Research - Black Tea
Coffee and Tea May Contribute to a Healthy Liver
Your morning cup of tea or coffee may be doing more than just perking you up before work.
An international team of researchers led by Duke-NUS Graduate Medical School (Duke-NUS) and the Duke University School of Medicine suggest that increased caffeine intake may reduce fatty liver in people with non-alcoholic fatty liver disease (NAFLD).
Worldwide, 70 percent of people diagnosed with diabetes and obesity have NAFLD, the major cause of fatty liver not due to excessive alcohol consumption. It is estimated that 30 percent of adults in the United States have this condition, and its prevalence is rising in Singapore. There are no effective treatments for NAFLD except diet and exercise.
Using cell culture and mouse models, the study authors -- led by Paul Yen, M.D., associate professor and research fellow, and Rohit Sinha, Ph.D of the Duke-NUS Graduate Medical School's Cardiovascular and Metabolic Disorders Program in Singapore -- observed that caffeine stimulates the metabolization of lipids stored in liver cells and decreased the fatty liver of mice that were fed a high-fat diet. These findings suggest that consuming the equivalent caffeine intake of four cups of coffee or tea a day may be beneficial in preventing and protecting against the progression of NAFLD in humans.
The findings will be published in the September issue of the journal Hepatology.
"This is the first detailed study of the mechanism for caffeine action on lipids in liver and the results are very interesting," Yen said. "Coffee and tea are so commonly consumed and the notion that they may be therapeutic, especially since they have a reputation for being "bad" for health, is especially enlightening."
The team said this research could lead to the development of caffeine-like drugs that do not have the usual side effects related to caffeine, but retain its therapeutic effects on the liver. It could serve as a starting point for studies on the full benefits of caffeine and related therapeutics in humans.
Source : Newswise
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A systematic review of anti-obesity medicinal plants - an update
Shirin Hasani-Ranjbar 1,2, Zahra Jouyandeh2 and Mohammad Abdollahi3*
1 Obesity & Eating Habits Research Center, Endocrinology & Metabolism Research Institute, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
2 Endocrinology & Metabolism Research Center, Endocrinology & Metabolism Research Institute, Tehran University of Medical Sciences, Tehran, Iran
3 Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran
Obesity is the most prevalent health problem affecting all age groups, and leads to many complications in the form of chronic heart disease, diabetes mellitus Type 2 and stroke. A systematic review about safety and efficacy of herbal medicines in the management of obesity in human was carried out by searching bibliographic data bases such as, PubMed, Scopus, Google Scholar, Web of Science, and IranMedex, for studies reported between 30th December 2008 to 23rd April 2012 on human or animals, investigating the beneficial and harmful effects of herbal medicine to treat obesity. Actually we limited our search to such a narrow window of time in order to update our article published before December of 2008. In this update, the search terms were “obesity” and (“herbal medicine” or “plant”, “plant medicinal” or “medicine traditional”) without narrowing or limiting search items. Publications with available abstracts were reviewed only. Total publications found in the initial search were 651. Total number of publications for review study was 33 by excluding publications related to animals study.
Studies with Nigella Sativa, Camellia Sinensis, Crocus Sativus L, Seaweed laminaria Digitata, Xantigen, virgin olive oil, Catechin enriched green tea, Monoselect Camellia, Oolong tea, Yacon syrup, Irvingia Gabonensi, Weighlevel, RCM-104 compound of Camellia Sinensis, Pistachio, Psyllium fibre, black Chinese tea, sea buckthorn and bilberries show significant decreases in body weight. Only, alginate-based brown seaweed and Laminaria Digitata caused an abdominal bloating and upper respiratory tract infection as the side effect in the trial group. No other significant adverse effects were reported in all 33 trials included in this article.
In conclusion, Nigella Sativa, Camellia Synensis, Green Tea, and Black Chinese Tea seem to have satisfactory anti-obesity effects. The effect size of these medicinal plants is a critical point that should be considered for interpretation. Although there was no report for side effect in these trials, we believe that safety of these plants still remains to be elucidated by further long-term studies.
