mental-health

Author: Agnieszka Augustyniak and Ewa Waszkiewicz and Elżbieta Skrzydlewska

Objective The present study investigated the influence of green tea as a source of water-soluble antioxidants on the liver antioxidant potential of different aged rats chronically intoxicated with ethanol. Methods Rats (2, 12, and 24 mo old) were fed for 5 wk on a control or an ethanol Lieber-DeCarli diet with and without green tea (7 g/L). The activity and level of enzymatic and non-enzymatic antioxidants and the level of markers of protein and lipid oxidation in the liver of rats were examined. Results The activities of superoxide dismutase and catalase and levels of vitamins C, E, A, and β-carotene were significantly decreased, whereas activities of glutathione peroxidase and glutathione reductase and the level of reduced glutathione significantly increased during aging. The ethanol diet caused a significant decrease in activity of antioxidant enzymes and in the level of non-enzymatic antioxidants tested. Administration of green tea to ethanol-treated rats of different ages partly normalized the activity of enzymes and the level of non-enzymatic antioxidants. Changes in antioxidant ability observed during aging were accompanied by increased levels of markers of lipid and protein modifications that also were intensified by ethanol. Green tea caused a decrease in lipid and protein oxidation in aged and ethanol-treated rats. The protective effect of green tea was confirmed by the significantly lower activity of biomarkers of liver damage (alanine and aspartate aminotransferases) in the serum of rats that received green tea with ethanol compared with rats from the control ethanol group. Conclusions The use of green tea appears to be beneficial to rat liver by decreasing oxidative stress caused by ethanol and/or aging.

Get the whole article here

Author: Susana Coimbra and Elisabeth Castro and Petronila Rocha-Pereira and Irene Rebelo and Susana Rocha and Alice Santos-Silva

Summary Background & aims Green tea, an infusion prepared with the leaves of Camellia sinensis is particularly rich in flavonoids, which are strong antioxidants. Tea drinking, by providing antioxidants, may become valuable in several oxidative stress conditions. Our aim was to evaluate the effect of green tea drinking on some factors reflecting the development of oxidative stress in plasma and in erythrocytes. Methods The study was performed in 34 Portuguese subjects. We evaluated the total antioxidant status (TAS), the lipid peroxidation products—malonyldialdehyde (MDA) and malonyldialdehyde+4-hydroxy-2(E)-nonenal (MDA+4-HNE)—and the oxidative changes in erythrocyte membrane, namely membrane bound haemoglobin (MBH) and the band 3 profile. Analytical evaluations were performed after 3 weeks drinking 1l of water daily, and after 4 weeks drinking 1l of green tea daily. Tea was prepared daily at the same conditions of temperature, time of infusion and concentration. Results After green tea drinking, we found a significant reduction in serum levels of MDA and MDA+4-HNE and in the oxidative stress within the erythrocyte, as suggested by a significantly lower value of MBH and by changes in band 3 profile towards a normal mean profile, namely an increase in the band 3 monomer. A rise in the antioxidant capacity was also observed. Conclusions Our data suggest for green tea drinking a beneficial effect, by reducing the development or the enhancement of oxidative stress and, therefore, protecting the individual for oxidative stress diseases. Moreover, we propose further studies about the value of band 3 profile and of MBH in providing a cumulative measurement of the effect of green tea drinking upon the oxidative stress in cells. Moreover, further studies are also needed, to clarify the effect of green tea consumption, the value of regular green tea consumption and the way it should be prepared to reach a healthy effect.

Get the whole article here

Author: Brad A. Sutherland and Rosanna M.A. Rahman and Ian Appleton

Catechins are dietary polyphenolic compounds associated with a wide variety of beneficial health effects in vitro, in vivo and clinically. These therapeutic properties have long been attributed to the catechins' antioxidant and free radical scavenging effects. Emerging evidence has shown that catechins and their metabolites have many additional mechanisms of action by affecting numerous sites, potentiating endogenous antioxidants and eliciting dual actions during oxidative stress, ischemia and inflammation. Catechins have proven to modulate apoptosis at various points in the sequence, including altering expression of anti- and proapoptotic genes. Their anti-inflammatory effects are activated through a variety of different mechanisms, including modulation of nitric oxide synthase isoforms. Catechins' actions of attenuating oxidative stress and the inflammatory response may, in part, account for their confirmed neuroprotective capabilities following cerebral ischemia. The versatility of the mechanisms of action of catechins increases their therapeutic potential as interventions for numerous clinical disorders. However, more epidemiological and clinical studies need to be undertaken for their efficacy to be fully elucidated.

