Beneficial effects of green tea: a literature review

Green Tea Liquid Consumption Alters the Human Intestinal and Oral Microbiome

SCOPE

GTPs (green tea polyphenols) exert anti-CRC (colorectal cancer) activity. The intestinal microbiota and intestinal colonization by bacteria of oral origin has been implicated in colorectal carcinogenesis. GT modulates the composition of mouse gut microbiota harmonious with anticancer activity. Therefore, the effect of green tea liquid (GTL) consumption on the gut and oral microbiome is investigated in healthy volunteers (n = 12).

METHODS AND RESULTS

16S sequencing and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis of both fecal and saliva samples (collected before intervention, after 2 weeks of GTL (400 mL per day) and after a washout period of one week) in healthy volunteers show changes in microbial diversity and core microbiota and difference in clear classification (partial least squares-discriminant analysis [PLS-DA]). An irreversible, increased FIR:BAC (Firmicutes to Bacteroidetes ratio), elevated SCFA producing genera, and reduction of bacterial LPS synthesis in feces are discovered in response to GTL. GTL alters the salivary microbiota and reduces the functional pathways abundance relevance to carcinogenesis. Similar bacterial networks in fecal and salivary microbiota datasets comprising putative oral bacteria are found and GTL reduces the fecal levels of Fusobacterium. Interestingly, both Lachnospiraceae and B/E (Bifidobacterium to Enterobacteriacea ratio-markers of colonization resistance [CR]) are negatively associated with the presence of oral-like bacterial networks in the feces.

CONCLUSION

These results suggest that GTL consumption causes both oral and gut microbiome alterations.

The impact of dietary habits on the pathogenesis of rheumatoid arthritis: a case-control study

It has not been clear what kinds and how much nutrients could be harmful, preventive, or healthful for development of rheumatoid arthritis. This study aimed to determine the impact of dietary habits on the pathogenesis of rheumatoid arthritis. This case-control study was conducted on a total of 500 rheumatoid arthritis patients and 500 healthy controls refereed to three clinics of Shiraz University of Medical Sciences in 2015-2016. Convenience sampling was used for data collection in both case and control groups. An approved valid and reliable questionnaire including information about the intake of different kinds of beverages, and nutritious and non-nutritious diet was used. Data were analyzed by SPSS, version 20, using t test, chi-square and Multiple Logistic Regression model. The associations between rheumatoid arthritis development and variables including drinking 1-7 cups of coffee (OR = .44, CI .25-.76), ≥ 8 cups of coffee (OR = .50, CI .28-.90), full-fat milk (OR = 1.01, CI 1.003-1.03) per month, and intake of green tea (OR = .65, CI .45-.93) and solid oils (OR = 2.29, CI:1.57-3.34) were significant. Based on the findings, coffee consumption more than one cup per month and green tea might have preventive effects on developing rheumatoid arthritis. On the other hand, patients who consumed more full-fat milk per month and solid oil might be at risk of development of rheumatoid arthritis. Therefore, modification of diet based on these findings is suggested. Performing a cohort study to determine the causality effect of dietary habits and development and prevention of rheumatoid arthritis is recommended.

Targeting Protein Quality Control Mechanisms by Natural Products to Promote Healthy Ageing

Organismal ageing is associated with increased chance of morbidity or mortality and it is driven by diverse molecular pathways that are affected by both environmental and genetic factors. The progression of ageing correlates with the gradual accumulation of stressors and damaged biomolecules due to the time-dependent decline of stress resistance and functional capacity, which eventually compromise cellular homeodynamics. As protein machines carry out the majority of cellular functions, proteome quality control is critical for cellular functionality and is carried out through the curating activity of the proteostasis network (PN). Key components of the PN are the two main degradation machineries, namely the ubiquitin-proteasome and autophagy-lysosome pathways along with several stress-responsive pathways, such as that of nuclear factor erythroid 2-related factor 2 (Nrf2), which mobilises cytoprotective genomic responses against oxidative and/or xenobiotic damage. Reportedly, genetic or dietary interventions that activate components of the PN delay ageing in evolutionarily diverse organisms. Natural products (extracts or pure compounds) represent an extraordinary inventory of highly diverse structural scaffolds that offer promising activities towards meeting the challenge of increasing healthspan and/or delaying ageing (e.g., spermidine, quercetin or sulforaphane). Herein, we review those natural compounds that have been found to activate proteostatic and/or anti-stress cellular responses and hence have the potential to delay cellular senescence and/or in vivo ageing.

Quantitative Analysis of Four Catechins from Green Tea Extract in Human Plasma Using Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry for Pharmacokinetic Studies

Green tea is consumed as a beverage worldwide and has beneficial effects, such as a lower risk of cardiovascular disease and cancer. A quantitative analysis of the beneficial components in plasma is important for understanding the potential health benefits of green tea. Four catechins—epigallocatechin-3-gallate (EGCG), epicatechin-3-gallate (ECG), epigallocatechin (EGC), and epicatechin (EC)—which account for the majority of the components of green tea, were analyzed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). In this study, a validated method was optimized to obtain the blood concentrations after the one-time ingestion of 630 mg green tea extract with digoxin and then after the ingestion of 630 mg green tea repeatedly for 15 days. The calibration curve, including the LLOQ, was constructed over 1–500 ng/mL for EGCG, ECG, and EGC and 0.1–50 ng/mL for EC. The method for inter- and intra-validation was applied, acceptable for both accuracy and precision. We successfully developed an appropriate UPLC-MS/MS method for human plasma with good reproducibility and sensitivity. Thus, this method could be applied for future preclinical and clinical studies on EGCG, ECG, EGC, and EC.

The Role of Catechins in Cellular Responses to Oxidative Stress

Catechins are polyphenolic compounds—flavanols of the flavonoid family found in a variety of plants. Green tea, wine and cocoa-based products are the main dietary sources of these flavanols. Catechins have potent antioxidant properties, although in some cases they may act in the cell as pro-oxidants. Catechins are reactive oxygen species (ROS) scavengers and metal ion chelators, whereas their indirect antioxidant activities comprise induction of antioxidant enzymes, inhibition of pro-oxidant enzymes, and production of the phase II detoxification enzymes and antioxidant enzymes. Oxidative stress and ROS are implicated in aging and related dysfunctions, such as neurodegenerative disease, cancer, cardiovascular diseases, and diabetes. Due to their antioxidant properties, catechins may be beneficial in preventing and protecting against diseases caused by oxidative stress. This article reviews the biochemical properties of catechins, their antioxidant activity, and the mechanisms of action involved in the prevention of oxidative stress-caused diseases.

