mental-health

Author: Helaine M Alessio and Ann E Hagerman and Mary Romanello and Stephane Carando and Melinda S Threlkeld and J Rogers and Yoana Dimitrova and Subiquah Muhammed and Ronald L Wiley

The effects of green tea on biomarkers of exercise-induced oxidative status were measured in young male Sprague-Dawley rats. Rats (n = 12) drank green tea or water ad lib for 6.5 weeks. Half of each group was sacrificed at rest, and the other half ran 25 m/min at 0% grade for approximately 30 min immediately before sacrifice. Green tea had no effect on resting heart rate, blood pressure, body weight, cholesterol, or triglycerides. Tea consumption had a mild influence on total plasma antioxidants, heart glutathione, and plasma ascorbic acid. Exercise had a major impact on malonaldehyde (MDA) equivalents in kidney (+290%, p = 0.0001), and to a lesser extent, liver (+81%, p = 0.18) in rats that drank water. In contrast, kidney MDA equivalents were unchanged by exercise in rats that drank green tea. Green tea may have selective protective effects within the body, especially on the kidney.

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Author: Sabu M.C and Smitha K and Ramadasan Kuttan

An aqueous solution of green tea polyphenols (GTP) was found to inhibit lipid peroxidation (LP), scavenge hydroxyl and superoxide radicals in vitro. Concentration needed for 50% inhibition of superoxide, hydroxyl and LP radicals were 10, 52.5 and 136 μg/ml, respectively. Administration of GTP (500 mg/kg b.wt.) to normal rats increased glucose tolerance significantly (P<0.005) at 60 min. GTP was also found to reduce serum glucose level in alloxan diabetic rats significantly at a dose level of 100 mg/kg b.wt. Continued daily administration (15 days) of the extract 50, 100 mg/kg b.wt. produced 29 and 44% reduction in the elevated serum glucose level produced by alloxan administration. Elevated hepatic and renal enzymes produced by alloxan were found to be reduced (P<0.001) by GTP. The serum LP levels which was increased by alloxan and was reduced by significantly (P<0.001) by the administration of 100 mg/kg b.wt. of GTP. Decreased liver glycogen, after alloxan administration showed a significant (P<0.001) increase after GTP treatment. GTP treated group showed increased antioxidant potential as seen from improvements in superoxide dismutase and glutathione levels. However catalase, LP and glutathione peroxidase levels were unchanged. These results indicate that alterations in the glucose utilizing system and oxidation status in rats increased by alloxan were partially reversed by the administration of the glutamate pyruvate transaminase.

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Author: Hong-li Jiao and Ping Ye and Bao-lu Zhao

Author: S. Coimbra and P. Rocha-Pereira and I. Rebelo and S. Rocha and A. Santos-Silva and E.M.B. Castro

Several studies suggest a protective effect of green tea prepared with leafs of Camellia sinensis for CVD. The interest of the green tea is due to its high content in catechins. Our aim was to evaluate the effect of green tea on some risk factors for CVD. A sample of 34 Portuguese individuals was used. We evaluated the total cholesterol, HDLc, LDLc, triglycerides, lipoprotein (a), apolipoprotein A-I and B, total antioxidant status, lipid peroxidation products, oxidative changes in erythrocyte membrane and the P-selectin levels. The analyses were performed at the beginning, after 3 weeks drinking 1 liter of water daily, and after 4 weeks drinking 1 liter of green tea daily. The tea was prepared everyday in the same conditions. We found no dilution effect on the analyzed parameters. After ingestion of green tea, we found a significant reduction in total cholesterol, LDLc, and apolipoprotein B; an increase in HDLc and apolipoprotein A-I; a decrease in lipid peroxidation and a significant reduction in the oxidative stress within the erythrocyte. We found also an increase in the antioxidant capacity and a decrease in P-selectin levels. Our resuts suggest that green tea has a beneficial effect, protecting for CVD, by improving the lipid profile and the oxidative stress. 

