Antioxidants of the beverage tea in promotion of human health

Effects of green tea on lipid profile in overweight and obese women

The effect of green tea administration on serum lipids' concentrations remains unclear as various investigations, which have explored this topic, have produced conflicting results. Gender might be one of the factors influencing the impact of green tea on the lipid profile. Hence, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the effect of green tea intake on the lipid profile in overweight and obese women. We searched five databases (Web of Science, SCOPUS, Embase, PubMed/Medline, and Google Scholar) using a combination of MeSH and non-MeSH terms. Results were expressed as weighted mean differences (WMDs) and 95% confidence intervals (CIs) and synthesized with a random-effects model. In total, 15 eligible RCTs with 16 arms (1818 participants) were included in the meta-analysis. The combined effect size revealed a significant reduction in total cholesterol (TC) (WMD: -4.45 mg/dl, 95% CI: -6.63, -2.27, P<0.001) and low-density lipoprotein cholesterol (LDL-C) (WMD: -4.49 mg/dl, 95% CI: -7.50 to -1.47, P=0.003) concentrations following green tea supplementation in overweight and/or obese women. In addition, a more pronounced reduction of triglyceride (TG) levels occurred when the baseline TG value was ≥150 mg/dL (WMD: -24.45 mg/dL, 95% CI: -40.63 to -8.26, P=0.003). Moreover, a significant decrease in TG concentrations occurred in RCTs conducted on overweight subjects (BMI: 25-29.99 kg/m2) (WMD: -5.88 mg/dl, 95% CI: -10.76 to -0.99, P=0.01). In the subgroup analyses based on the study population, a notable increase in high-density lipoprotein cholesterol (HDL-C) values was observed in obese individuals (>30 kg/m2) (WMD: 2.63 mg/dl, 95% CI: 0.10 to 5.16, P=0.041). Consumption of green tea causes a reduction in LDL-C and TC concentrations in overweight and obese women. The decline in TG levels was notable particularly in overweight patients with hypertriglyceridemia at baseline. In addition, a significant increase in HDL-C was detected in obese subjects following intake of green tea.

Investigating the antidepressant effect of Ziyan green tea on chronic unpredictable mild stress mice through fecal metabolomics

Introduction

Some studies have shown the effectiveness of tea in reducing depression. Gut flora dysfunction is strongly associated with depression. The mechanism by which Ziyan green tea ameliorates depression is not clear.

Methods

In this study, we examined the impact of Ziyan green tea on mice exhibiting symptoms similar to depression. We specifically focused on the role of intestinal flora and its metabolites. We first established a chronic unpredictable mild stress (CUMS) mouse model to induce depressive symptoms and conducted behavioural tests, biochemical tests, and pathological tissue analysis. We also investigated gut microbiota changes by 16S rRNA sequencing and measured faecal metabolites in mice using UHPLC-MS/MS.

Results

The results showed that Ziyan green tea intervention improved depression-like behaviour, neurobiochemical factors, and reduced levels of pro-inflammatory factors in CUMS mice. Spearman's correlation analysis showed that different microbial communities (Corynebacterium, Faecalibaculum, Enterorhabdus, Desulfovibrio) correlation with differential metabolites (Cholic acid, Deoxycholic acid, etc.) and depression-related biochemical indicators (5-HT, DA, BDNF, IL-6, and TNF-α).

Discussion

In conclusion, our findings suggest that both low and high-dose interventions of Ziyan green tea have positive preventive effects on CUMS mice without dose dependence, partly because they mainly affect intestinal Purine Metabolism, Bile Acid Biosynthesis and Cysteine Metabolism in CUMS mice, thus stimulating brain 5-HT, DA and BDNF, and decreasing the inflammatory factors IL-6, TNF-α, activate the composition of intestinal flora, improve the intestinal flora environment and thus promote the production of intestinal metabolites, which can be used for depression treatment. It is suggested that Ziyan green tea may achieve an antidepressant effect through the gut-microbiota-brain axis.