Diabetes and Alzheimer's Disease: Can Tea Phytochemicals Play a Role in Prevention?

Dementia and diabetes mellitus are prevalent disorders in the elderly population. While recognized as two distinct diseases, diabetes has more recently recognized as a significant contributor to risk for developing dementia, and some studies make reference to type 3 diabetes, a condition resulting from insulin resistance in the brain. Alzheimer's disease, the most common form of dementia, and diabetes, interestingly, share underlying pathological processes, commonality in risk factors, and, importantly, pathways for intervention. Tea has been suggested to possess potent antioxidant properties. It is rich in phytochemicals including, flavonoids, tannins, caffeine, polyphenols, boheic acid, theophylline, theobromine, anthocyanins, gallic acid, and finally epigallocatechin-3-gallate, which is considered to be the most potent active ingredient. Flavonoid phytochemicals, known as catechins, within tea offer potential benefits for reducing the risk of diabetes and Alzheimer's disease by targeting common risk factors, including obesity, hyperlipidemia, hypertension, cardiovascular disease, and stroke. Studies also show that catechins may prevent the formation of amyloid-β plaques and enhance cognitive functions, and thus may be useful in treating patients who have Alzheimer's disease or dementia. Furthermore, other phytochemicals found within tea offer important antioxidant properties along with innate properties capable of modulating intracellular neuronal signal transduction pathways and mitochondrial function.

Development and validation of a simple and rapid UPLC method for the in-vitro estimation of (-)-epigallocatechin-3-gallate in lipid-based formulations

(-)-Epigallocatechin gallate (EGCG) is a catechin found in green tea that has potential health benefits, such as anti-oxidant, anti-carcinogenic and anti-inflammatory effects. A rapid and sensitive Ultra-Performance Liquid Chromatographic (UPLC) method was developed and validated for the estimation of (-)-epigallocatechin-3-gallate in lipid-based formulation. The UPLC method was conducted on C18 analytical column (50 mm × 2.1 mm, 1.8 μm particle size). The mobile phase consisted of a mixture of acetic acid (1%, v:v; pH = 3), acetonitrile and water at volume ratio of 13:15:72 delivered at a flow rate of 0.5 mL/min. The diode array detector (DAD) acquisition wavelength was set at wavelengths 210 and 280 nm. Caffeine was used as internal standard. The tested validation parameters, i.e., selectivity, linearity, accuracy, precision, and sensitivity (Limit of detection and limit of quantification) were determined at both wavelengths. Results revealed that caffeine and EGCG peaks were eluted at retention times of 0.55 and 0.85 minutes, respectively. The calibration curve was linear over the concentration range of 10-60 μg/mL, with coefficients of determination (r2) of 0.9993 and 0.9998 nm at 210 and 280 nm, respectively. All the validation parameters were found within the acceptable range. The proposed method was successfully applied for the quantitation of EGCG in lipid-based formulation and statistical analysis with a reported method showed no significant difference at p < 0.05. Therefore, the proposed analytical method for EGCG can be considered as a rapid, selective and accurate analytical method that can be used for the quantitative analysis of EGCG.

Herbal medicine for sports: a review

The use of herbal medicinal products and supplements has increased during last decades. At present, some herbs are used to enhance muscle strength and body mass. Emergent evidence suggests that the health benefits from plants are attributed to their bioactive compounds such as Polyphenols, Terpenoids, and Alkaloids which have several physiological effects on the human body. At times, manufacturers launch numerous products with banned ingredient inside with inappropriate amounts or fake supplement inducing harmful side effect. Unfortunately up to date, there is no guarantee that herbal supplements are safe for anyone to use and it has not helped to clear the confusion surrounding the herbal use in sport field especially. Hence, the purpose of this review is to provide guidance on the efficacy and side effect of most used plants in sport. We have identified plants according to the following categories: Ginseng, alkaloids, and other purported herbal ergogenics such as Tribulus Terrestris, Cordyceps Sinensis. We found that most herbal supplement effects are likely due to activation of the central nervous system via stimulation of catecholamines. Ginseng was used as an endurance performance enhancer, while alkaloids supplementation resulted in improvements in sprint and cycling intense exercises. Despite it is prohibited, small amount of ephedrine was usually used in combination with caffeine to enhance muscle strength in trained individuals. Some other alkaloids such as green tea extracts have been used to improve body mass and composition in athletes. Other herb (i.e. Rhodiola, Astragalus) help relieve muscle and joint pain, but results about their effects on exercise performance are missing.

Natural approaches in metabolic syndrome management

Metabolic syndrome (MetS) is characterized as a group of cardiometabolic risk factors that raise the risk for heart disease and other health problems, such as diabetes mellitus and stroke. Treatment strategies include pharmacologic interventions and supplementary (or "alternative") treatments. Nutraceuticals are derived from food sources (isolated nutrients, dietary supplements and herbal products) that are purported to provide health benefits, in addition to providing basic nutritional value. Nutraceuticals are claimed to prevent chronic diseases, improve health, delay the aging process, increase life expectancy, and support the structure and function of the body. The study of the beneficial effects of nutraceuticals in patients with MetS, including product standardization, duration of supplementation and definition of optimal dosing, could help better define appropriate treatment. This review focuses on widely marketed nutraceuticals (namely polyphenols, omega-3 fatty acids, macroelements and vitamins) with clinically demonstrated effects on more than one component of MetS.

Black Tea Samples Origin Discrimination Using Analytical Investigations of Secondary Metabolites, Antiradical Scavenging Activity and Chemometric Approach

A comprehensive study on the composition and antioxidant properties of black tea samples with a chemometric approach was performed via LC-ESI-Q-TOF-MS, DPPH radical scavenging assay, and Folin-Ciocalteu assay (TPC). Marked differences between the teas from seven different countries (China, India, Iran, Japan, Kenya, Nepal, Sri Lanka) were shown. The Indian samples demonstrated the highest total catechin content (184.8 mg/100 mL), the largest TPC and DPPH scavenging potential (58.2 mg/100 mL and 84.5%, respectively). The applied principal component analysis (PCA) and ANOVA revealed several correlations between the level of catechins in tea infusions. EC (epicatechin), ECG (epicatechin gallate), EGC (epigallocatechin), and EGCG (epigallocatechin-3-gallate) content was not correlated with DPPH, gallic acid, and TPC; however, a strong correlation of EC and ECG between themselves and a negative correlation of these two catechins with EGCG and EGC was noted. Interestingly, simple catechins were not found to be responsible for antioxidant properties of the black teas. The samples collected in the higher altitudes were similar.

