level with a concentration of 0.16%±0.03. For EC, C and CG the concentrations were 0.16% ± 0.06; 0.06%± 0.016 and 0.04%± 0.009, respectively. Among the cultivars they presented significant differences, cultivar CH 410 INTA present the biggest contents in EGCG, EGC, EC and C, with 1.30; 0.19; 0.29 and 0.11% respectively; for CG cultivar CH 318 INTA presents the biggest content with 0.068%. For the harvest times, they registered significant differences, with the biggest contents average to the beginning for all the analyzed catechins. Their contents for CGCG, EGC, EC, C and CG, were 1.47; 0.22; 0.27; 0.13 and 0.063% respectively., El presente proyecto tuvo como objetivo determinar el contenido de materia seca de las siguientes catequinas, epigalocatequina-3-galato (EGCG), epigalocatequina (EGC), epicatequina (EC), catequina (C) y catequina galato (CG), en los cultivares de té CH 14 INTA, CH 112 INTA, CH 318 INTA, CH 410 INTA y CH 732 INTA elaborados como té negro, durante tres épocas de zafra. Se empleó un sistema de extracción acuosa y la determinación de los compuestos se efectuó por cromatografía líquida de alta resolución (HPLC), con elución isocrática. Los contenidos de catequinas se analizaron por análisis de variancia (P<0,05), se estudiaron las diferencias entre cultivares y la población control, épocas e interacciones. Se compararon las medias entre cultivares y la población control por medio de la prueba de Comparación Múltiple (P<0,05). Los resultados obtenidos permiten establecer que el contenido total promedio de todas las catequinas analizadas, alcanzó a 1,53 de materia seca (%). EGCG fue la catequina con más alta concentración, alcanzado un promedio 1,10% ± 0,13, no registrando diferencias significativas entre cultivares. EGC alcanzó un segundo nivel con una concentración de 0,16%±0,03. Para EC, C y CG las concentraciones fueron de 0,16% ± 0,06; 0,06%± 0,016 y 0,04%± 0,009, respectivamente. Entre los cultivares se presentaron diferencias significativas respecto al resto, el cultivar CH 410 INTA presento los mayores contenidos de EGCG, EGC, EC y C, con 1,30; 0,19; 0,29 y 0,11% respectivamente; para CG el cultivar CH 318 INTA presenta el mayor contenido con 0,068%. Entre las épocas de zafra, se registraron diferencias significativas, con los mayores contenidos promedio al inicio de zafra para todas las catequinas analizadas. Sus contenidos para CGCG, EGC, EC, C y CG, fueron 1,47; 0,22; 0,27; 0,13 y 0,063% respectivamente.

Chromatographic separation of black tea polyphenols is too difficult to supply sufficient quantities of pure compounds for biological experiments. Thus, facile methods to prepare black tea constituents were desired. Treatment of epigallocatechin gallate with copper(II) chloride efficiently afforded an unstable quinone dimer, dehydrotheasinensin A, and subsequent treatment with ascorbic acid stereoselectively yielded theasinensin A. The latter is a dimer with an R-biphenyl bond, one of the major polyphenols found in black tea. The method is simpler and more effective than enzymatic preparation., CHEMICAL & PHARMACEUTICAL BULLETIN, 59(9), pp.1183-1185; 2011

Black tea is rich in polyphenols and has been shown to have various health benefits; however, its components have not yet been clarified in detail. Enzymatic oxidation of epigallocatechin-3-O-gallate, the most abundant polyphenol in tea, is thought to contribute significantly to the production of black tea polyphenols. We identified theacitrin C, an unstable black tea pigment, as an enzymatic oxidation product of epigallocatechin-3-O-gallate. Degradation of theacitrin C afforded theacitrinin A and 2,3,5,7- tetrahydroxychroman-3-O-gallate. Furthermore, theacitrinin B, which was isolated from black tea, is deduced to be a degradation product of theacitrin A, the desgalloyl analogue of theacitrin C. The structures of theacitrinins A and B were elucidated based on spectroscopic data. This is the first time that a degradation product of theacitrin has been isolated from black tea. We also examined the influence of esterification of the epigallocatechin C-3 hydroxyl group on the decomposition of bicyclo[3.2.1]octane-type intermediates., Tetrahedron, 67(11), pp.2051-2059; 2011

