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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.
Recent Research Papers on
cancer-prevention
Green tea aqueous extract reduces visceral fat and decreases protein availability in rats fed with a high-fat diet
Author: Joanna Bajerska and Małgorzata Wozniewicz and Jan Jeszka and Slawomira Drzymala-Czyz and Jaroslaw Walkowiak
Green tea is associated with beneficial health effects mainly because of its body fat–reducing and hypocholesterolemic activities, but an effective dose without pronounced influence on protein availability is unknown. The objective of this study was to examine the hypothesis that green tea aqueous extract (GTAE) depending on dose improves cardiovascular risk indicators such as body weight, visceral fat content, and atherogenic index of plasma and does not have unfavorable effect on protein availability in rats fed with a high-fat diet. The rats fed with a high-fat diet enriched with 1.1 and 2.0% GTAE for 8 weeks had significantly (P < .05) lower atherogenic index (in both groups, about 14.3%). Only administration of 2.0% GTAE significantly (P < .05) decreased body weight gain (5.6%) and prevented visceral fat accumulation (17.8%) in rats. However, considerably (P < .05), reduction in the digestion of protein (but not fat) was observed in both GTAE groups (1.1% GTAE: 82.6% ± 1.8%; 2.0% GTAE: 84.3% ± 0.8%) when compared to the control (93.3% ± 1.5%). It was concluded that GTAE may have preventive effects on the accumulation of visceral fat but only in higher doses. Although both doses improved cardiovascular risk indicators, they, in addition, significantly inhibited protein digestion.
847 EFFECT OF COFFEE AND GREEN TEA CONSUMPTION ON LIVER ENZYME AND METABOLIC SYNDROME IN KOREAN POPULATION
Author: D.W. Jun and E.K. Kim and H.S. Choi and Y.I. Kown and W. Sohn and O.W. Kwon and K.N. Lee and H.L. Lee and O.Y. Lee and B.C. Yoon and T.Y. Kim and J.H. Sohn
Background: There are several epidemiologic studies that coffee and tea consumption could lower serum liver enzyme activity, and inhibit the progression of liver disease in high-risk subjects. However, many conflicting results have been also reported according to type of coffee and whether the use of filters. Most studies were base on specific cohort group and there are few general population base studies. This study examined on population based study whether coffee has a protective effect when consumed in moderate quantities in metabolic syndrome and liver inflammation. Methods: We used cross-sectional data on coffee, tea consumption frequency, and metabolic parameters of 5,283 adults, aged 20 years and older, who participated in the third Korea National Health and Nutrition Examination Survey (KNHANES). We examined the relationship between coffee, tea, and caffeine intake and metabolic parameters using linear regression. Additionally, we examined the relationship with liver enzyme activity using logistic regression. Intake was assessed by a food frequency questionnaire. Result: In our study, more than 90% subjects intake instant coffee mix (mix with confectioners’ sugar, powdered creamer, and soluble coffee). Total calorie intake and body mass index were higher in individuals with coffee intake >2 cups daily compared with those with no coffee use (p < 0.001 vs. p = 0.021, respectively). However, a gradual increase in the frequency of coffee consumption was associated with stepwise decrease in prevalence of hypertension, dyslipidemia, and abnormal fating glucose, which was independent of total calorie, and BMI. The prevalence of metabolic syndrome was strikingly decreased from 48.8%, 46.5%, to 40.9% according to the quartile of coffee consumption (p = 0.01, p for trend <0.001). After adjusting for other covariates, the differences remained significant. But frequency of coffee consumption did not affect the liver enzyme activity on general population and high risk group. In cases of normal BMI subjects (23–25 kg/m2), coffee intake had a tendency to increased liver enzyme activity. Frequency of green tea intake did not showed protective effects on liver and metabolic aspects. Conclusion: In this large, national, population-based study, consumption of coffee was associated with lower the risk of metabolic syndrome.