Source : BMC Complementary and Alternative Medicine
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Effect of black tea extract on herpes simplex virus-1 infection of cultured cells
Anthony Cantatore, Sade D Randall, Daniel Traum and Sandra D Adam
The purpose of this investigation was to determine if black tea extract (BTE), consisting primarily of flavanol compounds called theaflavins, could inhibit herpes simplex virus type-1 (HSV-1) infection in cultured A549(human epithelial) and Vero cells.
The effect of BTE both on A549 and Vero cultured cells and on HSV-1 was assessed by using phase contrast and fluorescent microscopy, and cell viability and proliferation assays. After establishing the maximumnon-cytotoxic concentration of BTE, A549 and Vero cells and HSV-1 virions were treated with varying concentrations of BTE, respectively. A549 and Vero cells were infected with HSV-1 with green fluorescent protein (GFP) insert at the UL46 gene. The effect of infectivity was determined by viral DNA extraction followed by PCR, plaque assays,adsorption assays, and electrophoresis of PCR products.
BTE was not cytotoxic to A549 and Vero cells, as confirmed by cell viability and proliferation assays, in which BTE treated groups paralleled the positive control group. For both cell lines, plaque assays and fluorescent microscopy indicated an inverse relationship between BTE concentration (from 0.14μM–1.4 mM) and HSV-1 infectivity. Specifically, PCR and electrophoresis showed a reduction in the viral genome following treatment with BTE. In addition, there was a noticeable decrease in the amount of viral plaques for BTE treated samples in the adsorption assays.
BTE consisting primarily of theaflavins is not cytotoxic and can reduce or block the production of infectious HSV-1 virions in cultured A549 and Vero cells, thus inhibiting the infectivity of the virus by interfering in the attachment, penetration and viral DNA replication of HSV-1 particles. These findings indicate that BTE enriched with theaflavins has the potential to be developed as a safe, therapeutic antiviral agent to prevent the spread of HSV-1
Source : BMC - Complementary and Alternative Medicine
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Tea Ingredients Can Kill Micro-Organisms and Inactivate Toxins, Expert Says
New research has revealed that a nice cup of tea could hold the solution to a range of deadly weapons in the bioterrorist's arsenal.
As well as being the UK's favorite drink, research has shown that the morning brew has the ability to kill micro-organisms and inactivate toxins.
Dr Simon Richardson, Senior Lecturer in Biopharmaceutical Sciences at the University of Greenwich's School of Science, is part of a team of researchers who have discovered that a principal component of black tea can neutralize ricin, a highly toxic substance which has been at the center of a number of attempted terrorist attacks.
Dr Richardson says: "One cup of char won't cure you if you have been poisoned, but compounds extracted from tea could, with further research, provide an antidote to poisoning following a terrorist attack. I've been working on neutralizing ricin poisoning for about six years as a by-product of my work in drug delivery. Professor Les Baillie from Cardiff University is leading this project, which is in its preliminary stages but there is real progress! The next stage, as well as securing more funding, is seeing if other components of tea have a greater effect."
Ricin was the poison used to kill the Bulgarian dissident Georgie Markov on Westminster bridge in 1978 after a small pellet containing the poison was fired out of what was thought to be a modified umbrella.
