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cognitive-function
Matcha consumption leads to much higher intake of green tea phytochemicals compared to regular green tea. Previous research on caffeine, L-theanine, and epigallocatechin gallate (EGCG) repeatedly demonstrated benefits on cognitive performance.
Recent Research Papers on
cognitive-function
Electronic nose and chiral-capillary electrophoresis in evaluation of the quality changes in commercial green tea leaves during a long-term storage
Author: Mara Mirasoli and Roberto Gotti and Massimo Di Fusco and Alberto Leoni and Carolina Colliva and Aldo Roda
Electronic nose and capillary electrophoresis were applied in quality control of green tea samples subjected to long-term storage. Twelve representative green teas were considered, available as an “aged” (tea leaves stored during a long-term period of two years) and/or “not aged” (fresh products) samples. Their infusions were analyzed by an electronic nose, equipped with an array of six metal oxide semiconductor (MOS) sensors to obtain olfactive fingerprints of the volatile compounds in the infusions headspace. Upon training and chemometric analysis of acquired data (linear discriminant analysis), the electronic nose was found to be able in correctly classifying unknown samples as “aged” or “not aged”. Concomitantly, the infusion samples were analyzed by Cyclodextrin-modified Micellar Electrokinetic Chromatography (CD-MEKC) for determination of catechins. The analysis of seven most represented catechins and the methylxanthines theobromine and caffeine revealed a general loss of the polyphenols in each of the considered aged samples (up to 45%, w/w). In addition, the applied enantioselective method based on (2-hydroxypropyl)-β-cyclodextrin (HP-βCD) as chiral selector, was exploited for the estimation of (+)-Gallocatechin in the presence of (−)-Gallocatechin; the latter, as the non-native enantiomer, can be associated to the epimerisation of (−)-Epigallocatechin and was assumed as a marker occurring in case of uncorrected storage conditions of tea leaves. Interestingly, it was observed that epimerization did not significantly occur during aging. The application of CD-MEKC and electronic nose allowed for a fast characterization of green teas taking into account that the aroma is a decisive parameter for the acceptance of the product, whereas the catechins content is associated to the biological value.
Resin selection for the separation of caffeine from green tea catechins
Author: David Méndez Sevillano and Luuk A.M. van der Wielen and Nasim Hooshyar and Marcel Ottens
This work focuses on the rapid selection of a resin from a defined set of macroporous polymeric resins for the decaffeination of catechins from green tea. High-throughput experimentation and design of experiments are used in order to retrieve as much information as possible from a small set of experiments on the interaction of components with the resins. A multicomponent Langmuir isotherm model is used to describe the adsorption and parameters are regressed with high accuracy. These parameters are subsequently used for the definition of criteria to calculate a weighted resin score. The optimal resin is Diaion 20HP with a score of 90.50%, mainly due to its good selectivity for caffeine over catechin (3).
Memory deficits and oxidative stress in cerebral ischemia–reperfusion: Neuroprotective role of physical exercise and green tea supplementation
Author: Helen L. Schimidt and Aline Vieira and Caroline Altermann and Alexandre Martins and Priscila Sosa and Francielli W. Santos and Pâmela B. Mello-Carpes and Ivan Izquierdo and Felipe P. Carpes
Ischemic stroke is a major cause of morbidity and mortality all over the world. Among impairments observed in survivors there is a significant cognitive learning and memory deficit. Neuroprotective strategies are being investigated to minimize such deficits after an ischemia event. Here we investigated the neuroprotective potential of physical exercise and green tea in an animal model of ischemia–reperfusion. Eighty male rats were divided in 8 groups and submitted to either transient brain ischemia–reperfusion or a sham surgery after 8 weeks of physical exercise and/or green tea supplementation. Ischemia–reperfusion was performed by bilateral occlusion of the common carotid arteries during 30 min. Later, their memory was evaluated in an aversive and in a non-aversive task, and hippocampus and prefrontal cortex were removed for biochemical analyses of possible oxidative stress effects. Ischemia–reperfusion impaired learning and memory. Reactive oxygen species were increased in the hippocampus and prefrontal cortex. Eight weeks of physical exercise and/or green tea supplementation before the ischemia–reperfusion event showed a neuroprotective effect; both treatments in separate or together reduced the cognitive deficits and were able to maintain the functional levels of antioxidant enzymes and glutathione.