Green tea polysaccharide-conjugates protect human umbilical vein endothelial cells against impairments triggered by high glucose
Author: Xiaoqiang Chen and Yuefei Wang and Yalin Wu and Baoyu Han and Yuejin Zhu and Xiaolin Tang and Qinglei Sun
Hot-water extracts of low-grade green tea were precipitated with ethanol, deproteinized with trichloroacetic acid, neutralized with NaOH and fractionated by DEAE-cellulose DE-52 column chromatography to yield three (3) of unexplored polysaccharide-conjugate fractions termed gTPC1, gTPC2 and gTPC3. Monosaccharide and amino acid composition, contents of total neutral sugars, proteins and moistures, HPGPC distribution and Zeta potentials of gTPC1–3 were investigated. Exposure of human umbilical vein endothelial (HUVE) cells to high glucose (33 mM) for 12 h significantly decreased cell viability relative to normal glucose control (p < 0.001). As compared with cell injury group, gTPC1–3 at all of three dose levels (50, 150 and 300 μg/mL) were found to possess remarkably protective effects on HUVE cells against impairments induced by high glucose in a dose-dependent manner (p < 0.05, p < 0.001). To contribute toward our understanding of the cell-based protection mechanism of gTPC1–3, the latter were subjected to self-oxidation of 1,2,3-phentriol assay, and their scavenging effects were observed as 55.1%, 47.6% and 47.9% at the concentration of 300 μg/mL, respectively. On the basis of the fact that high glucose-induced endothelial dysfunction involves in the overproduction of reactive oxygen species (ROS) and contributes to the vascular complications in patients with diabetes, inhibitory effects of gTPC1–3 on high glucose-mediated HUVE cell loss are, at least in part, correlated with their potential scavenging potency of ROS. Taken together, gTPC1–3 could be developed as non-cytotoxic candidates of therapeutic agent for diabetic vascular complications.
Green tea epigallocatechin gallate enhances therapeutic efficacy of temozolomide in orthotopic mouse glioblastoma models
Author: Thomas C. Chen and Weijun Wang and Encouse B. Golden and Simmy Thomas and Walavan Sivakumar and Florence M. Hofman and Stan G. Louie and Axel H. Schönthal
The alkylating agent temozolomide, in combination with surgery and radiation, is the current standard of care for patients with glioblastoma. However, despite this extensive therapeutic effort, the inclusion of temozolomide extends survival only by a few short months. Among the factors contributing to chemoresistance is elevated expression of the endoplasmic reticulum (ER) chaperone GRP78 (glucose-regulated protein 78; BiP), a key pro-survival component of the ER stress response system. Because the green tea component EGCG (epigallocatechin 3-gallate) had been shown to inhibit GRP78 function, we investigated whether this polyphenolic agent would be able to increase the therapeutic efficacy of temozolomide in preclinical models of glioblastoma. Mice with intracranially implanted human U87 (p53 wild type) or U251 (p53 mutant) glioblastoma cells were treated with temozolomide and EGCG, alone and in combination. We found that EGCG alone did not provide survival benefit, but significantly improved the existing therapeutic effect of temozolomide, i.e., life extension was substantially greater under combination therapy as compared to temozolomide therapy alone. Immunohistochemical analysis of tumor tissue revealed increased expression levels of GRP78 in temozolomide-treated animals, which was diminished when temozolomide was combined with EGCG. Parallel in vitro experiments with siRNA targeting GRP78 or its major pro-apoptotic antagonist CHOP (CCAAT/enhancer binding protein homologous protein/GADD153) further established a critical role of the ER stress response system, where si-GRP78 sensitized cells to treatment with temozolomide, and si-CHOP provided protection from drug-induced toxicity. Thus, ER stress-regulatory components affect the chemotherapeutic response of glioblastoma cells to treatment with temozolomide, and inclusion of EGCG is able to increase the therapeutic efficacy of this DNA-damaging agent.
The influence of domestic culinary processes on the Trolox Equivalent Antioxidant Capacity of green tea infusions
Author: C. Samaniego-Sánchez and Y. Inurreta-Salinas and J.J. Quesada-Granados and R. Blanca-Herrera and M. Villalón-Mir and H. López-García de la Serrana and M.C. López Martínez
This paper presents an investigation into the influence of several culinary factors, such as water temperature, infusion time, stirring and dosage form, on polyphenol content and antioxidant capacity (TEAC values) during the domestic preparation of green tea. The results obtained show that water temperature and infusion time strongly influence total polyphenol levels and the antioxidant capacity of green tea. Temperatures of 70–80 °C together with infusion times of 3–5 min produced greatest effect, in this respect. At 90 °C, extraction was faster and more effective. However, prolonged infusion at this temperature may cause a loss of polyphenol compounds and, consequently, of antioxidant capacity. Factors such as agitation and dosage form do not seem to have much influence. Furthermore, it was found that pure green tea infusions have higher antioxidant properties than do blends of green tea with aromatic herbs and fruits.