Ethnopharmacological Approaches for Dementia Therapy and Significance of Natural Products and Herbal Drugs

Dementia is a clinical syndrome wherein gradual decline of mental and cognitive capabilities of an afflicted person takes place. Dementia is associated with various risk factors and conditions such as insufficient cerebral blood supply, toxin exposure, mitochondrial dysfunction, oxidative damage, and often coexisting with some neurodegenerative disorders such as Alzheimer's disease (AD), Huntington's disease (HD), and Parkinson's disease (PD). Although there are well-established (semi-)synthetic drugs currently used for the management of AD and AD-associated dementia, most of them have several adverse effects. Thus, traditional medicine provides various plant-derived lead molecules that may be useful for further medical research. Herein we review the worldwide use of ethnomedicinal plants in dementia treatment. We have explored a number of recognized databases by using keywords and phrases such as “dementia”, “Alzheimer's,” “traditional medicine,” “ethnopharmacology,” “ethnobotany,” “herbs,” “medicinal plants” or other relevant terms, and summarized 90 medicinal plants that are traditionally used to treat dementia. Moreover, we highlight five medicinal plants or plant genera of prime importance and discuss the physiological effects, as well as the mechanism of action of their major bioactive compounds. Furthermore, the link between mitochondrial dysfunction and dementia is also discussed. We conclude that several drugs of plant origin may serve as promising therapeutics for the treatment of dementia, however, pivotal evidence for their therapeutic efficacy in advanced clinical studies is still lacking.

Influence of Graded Levels of l-Theanine Dietary Supplementation on Growth Performance, Carcass Traits, Meat Quality, Organs Histomorphometry, Blood Chemistry and Immune Response of Broiler Chickens

l-theanine is a water-soluble non-proteinous amino acid mainly found in green tea leaves. Despite the availability of abundant literature on green tea, studies on the use of l-theanine as a feed additive in animals, and especially broilers are limited. The objective of this study was, therefore, to evaluate the effect of different dietary levels of l-theanine on meat quality, growth performance, immune response, and blood metabolites in broilers. A total of 400 day-old broiler chicks were randomly divided into four treatment groups using a completely randomized design; C-control, basal diet; 100LT-basal diet + 100 mg l-theanine/kg diet; 200LT-basal diet + 200 mg l-theanine/kg diet; and 300LT-basal diet + 300 mg l-theanine/kg diet. Results revealed that the intermediate level of l-theanine (200 mg/kg diet) showed better results in terms of body weight gain (BWG), feed consumed (FC), and feed conversion ratio (FCR) as compared with the other supplemented groups and the control. The live weight eviscerated weight and gizzard weight were higher in all l-theanine levels as compared to those of the control group. Increased weight (p ≤ 0.05) of spleen and bursa were found in group 200LT (200 mg l-theanine/kg diet). Concerning meat color parameters, values for yellowness (b*), and redness (a*) were greater in l-theanine-supplemented groups than the control. Supplementing broiler diet with l-theanine reduced (p = 0.02) total serum cholesterol contents while increased HDL. Further analysis revealed lower relative serum cytokines (IL-2 and INF-γ) and reduced mRNA expression of TNF-α and IL-6 in thymus, and IFN-γ and IL-2 in spleen in the treated group. Moreover, supplementation with 200 mg/kg of l-theanine improved antioxidant status in blood by increasing SOD, GSH-Px, and relative CAT levels. It is concluded that the optimum supplementation level of l-theanine is 200 mg/kg of diet because it resulted in improved performance parameters in broilers. However, higher levels of l-theanine (300 mg/kg diet) may have deleterious effects on performance and health of broiler chickens.

Molecular understanding of Epigallocatechin gallate (EGCG) in cardiovascular and metabolic diseases

ETHNOPHARMACOLOGICAL RELEVANCE

The compound epigallocatechin-3-gallate (EGCG), the major polyphenolic compound present in green tea [Camellia sinensis (Theaceae], has shown numerous cardiovascular health promoting activity through modulating various pathways. However, molecular understanding of the cardiovascular protective role of EGCG has not been reported.

AIM OF THE REVIEW

This review aims to compile the preclinical and clinical studies that had been done on EGCG to investigate its protective effect on cardiovascular and metabolic diseases in order to provide a systematic guidance for future research.

MATERIALS AND METHODS

Research papers related to EGCG were obtained from the major scientific databases, for example, Science direct, PubMed, NCBI, Springer and Google scholar, from 1995 to 2017.

RESULTS

EGCG was found to exhibit a wide range of therapeutic properties including anti-atherosclerosis, anti-cardiac hypertrophy, anti-myocardial infarction, anti-diabetes, anti-inflammatory and antioxidant. These therapeutic effects are mainly associated with the inhibition of LDL cholesterol (anti-atherosclerosis), inhibition of NF-κB (anti-cardiac hypertrophy), inhibition of MPO activity (anti-myocardial infarction), reduction in plasma glucose and glycated haemoglobin level (anti-diabetes), reduction of inflammatory markers (anti-inflammatory) and the inhibition of ROS generation (antioxidant).

CONCLUSION

EGCG shows different biological activities and in this review, a compilation of how this bioactive molecule plays its role in treating cardiovascular and metabolic diseases was discussed.

Evaluation of green tea extract as a safe personal hygiene against viral infections

Background

Viral infections often pose tremendous public health concerns as well as economic burdens. Despite the availability of vaccines or antiviral drugs, personal hygiene is considered as effective means as the first-hand measure against viral infections. The green tea catechins, in particular, epigallocatechin-3-gallate (EGCG), are known to exert potent antiviral activity. In this study, we evaluated the green tea extract as a safe personal hygiene against viral infections.