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Author: Orly Weinreb and Silvia Mandel and Tamar Amit and Moussa B.H. Youdim

Tea consumption is varying its status from a mere ancient beverage and a lifestyle habit, to a nutrient endowed with possible prospective neurobiological–pharmacological actions beneficial to human health. Accumulating evidence suggest that oxidative stress resulting in reactive oxygen species generation and inflammation play a pivotal role in neurodegenerative diseases, supporting the implementation of radical scavengers, transition metal (e.g., iron and copper) chelators, and nonvitamin natural antioxidant polyphenols in the clinic. These observations are in line with the current view that polyphenolic dietary supplementation may have an impact on cognitive deficits in individuals of advanced age. As a consequence, green tea polyphenols are now being considered as therapeutic agents in well controlled epidemiological studies, aimed to alter brain aging processes and to serve as possible neuroprotective agents in progressive neurodegenerative disorders such as Parkinson's and Alzheimer's diseases. In particular, literature on the putative novel neuroprotective mechanism of the major green tea polyphenol, (−)-epigallocatechin-3-gallate, are examined and discussed in this review.

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Author: Woochang Lee and Won-Ki Min and Sail Chun and Yong-Wha Lee and Hyosoon Park and Do Hoon Lee and You Kyoung Lee and Ji Eun Son

Objectives: Smoking is a risk factor for coronary artery disease and triggers vascular injury by platelet aggregation and induces atherosclerosis through induction of oxidative stress. Green tea is known to have antioxidant capacity and anti-platelet activity. Design and methods: Twenty adult male smokers ingested 600 mL of green tea for 4 weeks. Their lipid profile, C-reactive protein (CRP), total antioxidant capacity, oxidized LDL, soluble VCAM-1, soluble ICAM-1, and soluble P-selectin were measured at baseline and 2 and 4 weeks after green tea ingestion. Results: Plasma soluble P-selectin (sP-selectin) levels decreased significantly after 2 and 4 weeks of green tea ingestion compared with those before green tea ingestion (P < 0.001). Plasma concentrations of oxidized LDL decreased significantly after green tea ingestion (P < 0.05). Conclusions:The results of this study suggest the effect of green tea on sP-selectin and oxidized LDL.

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Author: Jeong-Sang Lee and Tae-Young Oh and Young-Kyung Kim and Joo-Hyun Baik and Sung So and Ki-Baik Hahm and Young-Joon Surh

There are multiple lines of compelling evidence from epidemiologic and laboratory studies supporting that frequent consumption of green tea is inversely associated with the risk of chronic human diseases including cancer. The chemopreventive and chemoprotective effects of green tea have been largely attributed to antioxidative and anti-inflammatory activities of its polyphenolic constituents, such as epigallocatechin gallate. The present study was designed to evaluate the efficacy of green tea polyphenols in protecting against alcohol-induced gastric damage and to elucidate the underlying mechanisms. Intragastric administration of ethanol to male Sprague–Dawley rats caused significant gastric mucosal damage, which was accompanied by elevated expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) as well as transient activation of redox-sensitive transcription factors, such as NF-κB and AP-1, and mitogen-activated protein kinases (MAPKs). Oral administration of the green tea polyphenolic extract (GTE) significantly ameliorated mucosal damages induced by ethanol and also attenuated the ethanol-induced expression of COX-2 and iNOS. Inactivation of MAPKs, especially p38 and ERKl/2, by GTE might be responsible for inhibition of ethanol-induced expression of COX-2 and iNOS.

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Author: Mindy Bixby and Lauren Spieler and Teresita Menini and Alejandro Gugliucci

Due to the increasing importance of nitrosative stress in pathology and the efficacy displayed by flavonoids in canceling the effects of peroxynitrite, we decided to conduct a comparative study of three commonly used beverages with the highest polyphenol contents and proven antioxidant properties: mate (Ilex paraguariensis); green tea (Camelia sinensis) extracts and white and red wines of the main varietals. We directly evaluated and compared the extracts and wines as protein nitration inhibitors using 3-nitrotyrosine as a biomarker, we studied the extracts as protectors from OONO-induced cytotoxicity in two mammalian cell lines. Both green tea and mate extracts have a high polyphenol content, in the case of Ip, its higher concentration and higher free radical quenching activity on the DPPH assay may be mainly due to the sui generis extraction procedure. When BSA was incubated in the presence of SIN-1, a time and dose dependent nitration of the protein is clearly shown. Co-incubation of BSA with Ip, green tea or red wines led to a dose dependent inhibition of the effect. Ip displayed the highest inhibitory activity, followed by red wines and the green tea. Dilutions as low as 1/1500 produced more than 80% inhibition of albumin nitration. When we studied peroxynitrite-induced cytotoxicity in murine RAW 264.7 macrophages and 31EG4 mammary cells., we found a potent, dose-dependent protective effect that was Ilex paraguariensis > red wines > green tea. Taken together, our results indicate that when the herbal preparations studied here are prepared the way they are usually drunk, Ip displays the highest inhibition of protein nitration, and the highest promotion of cell survival, whereas green tea or red wines display significant but lesser effects at the same concentrations. Further studies aiming at isolation of the active principles and assessment of their bioavailability are warranted.