Get the whole article here

Author: Pon Velayutham Anandh Babu and Kuruvimalai Ekambaram Sabitha and Chennam Srinivasulu Shyamaladevi

Diabetes-induced hyperlipidemia, oxidative stress and protein glycation impair cellular calcium and sodium homeostasis associated with abnormal membrane-bound enzyme activities resulting in cardiac dysfunction in diabetes. To explore the cardioprotective mechanism of green tea in diabetes, we measured the changes in the levels of calcium, sodium, potassium and the activities of Na+/K+-ATPase and Ca2+-ATPase in green tea treated diabetic rat hearts. The effect of green tea on triglycerides, lipid peroxidation and protein glycation in diabetic heart were also measured to elucidate the underlying mechanisms. Diabetes was induced by streptozotocin (STZ, 60 mg/kg i.p.). Six weeks after the induction of diabetes, some of the diabetic rats were treated orally with green tea extract (GTE) (300 mg/kg/day) for 4 weeks. GTE produced reduction in blood glucose and lowered the levels of lipid peroxides, triglycerides and extent of protein glycation in the heart of diabetic rats. GTE blunted the rise in cardiac [Ca2+] and [Na+] whereas increased the activities of Ca2+-ATPase and Na+/K+-ATPase in diabetic rats. In conclusion, the data provide support to the therapeutic effect of GTE and suggest that a possible mechanism of action may be associated with the attenuation of the rise in [Ca2+] and [Na+] by ameliorating Ca2+-ATPase and Na+/K+-ATPase activities.

Get the whole article here

Author: A. Soussi and Y. Gaubin and B. Beau and J.C. Murat and J.P. Soleilhavoup and F. Croute and A. El Feki

Expression pattern of heat shock proteins (Hsp) 72/73 and glucose regulated protein (Grp) 94 was studied in liver, kidney and testis of rats injected with sublethal doses of ammonium metavanadate (5 mg/kg/day). In addition, some batches of animals were given green tea decoction, known to be rich in anti-oxidative compounds, as sole beverage in order to evaluate its protective properties. In control animals, the stress proteins expression was found to be organ-dependant: anti-Grp94 antibody revealed two bands at 96 and 98 kDa in kidney and liver whereas the 98 kDa band only was found in testis; anti-Hsp72/73 antibody revealed that the constitutive Hsp73 was present in all organs whereas the inducible Hsp72 was only present in kidney and testis. In kidney of vanadium-treated rats, Hsp73 was over-expressed by about 50% whereas Hsp72 was down-regulated by 50–80%. No such effects were observed in liver and testis. In liver and kidney of vanadium-treated rats, Grp94 was over-expressed by 50% and 150% respectively whereas no change was found in testis. In rats given green tea as sole beverage, the 96 kDa protein expression level in liver was reduced both in controls and in vanadium-treated animals. However, green tea drinking failed to prevent the vanadium-induced Hsp72 under-expression in kidney of vanadium-treated rats.

Get the whole article here

Author: Pon Velayutham Anandh Babu and Kuruvimalai Ekambaram Sabitha and Chennam Srinivasulu Shyamaladevi

Hyperglycemia induced oxidative stress has been proposed as a cause of many complications of diabetes including cardiac dysfunction. The present study depicts the therapeutic effect of green tea extract on oxidative stress in aorta as well as heart of streptozotocin diabetic rats. Six weeks after diabetes induction, green tea was administered orally for 4 weeks [300 mg (kg body weight)−1 day−1]. In aorta and heart of diabetic rats there was a significant increase in the activity of superoxide dismutase, catalase and glutathione peroxidase with an increase in lipid peroxides. Diabetic rats showed a significant decrease in the levels of serum and cardiac glutathione. Green tea administration to diabetic rats reduced lipid peroxides and activity of antioxidant enzymes whereas increased glutathione content. The results demonstrate that the induction of antioxidant enzymes in diabetic rats is not efficient and sufficient to reduce the oxidative stress. But green tea by providing a competent antioxidative mechanism ameliorates the oxidative stress in the aorta and heart of diabetic rats. The study suggests that green tea may provide a useful therapeutic option in the reversal of oxidative stress induced cardiac dysfunction in diabetes mellitus.