Changes in the Bio-Compounds and Biological Activities of Eight Whole Grains Fermentation Starter with Different Oxidized Chin-Shin Oolong Teas

Chin-shin oolong tea is the most widely planted variety in Taiwan. This study fermented eight whole grains fermentation starter (EGS) with light (LOT), medium (MOT), and fully (FOT) oxidized Chin-shin oolong teas for ten weeks. Comparing the three fermentation beverages, it was found that LOT fermentation can obtain the highest catechins (1644.56 ± 60.15 ppm) among the functional and antioxidant components. MOT can obtain the highest glucuronic acid (19,040.29 ± 2903.91 ppm), tannins, total phenols, flavonoids, and angiotensin-converting enzyme (ACE) inhibitory activity. FOT can obtain the highest GABA (1360.92 ± 123.24 ppm). In addition, both the LOT and MOT showed a significant increase in their ability to scavenge DPPH radicals after fermentation. EGS fermented with lightly or moderately oxidized Chin-shin oolong tea may be considered a novel Kombucha.

Comparison and Risk Assessment of Macroelements and Trace Metals in Commercial Teas from Different Regions of China

Tea (Camellia sinensis L.) is one of the most widely consumed non-alcoholic beverages worldwide. In the present study, 73 commercial tea samples were collected from tea plantations in the Southwest, South, Jiangnan, and Jiangbei regions of China. The contents of four macroelements (phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg)) and 15 trace metals (arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), lead (Pb), zinc (Zn), aluminium (Al), copper (Cu), manganese (Mn), iron (Fe), nickel (Ni), thorium (Th), thallium (Tl), rubidium (Rb) and barium (Ba)) in tea samples were determined. The mean concentrations of As, Cd, Cr, Hg, Pb, Zn, Al, Cu, Mn, Fe, Ni, Th, Tl, Rb and Ba were in the range of 0.02-0.61, 0.008-0.126, 0.09-1.12, 0.001-0.012, 0.07-1.62, 19.5-73.2, 170-2100, 5.9-43.3, 228-2040, 60-337, 2.09-17.95, 0.002-0.08, 0.004-0.409, 0-150.50 and 3.1-41.2 µg/g, respectively, which were all lower than the maximum permissible limits stipulated by China (NY/T 288-2012, NY 659-2003). The target hazard quotients of each heavy metal were lower than one, and the combined risk hazard index of all heavy metals for adults was in the range of 0.10-0.85; therefore, there was no significant carcinogenic health risks to tea drinking consumers under the current dietary intake. Significant differences were found in the content of trace elements (Zn, Cu, Fe, Ni, Th, Tl, Rb and Ba) (p < 0.05); however, no significant differences were found in the content of macroelements (P, K, Ca and Mg) and trace metals (As, Cd, Cr, Hg, Pb, Al and Mn) in teas from different regions. Therefore, the region did not affect the heavy metal exposure risk. Correlation coefficient and principal component analyses were performed to determine the source of the elements. Three principal factors were obtained: factor 1 was positively related to Ca, Mg, As, Cd, Cr, Hg, Pb, Al, Mn, Fe and Th (32.63%); factor 2 to P, Zn, Cu and Ni (18.64%) and factor 3 to K and Rb (10.10%). Thus, the elements in the same factor might originate from the same source. This study provides an essential basis to understand the variance and potential risks of different elements in tea from different regions of China.

Major chemical carcinogens and health exposure risks in some therapeutic herbal plants in Nigeria

People of all ages and genders utilize herbal medicine to treat varieties of problems all around the world. The accumulation of Cd and Cr in therapeutic herbs (Adansonia digitata, Psidium guajava, and Carica papaya) can lead to a variety of health complications. These leaf extracts are used to treat varieties of ailments, including cancer, in the northern Nigerian states of Borno, Jigawa, and Kano. The researchers employed high-resolution continuous source atomic absorption spectrometry. The statistical parameters such as mean, range, minimum and maximum were computed along with one-way analysis of variance (ANOVA) to assess activity concentrations of Major Chemical Carcinogens (MCCs) in the herb extracts from the three states. The result demonstrated substantial statistical variation in the concentration of Chromium between groups with C. papaya (F = 190.683, p = 0.000), P. guajava (F = 5.698, p = 0.006), A. digitata (F = 243.154, p = 0.000). The post hoc test revealed that the C. papaya and A. digitata observed concentrations were statistically significant across the three states (p = 0.000). It was observed that there is no statistically significant difference between concentrations of the extracts between Kano and Borno states for P. guajava (p = 0.686). For Cd, the one-way ANOVA showed significant statistically variation in the concentration between groups with C. papaya (F = 77.393, p = 0.000), P. guajava (F = 4.496, p = 0.017), A. digitata (F = 69.042, p = 0.000). The post hoc test with multiple comparisons revealed that the activity concentration of all extracts was statistically significant across the three states (p<0.05). The target risk quotient (THQ) for Cd was more than unity in A. digitata and C. papaya, except for P. guajava from Borno State. The probable cancer risk was observed for consumption of plant extracts as a result of Cr and Cd.

