Tea Mixtures Research Articles

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Obesity and thermogenesis related to the consumption of caffeine, ephedrine, capsaicin, and green tea

The global prevalence of obesity has increased considerably in the last decade. Tools for obesity management, including caffeine, ephedrine, capsaicin, and green tea have been proposed as strategies for weight loss and weight maintenance, since they may increase energy expenditure and have been proposed to counteract the decrease in metabolic rate that is present during weight loss. A combination of caffeine and ephedrine has shown to be effective in long-term weight management, likely due to different mechanisms that may operate synergistically, e.g., respectively inhibiting the phosphodiesterase-induced degradation of cAMP and enhancing the sympathetic release of catecholamines. However, adverse effects of ephedrine prevent the feasibility of this approach. Capsaicin has been shown to be effective, yet when it is used clinically it requires a strong compliance to a certain dosage, that has not been shown to be feasible yet. Also positive effects on body-weight management have been shown using green tea mixtures. Green tea, by containing both tea catechins and caffeine, may act through inhibition of catechol O-methyl-transferase, and inhibition of phosphodiesterase. Here, the mechanisms may also operate synergistically. In addition, tea catechins have antiangiogenic properties that may prevent development of overweight and obesity. Furthermore, the sympathetic nervous system is involved in the regulation of lipolysis, and the sympathetic innervation of white adipose tissue may play an important role in the regulation of total body fat in general.

Synthesis of branched polyethylene by in situ polymerization of ethylene with combined iron catalyst and Ziegler–Natta catalyst

Abstract2,6‐Bis(imino)pyridyl iron catalyst and traditional Ziegler–Natta catalyst were combined together as tandem catalytic system, activated with the mixture of TEA and MAO, and used for synthesis of branched polyethylene by in situ polymerization of ethylene. The branched polyethylene with branches from 8/1000C to 29/1000C was produced by adjusting reaction conditions: the amount of TEA, MAO, iron catalyst used, and reaction temperatures. Not only the short branches such as ethyl and butyl but also the longer branches (hexyl and longer than hexyl) were detected in the products. The products exhibited higher molecular weight and broader molecular weight distribution than those obtained from metallocene catalysts, which would provide the materials excellent mechanical properties and processability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 2006

Variability of some traits of flax seed in respect to genotype and climatic conditions

Beside its multiple use in oil producing and feed industry, flax seed is used also in pharmaceutical industry as additional medicinal component, whether as mono component or in tea mixtures. Results of a two-year cultivation of several flax genotypes are analyzed. The highest yield of seed in both study years was achieved in genotype "Z" and the lowest in standard cultivar "Mira". In regard to germination energy and total germination, the best value was determined for genotype "B" and the lowest for standard cultivar "Mira". The greatest swelling of flax seeds was established for genotype "B", and the least in the case of genotype "Z". Climatic conditions in the year of cultivation had effects on yield and quality of flax seed. During 2001. the year with high rainfall, higher yields were produced in all tested genotypes, and better germination energy, total germination and mass of 100 seeds established. In seed obtained in 2002, when average temperatures were higher, number of swollen seeds was higher. .

Effects of encapsulated green tea and Guarana extracts containing a mixture of epigallocatechin-3-gallate and caffeine on 24 h energy expenditure and fat oxidation in men

It has been reported that green tea has a thermogenic effect, due to its caffeine content and probably also to the catechin, epigallocatechin-3-gallate (EGCG). The main aim of the present study was to compare the effect of a mixture of green tea and Guarana extracts containing a fixed dose of caffeine and variable doses of EGCG on 24 h energy expenditure and fat oxidation. Fourteen subjects took part to this randomized, placebo-controlled, double-blind, cross-over study. Each subject was tested five times in a metabolic chamber to measure 24 h energy expenditure, substrate oxidation and blood pressure. During each stay, the subjects ingested a capsule of placebo or capsules containing 200 mg caffeine and a variable dose of EGCG (90, 200, 300 or 400 mg) three times daily, 30 min before standardized meals. Twenty-four hour energy expenditure increased significantly by about 750 kJ with all EGCG-caffeine mixtures compared with placebo. No effect of the EGCG-caffeine mixture was observed for lipid oxidation. Systolic and diastolic blood pressure increased by about 7 and 5 mmHg, respectively, with the EGCG-caffeine mixtures compared with placebo. This increase was significant only for 24 h diastolic blood pressure. The main finding of the study was the increase in 24 h energy expenditure with the EGCG-caffeine mixtures. However, this increase was similar with all doses of EGCG in the mixtures.