The present project was conducted with the objective of evaluation the content of the following catechins, epigallocatechin-3-gallate (EGCG), epigalocatechin (EGC), epicatechin (EC), catechin (C) and catechin gallate (CG), in the tea cultivar CH 14 INTA, CH 112 INTA, CH 318 INTA, CH 410 INTA and CH 732 INTA elaborated as black tea, during three harvest times. A system of water extraction was used and the determination was made by high performance liquid chromatography (HPLC), with isocratic elution. The catechin contents were analyzed by analisis of variance (P < 0.05), the differences were studied among cultivars and the population control, times and interactions. The means were compared among cultivars and the population control by Multiple Range Test (P < 0.05). The obtained results allow to establish the following conclusions. The total average content of all the analyzed catechins, reaching at 1.53 of dry matter (%). EGCG was the catechins with higher concentration, reaching at an average of 1.10% ± 0.13, not registering significant differences among cultivars. EGC reached a second level with a concentration of 0.16%±0.03. For EC, C and CG the concentrations were 0.16% ± 0.06; 0.06%± 0.016 and 0.04%± 0.009, respectively. Among the cultivars they presented significant differences, cultivar CH 410 INTA present the biggest contents in EGCG, EGC, EC and C, with 1.30; 0.19; 0.29 and 0.11% respectively; for CG cultivar CH 318 INTA presents the biggest content with 0.068%. For the harvest times, they registered significant differences, with the biggest contents average to the beginning for all the analyzed catechins. Their contents for CGCG, EGC, EC, C and CG, were 1.47; 0.22; 0.27; 0.13 and 0.063% respectively., El presente proyecto tuvo como objetivo determinar el contenido de materia seca de las siguientes catequinas, epigalocatequina-3-galato (EGCG), epigalocatequina (EGC), epicatequina (EC), catequina (C) y catequina galato (CG), en los cultivares de té CH 14 INTA, CH 112 INTA, CH 318 INTA, CH 410 INTA y CH 732 INTA elaborados como té negro, durante tres épocas de zafra. Se empleó un sistema de extracción acuosa y la determinación de los compuestos se efectuó por cromatografía líquida de alta resolución (HPLC), con elución isocrática. Los contenidos de catequinas se analizaron por análisis de variancia (P<0,05), se estudiaron las diferencias entre cultivares y la población control, épocas e interacciones. Se compararon las medias entre cultivares y la población control por medio de la prueba de Comparación Múltiple (P<0,05). Los resultados obtenidos permiten establecer que el contenido total promedio de todas las catequinas analizadas, alcanzó a 1,53 de materia seca (%). EGCG fue la catequina con más alta concentración, alcanzado un promedio 1,10% ± 0,13, no registrando diferencias significativas entre cultivares. EGC alcanzó un segundo nivel con una concentración de 0,16%±0,03. Para EC, C y CG las concentraciones fueron de 0,16% ± 0,06; 0,06%± 0,016 y 0,04%± 0,009, respectivamente. Entre los cultivares se presentaron diferencias significativas respecto al resto, el cultivar CH 410 INTA presento los mayores contenidos de EGCG, EGC, EC y C, con 1,30; 0,19; 0,29 y 0,11% respectivamente; para CG el cultivar CH 318 INTA presenta el mayor contenido con 0,068%. Entre las épocas de zafra, se registraron diferencias significativas, con los mayores contenidos promedio al inicio de zafra para todas las catequinas analizadas. Sus contenidos para CGCG, EGC, EC, C y CG, fueron 1,47; 0,22; 0,27; 0,13 y 0,063% respectivamente.

Cílem této práce bylo stanovení antioxidantů v čajích. Antioxidanty jsou důležité látky mající schopnost eliminovat působení volných radikálů, které poškozují tkáně organismu, jsou příčinou vzniku různých onemocnění a stárnutí organismu. Antioxidanty byly stanovovány v černém, bílém a zeleném čaji. V práci je také zmíněno technologické zpracování jednotlivých čajů a jejich příznivé účinky na zdraví člověka. Stanovení bylo provedeno pomocí vysoce účinné kapalinové chromatografie HPLC s elektrochemickým detektorem ECD. Poté byla vyzkoušena metoda HPLC UV/MS., The aim of this thesis is the determination of antioxidants in the tea. Antioxidants are important substances that have the ability to eliminate free toxic radicals, which damage the body tissue, are the cause of various diseases ang aging. Antioxidants are measured in black, white and green tea. The paper also mentioned the processing of tea and its benefical effects on human health. The assay was performed using hight performance liquid chromatography HPLC with electrochemical detector ECD. Next was tried method HPLC UV/MS., Ústav biochemie a analýzy potravin, obhájeno

