Research Database

Author: Sara M. Meltzer and Bradley J. Monk and Krishnansu S. Tewari

This review evaluates the antiviral, antioxidant, and immunostimulatory properties of green tea catechins. Two randomized trials evaluating the activity and efficacy of green tea catechins in the management of external genital warts are presented, and the reported side effects associated with this topical treatment modality are outlined. Finally, the mechanism of action, percent of wart clearance, time to clearance, and toxicity profile of green tea catechins are compared with those of podofilox and imiquimod, 2 other patient-administered topical agents approved for treatment of anogenital warts.

 

 

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Author: Sara A. Khan and Shubha Priyamvada and Wasim Khan and Sheeba Khan and Neelam Farooq and Ahad N.K. Yusufi

Cisplatin (CP) an anticancer drug is known to induce nephrotoxicity, which limits its long-term clinical use. Green tea (GT), consumed since ancient times is known for its numerous health benefits. It has been shown to improve kidney functions in animal models of acute renal failure. The present study was undertaken to see whether GT can prevent CP-induced nephrotoxic and other deleterious effects. A nephrotoxic dose of CP was co-administered to control and GT-fed male Wistar rats every fifth day for 25 days. The effect of GT was determined on CP-induced alterations in various serum parameters and on enzymes of carbohydrate metabolism, brush border membrane, and antioxidant defense system in renal cortex and medulla. CP nephrotoxicity was recorded by increased serum creatinine and blood urea nitrogen. CP increased the activities of lactate dehydrogenase and acid phosphatase whereas, the activities of malate dehydrogenase, glucose-6-phosphatase, superoxide dismutase, catalase, and 32Pi transport significantly decreased. GT consumption increased the activities of the enzymes of carbohydrate metabolism, brush border membrane, oxidative stress, and 32Pi transport. GT ameliorated CP-induced nephrotoxic and other deleterious effects due to its intrinsic biochemical/antioxidant properties.

 

 

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Author: Yuri Clement

Objective Habitual green tea consumption has long been associated with health benefits including chemoprevention and cardiovascular protection. This non-systematic literature review presents the clinical evidence to date. Method A literature review of peer-reviewed articles on observational and interventional studies was conducted to include green tea, its extract or its purified polyphenol (−)-epigallocatechin-3-gallate (EGCG). Electronic databases searched included PubMed (1966–2009) and the Cochrane Library (Issue 4, 2008). Results Observational studies are inconclusive on the benefits of habitual consumption of green tea in the prevention of most cancers. However, there are trends towards prevention in breast and prostate cancers. Interventional studies have demonstrated reduction in relapses following surgical resection in colorectal adenomas and increased survival rates in epithelial ovarian cancer. Observational studies indicate that green tea may provide protection against hypertension and reduce the risk for stroke, and interventional studies are providing biochemical and physiological evidence. Conclusion Although the overall clinical evidence is inconclusive, habitual green tea consumption may be providing some level of chemoprevention in prostate and breast cancer. Green tea may also attenuate the risk factors association with the development of atherosclerosis thus reducing the incidence of cardiovascular events and stoke.

 

 

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Author: Osamu Morita and Jeannie B. Kirkpatrick and Yasushi Tamaki and Christopher P. Chengelis and Melissa J. Beck and Richard H. Bruner

Evidence suggests that the purported health benefits associated with green tea consumption are related to tea catechins. In the present study, potential adverse effects of a standardized heat-sterilized green tea catechin (GTC-H) preparation was investigated following gavage administration to rats at doses of 0, 120, 400, 1200 mg/kg/day for 6 months. A decaffeinated high-dose group (1200 mg/kg/day) (GTC–HDC), was included for comparison. A possibly test article-related clinical finding of intermittent increased activity was noted in the 400 and 1200 mg/kg/day GTC-H groups, but was not considered to be adverse. Lower body weight gains without any decrease in food consumption were noted in the high-dose (1200 mg/kg/day)-treated GTC-H and GTC–HDC females. In the high-dose male GTC-H group, a lower total motor activity count for the 60-min session was noted prior to dosing at the study week 25 evaluations compared to the control group. Similar changes were not observed in the GTC–HDC group. Based on the results of this study, the no-observed-adverse-effect level (NOAEL) for GTC-H was 1200 mg/kg/day for males, the highest dose tested, and 400 mg/kg/day for females based on reduced body weight gains. The NOAEL for GTC–HDC was 1200 mg/kg/day for males and could not be determined in females.