Optical Readout Time Projection Chamber (O-TPC) for a Study of Oxygen Formation in Stellar Helium Burning

We are developing an Optical Readout Time Projection Chamber (O-TPC) detector for the study of the 12C(a,g)16O reaction that determines the ratio of carbon to oxygen in helium burning. This ratio is crucial for understanding the final fate of a progenitor star and the nucleosynthesis of elements prior to a Type II supernova; an oxygen rich star is predicted to collapse to a black hole, and a carbon rich star to a neutron star. Type Ia supernovae (SNeIa) are used as standard candles for measuring cosmological distances with the use of an empirical light curve-luminosity stretching factor. It is essential to understand helium burning that yields the carbon/oxygen white dwarf and thus the initial stage of SNeIa. The O-TPC is intended for use with high intensity photon beams extracted from the HIgS/TUNL facility at Duke University to study the 16O(g,a)12C reaction, and thus the direct reaction at energies as low as 0.7 MeV. We are conducting a systematical study of the best oxygen containing gas with light emitting admixture(s) for use in such an O-TPC. Preliminary results with CO_2 + TEA mixture were obtained

Effects of iron, ascorbate, meat and casein on the antioxidant capacity of green tea under conditions of in vitro digestion

The hypothesis that interactions of dietary polyphenols with dietary iron occur during digestion and result in a decrease of the post-absorptive antioxidant properties of polyphenols was investigated. The hypothesis was tested in vitro, under conditions that simulate gastrointestinal digestion. Mixtures of green tea, iron, and three dietary factors that modify the form of iron in the lumen, namely ascorbic acid, meat or casein, were subjected to an in vitro gastrointestinal digestion. Antioxidant capacity (FRAP assay), iron concentration (ferrozine assay) and polyphenol concentration (Folin–Ciocalteau assay) were measured in the in vitro digests. The presence of iron decreased the antioxidant capacity and the polyphenol concentration of green tea digests. The presence of ascorbic acid increased, while meat and casein decreased the antioxidant capacity of green tea. The factorial analysis of the data suggests that protein and iron interact with green tea polyphenols during the in vitro digestion and decrease their antioxidant capacity. These results support the aforementioned hypothesis.

Responses of Modern Broiler Chicks to Stocking Density, Green Tea, Commercial Multi Enzymes and Their Interactions on Productive Performance, Carcass Characteristics, Liver Composition and Plasma Constituents

The objective of this work was to study the responses of modern broiler chicks to stocking density, green tea, commercial Multi enzymes (Optizyme® p-5) and their interaction on productive performance, carcass characteristics, chemical composition of liver and plasma constituents. Commercial breeds (Lohman) of broiler chicks were housed at different densities of 10, 14 and 18 bird/m during the period from 2 7 to 43 days of age. Chicks within each density were fed four experimental diets; one of them was used as a control diet. In the other three diets the control diet was supplemented with green tea (5g/kg feed) or Multi enzymes (1 g /kg feed), or mixture of both. Therefore, there were 12 experimental treatments in which each treatment was replicated four times. Results could be summarized as follows: Stocking density had no significant effect on growth of broiler chicks, feed intake and feed conversion ratio (FCR) during 7-43 days of age, except for increasing stocking density of 18 bird/m during only the period from 22 to 43 days of age 2 while reduced growth and feed intake significantly. Addition of green tea, Multi enzymes or their mixture had no significant effect on growth, feed intake and FCR of broiler chicks. There were significant interactions among stocking density and feed additives. The best dressing percentage was obtained from group stocked at 14 bird/m and fed the control diet. Also, hind part weight and % were the highest of birds stocked at 10/m 2 2 and fed diet supplemented with Multi enzymes or those stocked at 14 bird/m and fed the control diet. There 2 diet, while addition of green tea, Multi enzymes and their mixture improved front part % significantly compared to the control diet. A mixture of green tea and Multi enzymes significantly increased liver%, while Multi enzymes decreased significantly absolute and heart % compared to the control group. A mixture of green tea and Multi enzymes significantly decreased intestinal weight and % compared with the control diet without or with green tea. Stocking density had no significant effect on chemical composition of liver and plasma constituents of broiler chicks as well as liver functions as judged by plasma ALT and AST activities during the experimental period. Green tea had no significant effect on chemical composition of liver and plasma total protein and its fraction, total lipids and cholesterol and plasma AST and ALT activities. In conclusion broiler chicks could be stocked up to 14 bird/m without adverse effect on growth performance, while addition 2 of green tea, Multi enzymes or their mixture had no enhancing effect on growth performance of broiler stocked at different densities.