Our overall goal is to develop a safe and feasible model for the chemoprevention of a wide range of tobacco-related diseases. Our immediate goal, that was addressed over a 5-year study period, is to determine the effects of high tea consumption on biological markers of oxidative stress that mediate lung cancer risk. We completed a 6-month randomized, controlled, double-blinded chemopreventive trial in a group of chronic obstructive pulmonary disease (COPD) subjects who are being randomized to green or black tea preparations or a control intervention (matching placebo). Levels of 8-hydroxydeoxyguanosine and 8-F2-isoprostanes are used to measure DNA and lipid damage respectively. Changes in biomarkers of oxidative damage were measured in urine and blood. The study protocol was approved by all parties in September 2003. Recruitment and screening of participants for eligibility criteria started in October 2003. Total recruitment was completed in December 2007. A total of 158 participants (86 females and 72 males) completed the study. All laboratory analyses, data entry, and quality control measures were completed. Our preliminary data show that although women have a significant lower pack/year smoking history, they have significantly higher DNA damage as measured by urinary 8-OhDG. Female smokers on green tea have a 35% significant decrease in DNA damage and a significant decrease in blood cholesterol and LDL levels. These data confirm our previous findings related to the beneficial effects of green tea on DNA damage among smokers., The original document contains color images.

An unstable intermediate proepitheaflagallin B (2), a precursor of proepitheaflagallin (3), was isolated as an enzymatic oxidation product of (?)-epigallocatechin (1), and the structure of 2 was determined based on spectroscopic data. The structure and its decomposition revealed that the detailed production mechanism of proepitheaflagallin (3) via a bicyclo[3.2.1]octane-type intermediate was related to that of major black tea pigments, theaflavins., Tetrahedron Letters, 50(12), pp.1348-1351; 2009

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 signals arising from the flavan A-ring and galloyl groups, although signals due to flavan B-rings were not detected, suggesting that the polymer-like substances were generated by oxidative condensation of flavan B-rings, a result which was previously deduced from our results of in vitro catechin oxidation experiments. Enzymatic oxidation of epicatechin 3-O-gallate produced a similar polymer-like substance and suggested that condensation between a B-ring and galloyl groups was involved in the polymerization reaction., Chemical & Pharmaceutical Bulletin v.56(3) p.266-272, 2008

The authors' overall goal is to develop a safe and feasible model for the chemoprevention of a wide range of tobacco-related diseases. Their immediate goal, addressed over a 4-year study period, is to determine the effects of high tea consumption on the biological markers of oxidative stress that mediate lung cancer risk. They are conducting a 6-month randomized, controlled, double-blinded chemopreventive trial with subjects who have chronic obstructive pulmonary disease (COPD) and who were, or are, chronic smokers. The subjects are being randomized to green or black tea preparations or a control intervention (matching placebo). Levels of 8-hydroxydeoxyguanosine and 8-F2-isoprostanes are being used to measure DNA damage and lipid damage, respectively. Changes in biomarkers of oxidative damage are being measured in urine, blood, and exhaled breath condensate. The study protocol was approved by all parties in September 2003. Recruitment and screening of participants for eligibility started in October 2003. By the end of December 2006, 275 participants had signed the consent form and were screened for confirmation of COPD eligibility (i.e., spirometry for lung function). Thirteen subjects were not eligible and 262 subjects were enrolled in the study. Ninety-six of the participants dropped out of the study in the first week. The main reported causes of drop-out were as follows: could not stop drinking coffee, did not like the taste of the tea, and caffeine intolerance. A total of 158 subjects completed the 1-month run-in and were randomized to one of the study arms: green tea, black tea, or placebo. All randomized subjects provided blood and urine samples, exhaled breath condensate, and buccal cell samples during the 6-month intervention period. To date, 114 subjects have completed the study and 19 subjects are actively enrolled in it. The authors expect that adherence to a regular pattern of tea is feasible and quantifiable in this high-risk population., The original document contains color images.