 

 

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Author: Fadi Annaba and Hongguang Liu and Amish K. Dudeja and Seema Saksena and Pradeep Kumar and Ravinder K. Gill and Waddah A. Alrefai

 

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Author: O. Rebai and N.E. Djebli and S. Douichene

 

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Author: Dong Wook Shin and Su Nam Kim and Sang Min Lee and Woojung Lee and Min Jeong Song and Sun Mi Park and Tae Ryong Lee and Joo-Hyun Baik and Han Kon Kim and Jeong-Ho Hong and Minsoo Noh

Green tea intake has been shown to confer various health benefits to patients suffering from metabolic disorders. Here, we studied the effect of several major green tea polyphenols on adipocyte differentiation in human bone marrow mesenchymal stem cells (hBM-MSCs) and compared it to the effect of representative antidiabetic drugs. (−)-Catechin was the most potent of the eight green tea polyphenols evaluated in promoting adipocyte differentiation in hBM-MSCs, and this effect was dose-dependent. (−)-Catechin increased the mRNA levels of various adipogenic markers, such as adiponectin, peroxisome proliferator-activated receptor gamma (PPARγ), FABP4, and LPL, as measured during adipocyte differentiation in hBM-MSCs. In addition, (−)-catechin upregulated the secretion of adiponectin in hBM-MSC culture. Using a reporter gene assay and a competitive ligand binding study, (−)-catechin also significantly activated PPARγ in a dose-dependent fashion; however, (+)-catechin, the enantiomer of (−)-catechin, was not effective as a PPARγ agonist, which seems to imply that the effect of (−)-catechin on PPARγ is stereospecific. In conclusion, our data suggest that (−)-catechin promotes adipocyte differentiation and increased sensitivity to insulin in part by direct activation of PPARγ, which could be at the basis of the observed pharmacological benefits of green tea intake in reducing the risk of type 2 diabetes.

 

 

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Author: T. Malik and D.J. Haleem

Haloperidol (HAL) a conventional antipsychotic is known to induce oxidative stress-related anxiety. Parkinsonism and Tardive Dyskinesia (TD) in patients treated with drug. Antioxidative agents may suppress the neuroleptic induced anxiety and TD. The constituents of green tea have found antioxidative. In a view of antioxidative properties of green tea, the present study was designed to monitor a possible suppression of anxiety and Tardive Vacuous Chewing Movement (tVCM) by green tea in rat model of TD and anxiety. Associated changes of Dopamine (DA) and Serotonin (5-hydroxytryptamine; 5-HT) metabolism were also monitored in the dorsal (dStr) and ventral striatum (vStr). Rats on HAL for 8 weeks exhibited tVCMs and anxiety. Green tea Extract (GTE) alone as a sole source of water did not produce tVCMs and anxiety but HAL induced significant anxiety and tVCMs were 100% (two fold) greater than water treated group. The metabolism of DA as indicated by Homovanellic acid (HVA) concentration increased in the dStr of HAL plus GTE treated animals. HAL plus GTE treated group exhibited smaller increase of HVA. The mteabolism of 5-HT as indicated by 5-hydroxyindoleacetic acid (5-HIAA) concentration also increased in the dStr of HAL but not GTE treated animals. Groups of co-treated with HAL and GTE exhibited a large increase 5 HIAA in the dStr. The results suggested that interaction of HAL with some constituents of GTE may exacerbated HAL induced  anxiety and TD by producing an imbalance of DA/5-HT control over anxiety and motor impairment.

 

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Author: Abdolhossein Moghbel and Ahmad Farajzadeh and Nasrin Aghel and Homaun Agheli and Nafiseh Raisi

 

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Author: Prakitpunthu Tomtitchong and Philip A. Robinson and Jean E. Crabtree

 

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