Green tea: potential health benefits.

Department of Family Medicine, Maine Medical Center, Portland, Maine 04102, USA.
American family physician (Impact Factor: 1.82). 05/2009; 79(7):591-4.
Source: PubMed

ABSTRACT Green tea has been used widely and in high doses for centuries as a health tonic in many societies. Evidence suggests that green tea is effective for treating genital warts. There is some supportive evidence for the use of green tea in cancer prevention. Drinking green tea is associated with a decrease in all-cause mortality, but not in cancer-related mortality. Small clinical studies have found that green tea may also be helpful in losing and managing weight, and lowering cholesterol. Epidemiologic evidence suggests that green tea may prevent stroke and cardiovascular disease. Green tea appears to be safe, although there have been case reports of hepatotoxicity possibly related to a specific extract in pill or beverage form. Green tea seems to be a low-risk complementary therapy for a number of conditions, but more studies are needed.

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    ABSTRACT: Recognition of the adverse effects of medicinal herbs is not routine and the reports on such effects are even less frequent in clinical practice. Potential herb-drug interactions are of a major safety concern, especially for drugs with narrow therapeutic indices like warfarin, which can lead to severe adverse reactions that are sometimes life-threatening. The interactions between warfarin and medicinal herbs described in the literature have been summarized in this paper relying on Medline database (via PubMed) using the key words: warfarin, herbal supplements and interactions. The references on the analyzed literature have been investigated in order to collect the existing data. The case reports with severe adverse effects such as spontaneous postoperative bleeding, formation of hematomas, hematemesis, melena, thrombosis, subarachnoid hemorrhage and/or subdural hematomas after concomitant use of warfarin and the medicinal herbs: Panax ginseng, Hypericum perforatum, Salvia milthiorizza, Gingko biloba, Serenoa repens, Angelica sinensis, Vaccinium species, Allium sativum, Zingiber officinale, Tanacetum parthenium, Lucium barbarum, Matricaria chamomilla, Boswellia serrata and Camellia sinensis have been estimated. Some of the interactions between warfarin and medicinal herbs have been well assessed proving that they are closely-dependent. The interactions between warfarin and medicinal herbs, not generally reported in previous reviews, are presented in our review. The health professionals who are involved in treating the patients are expected to be fully informed about the interactions between warfarin and medicinal herbs in order to minimize the health risks of the patients.
    Natural product communications 01/2014; 9(8):1211-1216. · 0.92 Impact Factor
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    ABSTRACT: This study was carried out as a pre-requisite to evaluate the therapeutic potential of Camellia varieties. The crude extracts of six different plants of green tea Camellia assamica and Camellia sinensis were tested against three Gram-positive and four Gram-negative bacteria using agar disk diffusion method at 50 mg/ml concentration. 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and diphenyl-(2,4,6-trinitrophenyl)iminoazanium free radical scavenging methods were performed to evaluate the antioxidant potential. Phytochemical constituents and trace metals were detected through thin layer chromatography and Inductively Coupled Plasma Atomic Emission Spectrophotometer, respectively. The maximum inhibition of Staphylococcus aureus was recorded by dimethyl sulphoxide extracts of green tea varieties. The measured zone of inhibition of dimethyl sulphoxide extracts by Qimen was (10.00±0.0 mm), Japanese (10.00±0.0 mm), Turkish (10.00±0.0 mm), Indonesian (8.33±1.0 mm), P3 clone (10.00±0.0 mm) and Sri Lankan (10.00±0.0 mm). Maximum scavenging potential activity was found with ethanol, methanol and dimethyl sulphoxide extracts. Spot screening of TLC-developed plates indicated that the presence of active biological compounds such as fl avonoids, proteins, phenols, alkaloids and glycosides also exhibited strong activity against tested bacterial strains. This study reveals the potential biological activities of Camellia assamica and Camellia sinensis having massive phytochemical constituents and trace elements.
    Indian Journal of Pharmaceutical Sciences 08/2014; 76(4):364-370. · 0.30 Impact Factor
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    ABSTRACT: Introduction: Promising experimental and clinical trials suggest that green tea decrease inflammatory process in cardiometabolic diseases, but evidence from epidemiologic studies about the effects on plasma C-reactive protein (CRP) seems inconsistent and ambiguous. Therefore the aim of the meta-analysis was to evaluate the impact of green tea supplementation on plasma CRP concentrations. Methods: We searched selected database up to October 26, 2014 to identify randomized controlled trials (RCTs) investigating the impact of green tea supplementation on plasma CRP concentrations. Two independent reviewers extracted data on study characteristics, methods and outcomes. Results: Meta-analysis of data from 11 RCTs arms did not indicate a significant effect of supplementation with green tea catechins on plasma CRP concentrations (WMD: 0.085 mg/L, 95%CI: -0.225, 0.395, p=0.592). This effect size was robust in sensitivity analysis and omission of each individual study did not have a significant effect. The non-significant effects of green tea catechins on plasma CRP concentrations were also observed in subgroups of studies with green tea supplementation duration of <8 weeks (WMD: 0.029 mg/L, 95%CI: -0.229, 0.286, p=0.828) and ≥8 weeks (WMD: 0.099 mg/L, 95%CI: -0.555, 0.754, p=0.766). Likewise there was no significant effect in subgroups of studies with total catechins doses <400 mg/day (WMD: 0.073 mg/L, 95%CI: -0.251, 0.398, p=0.658) and ≥400 mg/day (WMD: 0.213 mg/L, 95%CI: -0.148, 0.574, p=0.247). The effect size were not significant after stratification of studies to those recruiting healthy subjects (WMD: -0.028 mg/L, 95%CI:-0.216, 0.160, p=0.769), and those recruiting subjects with cardiometabolic diseases (WMD: 0.260 mg/L, 95%CI: -0.815, 1.334, p=0.636). Conclusions: This meta-analysis of data from 11 RCT arms did not indicate a significant effect of supplementation with green tea catechins on plasma CRP concentrations. Further, well-designed trials are necessary to validate these results.
    Nutrition 02/2015; DOI:10.1016/j.nut.2015.02.004 · 3.05 Impact Factor

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