Results

Using the influenza virus A/Puerto Rico/8/34 (H1N1) as a model, we examined the duration of the viral inactivating activity of green tea extract (GTE) under prolonged storage at various temperature conditions. Even after the storage for 56 days at different temperatures, 0.1% GTE completely inactivated 10⁶ PFU of the virus (6 log₁₀ reduction), and 0.01% and 0.05% GTE resulted in 2 log₁₀ reduction of the viral titers. When supplemented with 2% citric acid, 0.1% sodium benzoate, and 0.2% ascorbic acid as anti-oxidant, the inactivating activity of GTE was temporarily compromised during earlier times of storage. However, the antiviral activity of the GTE was steadily recovered up to similar levels with those of the same concentrations of GTE without the supplements, effectively prolonging the duration of the virucidal function over extended period. Cryo-EM and DLS analyses showed a slight increase in the overall size of virus particles by GTE treatment. The results suggest that the virucidal activity of GTE is mediated by oxidative crosslinking of catechins to the viral proteins and the change of physical properties of viral membranes.

Conclusions

The durability of antiviral effects of GTE was examined as solution type and powder types over extended periods at various temperature conditions using human influenza A/H1N1 virus. GTE with supplements demonstrated potent viral inactivating activity, resulting in greater than 4 log₁₀ reduction of viral titers even after storage for up to two months at a wide range of temperatures. These data suggest that GTE-based antiviral agents could be formulated as a safe and environmentally friendly personal hygiene against viral infections.

Dietary Copper Reduces the Hepatotoxicity of (-)-Epigallocatechin-3-Gallate in Mice

We developed Cu-deficient, -sufficient and -super nutrition mice models by feeding them with diet containing 1.68, 11.72 or 51.69 mg of Cu/kg for 28 days, respectively. Then, the mice were treated to (−)-epigallocatechin-3-gallate (EGCG, 750 mg/kg BW) by oral in order to assess the acute toxicity of the drug. Following EGCG treatment, the survival rates were 12.5%, 50% and 100% in the Cu-deficient, -sufficient and Cu-super nutrition groups of mice, respectively. Cu level and ceruloplasmin activity in serum were significantly increased with the increase of dietary Cu. However, the Cu supplementation did not produce any obvious impact on serum superoxide dismutase activity. Furthermore, ceruloplasmin, in vitro, significantly promotes EGCG oxidation accompanied with increasing oxidation products and decreasing levels of reactive oxygen species. These results, therefore, suggest that Cu can relieve EGCG hepatotoxicity, possibly by up-regulating ceruloplasmin activity, which can be used to promote EGCG applications.

The effect of green tea ointment on episiotomy pain and wound healing in primiparous women: A randomized, double-blind, placebo-controlled clinical trial

The delayed healing of episiotomy wound and its associated pain is a major problem in obstetrics. Because green tea has analgesic and wound-healing properties, the present study was conducted to determine the effect of green tea ointment on episiotomy pain and wound-healing. The green tea extract was also standardized by measuring its Phenolic and flavonoid compounds, antioxidant activity, and one of its active components, that is, Epigallocatechin gallate. The present clinical trial was conducted on 99 primiparous women visiting Afzalipour Hospital in Kerman in 2015. The subjects were randomly divided into 3 groups, including a green tea ointment group, a placebo ointment group, and a routine care group. The 2 ointment groups smeared 2 cm of the green tea or placebo ointments onto their sutured area twice daily for a total of 10 days. The severity of pain was assessed in the subjects using the visual pain scale and wound-healing using the Redness, Edema, Ecchymosis, Discharge, Approximation (REEDA) scale before the intervention and on the 5th and 10th days after delivery. To standardize the extract, Epigallocatechin gallate was measured by high-performance liquid chromatography (HPLC). Phenolic and flavonoid compounds, as well as antioxidant activity of the extract were also determined by spectrometry methods. Before the intervention, no significant differences were observed between the 3 groups in terms of their personal and obstetric details (p > .05), the severity of pain (p = .118), and the REEDA score (p = .212). On the 5th and 10th days after delivery, the severity of pain was significantly lower in the green tea group than in the other 2 groups (p < .0001). The mean REEDA score on the 5th and 10th days showed a better and faster healing in the green tea group compared to the other 2 groups (p < .0001). Total content of phenolic and flavonoids contents of green tea were 74.2 mg/g Gallic acid equivalent and 16.3 mg/g Rutin equivalent, respectively, and its antioxidant capacity was 46% of b-carotene. Green tea ointment appears to be effective in relieving episiotomy pain and improving wound-healing in this study. Further studies are recommended to be conducted on the effectiveness and safety of the different doses of green tea ointment.

Herbal Therapy in Pregnancy-What to Expect when you Expect?

The use of herbal therapy in pregnancy is common for pregnancy related nausea, vomiting, gestational diabetes, anxiety, insomnia, and preparation for labor, as well as for treating infections. Many conventional drugs may interfere with fetal development and herbal products are considered to be safe. However, herbal therapy requires competent healthcare professional advice before prescribing. Knowledge about the possible adverse effects of active compounds of the herbs on pregnancy outcome is limited. Interference of herbal ingredients with conventional medication or the ailment should also not be excluded. For many herbal products, the pharmacological effect is not clinically proven, and the safe usage in pregnancy is not guaranteed. Here, based on published clinical trials, an overview is given of the efficacy and safety for fetal development and pregnancy outcome of the most frequently used herbs: ginger, cranberry, echinacea, mint, chamomile, valerian, flaxseed, tea and raspberry leaf.

Green tea (Camellia sinensis) and l-theanine: Medicinal values and beneficial applications in humans-A comprehensive review

Green tea (Camellia sinensis) is a famous herb, and its extract has been extensively used in traditional Chinese medicinal system. In this context, several studies have revealed its health benefits and medicinal potentialities for several ailments. With ever increasing scientific knowledge, search for safer, potential and novel type of health-related supplements quest, scientists are re-directing their research interests to explore natural resources i.e. medicinal herbs/plant derived compounds. Green tea consumption has gained a special attention and popularity in the modern era of changing lifestyle. The present review is aimed to extend the current knowledge by highlighting the importance and beneficial applications of green tea in humans for safeguarding various health issues. Herein, we have extensively reviewed, analyzed, and compiled salient information on green tea from the authentic published literature available in PubMed and other scientific databases. Scientific literature evidenced that owing to the bioactive constituents including caffeine, l-theanine, polyphenols/flavonoids and other potent molecules, green tea has many pharmacological and physiological functions. It possesses multi-beneficial applications in treating various disorders of humans. This review also provides in-depth insights on the medicinal values of green tea which will be useful for researchers, medical professionals, veterinarians, nutritionists, pharmacists and pharmaceutical industry. Future research emphasis and promotional avenues are needed to explore its potential therapeutic applications for designing appropriate pharmaceuticals, complementary medicines, and effective drugs as well as popularize and propagate its multidimensional health benefits.