Different associations of specific non-alcoholic beverages with elevated high-sensitivity C-reactive protein in Korean adults: results from the Korea National Health and Nutrition Examination Survey (2015-2016)

This study examined the associations between specific non-alcoholic beverages and high-sensitivity C-reactive protein (hs-CRP) and their interactions with obesity. The study participants were 4,999 adults aged 19-64 years from the 2015-2016 Korean National Health and Nutrition Examination Survey. The odds ratios (ORs) and 95% confidence intervals (CIs) were obtained using multivariable logistic regression analyses. In women, there was an inverse linear trend between coffee and hs-CRP status (p trend = 0.0137), and a positive linear trend for soda was also found (≥1/week vs never or almost never, OR = 1.79, 95% CI 1.23-2.61, p trend = 0.0127). In the stratification analyses, the associa-tions were only observed in obese women. The associations were inverse for coffee and tea but linearly positive for soda in obese women (p trend<0.05). In men, an inverted J-shaped association between commercial fruit juice/drink and hs-CRP status was found; but after stratification by obesity, the association was linear only in obese men (p trend<0.05, OR = 2.44, 95% CI 1.44-4.16 in ≥1/week vs never or almost never). Coffee and tea in women may be beneficially associated with hs-CRP status, but soda in women and commercial fruit juice/drink in men may be adversely, particularly for obese adults.

Relationship between Regular Green Tea Intake and Osteoporosis in Korean Postmenopausal Women: A Nationwide Study

Mixed results have been reported regarding whether habitual tea intake affects bone health. This study investigated the relationship between green tea intake and bone mineral density (BMD) in postmenopausal Korean women. We used data from the Korean National Health and Nutrition Examination Surveys from 2008 to 2011 and divided the participants into three groups according to their frequency of green tea intake over the past 12 months. BMD of the lumbar spine, total femur, and femur neck was measured using dual-energy X-ray absorptiometry. The odds ratios (ORs) and 95% confidence intervals (CIs) of osteoporosis and osteopenia according to green tea consumption were analyzed. Participants who did not consume green tea or consumed less than one cup per day were more likely to have osteopenia of the lumbar spine or femur than those who consumed it once to three times a day (OR 1.81 and 1.85, 95% CI, 1.20–2.71; and 1.23–2.77). Moreover, ORs for osteoporosis were 1.91 (95% CI 1.13–3.23) and 1.82 (95% CI 1.09–3.05) in non-consumers and consumers who drank less than one cup per day, respectively, compared with the reference group. These results support that green tea consumption may have benefits on bone health.

Understanding the Role and Uses of Alternative Therapies for Management of Rheumatoid Arthritis

With growing popularity of complementary and alternative medicine (CAM) among the individuals with chronic pain and muscular problems, a number of patients with rheumatoid arthritis (RA) show their interest in CAM interventions for disease improvement. Various reports published on CAM are based on animal model of RA however there is often lack of high quality clinical investigations for explaining the success stories of CAM therapies in patients with RA. CAMs having potential to be used for therapy in patients with RA have been identified, however lack of awareness and scepticism of their efficacy has made the patients reluctant to choose these drug less therapies. In this review, we have summarized the existing evidences which suggest promising efficacy of different alternative therapies in managing RA and providing both physical and mental well being to RA patients.

Beneficial Effects of Green Tea Catechins on Female Reproductive Disorders: A Review

Tea is one of the most widely consumed beverages worldwide after water, and green tea accounts for 20% of the total tea consumption. The health benefits of green tea are attributed to its natural antioxidants, namely, catechins, which are phenolic compounds with diverse beneficial effects on human health. The beneficial effects of green tea and its major bioactive component, (-)-epigallocatechin-3-gallate (EGCG), on health include high antioxidative, osteoprotective, neuroprotective, anti-cancer, anti-hyperlipidemia and anti-diabetic effects. However, the review of green tea's benefits on female reproductive disorders, including polycystic ovary syndrome (PCOS), endometriosis and dysmenorrhea, remains scarce. Thus, this review summarises current knowledge on the beneficial effects of green tea catechins on selected female reproductive disorders. Green tea or its derivative, EGCG, improves endometriosis mainly through anti-angiogenic, anti-fibrotic, anti-proliferative and proapoptotic mechanisms. Moreover, green tea enhances ovulation and reduces cyst formation in PCOS while improving generalised hyperalgesia, and reduces plasma corticosterone levels and uterine contractility in dysmenorrhea. However, information on clinical trials is inadequate for translating excellent findings on green tea benefits in animal endometriosis models. Thus, future clinical intervention studies are needed to provide clear evidence of the green tea benefits with regard to these diseases.