Green tea and type 2 diabetes
Author: Jae-Hyung Park and Jae-Hoon Bae and Sung-Soon Im and Dae-Kyu Song
Green tea and coffee consumption have been widely popular worldwide. These beverages contain caffeine to activate the central nervous system by adenosine receptor blockade, and due to the caffeine, addiction or tolerance may occur. In addition to this caffeine effect, green tea and coffee consumption have always been at the center of discussions about human health, disease, and longevity. In particular, green tea catechins are involved in many biological activities such as antioxidation and modulation of various cellular lipid and proteins. Thus, they are beneficial against degenerative diseases, including obesity, cancer, cardiovascular diseases, and various inflammatory diseases. Some reports also suggest that daily consumption of tea catechins may help in controlling type 2 diabetes. However, other studies have reported that chronic consumption of green tea may result in hepatic failure, neuronal damage, and exacerbation of diabetes, suggesting that interindividual variations in the green tea effect are large. This review will focus on the effect of green tea catechins extracted from the Camellia sinensis plant on type 2 diabetes and obesity, and the possible mechanistic explanation for the experimental results mainly from our laboratory. It is hoped that green tea can be consumed in a suitable manner as a supplement to prevent the development of type 2 diabetes and obesity.
UHPLC determination of catechins for the quality control of green tea
Author: Marina Naldi and Jessica Fiori and Roberto Gotti and Aurélie Périat and Jean-Luc Veuthey and Davy Guillarme and Vincenza Andrisano
An ultra-high performance liquid chromatography (UHPLC) with UV detection method was developed for the fast quantitation of the most represented and biologically important green tea catechins and caffeine. UHPLC system was equipped with C18 analytical column (50 mm × 2.1 mm, 1.8 μm), utilizing a mobile phase composed of pH 2.5 triethanolamine phosphate buffer (0.1 M) and acetonitrile in a gradient elution mode; under these conditions six major catechins and caffeine were separated in a 3 min run. The method was fully validated in terms of precision, detection and quantification limits, linearity, accuracy, and it was applied to the identification and quantification of catechins and caffeine present in green tea infusions. In particular, commercially available green tea leaves samples of different geographical origin (Sencha, Ceylon Green and Lung Ching) were used for infusion preparations (water at 85 °C for 15 min). The selectivity of the developed UHPLC method was confirmed by comparison with UHPLC–MS/MS analysis. The recovery of the main six catechins and caffeine on the three analyzed commercial tea samples ranged from 94 to 108% (n = 3). Limits of detection (LOD) were comprised in the range 0.1–0.4 μg mL−1. An orthogonal micellar electrokinetic (MEKC) method was applied for comparative purposes on selectivity and quantitative data. The combined use of the results obtained by the two techniques allowed for a fast confirmation on quantitative characterization of commercial samples.
Modeling and optimization of green tea precipitation for the recovery of catechins
Author: Miguel Monsanto and Nasim Hooshyar and Jan Meuldijk and Edwin Zondervan
Green tea catechins are claimed to have several health benefits (e.g. antioxidant, antimutagenic and antiviral) with increasing applications in the food and pharmaceutical markets. By using the tea creaming effect and by enhancing it, as a phase separation via precipitation, it is possible to recover a large amount of polyphenols from the cream phase without using toxic solvents. A design of experiments (DoE) together with statistical analysis allows a description of the system with polynomial models and enables the determination of the optimal conditions that maximize the catechins recovery, while minimizing the amount of caffeine, which is considered a contaminant. A total of four influence factors are studied in this DoE: hydroxypropylmethylcellulose and polyvinylpyrrolidone (used as precipitation agents), temperature and pH, of which only pH is found not to be significant. With the optimal combination of factors it is possible to separate and recover up to 67% of the catechins present in the green tea extract solution, while increasing the ratio of catechins/caffeine by 60%.
