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Research Database
The only comprehensive database for clinical and medical research papers on the healthy benefits of matcha/green tea.
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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.
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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.
Learn MoreMost Recent Research Articles
Artificial neural network modeling and optimization of ultrahigh pressure extraction of green tea polyphenols
Author: Jun Xi and Yujing Xue and Yinxiang Xu and Yuhong Shen
In this study, the ultrahigh pressure extraction of green tea polyphenols was modeled and optimized by a three-layer artificial neural network. A feed-forward neural network trained with an error back-propagation algorithm was used to evaluate the effects of pressure, liquid/solid ratio and ethanol concentration on the total phenolic content of green tea extracts. The neural network coupled with genetic algorithms was also used to optimize the conditions needed to obtain the highest yield of tea polyphenols. The obtained optimal architecture of artificial neural network model involved a feed-forward neural network with three input neurons, one hidden layer with eight neurons and one output layer including single neuron. The trained network gave the minimum value in the MSE of 0.03 and the maximum value in the R2 of 0.9571, which implied a good agreement between the predicted value and the actual value, and confirmed a good generalization of the network. Based on the combination of neural network and genetic algorithms, the optimum extraction conditions for the highest yield of green tea polyphenols were determined as follows: 498.8 MPa for pressure, 20.8 mL/g for liquid/solid ratio and 53.6% for ethanol concentration. The total phenolic content of the actual measurement under the optimum predicated extraction conditions was 582.4 ± 0.63 mg/g DW, which was well matched with the predicted value (597.2 mg/g DW). This suggests that the artificial neural network model described in this work is an efficient quantitative tool to predict the extraction efficiency of green tea polyphenols.
Simultaneous determination of selenium containing amino acids and their sulfur-analogues in green tea and gynostemma pentaphyllum infusion with high performance liquid chromatography based on fluorescence labeling
Author: Hui-Juan Zhang and Pan-Feng Gao and Xiao-Feng Guo and Hong Wang
In this study, an analytical method using 1,3,5,7-tetramethyl-8-(N-hydroxysuccinimidyl butyric ester)-difluoroboradiaza-s-indacene (TMBB-Su) as the labeling reagent has been developed to simultaneously detect Se-methylselenocysteine (SeMeCys), selenomethionine (SeMet), S-methylcysteine (SMeCys) and methionine (Met) in green tea and gynostemma pentaphyllum infusion by high performance liquid chromatography (HPLC) coupled to fluorescence detection. The derivatization of four targeted amino acids proceeded with 80 μmol/L TMBB-Su in 10 mmol/L mixed acid buffer (pH 7.20) at 25°C for 25 min, which was optimized by orthogonal array design. The baseline separation of these amino acid derivatives was obtained on a C8 column with a binary gradient elution using the mobile phase of 20 mmol/L mixed acid buffer solution (pH 6.40) and methanol with 2.5% tetrahydrofuran (THF). Under the optimal derivatization and separation conditions, the detection limit of each targeted amino acid was achieved to 0.2 nmol/L. A good linear relationship in the range of 0.001–1 μmol/L was obtained with a regression coefficient higher than 0.9912 for each targeted amino acids, and the relative standard deviations (RSDs) ranged from 1.8% to 3.5% for within-day determination (n = 6) and from 3.8% to 4.1% for between-day determination (n = 6). The proposed method can be used to detect selenium- and sulfur-containing amino acids simultaneously, compared to the existing HPLC with element-specific detection methods. Recoveries within 94.4–108.3% from tea and gynostemma pentaphyllum samples indicated that the matrix effect could be negligible in sample analysis. SeMeCys, SeMet, SMeCys and Met were all found in selenium enriched green tea and gynostemma pentaphyllum infusion. SeMeCys was also detected in normal green tea infusion with a mean content of 0.98 μg/g.
A cross-cultural study using Napping®: Do Korean and French consumers perceive various green tea products differently?
Author: Young-Kyung Kim and Laureen Jombart and Dominique Valentin and Kwang-Ok Kim
With the increasing demands of global trading, interests in cross-cultural comparisons have increased to gain understanding in the differences of sensory perception and consumer acceptability. The objective of this study was to compare the differences in perception by Korean and French consumers of green tea produced in Korea, China, and Japan, using Napping® followed by ultra flash profile. In addition, overall acceptability was examined in both countries. The results of Napping® showed that the Korean consumers were able to discriminate the green teas according to their origins and processing methods while the French consumers were less perceptive of these factors. The Korean consumers used more tea-related and roasting-related terms to describe the green teas. The sensory properties seemed to be the main factors in Napping® for the Korean consumers. On the other hand, the French consumers who were less familiar with green teas perceived the differences of green teas based on their acceptability. The result of this study indicated that familiarity affected the consumers' perception of green tea samples.