Efficacy of Arabic Coffee and Black Tea in Reducing Halitosis: A Randomized, Double-Blind, Controlled, Crossover Clinical Trial

The aim of the study was to objectively evaluate the short-term effect of Arabic coffee and black tea on oral halitosis. This study was a single-center, randomized, double-blind, placebo-controlled, crossover clinical trial on 17 healthy individuals. During the initial visit, pre-treatment breath samples were collected from each subject and analyzed using portable gas chromatography (OralChroma™). Four interventions were evaluated, with Arabic coffee and black tea as the test intervention tools, mouthwash containing a solution (0.05% chlorhexidine, 0.05% cetylpyridinium chloride, and 0.14% zinc lactate (CHX-CPC-Zn)) as a positive control, and drinking water as a negative control. Halitosis was induced by rinsing with 10 mL solution of L-cysteine for 30 s. Twenty minutes later, a breath sample was taken to record the baseline volatile sulfur compounds (VSC) levels (T0). Then, the participants were asked to rinse with 10 mL of a randomly-assigned solution for 30 s. Sixty minutes later, another breath sample was recorded (T1). Finally, after 120 min, the final breath sample was recorded (T2). It was found that rinsing with Arabic coffee decreased the level of H2S both in the first hour (T1) and the second hour (T2). The reduction was significantly greater at T1 (p = 0.017). There was a similar result after the volunteers rinsed with black tea. At T2, Arabic coffee showed a substantially greater reduction in H2S (p < 0.001). On the contrary, using CHX-CPC-Zn showed a significant and continuous decrease in H2S values in the breath throughout the experiment (p < 0.001). Water showed no significant impact on the level of VSC (p = 0.71). This study demonstrates that black tea and Arabic coffee had inhibitory effects on halitosis that was greater in the first hour and was not sustained over a long period. Additionally, Arabic coffee had a greater inhibitory effect on halitosis than black tea.

Tea Consumption and Depression from Follow Up in the Singapore Longitudinal Ageing Study

OBJECTIVES

Experimental evidence suggest that tea polyphenols have anti-depressant effect and tea consumption may reduce the risk and severity of depression. We investigated whether tea consumption was associated with changes in depressive symptoms over time among Asian older adults.

DESIGN

Population-based prospective cohort study with mean 4 years of follow up.

SETTING

Singapore Longitudinal Ageing Study (SLAS) of community-living older persons.

PARTICIPANTS

3177 participants overall (mean age 67 years) and 3004 participants who were depression-free at baseline.

MEASUREMENTS

Baseline tea consumption which include Chinese (black, oolong or green) tea or Western (mixed with milk) tea and change in Geriatric Depression Scale (GDS) measure of depression. Incident depression was defined by GDS≥5, and GDS depression improvement or deterioration by GDS change of ≥4 points. Estimated odds ratio and 95% confidence intervals (OR, 95%CI) were adjusted for baseline age, sex, ethnicity, education, housing type, single/divorced/widowed, living alone, physical and social activity, smoking, alcohol, number of comorbidities, MMSE, and baseline GDS level.

RESULTS

Compared to non-tea drinkers, participants who consumed ≥3 cups of tea of all kinds were significantly less likely to have worsened GDS symptoms: OR=0.32, 95% CI=0.12, 0.84. Among baseline depression-free participants, the risk of incident GDS (≥5) depression was significantly lower (OR=0.34, 95%CI=0.13, 0.90) for daily consumption of all types of tea, and Chinese (black, oolong or green) tea (OR=0.46, 95%CI=0.21,0.99).

CONCLUSION

This study suggests that tea may prevent the worsening of existing depressive symptoms and the reduce the likelihood of developing threshold depression.