Protective effects of tea polyphenols and β-carotene against γ-radiation induced mutation and oxidative stress in Drosophila melanogaster

Background

The commonly consumed antioxidants β-carotene and tea polyphenols were used to assess their protective effects against γ-radiation induced sex-linked recessive lethal (SLRL) mutation and oxidative stress in Drosophila melanogaster. Third instar larvae and adult males of wild-type Oregon-K (ORK) were fed on test agents for 24 and 72 h respectively before exposure to 10Gy γ-irradiation. The treated/control flies were used to assess the induction of SLRLs. We also evaluated antioxidant properties of these phytochemicals in the third instar larvae.

Results

Different stages of spermatogenesis in adult males showed a decrease in γ-radiation induced SLRL frequencies upon co-treatment with test agents. A similar trend was observed in larvae. Furthermore, a significant increase in antioxidant enzymatic activities with a decrease in malondialdehyde content was observed.

Conclusion

β-carotene and tea polyphenols have exerted antigenotoxic and antioxidant effects in Drosophila. This study demonstrated the suitability of Drosophila as an alternative to mammalian testing for evaluating the antigenotoxic and antioxidant activity of natural products.

Effects of chronic consumption of green tea on weight and body fat distribution of Wistar rats evaluated by computed tomography

Purpose:

To evaluate the effects of chronic consumption of green tea on body weight and distribution of visceral fat by Computed tomography in female Wistar rats.

Methods:

Wistar rats were divided into control group (n = 5), which received water and feed ad libitum, and green tea group (n = 8), in which water has been replaced by green tea. The animals were weighed weekly and Computed Tomography was used at the beginning (1st week) and end (18th week) of the experiment for evaluating the distribution of visceral fat. The animals were followed for 18 weeks.

Results:

There was no significant difference in body weight between the groups. However, there was significant difference in visceral fat area. The green tea group had less visceral fat area at the end of the experiment, 3.67 ± 1.2 cm2, while the control group showed an area of 6.25 ± 2.2 cm (p = 0.00).

Conclusions:

Chronic consumption of green tea leads to decreased visceral adipose tissue area.

Green Tea Extracts Epigallocatechin-3-gallate for Different Treatments

Epigallocatechin-3-gallate (EGCG), a component extracted from green tea, has been proved to have multiple effects on human pathological and physiological processes, and its mechanisms are discrepant in cancer, vascularity, bone regeneration, and nervous system. Although there are multiple benefits associated with EGCG, more and more challenges are still needed to get through. For example, EGCG shows low bioactivity via oral administration. This review focuses on effects of EGCG, including anti-cancer, antioxidant, anti-inflammatory, anticollagenase, and antifibrosis effects, to express the potential of EGCG and necessity of further studies in this field.

A Review of the Antiviral Role of Green Tea Catechins

Over the centuries, infectious diseases caused by viruses have seriously threatened human health globally. Viruses are responsible not only for acute infections but also many chronic infectious diseases. To prevent diseases caused by viruses, the discovery of effective antiviral drugs, in addition to vaccine development, is important. Green tea catechins (GTCs) are polyphenolic compounds from the leaves of Camelliasinensis. In recent decades, GTCs have been reported to provide various health benefits against numerous diseases. Studies have shown that GTCs, especially epigallocatechin-3-gallate (EGCG), have antiviral effects against diverse viruses. The aim of this review is to summarize the developments regarding the antiviral activities of GTCs, to discuss the mechanisms underlying these effects and to offer suggestions for future research directions and perspectives on the antiviral effects of EGCG.

[Brushing abrasion of the enamel surface after erosion]

Objective A study was conducted to compare the effect of different enamel remineralization periods after erosion on the depth of brushing abrasion. Methods Ten volunteers were selected for a 4-day experiment. A total of 60 enamels were randomly assigned into six groups (A-F) and placed in intraoral palatal devices. On the first day, the palatal devices were placed in oral cavity (24 h) . On the following three days, brushing experiments were performed extraorally, two times per day. The specific experimental method of brushing follows these next steps. First, the group F specimens were covered with a film of wax, and then acid etched for 2 min. Subsequently, the film of wax was detached. The groups from A to D were brushed after remineralization at the following time intervals: group A, 0 min; group B, 20 min; group C, 40 min; group D, 60 min. Erosion and remineralization were performed on group E, but without brushing. Remineralization was performed on group F, but without acid etching and brushing. The depth of enamel abrasion was determined by a mechanical profilometer. The surface morphology of the enamel blocks was observed using a scanning electron microscope. Results 1) The depth of abrasion was different in varied enamel remineralization time after acid etching. The statistical significant differences between groups were as follows. 2) When the time of enamel remineralization after acid etching was short, the surface depression in the electron microscope was deep, and the surface morphology was rough. Conclusion Brushing immediately after acid etching would cause much serious abrasion to the enamel surface. Brushing after 60 min can effectively reduce the abrasion of acid etching enamel.

Therapeutic benefits of green tea extract on various parameters in non-alcoholic fatty liver disease patients

BACKGROUND AND OBJECTIVE

NAFLD affecting up to 30% of the population globally. Drug treatment options are limited with disappointing results. The dietary supplementation in the form of green tea is another option. Our objective was toinvestigate the effect of Green tea extract (GTE) supplementation on various parameters innon-alcoholicfatty liver disease (NAFLD) patients.

METHODS

This study was conducted Dept. of Medicineof Sheikh Zayed Medical College/Hospital, Rahim Yar Khan from 15 April 2016 to 15 July 2016. Eighty overweight, non diabeticand dyslipidemic patients of NAFLD, diagnosed on the basis of ultrasound and aminotransferases level were randomized for treatmentwith capsule GTE500mg (n=40)and capsule placebo (n=40) twice a day for twelve weeks. Anthropometric parameters, liver enzymes, inflammatory markers and liver ultrasound imaging were estimated by SPSS-16 pre and post treatment.