Source : Science Daily
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(-)-Epigallocatechin gallate attenuates acute stress responses through GABAergic system in the brainAndrew Steptoe1 , E. Leigh Gibson1, Raisa Vounonvirta1, Emily D. Williams1, Mark Hamer1, Jane A. Rycroft2, Jorge D. Erusalimsky3 and Jane Wardle1
Abstract Rationale Tea has anecdotally been associated with stress relief, but this has seldom been tested scientifically. Objectives To investigate the effects of 6 weeks of black tea consumption, compared with matched placebo, on subjective, cardiovascular, cortisol and platelet responses to acute stress, in a parallel group double-blind randomised design. Materials and methods Seventy-five healthy nonsmoking men were withdrawn from tea, coffee and caffeinated beverages for a 4-week wash-out phase during which they drank four cups per day of a caffeinated placebo. A pretreatment laboratory test session was carried out, followed by either placebo (n = 38) or active tea treatment (n = 37) for 6 weeks, then, a final test session. Cardiovascular measures were obtained before, during and after two challenging behavioural tasks, while cortisol, platelet and subjective measures were assessed before and after tasks. Results The tasks induced substantial increases in blood pressure, heart rate and subjective stress ratings, but responses did not differ between tea and placebo treatments. Platelet activation (assessed using flow cytometry) was lower following tea than placebo treatment in both baseline and post-stress samples (P < 0.005). The active tea group also showed lower post-task cortisol levels compared with placebo (P = 0.032), and a relative increase in subjective relaxation during the post-task recovery period (P = 0.036). Conclusions Compared with placebo, 6 weeks of tea consumption leads to lower post-stress cortisol and greater subjective relaxation, together with reduced platelet activation. Black tea may have health benefits in part by aiding stress recovery.
Source : Psychopharmacology
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Daily intakes of more than 100 ml of tea or coffee may significantly reduce the risk of certain brain tumors, according to new research published in the American Journal of Clinical Nutrition.
The study is based on data from over half a million people in the European Prospective Investigation into Cancer and Nutrition (EPIC) study, and finds that people consuming over 100 ml of tea, coffee, or both, per day are at significantly lower risk of glioblastoma tumours (glioma) than those consuming less than 100 ml per day.
“In this large cohort study, we observed an inverse association between total coffee and tea consumption and risk of glioma,” wrote the researchers, led by Dr. Dominique S Michaud from the Department of Epidemiology and Public Health at Imperial College, London.
According to the American Brain Tumor Association, glioma's are tumors that start in the supportive tissue brain. The exact causes of gliomas are not known, however the prognosis for people once diagnosed with the type of tumour is usually very poor.
A recent US study found total coffee and tea consumption was inversely associated with risk of glioma, whilst experimental studies have shown caffeine can slow the invasive growth of glioblastoma tumours.
However very few large scale epidemiologic studies have measured the association between coffee, tea, or caffeinated beverages and glioma risk. The authors noted that the results of these studies “have been inconsistent”.
“Given the limited evidence suggesting that coffee and tea intake may reduce the risk of glioma, more studies are needed to address this hypothesis,” stated the researchers.
In the new study, the researchers examined the relation between coffee and tea intake and risk of glioma and meningioma.
A significant inverse association was observed for glioma risk when consuming more than 100 ml coffee and tea per day, compared consuming less than 100 ml per day.
However, the researchers observed no association between coffee, tea, or combined coffee and tea consumption and risk of either type of brain tumor when looking at data based on country-specific intakes.
No association was reported for meningioma risk with the same intake values for coffee and tea intake combined, or when a higher cutoff of 200 ml per day was used.
“Given that we did not observe an association between coffee and tea consumption and meningioma risk, it is possible that the effect of coffee, if causal, is acting late in the process of carcinogenesis by preventing tumor growth,” suggested the researchers.
Another potential mechanism that may be implicated in the observed effects, involves the DNA repair protein MGMT. Higher activation of MGMT is believed to have a protective effect against development of several types of cancer, including colon cancer and glioma.
Coffee compounds kahweol and cafestol have been reported to increase MGMT activity in rats, whilst certain tea polyphenols are known to reactivate genes in cancer cells – including MGMT.
“These findings, if further replicated in other studies, may provide new avenues of research on gliomas,” they added.
Source: American Journal of Clinical Nutrition
Published online ahead of print, doi:
“Coffee and tea intake and risk of brain tumors in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort study”
Authors: D.S Michaud, V. Gallo, B. Schlehofer, A. Tjønneland, A. Olsen, K. Overvad, et al.
source : NutraIngredients-usa.com
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