Flavonoids from duckweeds: potential applications in the human diet

Duckweeds are the smallest free-floating flowering aquatic plants. Their biotechnological applications include their use as food, bioenergy, and environmental sustainability, as they can help clean polluted water. The high growth capacity and their chemical properties make them suitable for human health applications. Here we evaluated the ethanolic extracts from five species of duckweeds by HPLC-DAD/MS-MS for chemical characterization. Sixteen compounds were identified and quantified, in which three were chlorogenic acid derivatives and eleven apigenin and luteolin derivatives. We describe for the first time the presence in duckweeds of 5-O-(E)-caffeoylquinic acid (1), 3-O-(E)-coumaroylquinic acid (2), luteolin-7-O-glucoside-C-glucoside (3), 4-O-(E)-coumaroylquinic acid (4), luteolin-6-C-glucoside-8-C-rhamnoside (5), and luteolin-8-C-glucoside-6-C-rhamnoside (6). The flavonoids diversity showed a significant content of luteolin and its derivatives, except for Landoltia punctata that had significant apigenin content. Flavones identified in duckweeds were mostly C-glycosides, which can benefit human diets, and its abundance seems to be related to the higher antioxidant and anticancer capacities of Wolffiella caudata, Wolffia borealis, and Landoltia punctata. Our findings reinforce the idea that duckweeds could be valuable additives to the human diet, and their potential should be further explored.

Phytochemical properties of black tea (Camellia sinensis) and rooibos tea (Aspalathus linearis); and their modulatory effects on key hyperglycaemic processes and oxidative stress

The comparative phytochemicals, antioxidative and antidiabetic activities of Camellia sinensis (black tea) and Aspalathus linearis (rooibos tea) were studied in vitro and ex vivo. Concentrated infusions of the teas showed significant free radical scavenging activities in vitro. They significantly increased the glutathione level, superoxide dismutase and catalase enzyme activities in oxidative hepatic injury, while concomitantly depleting malondialdehyde level. The teas significantly inhibited intestinal glucose absorption and α-amylase activities, and elevated muscle glucose uptake. LCMS phytochemical profiling revealed the presence of hydroxycaffeic acid, l-threonate, caffeine, vanillic acid, n-acetylvaline, and spinacetin 3-glucoside in C. sinensis. While quinolinic acid, coumestrol, phloroglucinol, 8-hydroxyquercetagetin, umbelliferone, and ajoene were identified in A. linearis. These results portray the antioxidant and antidiabetic potencies of both teas, with A. linearis showed better activity compared to C. sinensis. These teas may thus be used as functional foods in the management of diabetes and other oxidative stress related metabolic disorders.

Tannase-Converted Green Tea Extract with High (-)-Epicatechin Inhibits Skeletal Muscle Mass in Aged Mice

The objective of this study was to investigate the effects of tannase-converted green tea extract on body composition, muscle oxidative stress-related factors, and differentiation-related factors. The mean bone-related parameters and body composition were determined by the live dual-energy X-ray absorptiometry (DEXA). Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting were used to determine mRNA expression and protein levels, respectively. The results of total mass testing in the epicatechin control (EC) and middle concentration tannase-converted green tea extract (T₁) intake groups were not significantly different compared with those in the control group; however, the high-concentration tannase-converted green tea extract (T₂) group showed a significantly higher effect to the lean than that of all other groups (p < 0.05). The results of the assay of muscle differentiation-related genes indicated that the expression levels in the EC and T₁ groups (p < 0.05) and the expression levels in the T₂ group (p < 0.01) were significantly different in the bicep femoris compared with that in the control group. The results of the SOD gene assay indicate that the expression levels in the EC and T₁ groups (p < 0.05) and the expression level in the T₂ group (p < 0.01) were significantly different in the bicep femoris compared with that in the control group. Additionally, SOD gene expression in the T₂ group was significantly increased (p < 0.05) in the soleus compared with that in the control, EC and T₁ groups. Our results suggest that tannase-converted green tea extract prevents muscle loss and regulates the quantity and quality of muscle by the levels of antioxidant stress-related enzymes and muscle differentiation factors to a greater extent than the administration of epicatechin and middle dose green tea extract.