RESULTS

As compared to placebo, GTE caused a significant improvement in body weight (29.5±3.8 to 27.2±3.2 kg/m2 p=0.03), BMI (86±10.5 to 80±12.4 kg p=0.026), HOMA-IR(4.32±2.25 to 3.16± 1.6 p=0.0081) lipid profile (i.e. TC: L242.5±20.5 to 215.4±18.6 mg/dl p=0.005; TG: 175±22.6 to145±18 mg/dlp=0.003; LDL-C:155±12.5 to 140±16.7 mg/dl p=0.011; HDL-C: 36.8±6.7 to46.4±5.8 mg/dl p =0.001, Aminotransferases (i.e. ALT: 70.4±15.8to52.8±12.2 IU/L p=0.04; AST: 65.8±12.4 to 44.3± 8.5U/L p =0.002) and Inflammatory markers (hs-CRP: 3.14±0.58 to 2.18±0.32 p =0.023 Adiponectin: 8.46±1.02 to 10.55±3.42μg/ml p =0.003)GTE also caused a 67.5% regression of fatty liver changes on ultrasound as compared to placebo which is 25%only.

CONCLUSION

GTEtherapy resulted in significant improvement in metabolic, chemical, inflammatory and radiological parameters of non-alcoholic fatty liver disease patients who were non-diabetic anddyslipidemic.

The Tea Tree Genome Provides Insights into Tea Flavor and Independent Evolution of Caffeine Biosynthesis

Tea is the world's oldest and most popular caffeine-containing beverage with immense economic, medicinal, and cultural importance. Here, we present the first high-quality nucleotide sequence of the repeat-rich (80.9%), 3.02-Gb genome of the cultivated tea tree Camellia sinensis. We show that an extraordinarily large genome size of tea tree is resulted from the slow, steady, and long-term amplification of a few LTR retrotransposon families. In addition to a recent whole-genome duplication event, lineage-specific expansions of genes associated with flavonoid metabolic biosynthesis were discovered, which enhance catechin production, terpene enzyme activation, and stress tolerance, important features for tea flavor and adaptation. We demonstrate an independent and rapid evolution of the tea caffeine synthesis pathway relative to cacao and coffee. A comparative study among 25 Camellia species revealed that higher expression levels of most flavonoid- and caffeine- but not theanine-related genes contribute to the increased production of catechins and caffeine and thus enhance tea-processing suitability and tea quality. These novel findings pave the way for further metabolomic and functional genomic refinement of characteristic biosynthesis pathways and will help develop a more diversified set of tea flavors that would eventually satisfy and attract more tea drinkers worldwide.

Exploring Anti-Prion Glyco-Based and Aromatic Scaffolds: A Chemical Strategy for the Quality of Life

Prion diseases are fatal neurodegenerative disorders caused by protein misfolding and aggregation, affecting the brain progressively and consequently the quality of life. Alzheimer’s is also a protein misfolding disease, causing dementia in over 40 million people worldwide. There are no therapeutics able to cure these diseases. Cellular prion protein is a high-affinity binding partner of amyloid β (Aβ) oligomers, the most toxic species in Alzheimer’s pathology. These findings motivate the development of new chemicals for a better understanding of the events involved. Disease control is far from being reached by the presently known therapeutics. In this review we describe the synthesis and mode of action of molecular entities with intervention in prion diseases’ biological processes and, if known, their role in Alzheimer’s. A diversity of structures is covered, based on glycans, steroids and terpenes, heterocycles, polyphenols, most of them embodying aromatics and a structural complexity. These molecules may be regarded as chemical tools to foster the understanding of the complex mechanisms involved, and to encourage the scientific community towards further developments for the cure of these devastating diseases.

The Effect of Isomaltulose Together with Green Tea on Glycemic Response and Antioxidant Capacity: A Single-Blind, Crossover Study in Healthy Subjects

Isomaltulose, a naturally-occurring isomer of sucrose, is commonly used as an alternative sweetener in foods and beverages. The goal of this study was to determine the effect of isomaltulose together with green tea on postprandial plasma glucose and insulin concentration, as well as antioxidant capacity in healthy subjects. In a randomized, single-blind, crossover study, 15 healthy subjects (eight women and seven men; ages 23.5 ± 0.7 years; with body mass index of 22.6 ± 0.4 kg/m²) consumed five beverages: (1) 50 g sucrose in 400 mL water; (2) 50 g isomaltulose in 400 mL of water; (3) 400 mL of green tea; (4) 50 g sucrose in 400 mL of green tea; and (5) 50 g isomaltulose in 400 mL of green tea. Incremental area under postprandial plasma glucose, insulin, ferric reducing ability of plasma (FRAP) and malondialdehyde (MDA) concentration were determined during 120 min of administration. Following the consumption of isomaltulose, the incremental 2-h area under the curve (AUC_{0-2 h}) indicated a higher reduction of postprandial glucose (43.4%) and insulin concentration (42.0%) than the consumption of sucrose. The addition of green tea to isomaltulose produced a greater suppression of postprandial plasma glucose (20.9%) and insulin concentration (37.7%). In accordance with antioxidant capacity, consumption of sucrose (40.0%) and isomaltulose (28.7%) caused the reduction of green tea-induced postprandial increases in FRAP. A reduction in postprandial MDA after drinking green tea was attenuated when consumed with sucrose (34.7%) and isomaltulose (17.2%). In conclusion, green tea could enhance the reduction of postprandial glucose and insulin concentration when consumed with isomaltulose. In comparison with sucrose, isomaltulose demonstrated less alteration of plasma antioxidant capacity after being consumed with green tea.

The Impact of Green Tea Supplementation on Anthropometric Indices and Inflammatory Cytokines in Women with Polycystic Ovary Syndrome

The present study aimed to determine the effect of a green tea supplement on anthropometric indices and inflammatory factors in women with polycystic ovary syndrome (PCOS). In this randomized clinical trial, 45 women with PCOS were randomly allocated into two groups receiving green tea tablets or placebo. The period of intervention was 45 days. The serum levels of interleukin 6, high-sensitivity C-reactive protein, and tumor necrosis factor α were measured before and after intervention period using the related kits. Anthropometric indices also were measured. The mean of body mass index, weight, waist circumference, and body fat percentage in the green tea group were reduced significantly. However, no significant difference was observed between the two groups. Also, there was no significant effect on the levels of inflammatory factors. The present results suggest that daily consumption of green tea tablets did not cause any effect on inflammation biomarkers in PCOS women. However, it may be effective as a complementary treatment for weight control in these women. Copyright © 2017 John Wiley & Sons, Ltd.