Consumption of green tea or green tea products: Is there an evidence for antioxidant effects from controlled interventional studies?
Author: S. Ellinger and N. Müller and P. Stehle and G. Ulrich-Merzenich
Purpose Epidemiological data suggest that green tea (GT) consumption may protect against cardiovascular diseases (CVDs) and different types of cancer. This effect is attributed primarily to the antioxidant properties of flavanols from GT. This review provides an overview of controlled intervention studies investigating the effect of GT consumption on antioxidant effects ex vivo and in vivo. Methods The Medline and Cochrane databases were searched independently by two investigators for controlled intervention studies (English) on GT consumption and antioxidant effects published up to June 2010. Thirty-one studies investigating antioxidant effects ex vivo [plasma antioxidant capacity (AC), DNA's resistance against oxidative induced damage) or in vivo (lipid and protein oxidation, DNA damage] met the criteria. Results were compared by considering the participants, the dose of GT, the amount of ingested flavanols, the duration of supplementation and the investigated biomarkers. Results The comparison between the studies was difficult as relevant data, e.g., on flavanol concentration in plasma (10 of 31 studies) or on major antioxidants contributing to AC, were often missing. Lipid peroxidation and DNA damage were commonly investigated. Data on protein oxidation are scarce. An antioxidant effect of at least one parameter (increase in AC or reduction of oxidative stress marker) was observed in 15 out of 22 studies by daily consumption of GT, primarily in participants exposed to oxidative stress (smokers or mixed collectives of smokers and non-smokers and physical activity) and in 6 out of 9 studies investigating the bolus consumption of GT. Conclusion There is limited evidence that regular consumption of GT in amounts of at least 0.6–1.5 l/day may increase AC and reduce lipid peroxidation (especially oxidation of LDL). This may contribute to the protection against CVDs and different types of cancer. Beneficial effects seem to be more likely in participants exposed to oxidative challenge.
Biochemical and biological properties of polyphenolic catechins in green tea extract for health benefits
Author: Forouzanfar Ali and Orafai Hossein and Maroofian Ahmad and Golestani Shayan
Introduction: Recently great interest has been focused on the biological properties of green tea catechins because of their health benefits such as anti-inflamatory, anti-oxigenicity, anti-mutagenicity, anti-tumorgenicity and anti-carcinogenicity. These catechins are polyphenolic compounds belonging to the flavonoid family, which are present in relatively high concentration in green tea leaves (Camellia sinensis) and, at lower levels, in grape seeds and Cistus species. The aim of this study is to introduce catechin molecules structure and their potential therapeutic properties on various diseases. Materials and methods: The catechins are composed of a family of four major substances, epicatechin (EC), epicatechin gallate (Ecg), epigallocatechin (EGC), and epigallocatechin gallate (EGCg) and four minor catechins, catechin©, catechin gallate (Cg), galloca- techin (GC) and gallocatechin gallate (GCg) as epimers of the major catechins. Organic solvents such as methanol and acetonitrile or hot water have been used as solvents to extract catechins from tea leaves. Results: Green tea catechins consumption have been linked to a lower incidence of various pathologies, including cancer, cardiovascular disease and hypertension, diabetes, obesity, allergy, asthma, arthritis, immune system disorders, oral and periodontal diseases, osteoporo- sis, bacterial and viral infections and dermatological lesions. Recently we have shown that green tea catechins have improved periodontal status of patients with gingivitis suffering from gum inflammation and bleeding. Conclusion: Based on the findings of this review green tea catechins can be extracted by various methods and used in different pharmaceutical forms. Several studies have shown that green tea catechins can be applied for preventing and treating numerous diseases.
