Research Database
The only comprehensive database for clinical and medical research papers on the healthy benefits of matcha/green tea
Recent Research Papers on
cancer-prevention
Author: Jinping Qiao and Chenxin Gu and Weihu Shang and Jinglei Du and Wei Yin and Meilin Zhu and Wei Wang and Mei Han and Weidong Lu
Tea drinking is widely practiced in the world and has recently increased among cancer patients. However, the effects of concurrent consumption of tea on the bioavailability and the net therapeutic potential of co-administered chemical drugs are not clear. In this study, the effects of green tea on the pharmacokinetics of 5-fluorouracil (5-FU) in rats and the pharmacodynamics in human cell lines in vitro were studied. The pharmacokinetic experiment indicated that there was an approximately 151% increase in the maximum plasma concentration (Cmax) and an approximately 425% increase in the area under the plasma concentration curve (AUC) of 5-FU in the green tea-treated group compared with the control group. Green tea consumption increased the plasma concentration of 5-FU. In addition, the pharmacodynamics experiment showed that at the moderate dose level (equivalent to 6 cups daily in human), neither fresh green tea extract nor (−)-epigallocatechin-3-gallate (EGCG) showed significant additive effects on the cytotoxicity of 5-FU in human cell lines. The results showed that it is crucial to perform therapeutic drug monitoring (TDM) when the cancer patients have a habit of drinking green tea.
Author: Yu-Wen Hsu and Chia-Fang Tsai and Wen-Kang Chen and Chun-Fa Huang and Cheng-Chieh Yen
Green tea is believed to be beneficial to health because it possesses antioxidant, antiviral and anticancer properties. The potential toxicity of green tea when administered at high doses via concentrated extracts, however, has not been completely investigated. The objective of the present study was to evaluate the safety of green tea extract in ICR mice using a subacute exposure paradigm. In this study, mice were orally administered (gavage) green tea extract at doses of 0 (as normal group), 625, 1250 and 2500 mg/kg body weight/day for 28 days. The results showed that oral administration of green tea extract did not cause adverse effects on body weight, organ weights, hematology, serum biochemistry, urinalysis or histopathology. Additionally, administering green tea extract via gavage significantly reduced triglyceride and cholesterol levels. These observed effects could be attributed to the high levels of catechins present in green tea as these compounds have been reported to have beneficial health effects. The no-observed-adverse-effect level for green tea extract derived from the results of the present study was 2500 mg/kg body weight/day.
Author: Vera Lavelli and Mark Corey and William Kerr and Claudia Vantaggi
Intermediate moisture products made from blanched apple flesh and green tea extract (about 6 mg of monomeric flavan 3-ols added per g of dry apple) or blanched apple flesh (control) were produced, and their quality attributes were investigated over storage for two months at water activity (aw) levels of 0.55 and 0.75, at 30 °C. Products were evaluated for colour (L∗, a∗, and b∗ Hunter’s parameters), phytochemical contents (flavan 3-ols, chlorogenic acid, dihydrochalcones, ascorbic acid and total polyphenols), ferric reducing antioxidant potential, 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl radical-scavenging activity and ability to inhibit formation of fructose-induced advanced glycation end-products. During storage of the fortified and unfortified intermediate moisture apples, water availability was sufficient to support various chemical reactions involving phytochemicals, which degraded at different rates: ascorbic acid > flavan 3-ols > dihydrochalcones and chlorogenic acid. Colour variations occurred at slightly slower rates after green tea addition. In the intermediate moisture apple, antioxidant and anti-glycoxidative properties decreased at similar rates (half-life was about 80 d at aw of 0.75, 30 °C). In the green tea-fortified intermediate moisture apple, the antioxidant activity decreased at a slow rate (half-life was 165 d at aw of 0.75, 30 °C) and the anti-glycoxidative properties did not change, indicating that flavan 3-ol degradation involved the formation of derivatives that retained the properties of their parent compounds. Since these properties are linked to oxidative- and advanced glycation end-product-related diseases, these results suggest that green tea fortification of intermediate moisture apple products could be a valuable means of product innovation, to address consumers’ nutritional needs.