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Author: Matthew R. Bonner and Nathaniel Rothman and Judy L. Mumford and Xingzhou He and Min Shen and Robert Welch and Meredith Yeager and Stephen Chanock and Neil Caporaso and Qing Lan

Experimental evidence suggests that green tea (Camellia sinesis) may reduce the risk of lung cancer through several hypothesized mechanisms including scavenging oxidative radicals, inhibition of tumor initiation, and modulation of detoxification enzymes. However, epidemiologic results have not been consistent as to the relationship between green tea consumption and lung caner prevention. We employed a population-based case-control study of 122 cases and 122 controls to investigate the effect that green tea consumption may have on the risk of lung cancer and whether polymorphisms in 8-oxoguanine-DNA glycosylase (OGG1), glutathione-S-transferase M1 (GSTM1), and aldo-keto reductase 1C3 (AKR1C3) modify such an association. Daily green tea consumption was associated with a non-significant reduction in lung cancer risk. However, the effect of smoky coal exposure was higher for non-drinkers (odds ratio (OR) = 4.93; 95% confidence interval (95% CI) = 1.27–19.13) than for drinkers (OR = 1.88; 95% CI = 1.01–3.48). Further, among individuals with the OGG1Cys326 allele, daily consumption was associated with a 72% reduction (95% CI = 0.09–0.94). Among GSTM1 null homozygotes, those who consumed green tea daily had a non-significant reduction in risk compared with non-consumers. Green tea consumption had no effect among OGG1 Ser326 homozygotes or GSTM1 carriers. In addition, AKR1C3 genotype did not modulate the effect of green tea consumption. The chemopreventive effects of green tea in this population may be restricted to individuals who are particularly susceptible to oxidative stress and oxidative DNA damage.

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Author: Elżbieta Skrzydlewska and Agnieszka Augustyniak and Kamil Michalak and Ryszard Farbiszewski

Oxidative stress induced by chronic ethanol consumption, particularly in aging subjects, has been implicated in the pathophysiology of many neurodegenerative diseases. Antioxidants with polyphenol structures, such as those contained in green tea, given alone for 5 weeks in liquid Lieber de Carli diet followed by administration with ethanol for 4 weeks with ethanol have been investigated as potential therapeutic antioxidant agents in the brain in rats of three ages (2, 12, and 24 months). Ethanol consumption caused age-dependent decreases in brain superoxide dismutase, glutathione peroxidase, glutathione reductase, and catalase activities. In addition, ethanol consumption caused age-dependent decreases in the levels of GSH, selenium, vitamins, E, A and C, and β-carotene and increases in the levels of oxidized glutathione (GSSG). Changes in the brain's antioxidative ability were accompanied by enhanced oxidative modification of lipids (increases in lipid hydroperoxides, malondialdehyde, and 4-hydroxynonenal levels) and proteins (increases in carbonyl groups and bistyrosine). Reduced risk of oxidative stress and protection of the central nervous system, particularly in young and adult rats, after green tea supplementation were observed. Green tea partially prevented changes in antioxidant enzymatic as well as nonenzymatic parameters induced by ethanol and enhanced by aging. Administration of green tea significantly protects lipids and proteins against oxidative modifications in the brain tissue of young and adult rats. The beneficial effect of green tea can result from the inhibition of free radical chain reactions generated during ethanol-induced oxidative stress and/or from green tea-induced increases in antioxidative abilities made possible by increases in the activity/concentration of endogenous antioxidants.

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