Determination of ginsenosides Rb1, Rc, and Re in different dosage forms of ginseng by negative ion electrospray liquid chromatography-mass spectrometry.

A method based on high-performance liquid chromatography (HPLC) and negative ion electrospray mass spectrometry (LC-MS) has been used to determine ginsenosides Rb1, Rc, and Re in six different samples of ginseng. These included a liquid extract, capsules, tea bags, and an instant tea. It was found that four of the six samples had detectable levels of at least one of the ginsenosides. The liquid extract, capsules, instant tea, and tea bags labeled ginseng had ginsenosides. The labels on the two samples that did not have ginsenosides indicated that they were a mixture of green tea, licorice, and ginseng. Also, 13C NMR was used to identify the types of complex carbohydrates present in the samples. One of the samples of tea bags had none of the ginsenosides, but did have complex carbohydrates found in most of the other samples. The instant tea had all three ginsenosides, but had no complex carbohydrates, only sucrose. The amounts of ginsenosides found in standard doses from six different sources of ginseng varied considerably. It was found that steeping a tea bag for a longer time than that recommended on the label produced a larger recovery of ginsenosides and that reusing a tea bag produced even higher recoveries.

Antimicrobial Activity of 10 Different Plant Polyphenols against Bacteria Causing Food-Borne Disease

The antibacterial activities of 10 different plant polyphenols were evaluated by comparing their minimum inhibitory concentrations (MICs) against several food-borne pathogenic bacteria, Staphylococcus aureus (20 strains), some serotypes of the genus Salmonella (26 strains), Escherichia coli (23 strains), and some species of the genus Vibrio (27 strains). The polyphenols examined were epigallocatechin (1), epigallocatechin-3-O-gallate (2), punicalagin (3), tannic acid (4), castalagin (5), prodelphinidin (6), geraniin (7), procyanidins (8), a theaflavin mixture of black tea (9), and green tea polyphenols treated with loquat polyphenol oxidase (10). The average MICs of all polyphenols against S. aureus and the genus Vibrio (192+/-91 and 162+/-165 microg/ml, respectively) were much lower than the values against the genus Salmonella and E. coli (795+/-590 and 1519+/-949 microg/ml, respectively) (p<0.01). The coefficient of variation of the MICs of all polyphenols against S. aureus was the least and that against the genus Vibrio was the greatest. The mean MICs of each plant polyphenol against S. aureus (98-389 microg/ml) and the genus Vibrio (68-488 microg/ml) were similar. The relatively lower mean MIC values of 1, 2, 5, and 6 suggest the importance of 3,4,5-trihydroxyphenyl groups in antibacterial activity.

In vitro inhibition of human cytochrome P450-mediated metabolism of marker substrates by natural products.

Spices, herbal and black teas, and soybean products were analyzed for their capacity to inhibit in vitro metabolism of drug marker substrates by human cytochrome P-450 (CYP) isoforms. Inhibition of drug metabolism was determined using aliquots or infusions from these products in a fluorescence-detection assay. Aliquots and infusions of all natural product categories inhibited 3A4 metabolism to some extent. Of the 26 aliquots from teas and spices further tested with 2C9, 2C19 and 2D6, many demonstrated significant inhibitory activity on the metabolism mediated by these isoforms. Black teas and herbal tea mixtures were generally more inhibitory than single-entity herbal teas. Spices and single-entity herbal teas showed species-specific isoform inhibition with sage, thyme, cloves, St John's Wort and goldenseal having the highest activity against several isoforms. Seven soybean varieties tested, as well as daidzein and genistein isolated from soybean, were found to inhibit 3A4-mediated metabolism. Genistein was found to inhibit 3A7- but not 3A5-mediated metabolism of the marker substrate. Assessment of the in vitro CYP inhibition potential for these natural products has important implications for predicting the likelihood of natural product-drug interactions if these products are taken concomitantly.