Effects of green tea and physical exercise on memory impairments associated with aging
Author: Maíra F. Flôres and Alexandre Martins and Helen L. Schimidt and Francielli W. Santos and Iván Izquierdo and Pâmela B. Mello-Carpes and Felipe P. Carpes
We investigated the effects of physical exercise and green tea supplementation (associated or not) on biochemical and behavioral parameters in the time course of normal aging. Male Wistar rats aged 9 months were divided into groups: control, physical exercise (treadmill running), and supplemented with green tea while either performing physical exercise or not. A young control group was also studied. Physical exercise and green tea supplementation lasted 3 months. Afterwards, behavioral and biochemical tests were performed. Biochemical measurements revealed differences in antioxidant and oxidant responses in hippocampus, prefrontal cortex and striatum. Behavioral testing showed age-related memory impairments reversed by physical exercise. The association of green tea supplementation and physical exercise did not provide aged rats with additional improvements in memory or brain oxidative markers. Green tea per se significantly decreased reactive oxygen species levels and improved antioxidant defenses although it did not reverse memory deficits associated with normal aging.
Correlation between nitrogen application to tea flushes and quality of green and black teas
Author: Po-An Chen and Shu-Yen Lin and Chiou-Fang Liu and Yen-Shuo Su and Hun-Yuan Cheng and Jian-Hsing Shiau and Iou-Zen Chen
We treated the tea cultivar \{TTES\} No. 12 with different nitrogen fertilizers and prepared black and green teas from these tea flushes. Analyses of nitrogen content and levels of catechins and caffeine of shoots with two leaves and a bud were conducted to understand the influence of these factors on tea quality. Only the nitrogen content showed consistent effects on tea quality, whereas the effects of the other chemical components varied with season. A positive linear regression relationship was observed between nitrogen content of tea flushes and green tea quality, whereas a negative linear regression relationship was observed between nitrogen content and black tea quality. Thus, the quality of black and green teas could be determined based on the nitrogen content of the tea flushes.
High-quality green tea leaf production by artificial cultivation under growth chamber conditions considering amino acids profile
Author: Shunsuke Miyauchi and Takayuki Yuki and Hiroshi Fuji and Kunio Kojima and Tsutomu Yonetani and Ayako Tomio and Takeshi Bamba and Eiichiro Fukusaki
The current study focused on the tea plant (Camellia sinensis) as a target for artificial cultivation because of the variation in its components in response to light conditions. We analyzed its sensory quality by multi-marker profiling using multicomponent data based on metabolomics to optimize the conditions of light and the environment during cultivation. From the analysis of high-quality tea samples ranked in a tea contest, the ranking predictive model was created by the partial least squares (PLS) regression analysis to examine the correlation between the amino-acid content (X variables) and the ranking in the tea contest (Y variables). The predictive model revealed that glutamine, arginine, and theanine were the predominant amino acids present in high-ranking teas. Based on this result, we established a cover-culture condition (i.e., a low-light intensity condition) during the later stage of the culture process and obtained artificially cultured tea samples, which were predicted to be high-quality teas. The aim of the current study was to optimize the light conditions for the cultivation of tea plants by performing data analysis of their sensory qualities through multi-marker profiling in order to facilitate the development of high-quality teas by plant factories.
Other Popular Research Topics
Heart Health
According to Harvard Medical School, “lowering your risk of cardiovascular disease may be as easy as drinking green tea. Studies suggest this light, aromatic tea may lower LDL cholesterol and triglycerides, which may be responsible for the tea's association with reduced risk of death from heart disease and stroke.”
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Mental Health
Matcha contains an amino acid called L-theanine, which has been shown to reduce physiological and psychological stresses. L-theanine also improves cognition and mood in a synergistic manner with caffeine, and promotes alpha wave production in the brain
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Cancer Prevention
Matcha/green tea has for many centuries been regarded as an essential part of good health in Japan and China. Many believe it can help reduce the risk of cancer, and a growing body of evidence backs this up.
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Immunity
A recent study in the journal Proceedings of the National Academy of Sciences concluded that drinking matcha daily greatly enhanced the overall response of the immune system. The exceedingly high levels of antioxidants in matcha mainly take the form of polyphenols, catechins, and flavonoids, each of which aids the body’s defense in its daily struggles against free radicals that come from the pollution in your air, water and foods.
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