Get the whole article here

Author: A. Reed and B. Raudenbush

Previous research indicates green tea extract can have beneficial effects on health and performance. The present study was designed to determine the extent to which green tea extract significantly impacts cognitive functioning, endurance, perceived workload, and mood over time. Participants were 18 student athletes who were tested over a 6-week time period. Results of the experiment reveal athletes show a significant improvement in the number of push-ups completed when given green tea extract. No statistically significant improvements were found for cognition, mood, or perceived workload; however, the majority of these measures were greater in the green tea condition. The implication of these results is that natural, and in the case of green tea, very healthy, substances could be used to enhance endurance, rather than pharmacological methods such as caffeine and steroids.

Get the whole article here

Author: Hyun-Seuk Moon and Hong-Gu Lee and Yun-Jaie Choi and Tae-Gyu Kim and Chong-Su Cho

Green tea catechins (GTCs) are polyphenolic flavonoids formerly called vitamin P. GTCs, especially (−)-epigallocatechin-3-gallate (EGCG), lower the incidence of cancers, collagen-induced arthritis, oxidative stress-induced neurodegenerative diseases, and streptozotocin-induced diabetes. Also, inhibition of adipogenesis by green tea and green tea extract has been demonstrated in cell lines, animal models, and humans. The obesity-preventive effects of green tea and its main constituent EGCG are widely supported by results from epidemiological, cell culture, animal, and clinical studies in the last decade. Studies with adipocyte cell lines and animal models have demonstrated that EGCG inhibits extracellular signal-related kinases (ERK), activates AMP-activated protein kinase (AMPK), modulates adipocyte marker proteins, and down-regulates lipogenic enzymes as well as other potential targets. Also, the catechin components of green tea have been shown to possess anti-carcinogenic properties possibly related to their anti-oxidant activity. In addition, it was shown that dietary supplementation with EGCG could potentially contribute to nutritional strategies for the prevention and treatment of type 2 diabetes mellitus. In this review, the biological activities and multiple mechanisms of EGCG in cell lines, animal models, and clinical observations are explained.

Get the whole article here

Author: Michele Antonello and Domenico Montemurro and Massimo Bolognesi and Marco Di Pascoli and Anna Piva and Franco Grego and Daniele Sticchi and Luisa Giuliani and Spiridione Garbisa and Gian Paolo Rossi

Author: Jerzy Juśkiewicz and Zenon Zduńczyk and Adam Jurgoński and Łucja Brzuzan and Irena Godycka-Kłos and Ewa Żary-Sikorska

Rats with severe streptozotocin (STZ)-induced diabetes were subjected to dietary green tea extract supplementation at 2 doses (0.01% and 0.2%; GTL and GTH groups, respectively) to evaluate their effects on antioxidant, gastrointestinal, and renal parameters of experimental animals. The lower dietary supplementation reflects daily consumption of 3 cups of green tea for an average adult weighing 70 kg. Supplementation of a diet with green tea extract had no influence on elevated food intake, body weight loss, increased glucose concentration, or declined antioxidant capacity of water-soluble substances in plasma in the diabetic rats. In cases of intestinal maltase activity, attenuation of liver and kidney hypertrophy, triacylglycerol concentration, and aspartate aminotransferase activity in the serum, both dietary treatments normalized metabolic disorders caused by STZ injection to a similar extent. Unlike the GTL group, the GTH treatment significantly ameliorated development of diabetes-induced abnormal values for small intestinal saccharase and lactase activities, renal microalbuminuria, thiobarbituric acid-reactive substance content in kidney tissue, as well as total antioxidant status in the serum of rats. The GTH group was also characterized by higher antioxidant capacity of lipid-soluble substances in plasma and superoxide dismutase activity in the serum. Although the higher dose of green tea extract did not completely protect against STZ-induced hyperglycemia and oxidative stress in experimental rats, this study suggests that green tea extract ingested at high amounts may prove to be a useful therapeutic option in the reversal of diabetic dysfunction.

Get the whole article here