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
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.
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.
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.
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.
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.
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.
Author: Natalie Glube and Lea von Moos and Guus Duchateau
Purpose In vitro disintegration and dissolution are routine methods used to assess the performance and quality of oral dosage forms. The purpose of the current work was to determine the potential for interaction between capsule shell material and a green tea extract and the impact it can have on the release. Methods A green tea extract was formulated into simple powder-in-capsule formulations of which the capsule shell material was either of gelatin or HPMC origin. The disintegration times were determined together with the dissolution profiles in compendial and biorelevant media. Results All formulations disintegrated within 30 min, meeting the USP criteria for botanical formulations. An immediate release dissolution profile was achieved for gelatin capsules in all media but not for the specified HPMC formulations. Dissolution release was especially impaired for HPMCgell at pH 1.2 and for both HPMC formulations in FeSSIF media suggesting the potential for food interactions. Conclusions The delayed release from studied HPMC capsule materials is likely attributed to an interaction between the catechins, the major constituents of the green tea extract, and the capsule shell material. An assessment of in vitro dissolution is recommended prior to the release of a dietary supplement or clinical trial investigational product to ensure efficacy.
Author: Heba-Alla H. Abd-ElSalam and Medhat A. Al-Ghobashy and Hala E. Zaazaa and Mohamed A. Ibrahim
Epigallocatechin gallate (EGCG) is a powerful antioxidant and commonly used nutraceutical. Accelerated stability of EGCG in tablet formulations was investigated. LLE and SPE were employed for sample clean-up and enrichment of EGCG over caffeine. Samples were analysed after spiking with fixed concentration of gallic acid (GA), in order to verify reproducibility of analysis. A TLC–densitometric assay was developed and validated for determination of % loss EGCG. EGCG, GA and caffeine were resolved with Rf values 0.54, 0.69 and 0.80, respectively. LC–MS/MS was used to verify identity and purity of the EGCG band. Determination was carried out over a concentration range of 0.50–5.00 μg/band and 0.20–2.40 μg/band for GA and caffeine, respectively. Results showed significant reduction in EGCG content after one, three and six months: 24.00%, 28.00% and 52.00% respectively. Results continue to demonstrate that stability of nutraceutical products should be investigated in-depth using industry-oriented protocols before granting marketing authorisation.
Author: Wanchun Wang and Yu’e Yang and Wenyi Zhang and Wenlong Wu
Summary Objectives Epidemiological studies evaluating the association of tea consumption and the risk of oral cancer risk have produced inconsistent results. Thus, we conducted a meta-analysis to assess the relationship between tea consumption and oral cancer risk. Methods Pertinent studies were identified by a search in PubMed, Web of Knowledge and Wan Fang Med Online. The fixed or random effect model was used based on heterogeneity test. Publication bias was estimated using Egger’s regression asymmetry test. Results Finally, 14 articles with 19 studies comprising 4675 oral cancer cases were included in this meta-analysis. The relative risk (95% confidence interval) of oral cancer for the highest versus the lowest category of tea consumption was 0.853 (0.779–0.934), and the association was significant between oral cancer risk and green tea consumption [0.798 (0.673–0.947)] but not in the black tea consumption [0.953 (0.792–1.146)]. The associations were also significant in Asian and Caucasian. Conclusions Our analysis indicated that tea consumption may have a protective effect on oral cancer, especially in green tea consumption.
Author: Chao-Ming Liu and Chung-Yu Chen and Yang-Wei Lin
A simple, inexpensive micellar electrokinetic chromatography (MEKC) method with UV detection was used to determine seven catechins and one xanthine (caffeine) in tea. All the compounds were successfully separated (15 kV) within a 15-min migration period with a high number of theoretical plates (>8.0 × 10 4) in a running buffer (pH 7) containing 10 mmol l−1 sodium tetraborate, 4 mmol l−1 sodium phosphate, and 25 mmol l−1 SDS. The regression lines of all standard catechins were linear within the range of 0.03–4 μg ml−1. Green tea infused at 95 °C for 10 min showed higher levels of catechins (especially epigallocatechin galate, epicatechin gallate, and epicatechin) than tea infused at 80 °C. In addition, major differences were observed in the levels of catechins in the first and second infusions (both brewed at 95 °C for 10 min). Finally, green tea leaves were infused separately with tap water, deionised water, spring water, reverse osmosis water, and distilled water at 95 °C, and the catechin content of the infusions was investigated by the proposed method. In the infusion brewed with tap water, catechins appeared to be epimerisation from the epistructure to the nonepistructure. This epimerisation may take place more readily in tap water than in distilled water owing to the complexity of the ions present in tap water.