Prototype studies for the CLEO III RICH

We describe a prototype RICH detector that has been built as part of design work for the CLEO III RICH. Cherenkov photons are produced in a LiF radiator, and are detected in a multiwire chamber with a CaF/sub 2/ entrance window containing a gas mixture of methane and TEA. Signals are read out from 2016 cathode pads using low noise Viking chips. First results from this prototype show a yield of 13 photoelectrons per image in agreement with our design studies.

A Simple Method for Isolation of Caffeine from Black Tea Leaves: Use of a Dichloromethane-Alkaline Water Mixture as an Extractant

A simple procedure for the isolation of caffeine from tea leaves has been established without using hot or boiling water. A mixture of tea leaves, dichloromethane, and 0.2 M NaOH was shaken for 7 min, and the organic layer was separated. After evaporation of the organic solvent, residual crystals were purified by recrystallization to give 20-30 mg (student yield) of pure caffeine from one tea bag (2 g).

Prototype studies for the CLEO III RICH

Abstract We describe a prototype RICH detector that has been built as part of design work for the CLEO III RICH. Cherenkov photons are produced in a LiF radiator, and are detected in an MWPC containing a gas mixture of methane and TEA. Signals are read out from 2016 cathode pads using low noise Viking chips. First results from this prototype show a yield of about 13 photoelectrons per image in agreement with our design studies.

Effect of Different Levels of an Ascorbic Acid and , ea Mixture on Nonheme Iron Absorption from a Typical Tunisian Meal Fed to Healthy Rats

The aim of our study was to evaluate the bioavailability of iron from a typical Tunisian meal 'couscous' provided to healthy rats with or without appropriate mixtures of tea plus ascorbic acid and to search for the optimal amount of ascorbic acid able to overcome the inhibitory effect of tea prepared under realistic Tunisian circumstances. Our findings show that a tea decoction (100 mg/ml) reduced nonheme iron absorption from couscous by 50% (16.5 vs. 33.1%; p < 0.01). In contrast, administration of 20 mg ascorbic acid increased nonheme iron absorption from couscous by more than 100% (66.8 vs. 33.1%; p < 0.001). Administration of ascorbic acid (20 mg) in a tea decoction (100 mg/ml) completely counteracted the inhibiting effect of tea and significantly improved the nonheme iron absorption from couscous (34 vs. 33% in the control group; NS). The same effect was shown when 10 mg ascorbic acid was added to the tea decoction; however, 5 mg ascorbic acid was not able to overcome the inhibitory effect of tea on nonheme iron absorption from couscous (33.1 vs. 19.4%; p < 0.01). Our findings demonstrate that a molar ratio of ascorbic acid and tea equal or superior to 0.25 or 0.50 is necessary to overcome the inhibitory effect in rats of tea prepared under Tunisian circumstances. In relation to human nutrition, for Tunisians who regularly drink tea, we suggest a much greater amount of ascorbic acid than that normally recommended for normal subjects.

A systematic study of the emission of light from electron avalanches in low-pressure TEA and TMAE gas mixtures

We have made a quantitative systematic study of the light emitted through the electron avalanche process in low-pressure gases. The mixtures under investigation were argon/(CH 4 or C 2H 6)/(TMAE or TEA). For a given avalanche charge gain, we measured comparable light yields for mixtures containing TEA and TMAE; typical values are of 0.1–1 photons per electrons in the avalanche. We found a linear increase of the light intensity with the amplification gap width. Light production by electrons drifting in these gas mixtures without charge multiplication was also demonstrated.