Herbal infusions bioelectrochemical polyphenolic index: Green tea – The gallic acid interference
Author: Dulce M.A. Gil and Pedro L.V. Falé and Maria L.M. Serralheiro and Maria J.F. Rebelo
An amperometric biosensor containing immobilised laccase from Trametes versicolor was used for the quantification of phenolic compounds in herbal infusions and green tea samples, from nine botanical families. The main purpose of this research was to correlate the bioelectrochemical polyphenolic index (BPI) of the samples with the total phenolic content according to the Folin–Ciocalteu spectrophotometric method (TPC), and the total antioxidant activity (TAA) measured by TEAC (Trolox Equivalent Antioxidant Capacity). A strong correlation between BPI, TPC, and TAA was obtained for 10 herbal infusion samples. However, when a green tea sample was taken into account, a decrease in the linear correlation coefficient (r2) from 0.9949 to 0.2599 and 0.5609 to 0.1086 for the relationship between BPI/TPC and BPI/TAA, respectively, was observed. Thus, we could conclude that the green tea’s matrix affects the laccase-based biosensor response. HPLC–DAD analysis showed the presence of gallic acid only in the green tea sample. The results have indicated that gallic acid inhibited the laccase activity regarding the ABTS oxidation in a concentration-dependent manner. The very strong correlation between BPI/TPC obtained for herbal infusions allow us to conclude that the laccase-based biosensor, used in this research, provides a valuable tool to obtain a valid estimation of the classical Folin–Ciocalteu index, in an uncomplicated and fast way.
Ultrahigh pressure extraction as a tool to improve the antioxidant activities of green tea extracts
Author: Jun Xi and Deji Shen and Ye Li and Rui Zhang
In this study, the effect of ultrahigh pressure extraction at pressures of 150 MPa, 250 MPa, 350 MPa and 450 MPa on the total phenolic contents, the extraction yields and the antioxidant activities of green tea were investigated. The antioxidant activities of these extracts were analyzed using DPPH radical scavenging activity and total antioxidant capacity. The results showed that the phenolic contents and the antioxidant activities of extracts were greatly influenced by high pressure. The total phenolic contents and the antioxidant activities of ultrahigh pressure extraction at 450 MPa were higher than those of other ultrahigh pressure extraction and conventional extraction. The high content of phenolic compounds in the green tea leaves could account for the antioxidant activity. This study indicated that this new technology can benefit the food and pharmaceutical industries.
Supplementation of green tea catechins in dentifrices suppresses gingival oxidative stress and periodontal inflammation
Author: Takayuki Maruyama and Takaaki Tomofuji and Yasumasa Endo and Koichiro Irie and Tetsuji Azuma and Daisuke Ekuni and Naofumi Tamaki and Tatsuo Yamamoto and Manabu Morita
Objective This study examined the effects of a dentifrice containing green tea catechins on gingival oxidative stress and periodontal inflammation using a rat model. Design Twenty-four male Wister rats were randomly divided into four groups. The first group (Control group) received no treatment for 8 weeks. Periodontal inflammation was induced in the second group for 8 weeks. Periodontal inflammation was induced in the last two groups for 8 weeks and dentifrices with or without green tea catechins were topically applied to the gingival sulcus daily for 4 weeks prior to the end of the experimental period. Results Rats that had experimental periodontal inflammation showed apical migration of the junctional epithelium, alveolar bone loss and inflammatory cell infiltration in the connective tissue subjacent to the junctional epithelium at 8 weeks, whilst the control group showed no pathologic changes. Topical application of a green tea catechin-containing dentifrice reduced inflammatory cell infiltration in the periodontal lesions to a greater degree than the control dentifrice at 8 weeks. The gingiva in which green tea catechin-containing dentifrice was applied also showed a lower level of expression of hexanoyl-lysine (a marker of lipid peroxidation), nitrotyrosine (a marker of oxidative protein damage), and tumour necrosis factor-α (an indicator of pro-inflammatory cytokines) at 8 weeks compared to gingiva in which the control dentifrice was applied. Conclusions Adding green tea catechins to a dentifrice may contribute to prevention of periodontal inflammation by decreasing gingival oxidative stress and expression of pro-inflammatory cytokines.
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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