Formation and Characterization of Green Tea Extract Loaded Liposomes

Green tea extract was encapsulated into liposomes to enhance bioavailability and stability of catechins by protecting their functional properties simultaneously. Encapsulation was achieved by dispersing 1% (w/v) soy lecithin through high pressure homogenization (microfluidization) and ultrasonication. Effects of homogenization type and pH of the dispersing medium on the physical properties and stability of the liposomes during 1-mo storage period were investigated. Mean particle size, total phenolic content by Folin-Ciocalteu method and antioxidant activity by 2-diphenyl-1-picrylhydrazyl radical scavenging and ferric reducing-antioxidant power methods, and transmission electron microscopy (TEM) experiments were conducted for characterization. Green tea extract loaded liposomes prepared by microfluidization in distilled water were determined as the most stable system which demostrated no significant difference (P > 0.05) on mean particle size, total phenolic content, and antioxidant activity between the first and final day of 1-mo storage time. Additionally, uniform size and shape in TEM images supported the results.

Molecular Mechanisms and Metabolomics of Natural Polyphenols Interfering with Breast Cancer Metastasis

Metastatic cancers are the main cause of cancer-related death. In breast primary cancer, the five-year survival rate is close to 100%; however, for metastatic breast cancer, that rate drops to a mere 25%, due in part to the paucity of effective therapeutic options for treating metastases. Several in vitro and in vivo studies have indicated that consumption of natural polyphenols significantly reduces the risk of cancer metastasis. Therefore, this review summarizes the research findings involving the molecular mechanisms and metabolomics of natural polyphenols and how they may be blocking breast cancer metastasis. Most natural polyphenols are thought to impair breast cancer metastasis through downregulation of MMPs expression, interference with the VEGF signaling pathway, modulation of EMT regulator, inhibition of NF-κB and mTOR expression, and other related mechanisms. Intake of natural polyphenols has been shown to impact endogenous metabolites and complex biological metabolic pathways in vivo. Breast cancer metastasis is a complicated process in which each step is modulated by a complex network of signaling pathways. We hope that by detailing the reported interactions between breast cancer metastasis and natural polyphenols, more attention will be directed to these promising candidates as effective adjunct therapies against metastatic breast cancer in the clinic.

Identification of transcripts involved in digestion, detoxification and immune response from transcriptome of Empoasca vitis (Hemiptera: Cicadellidae) nymphs

Tea production has been significantly impacted by the false-eye leafhopper, Empoasca vitis (Göthe), around Asia. To identify the key genes which are responsible for nutrition absorption, xenobiotic metabolism and immune response, the transcriptome of either alimentary tracts or bodies minus alimentary tract of E. vitis was sequenced and analyzed. Over 31 million reads were obtained from Illumina sequencing. De novo sequence assembly resulted in 52,182 unigenes with a mean size of 848nt. The assembled unigenes were then annotated using various databases. Transcripts of at least 566 digestion-, 224 detoxification-, and 288 immune-related putative genes in E. vitis were identified. In addition, relative expression of highly abundant transcripts was verified through quantitative real-time PCR. Results from this investigation provide genomic information about E. vitis, which will be helpful in further study of E. vitis biology and in the development of novel strategies to control this devastating pest.

Both Phenolic and Non-phenolic Green Tea Fractions Inhibit Migration of Cancer Cells

Green tea consumption is associated with chemoprevention of many cancer types. Fresh tea leaves are rich in polyphenolic catechins, which can constitute up to 30% of the dry leaf weight. While the polyphenols of green tea have been well investigated, it is still largely unknown, whether or not non-phenolic constituents also reveal chemopreventive and anti-metastatic effects. In this study, we investigated the effects of a fraction of green tea rich in phenolic compounds (PF), a non-phenolic fraction (NPF), which contains glyceroglycolipids (GGL), and a pure glyceroglycolipid compound isolated from the non-phenolic fraction in human cancer. Dried green tea leaves were extracted and applied to a Sephadex LH-20 column. The resazurin reduction assay was used to investigate the cytotoxicity of green tea samples toward human HepG2 hepatocellular carcinoma and normal AML12 hepatocytes cells. Gene expression profiling was performed by mRNA microarray hybridization and the microarray results were validated by RT-PCR. The scratch migration assay was used to investigate the effects of green tea samples on cell migration in vitro. The changes of microtubule dynamics were observed using fluorescence microscopy. PF and NPF were prepared from methanol extract of green tea. A GGL was isolated from NPF. All three green tea samples did not show significant cytotoxic activity up to 10 μg/mL in both HepG2 and AML12 cells, whereas cytotoxicity of the control drug doxorubicin was observed with both cell lines (IC₅₀ on AML12: 0.024 μg/mL, IC₅₀ on HepG2: 2.103 μg/mL). We identified three sets of genes differentially expressed upon treatment with the green tea samples. The genes were associated with cytoskeleton formation, cellular movement, and morphology. The correlation coefficients between mRNA expression values determined by microarray and RT-PCR were R = 0.94. HepG2 and U2OS cells treated with green tea extracts showed the delayed closures. Besides, the number of distinct tubulin filaments decreased upon treatment with green tea samples. We identified not only PF, but also glyceroglycolipids in NPF as contributing factors to the chemopreventive effects of green tea. Both PF and NPF of green tea inhibited cancer cell migration by the disassembly of microtubules, even though they were not cytotoxic.