Protein Binding Characteristics of the Principal Green Tea Catechins: A QCM Study Comparing Crude Extract to Pure EGCG

Label-free detection methods such as the quartz crystal microbalance (QCM) are well suited to the analysis of molecular interactions in complex mixtures such as crude botanical extracts. In the present study, the binding characteristics of epigallocatechin gallate (EGCG) and crude green tea extract solutions to bovine serum albumin (BSA) have been investigated. The adsorbed mass levels onto BSA-functionalized surfaces were measured at various solution concentrations. Langmuir and Freundlich isotherms were used to model the adsorption data. The Langmuir isotherm better described the adsorption behavior with correlations of 0.68 and 0.70 for the EGCG and the crude extract solutions, respectively. The better fit of the Langmuir model indicates that adsorption occurs homogeneously and that aggregation is negligible. The mass saturation is estimated to be 58% higher for the crude green tea solution as compared to the pure EGCG solution (7.9 ng/cm² for green tea and 5 ng/cm² for EGCG). The increased adsorption for the crude extract indicates that the additional tea chemical constituents are binding to alternate sites on the protein molecule and that competitive binding is a nondominant effect. However, a reduced adsorption rate for the crude extract was also observed, indicating some presence of competitive mechanisms. The results demonstrate the utility of the QCM for the analysis of protein binding in crude mixtures as well as pure compounds.

The Polyphenols as Potential Agents in Prevention and Therapy of Prostate Diseases

In recent years, the progress of science and medicine greatly has influenced human life span and health. However, lifestyle habits, like physical activity, smoking cessation, moderate alcohol consumption, diet, and maintaining a normal body weight represent measures that greatly reduce the risk of various diseases. The type of diet is very important for disease development. Numerous epidemiological clinical data confirm that longevity is linked to predominantly plant-based diets and it is related to a long life; whereas the western diet, rich in red meat and fats, increases the risk of oxidative stress and thus the risk of developing various diseases and pre-aging. This review is focused on the bioavailability of polyphenols and the use of polyphenols for the prevention of prostate diseases. Special focus in this paper is placed on the isoflavonoids and flavan-3-ols, subgroups of polyphenols, and their protective effects against the development of prostate diseases.

Phenolic Profiles and Antioxidant Activities of 30 Tea Infusions from Green, Black, Oolong, White, Yellow and Dark Teas

Tea is among the most consumed drink worldwide, and its strong antioxidant activity is considered as the main contributor to several health benefits, such as cardiovascular protection and anticancer effect. In this study, the antioxidant activities of 30 tea infusions, which were obtained by the mimic of drinking tea of the public, from green, black, oolong, white, yellow and dark teas, were evaluated using ferric-reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays, ranging from 504.80 ± 17.44 to 4647.47 ± 57.87 µmol Fe²⁺/g dry weight (DW) and 166.29 ± 24.48 to 2532.41 ± 50.18 µmol Trolox/g DW, respectively. Moreover, their total phenolic contents (TPC) were detected by Folin-Ciocalteu assay and were in the range of 24.77 ± 2.02 to 252.65 ± 4.74 mg gallic acid equivalent (GAE)/g DW. Generally, Dianqing Tea, Lushan Yunwu Tea, and Xihu Longjing Tea showed the strongest antioxidant activities among 30 teas. Furthermore, the phenolic compounds in tea infusions were identified and quantified, with catechins most commonly detected, especially in green tea infusions, which were main contributors to their antioxidant activities. Besides tea polyphenols, considerable content of caffeine also presented in 30 tea infusions.

Hepatotoxicity in an Adolescent with Black Iced Tea Overconsumption

Tea is the most widely consumed beverage after water in the world. The consumption of iced tea has increased in Western countries and spiked among teenagers for enjoyment, freshening up and alertness. A teenager presented with symptoms of hepatitis. Liver ultrasound revealed sludge in the gallbladder. Laboratory investigations excluded all known causes of hepatotoxicity. Detail nutritional history revealed that the patient had been drinking 1.5-2 liters of black iced tea per day for the last three months. He was immediately advised to stop drinking any tea. Gradually all symptoms disappeared and two months after discontinuation of the tea, all liver enzymes returned to normal and the sludge in the gallbladder disappeared. This case report underlines the importance of a meticulous assessment of a child's dietary behavior when investigating a case of hepatotoxicity and raises awareness about the potential side effects of tea overconsumption.