Author: Carol López-de-Dicastillo and Joaquin Gómez-Estaca and Ramón Catalá and Rafael Gavara and Pilar Hernández-Muñoz
Active antioxidant food packaging films were produced by the incorporation of ascorbic acid, ferulic acid, quercetin, and green tea extract into an ethylene vinyl alcohol copolymer (EVOH) matrix. The characterisation of the thermal and barrier properties of the developed film showed that the addition of these bioactive compounds did not greatly modify their properties. However, the presence of ascorbic and ferulic acids resulted in a significant decrease in water vapour permeability, possibly due to the high affinity for water of these substances. Exposure of the films to various food simulants showed that the release from the films was dependent on the type of food simulant and the antioxidant incorporated: in the aqueous food simulant, materials containing ascorbic acid produced the largest release; in the fatty food simulant, quercetin and green tea extract presented the best performance. The efficiency of the films developed was determined by real packaging applications of brined sardines. The evolution of the peroxide index and the malondialdehyde content showed that, in general, the films improved sardine stability. Films with green tea extract offered the best protection against lipid oxidation.
Author: A.S.G. Costa and M.A. Nunes and I.M.C. Almeida and M.R. Carvalho and M.F. Barroso and R.C. Alves and M.B.P.P. Oliveira
Nowadays, new emerging products claiming antioxidant properties are becoming more frequent. However, information about this topic in their labels is usually scarce. In this paper, we analyzed total phenolics, total flavonoids and ascorbic acid contents, as well as DPPH scavenging activity of several commercial samples, namely green tea and other herbal infusions, dietary supplements, and fruit juices, available in the Portuguese market. In general, beverages containing green tea and hibiscus showed higher phenolics contents (including flavonoids) and antioxidant activity than those without these ingredients. A borututu infusion presented the lowest concentrations of bioactive compounds and scavenging activity, due to the low recommended amount of plant to prepare the beverage. Some juices without antioxidant claims in the label presented similar values to those with it.
Author: Jaqueline Minatti and Elisabeth Wazlawik and Mariana A. Hort and Fernanda L. Zaleski and Rosa M. Ribeiro-do-Valle and Marcelo Maraschin and Edson L. da Silva
The aim of this study was to evaluate the effects of green tea extract (GTE) administration on vascular reactivity and atherosclerosis progression in low-density lipoprotein receptor knockout mice. We hypothesized that GTE intake may ameliorate atherosclerosis by improving endothelial dysfunction. Animals (n = 12 per group) were fed a hypercholesterolemic diet and received either water or GTE at a dose of 50, 100, or 300 mg/kg once a day by gavage (100 μL/10 g weight). After 4 weeks, atherosclerosis extension and vascular reactivity were evaluated in the aorta, and the levels of lipids, monocyte chemotactic protein-1(MCP-1), and tumor necrosis factor α were measured in the plasma. Administration of GTE at a dose of 50 mg/kg significantly decreased the area of atherosclerotic lesions by 35%, improved the vascular reactivity in the isolated thoracic aorta, and lowered the plasma levels of both MCP-1 and triglycerides. Delivery of 100 mg/kg of GTE only promoted vasocontraction and vasorelaxation (P < .05), whereas a dose of 300 mg/kg was ineffective. Maximum contraction and relaxation negatively correlated with the lesion area (r = −0.755 and −0.767, respectively), whereas the plasma levels of MCP-1 and triglycerides positively correlated with plaque size (r = 0.549 and 0.421, respectively). In summary, our results supported the hypothesis that administration of GTE at low doses may contribute to a decrease in atherosclerosis progression by reversing endothelial dysfunction.
Author: Ubonrat Siripatrawan and Suparat Noipha
Chitosan film incorporating green tea extract (CGT-film) was used as active packaging for shelf life extension of pork sausages. The physical, chemical, microbiological, and sensory qualities of pork sausages wrapped with CGT-film were compared with those wrapped with chitosan-alone film (C-film) and those without chitosan film wrapping (control). Changes in the qualities of pork sausages including color, texture, lipid oxidation with respect to thiobarbituric value (TBA), and microbiological qualities including total plate counts, yeasts and molds, and lactic acid bacteria were determined throughout the storage at 4 °C. The sensory qualities including odor, color, slime formation, and overall acceptability were evaluated using Quantitative Descriptive Analysis. It was found that samples wrapped with CGT-film showed lower changes in color, texture, TBA value, microbial growth, and sensory characteristics than those wrapped with C-film and control, respectively. Successful inhibition of lipid oxidation and microbial growth in the refrigerated pork sausages was possible with chitosan film incorporating green tea extract. The results suggested that incorporation of green tea extract into chitosan film could enhance the antioxidant and antimicrobial properties of the film and thus maintained the qualities and prolonged the shelf life of the sausages.