In 1808, Thomas Thomson presented On Oxalic Acid to the Royal Society. He credited the disovery of oxalic acid to Scheele, but claimed Bergman s 1776 dissertation as the first discussion of its properties. Oxalic acid belongs to the family of carboxylic acids, found in the form of an odorless, colorless white crystal. Many foods contain oxalates, such as black tea, green leafy vegetables and chocolate. Upon ingestion, oxalic acid enters the bloodstream and precipitates out as calcium oxalate, which is generally excreted through urine, but can collect in the tubules of the kideys to form what is commonly known as kidney stones. However, oxalates have many pharmacological applications, such as escitalopram oxalate, which acts as a selective serotonin uptake inhibitor, and is thus useful in the treatment of depression. However, too much oxalate can be toxic due to the lack of serotonin uptake. Some fruits, such as star fruit, have neurotoxic properties because of their high levels of oxalate.

In 1808, Thomas Thomson presented On Oxalic Acid to the Royal Society. He credited the disovery of oxalic acid to Scheele, but claimed Bergman s 1776 dissertation as the first discussion of its properties. Oxalic acid belongs to the family of carboxylic acids, found in the form of an odorless, colorless white crystal. Many foods contain oxalates, such as black tea, green leafy vegetables and chocolate. Upon ingestion, oxalic acid enters the bloodstream and precipitates out as calcium oxalate, which is generally excreted through urine, but can collect in the tubules of the kideys to form what is commonly known as kidney stones. However, oxalates have many pharmacological applications, such as escitalopram oxalate, which acts as a selective serotonin uptake inhibitor, and is thus useful in the treatment of depression. However, too much oxalate can be toxic due to the lack of serotonin uptake. Some fruits, such as star fruit, have neurotoxic properties because of their high levels of oxalate.

Tato diplomová práce se zabývá stanovením celkové antioxidační aktivity (total antioxidant activity, TAA) různých druhů čajů (zelených, černých, polofermentovaných, bílých, maté, rooibosu a bylinných) v závislosti na způsobu a délce doby jejich zpracování. Hlavní důraz je kladen na ověření nové metody měření celkové antioxidační aktivity využívající průtokové coulometrie. Výsledky získané touto metodou jsou porovnány s výsledky zjištěnými chemiluminiscenční metodou (Trolox equivalent antioxidant capacity, TEAC), která se standardně využívá pro měření celkové antioxidační kapacity v různých materiálech a surovinách. V práci jsou diskutovány příčiny rozdílů v hodnotách TAA zjištěných oběma metodami., This thesis deals with the total antioxidant activity (TAA) evaluation of various sorts of tea (green, black, half-fermented, white, mate, rooibos and herbal) depending on the process and time of their treatment. The main emphasis is put on testing a new method of measuring the total antioxidant activity by flow coulometry. The results acquired by this method are compared to the results of the chemiluminescent Trolox equivalent antioxidant capacity (TEAC) method which is a standard for measuring the total antioxidant capacity in various materials and raw materials. The work discusses the reasons for the differences in the values found by both methods.

Tato diplomová práce se zabývá stanovením celkové antioxidační aktivity (total antioxidant activity, TAA) různých druhů čajů (zelených, černých, polofermentovaných, bílých, maté, rooibosu a bylinných) v závislosti na způsobu a délce doby jejich zpracování. Hlavní důraz je kladen na ověření nové metody měření celkové antioxidační aktivity využívající průtokové coulometrie. Výsledky získané touto metodou jsou porovnány s výsledky zjištěnými chemiluminiscenční metodou (Trolox equivalent antioxidant capacity, TEAC), která se standardně využívá pro měření celkové antioxidační kapacity v různých materiálech a surovinách. V práci jsou diskutovány příčiny rozdílů v hodnotách TAA zjištěných oběma metodami., This thesis deals with the total antioxidant activity (TAA) evaluation of various sorts of tea (green, black, half-fermented, white, mate, rooibos and herbal) depending on the process and time of their treatment. The main emphasis is put on testing a new method of measuring the total antioxidant activity by flow coulometry. The results acquired by this method are compared to the results of the chemiluminescent Trolox equivalent antioxidant capacity (TEAC) method which is a standard for measuring the total antioxidant capacity in various materials and raw materials. The work discusses the reasons for the differences in the values found by both methods.