Association between Green Tea Consumption and Risk of Stroke in Middle-Aged and Older Korean Men: The Health Examinees (HEXA) Study

Green tea consumption is known to have varying effects on health and disease. The aim of this study was to investigate the association between green tea consumption and risk of stroke in Korean adult men. Data were obtained from the Health Examinees (HEXA) Study, which included 50,439 subjects aged 40 years and older. Information regarding dietary intake was collected from semi-quantified food frequency questionnaires consisting of 106 items. Green tea consumption was categorized as none, <1 cup/d, 1 to <3 cups/d, and ≥3 cups/d. Binary logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CIs) to examine a possible association between green tea consumption and risk of stroke by controlling for potential confounders. Subgroup analyses by age, body mass index, hypertension, diabetes mellitus, smoking status, and alcohol consumption were also performed. Compared with green tea non-drinkers, individuals that consumed 1 to <3 cups/d or ≥3 cups/d of green tea had multivariable adjusted OR (CI) of stroke of 0.75 (0.59~0.97) and 0.62 (0.39~0.98), respectively, after adjusting for age and various confounders. In the subgroup analyses, an inverse association between green tea consumption and risk of stroke was identified among younger, non-hypertensive, and non-diabetic men. Higher consumption of green tea was inversely associated with stroke risk in middle-aged and older Korean men.

Green Tea, Coffee, and Caffeine Consumption Are Inversely Associated with Self-Report Lifetime Depression in the Korean Population

This study investigated the associations of green tea, coffee, and caffeine consumption with self-report lifetime depression in the Korean population using data from the Korean National Health and Nutrition Examination Survey. In total, 9576 participants (3852 men and 5724 women) aged 19 years or older were selected for the present study. Green tea, coffee, and caffeine consumption levels were assessed with a validated food frequency questionnaire. Multivariate logistic regression analysis was used to determine the odds ratios (OR) and 95% confidence intervals (CIs) for depression according to green tea, coffee, and caffeine consumption. Frequent green tea consumers (≥3 cups/week) had 21% lower prevalence of depression (OR = 0.79, 95% CI = 0.63–0.99, p for trend = 0.0101) than green tea non-consumers after adjustment for potential confounders. Likewise, frequent coffee drinkers (≥2 cups/day) had 32% lower prevalence of depression (OR = 0.68, 95% CI = 0.55–0.85, p for trend = 0.0026) than coffee non-drinkers after adjustment for potential confounders. Also, participants in the highest quartile of caffeine consumption had 24% lower prevalence of depression than those in the lowest quartile (OR = 0.76, 95% CI = 0.62–0.92, p for trend = 0.0032). Frequent consumption of green tea, coffee, or caffeine was associated with a reduced prevalence of self-report lifetime depression in Korean adults. A prospective study and randomized clinical trials should be conducted to confirm the inverse relationships of green tea and coffee consumption with risk of depression.

Effect of teapot materials on the chemical composition of oolong tea infusions

BACKGROUND

The flavor and quality of tea are widely believed to be associated with the pot in which the tea is made. However, this claim is mostly by experiences and lacks solid support from scientific evidence. The current study investigated and compared the chemical compositions of oolong tea made with six different teapot materials, namely Zisha, Zhuni, stainless steel, ceramic, glass and plastic.

RESULTS

For each tea sample, polyphenols and caffeine were examined by HPLC-UV, volatile compounds by GC/MS, amino acids by LC/MS and minerals by ICP-MS. The results suggested that tea infusions from Zisha and Zhuni pots contain higher levels of EGC, EGCG and total catechins and less caffeine than those from ceramic, glass and plastic pots and tend to have the lowest total mineral contents, potassium and volatile compounds in tea soup. The statistical differences were not all significant among Zisha, Zhuni and stainless steel pots.

CONCLUSION

Based on the overall chemical composition of the tea infusion, Yixing clay pots (Zisha and Zhuni) produce tea infusions that are presumably less bitter and more fragrant and tend to contain more healthful compounds than tea infusions from other pots. The results could partially explain why Yixing clay pots are among the most popular teapots. The beneficial effects of long-term repeated use of these teapots warrants further study. © 2017 Society of Chemical Industry.

Tea regimen, a comprehensive assessment of antioxidant and antitumor activities of tea extract produced by Tie Guanyin hybridization

A comprehensive assessment was conducted in this study to examine the antioxidant and antitumor activities of tea extract produced by Tie Guanyin hybridization. Two radical-scavenging systems of assay in vitro, namely ABTS and DPPH assays, were used to investigate the antioxidant activity of the summer tea and autumn tea extract (STE and ATE) derived from the Jin Guanyin. The results indicated that the major active ingredients were catechins, and the theaflavin is rare in the STE and ATE. Moreover, STE and ATE could significantly suppress the growth of human breast cancer cells MDA-MB-231 in a dose-dependent manner, and wrecked the morphology of mitochondria, activated caspase families, leading to the cancer cell death by both apoptosis and cell cycle arrest pathways. Based on the results from an MDA-MB-231 xenograft nude mice model, STE could effectively prevent the tumor formation, and greatly improve the mice immunity and thus improve their living conditions. Taken together, ATE and STE could act as a healthy and prospective substitute for natural antioxidants and a promising prophylactic agent against cancer. This finding provides a great promising nutritional approach to treat diseases related with oxidative stress.