Author: Young Jun Kim and Soung-Jin Houng and Jae Hoon Kim and Young-Rok Kim and Hong Geun Ji and Sung-Joon Lee
Nanoemulsification of nutrients could improve bioavailability by enhancing intestinal uptake. We investigated the antioxidant and hypolipidemic effects of nanoemulsified green tea extract (NGTE). Antioxidant effect was measured by 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging assay and dichlorofluorescein diacetate (DCFH-DA) assay. C57BL/6 mice were fed a control high-fat diet, green tea extract (GTE), or NGTE diet for 4 weeks. In composition analysis, GTE and NGTE contained similar total catechin concentrations. The antioxidative effect of GTE was comparable with that of NGTE. In the ABTS assay, GTE had a marked effect, although NGTE was more effective than GTE in the DCFH-DA assay. In the mouse feeding experiment, total and low-density lipoprotein (LDL) cholesterol concentrations were significantly reduced after NGTE treatment in comparison with GTE treatment in high-fat-fed C57BL/6J mice over the course of 4 weeks. The hypocholesterolemic effects were greater in the NGTE group compared with the GTE group (24% vs. 15.4% LDL cholesterol reduction compared with the control). Expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase was significantly down-regulated. Protein expression of LDL receptor was significantly increased in the livers of both the GTE- and NGTE-treated groups (+234.1%, P<.01 and +274.7%, P<.001), with a greater effect in the NGTE than in the GTE group. Cholesterol 7α-hydroxylase gene expression was similarly increased in both the GTE and NGTE groups. These results suggest that nanoemulsification significantly increased hypocholesterolemic effects of GTE in vivo due to increased bioavailability.
Author: Ying Zhang and Yingjie Yu and Xu Li and Shinichi Meguro and Satoshi Hayashi and Mitsuhiro Katashima and Takeshi Yasumasu and Jingzhong Wang and Keji Li
The effects of catechin-enriched green tea on Chinese adults with a high proportion of abdominal visceral fat were evaluated. Subjects (118) were randomly assigned to consume daily a beverage containing 609.3 mg catechins and 68.7 mg caffeine or a control beverage for 12 weeks. Abdominal fat area, body weight and composition were measured at week 0, week 8, and week 12. One hundred and four subjects completed the trial. Average visceral fat area, body weight, and body fat were reduced significantly by catechin-enriched green tea treatment but these effects were not seen in the control group with per-protocol sets analysis. The decrease at week 12 in the visceral fat area in the catechin group was greater than that in the control group (P = 0.04). Thus, consumption of the catechin-enriched green tea beverage for 12 weeks induced visceral fat loss in Chinese adults with a high proportion of abdominal visceral fat.
Author: Mona F. Mahmoud and A. Fahmy and Marwa A. Auf
Background & aims This investigation aimed to evaluate the possible hepatoprotective effects of green tea extract and selenium on liver fibrosis in comparison with silymarin and to study the underlying mechanisms. Methods Liver fibrosis was induced in rats by i.p. injection of CCL4 (3 times a week for 6 weeks in a dose of 25 μl/100 gb.w). Green tea extract (200 mg/kg), selenium (0.945 mg/kg) and silymarin (100 mg/kg) were given orally and daily for 8 weeks (2 weeks before CCL4 and 6 weeks along with CCL4). Results CCL4-induced fibrosis as indicated by increased activities of liver enzymes and increased lactate dehydrogenase (LDH) activity is an indicator of cell death. It also elevated serum nitric oxide (NO), inflammatory mediators like tumor necrosis factor alpha (TNF-α) and liver lipid peroxidation and decreased liver reduced glutathione (GSH) content. It also increased liver collagen fiber percent and caused liver cell damage. On the other hand, green tea and selenium reduced these changes and improved the pathological effects caused by CCL4. Both drugs’ effects were similar to silymarin hepatoprotective effects but they cause greater reduction of collagen fiber percent than silymarin. Conclusions Findings of the present study suggest that green tea extract and selenium have protective effects similar in most aspects to silymarin via anti-inflammatory and antioxidant effects. In addition, their antifibrotic effect was stronger than that of silymarin. So both natural products may be used as adjunctive therapy in liver fibrosis.
Other Popular Research Topics
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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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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