Green tea and exercise interventions as nondrug remedies in geriatric patients with rheumatoid arthritis

This study aimed to evaluate the effects of green tea and supervised exercise training interventions on improvement of disease activity and bone metabolism markers in rheumatoid arthritis patients. [Subjects and Methods] One-hundred and twenty subjects who had a mean age of (60.7 ± 2.53 years) and had been diagnosed with rheumatoid arthritis at least ten years previously were randomly included in this study. Patients were treated with infliximab, green tea, or a supervised exercise program for six months. Disease activity markers as well as antioxidant activity of green tea extracts were estimated before supplementation using in vitro assays. [Results] Rheumatoid arthritis patients treated with green tea for 6 months alone or in combination with infliximab or an exercise program showed significant improvement in disease activity parameters, including C-reactive protein, and erythrocyte sedimentation rate, swollen and tender joints counts, and modified Stanford Health Assessment Questionnaire score, along with an increase in serum levels of bone resorption markers, i.e., deoxypyridinoline, amino-terminal telopeptide of type 1 collagen, and bone alkaline phosphatase, at 6 months of after initial treatment. The European League Against Rheumatism and American College of Rheumatology scores revealed more clinical improvement in the disease activity of rheumatoid arthritis patients treated with green tea along with exercise compared with rheumatoid arthritis patients treated with infliximab or exercise combinations. This may have been due to the higher potential antioxidant activity of green tea (89.6% to 96.5%). [Conclusion] Both exercise and green tea interventions appeared to be beneficial as nondrug modulates for rheumatoid arthritis disorders.

Potential of Camellia sinensis proanthocyanidins-rich fraction for controlling malaria mosquito populations through disruption of larval development

BACKGROUND

Anopheles arabiensis and A. gambiae (sensu stricto) are the most prolific Afrotropical malaria vectors. Population control efforts of these two vectors have been hampered by extremely diverse larval breeding sites and widespread resistance to currently available insecticides. Control of mosquito larval stages using bioactive compounds of plant origin has the potential to suppress vector populations leading to concomitant reduction in disease transmission rates. In this study, we evaluated the efficacy of Camellia sinensis crude leaf extract and its fraction against the larvae of A. arabiensis and A. gambiae (s.s.).

METHODS

Late third/early fourth instar larvae (L3/L4) of A. arabiensis and A. gambiae (s.s.) were exposed to increasing doses of C. sinensis leaf extract and its active fraction for 72 h, with mortality rates recorded every 24 h in both control and test groups. Ultra performance liquid chromatography electron spray ionization quadruple time of flight coupled with mass spectrometry (UPLC/ESI-Qtof/MS) was used to determine the main active constituents in the fraction.

RESULTS

The major bioactive chemical constituents in the C. sinensis leaf extract were identified to be proanthocyanidins. The extract significantly interfered with larval survival and adult emergence in both species (ANOVA, F _(5,24) = 1435.92, P < 0.001). Additionally, larval exposure to crude extract at 250 ppm and 500 ppm for 24 h resulted in larval mortality rates of over 90 % in A. gambiae (s.s.) and 75 % in A. arabiensis. A relatively lower concentration of 100 ppm resulted in moderate mortality rates of < 50 % in both species, but induced growth disruption effects evident as abnormal larval-pupal intermediates and disrupted adult emergence. The estimated LC₅₀ concentrations of the crude leaf extract against A. arabiensis and A. gambiae (s.s.) larvae at 24 h were 154.58 ppm (95 % CI: 152.37-158.22) and 117.15 ppm (95 % CI: 112.86-127.04), respectively. The bioactive polar fraction caused 100 % larval mortality in both vector species at 25 ppm.

CONCLUSIONS

Our findings demonstrate the potential of green tea extract and its active constituents in disrupting mosquito larval development. This could contribute to the control of mosquito populations and improved management of malaria.

A green tea-containing starch confection increases plasma catechins without protecting against postprandial impairments in vascular function in normoglycemic adults

Postprandial hyperglycemia (PPH) increases cardiovascular disease risk regardless of glucose intolerance by transiently impairing vascular endothelial function (VEF) by limiting nitric oxide bioavailability in an oxidative stress-dependent manner. Preclinical studies show that green tea catechins attenuate PPH by inhibiting starch digestion. We hypothesized that a starch-based confection containing catechin-rich green tea extract (GTE) would limit PPH-mediated impairments in VEF in normoglycemic adults. We formulated a unique GTE confection and then conducted a double-blind, randomized, controlled, crossover study in healthy men (n = 15; 25.3 ± 1.0 years; 22.4 ± 1.8 kg m(-2)) in which they ingested starch confections (50 g carbohydrate) formulated with or without GTE (1 g) prior to evaluating sensory characteristics of confections and plasma glucose, biomarkers of lipid peroxidation and nitric oxide homeostasis, and brachial artery flow-mediated dilation (FMD) at 30 min intervals for 3 h. Sensory evaluation of confections indicated acceptable consumer appeal and an inability to distinguish between confections regardless of GTE. Plasma catechins concentrations increased following ingestion of the GTE confection. However, plasma glucose peaked at 60 min (P < 0.05) following confection ingestion and was unaffected throughout the postprandial period by the GTE confection (P > 0.05). FMD was significantly decreased only at 60 min regardless of confections containing GTE. Also at 60 min, both confections similarly increased plasma malondialdehyde while decreasing arginine and increasing asymmetric dimethylarginine/arginine. The successfully formulated GTE-containing confection effectively delivered catechins, but without mitigating PPH-mediated impairments in VEF in association with oxidative stress that likely limits nitric oxide bioavailability.

Epigallocatechin gallate affects glucose metabolism and increases fitness and lifespan in Drosophila melanogaster

In this study, we tested whether a standardized epigallocatechin-3-gallate (EGCG) rich green tea extract (comprising > 90% EGCG) affects fitness and lifespan as well as parameters of glucose metabolism and energy homeostasis in the fruit fly, Drosophila melanogaster. Following the application of the green tea extract a significant increase in the mean lifespan (+ 3.3 days) and the 50% survival (+ 4.3 days) as well as improved fitness was detected. These effects went along an increased expression of Spargel, the homolog of mammalian PGC1α, which has been reported to affect lifespan in flies. Intriguingly, in flies, treatment with the green tea extract decreased glucose concentrations, which were accompanied by an inhibition of α-amylase and α-glucosidase activity. Computational docking analysis proved the potential of EGCG to dock into the substrate binding pocket of α-amylase and to a greater extent into α-glucosidase. Furthermore, we demonstrate that EGCG downregulates insulin-like peptide 5 and phosphoenolpyruvate carboxykinase, major regulators of glucose metabolism, as well as the Drosophila homolog of leptin, unpaired 2. We propose that a decrease in glucose metabolism in connection with an upregulated expression of Spargel contribute to the better fitness and the extended lifespan in EGCG-treated flies.