Protection of renal function by green tea extract during Plasmodium berghei infection
Author: Voravuth Somsak and Ubonwan Jaihan and Somdet Srichairatanakool and Chairat Uthaipibull
Impairment of renal function from oxidative stress during malaria infection is one of the leading causes of death in endemic areas. Since blood urea nitrogen and creatinine levels in plasma can be used as markers for monitoring renal damage, this study investigated the effect of green tea extract on reduction of blood urea nitrogen and creatinine levels during malaria infection using Plasmodium berghei ANKA infected mice as in vivo model. For in vivo testing, ICR mice were infected with 1 × 10 7 parasitized erythrocytes and green tea extract was subsequently administered orally twice a day for 10 consecutive days. Parasitemia was estimated by standard microscopy, and blood urea nitrogen and creatinine levels in plasma were also measured. It was found that parasitemia kept increasing until animal death, and is strongly correlated with high blood urea nitrogen and creatinine. The highest levels of blood urea nitrogen and creatinine in plasma were found on day 10 after infection. However, blood urea nitrogen and creatinine levels in plasma were reduced and decreased significantly (p < 0.01) in green tea extract treated mice, compared with untreated group. It can be concluded that green tea extract can protect and maintain renal function during malaria infection, and this extract can be developed for use as a supplement and combination therapy.
Modulation of signaling pathways in prostate cancer by green tea polyphenols
Author: Naghma Khan and Hasan Mukhtar
Prostate cancer (PCa) is the most common malignancy found in American men and the risk factors for PCa include age, family history, ethnicity, hormonal status, diet and lifestyle. For the successful development of cancer-preventive/therapeutic approaches, consumption of dietary agents capable of inhibiting or delaying the growth and proliferation of cancer cells without significantly affecting normal cells could be an effective strategy. Polyphenols derived from green tea, termed as green tea polyphenols (GTP) have received great attention in recent years for their beneficial effects, in particular, their significant involvement in cancer chemoprevention and chemotherapy. Several studies have reported beneficial effects of GTP using in vitro and in vivo approaches and in human clinical trials. Among green tea catechins, epigallocatechin-3-gallate (EGCG) is best studied for its cancer preventive properties. In this review article, we present available scientific literature about the effects of GTP and EGCG on signaling pathways in PCa.
Green tea catechins during food processing and storage: A review on stability and detection
Author: Victoria K. Ananingsih and Amber Sharma and Weibiao Zhou
Green tea catechins can undergo degradation, oxidation, epimerization and polymerization during food processing. Many factors could contribute to the chemical changes of green tea catechins, such as temperature, pH of the system, oxygen availability, the presence of metal ions as well as the ingredients added. Several detection methods have been developed for tea catechin analysis, which are largely based on liquid chromatography (LC) and capillary electrophoresis (CE) methods for getting a good separation, identification and quantification of the catechins. Stability of green tea catechins is also influenced by storage conditions such as temperature and relative humidity. The stability of each catechin varies in different food systems and products. Pseudo first-order kinetic model has been developed and validated for the epimerization and degradation of tea catechins in several food systems, whereas the rate constant of reaction kinetics followed Arrhenius equation.
Oxidative stability and rheological properties of nanoemulsions with ultrasonic extracted green tea infusion
Author: Anna Lante and Dario Friso
Epigallocatechin-3-gallate (EGCG) is considered the most significant tea catechin because it has the highest free radical scavenging activity and because of its role in preventing carcinogenesis. Thus, adding green tea infusion to food products imparts a safe, natural antioxidant that prevents rancidity and promotes good health. Even if mild technologies could be developed to optimize the extraction of EGCG from green tea, questions remain regarding the best means of delivering EGCG through food and its disposition in the body after ingestion. Recent reports indicate that the bioavailability of EGCG is very poor due to its large molecular size and number of hydrogen bonds. The present study demonstrates the use of ultrasound to extract catechins from green tea leaves with improved EGCG yield, and subsequent preparation of water-in-oil (W/O) green tea nanoemulsions with soy, peanut, sunflower, and corn oils. The green tea/peanut oil emulsion displayed the highest oxidative stability. All W/O emulsions examined demonstrated a shear thinning behavior in good agreement with the Carreau model (R2 = 0.980 ± 0.033). Values for shear viscosity at a shear rate of 10 s−1 were found to be compatible with the semi-empirical equation of Larson and McClements, with an effective volume fraction slightly higher than the actual volume fraction and still increasing with homogenization time. Moreover, the specific surface area of the nanoemulsions was very high and with an average value of about 40 m2/mL.