MATHEMATICS OF A LADY TASTING TEA REVISITED

ABSTRACT.The British Standards Institution and the International Standards Organization specify that when mixtures of tea and milk are to be evaluated sensorially, the tea should be added to the milk. Four cups of tea prepared by pouring the tea into the cup first (TIF) and four cups prepared by placing the milk in the cup first (MIF) were presented to 155 panelists in the dark. They were instructed to select by taste the four cups containing the MIF tea. The frequency of correct selection was well above the chance level, indicating that the panelists had detected a difference in flavor. The same task was performed by 131 panelists except they evaluated the tea in light. The panelists were not highly trained tea tasters; in fact, most were not regular drinkers of hot tea. Notwithstanding that, their discriminating power was sufficient to resolve the subtle differences which did exist.

Calcium-mediated inactivation of calcium current in Paramecium.

1. The Ca current seen in response to depolarization was investigated in Paramecium caudatum under voltage clamp. Inactivation of the current was measured with the double pulse method; a fixed test pulse of an amplitude sufficient to evoke maximal inward current was preceded by a conditioning pulse of variable amplitude (0-120 mV).2. The amplitude of the current recorded during the test pulse was related to the potential of the conditioning pulse. Reduction of test pulse current was taken as an index of Ca current inactivation. The current recorded during a test pulse showed a progressive decrease to a minimum as the potential of the conditioning pulse approached +10 to +30 mV. Further increase in conditioning pulse amplitude was accompanied by a progressive restoration of the test pulse current. Conditioning pulses near the calcium equilibrium potential had only a slight inactivating effect on the test pulse current.3. Injection of a mixture of Cs and TEA which blocked late outward current had essentially no effect on the inward current or its inactivation.4. Elevation of external Ca from 0.5 to 5 mM was accompanied by increased inactivation of the test pulse current. The enhanced inactivation of the test pulse current was approximately proportional to the increase in current recorded during the conditioning pulse.5. Following injection of the Ca chelating agent, EGTA, the inactivation of the test pulse current was diminished; in addition, the transient inward current relaxed slightly more slowly, and the transient was followed by a steady net inward current.6. The time course of recovery from inactivation in the double pulse experiment approximated a single exponential having a time constant of 80-110 msec. Injection of EGTA shortened the time constant by as much as 50%.7. It is concluded that interference with the entry of Ca or enhanced removal of intracellular free Ca(2+) interferes with the process of Ca current inactivation, while enhanced entry of Ca promotes the process of inactivation. While the mechanism of inactivation is unknown, arguments are presented that the accumulation of intracellular Ca influences the Ca channel conductance.

Aqueous extraction of black leaf tea

SummaryTotal solids contents are reported for tea extracts prepared at 80°C from mixtures of (1) black tea and water, (2) black tea and tea extracts (up to 11 mass percent of total solids) and (3) residues from a first extraction and water, shaken for 4hr in sealed bottles and centrifuged at 1000g for 30 min, and the fraction of leaf dissolving inferred by materials balances. At the highest mixing ratio of solid to extracting medium employed (1:10), leaf solubility is essentially independent of extract concentration. Solubility in water alone lies between two limits: 35% at the highest mixing ratio and 47% at infinite dilution (dry leaf basis), indicating the presence of highly soluble and sparingly soluble fractions. Interpretation of the results in terms of three components; solubles, insolubles and water is discussed and a simple adjunct to a triangular composition diagram proposed to allow for the variable amounts of sparingly soluble matter remaining undissolved.

Inhibitory Effect of Tea Catechins on Some Plant Virus Diseases

To develope a new use of tea, inhibitory effects of water-soluble components of tea on plant viruses were investigated in 1966-1968.The aqueous solutions of them were injected into the soil around the base of the plants. The combinations of viruses and host plants were as follows :TMV : Physalis alkekengi L. ; N. tobacum (Bright Yellow-4) ; Tomato ; N. glutinosaCMV : N. tobacum (KY-57) ; vigna sinensis SAVI.In experiments of systemic, infection by TMV, free catechins, catechin mixture and aqueous extract of tea seemed to be slightly inhibitory. Free catechins and catechin mixture were also a little effective for the inhibition of CMV Infectivity.In local infections by TMV and CMV, it was observed that the number of lesions on the inoculated leaves of plants treated with tea catechins (free, ester and their mixture) and caffein was compared to less than the untreated ones.