Immobilization of green tea extract on polypropylene films to control the antioxidant activity in food packaging
Author: Carol López de Dicastillo and María del Mar Castro-López and José Manuel López-Vilariño and María Victoria González-Rodríguez
In this work, we report the successful immobilization of green tea extract, as a natural antioxidant, on polypropylene through the incorporation of anhydride maleic grafted polypropylene on polymer formulation owing to control active compound release and prolong antioxidant activity. The extruded films were thermally characterized showing that the incorporation of green tea extract improved polymer stability, and the presence of grafted polymer did not affect polymer morphology. Green tea components release profiles depending on the type of food and polymer formulation. The use of grafted polypropylene changed the ability of the polymer to release green tea antioxidants; the amount of components released decreased with an increasing degree of grafted polypropylene. Materials were submitted to sterilization and microwave heating conditions. The immobilization of the active compounds implied a lower release during these typical food package treatments, and the available antioxidant components on the modified materials presented a good correlation with the antiradical activity toward ABTS+ radicals, prolonging their antioxidant ability.
Influence of addition of green tea and green coffee extracts on the properties of fine yeast pastry fried products
Author: Grażyna Budryn and Dorota Żyżelewicz and Ewa Nebesny and Joanna Oracz and Wiesława Krysiak
This study investigated the influence of antioxidants of green tea aqueous extract (GTE) and green coffee aqueous extract (GCE) in concentrations of 0.25, 0.5 and 1 g·100 g− 1 on the nutritional properties of fine yeast pastry fried products such as donuts. Yeast donuts were made according to the traditional processing technology. In fried donuts physical properties (water activity, pH, hardness and color with the use of instrumental methods) as well as sensory properties were established. Moreover, quality of fat extracted from donuts (composition of fatty acids and peroxide value), content of acrylamide, composition of polyphenols and antioxidant activity were analyzed. Obtained extracts of GTE and GCE contained 26 and 41% of polyphenols, respectively, and the degree of polyphenol degradation during production of donuts was less when the dilution in dough was greater. Both tests indicated that the highest antioxidant activity had donuts with the highest analyzed addition of extract, however depending on the applied test or GTE or GCE had better antioxidant properties. Fatty acid composition was the most beneficial when the addition of GTE and GCE was on a level of 0.25 and 0.5 g·100 g− 1, respectively. In fried donuts relatively low amounts of acrylamide were obtained, amounting to 18–46 μg·kg− 1. Only the lowest addition of GTE and the highest addition of GCE caused an increase of acrylamide content in donuts, while all other levels of added extracts caused a decrease in the content of formed acrylamide.
Effects of green tea extract and (−)-epigallocatechin-3-gallate on pharmacokinetics of nadolol in rats
Author: S. Misaka and N. Miyazaki and T. Fukushima and S. Yamada and J. Kimura
Green tea catechins have been shown to affect the activities of drug transporters in vitro, including P-glycoprotein and organic anion transporting polypeptides. However, it remains unclear whether catechins influence the in vivo disposition of substrate drugs for these transporters. In the present study, we investigated effects of green tea extract (GTE) and (−)-epigallocatechin-3-gallate (EGCG) on pharmacokinetics of a non-selective hydrophilic β-blocker nadolol, which is reported to be a substrate for several drug transporters and is not metabolized by cytochrome P450 enzymes. Male Sprague-Dawley rats received GTE (400 mg/kg), EGCG (150 mg/kg) or saline (control) by oral gavage, 30 min before a single intragastric administration of 10 mg/kg nadolol. Plasma and urinary concentrations of nadolol were determined using high performance liquid chromatography. Pharmacokinetic parameters were estimated by a noncompartmental analysis. Pretreatment with GTE resulted in marked reductions in the maximum concentration (Cmax) and area under the time–plasma concentration curve (AUC) of nadolol by 85% and 74%, respectively, as compared with control. In addition, EGCG alone significantly reduced Cmax and AUC of nadolol. Amounts of nadolol excreted into the urine were decreased by pretreatments with GTE and EGCG, while the terminal half-life of nadolol was not different among groups. These results suggest that the coadministration with green tea catechins, particularly EGCG, causes a significant alteration in the pharmacokinetics of nadolol, possibly through the inhibition of its intestinal absorption mediated by uptake transporters.