Herein we demonstrate that Jin Guanyin extracts shows antioxidative activity, thus inhibiting ROS generation, promoting mitochondrial fragmentations and caspase activations in cancer cells, finally leading cell apoptosis and cycle arrest.

Tea polyphenols for the prevention of UVB-induced skin cancer

Skin cancer is the most common type of cancer with increasing incidence rate and public health burden. Solar ultraviolet (UV) radiation causes an array of damaging cellular and molecular events that eventually lead to the development of skin cancer. Despite increased awareness about sun protection, the exposure rate remains high with less than 15% of men and 30% of women using sunscreen on a regular basis. Therefore, there is an imperative need for the development of novel preventive approaches. Skin cancer chemoprevention using phytochemicals either as dietary supplements or by topical applications has gained considerable attention due to their low toxicity, availability, and anticarcinogenic properties. Tea, the second most commonly consumed beverage in the world, is a rich source of promising phytochemicals known as polyphenols. In this review, we discuss the findings of various in vitro, in vivo and human studies signifying the chemopreventive effects of tea polyphenols against UVB-induced skin cancer. This is accomplished by exploring the role of tea polyphenols in DNA repair, inflammation, oxidative stress, signaling pathways, and epigenetics. Finally, this review discusses a variety of innovative delivery methods that enhance the photochemopreventive effects of tea polyphenols against skin cancer.

(-)-Epigallocatechin-3-gallate decreases colonic inflammation and permeability in a mouse model of colitis, but reduces macronutrient digestion and exacerbates weight loss

SCOPE

(-)-Epigallocatechin-3-gallate (EGCG) has been reported to have putative health effects including the prevention of inflammation and obesity. Historically, polyphenols have been regarded as antinutritionals and while such effects may be beneficial in obese subjects, they may be deleterious in nutritionally compromised individuals.

METHODS AND RESULTS

We examined the effect of EGCG in the dextran sulfate sodium (DSS)-treated mouse model of ulcerative colitis. Following induction of colitis, mice were treated with EGCG (3.2 mg/g) as the sole source of drinking fluid for 3 days. EGCG treatment mitigated DSS-induced colon shortening and spleen enlargement. EGCG also decreased colonic protein levels of IL-1β, IL-6, and tumor necrosis factor-α, as well as colonic lipid peroxides compared to DSS-treated controls. We observed that EGCG reduced DSS-induced gastrointestinal permeability. These beneficial effects were offset by enhanced body weight loss in EGCG-treated mice compared to DSS-treated controls. These effects were related to decreased protein and lipid digestion in EGCG-treated mice compared to DSS-treated controls.

CONCLUSIONS

Our results suggest that although EGCG may exert anti-inflammatory effects, its ability to modulate macronutrient digestion may represent a dose-limiting adverse effect that must be considered in the context of its use for treating inflammatory bowel disease.

Dietary patterns and colorectal cancer

BACKGROUND & AIMS

Dietary pattern and lifestyle have been reported to be important risk factors in the development of colorectal cancer (CRC). However, the mechanism of action of dietary factors in CRC disease is unclear. The aim of this study is the examination of several dietary choices and their potential association with the risk of developing CRC.

METHODS

Dietary data was collected from 220 subjects who were previously diagnosed with CRC, and 281 control subjects (matched by age, gender, occupation and marital status). The data was collected between January 2010 and December 2012, using interview-based questionnaires. Multivariate logistic regression was used to estimate the relationship between dietary choices and risk of developing colorectal cancer.

RESULTS

Factor analysis revealed three major dietary patterns. The first pattern we identified as the "Healthy Pattern", the second was identified as "High Sugar/High Tea Pattern" and the third as "Western Pattern". In the Healthy Pattern group we found a 10.54% variation in food intake, while the intake variation was 11.64% in the Western Pattern. After adjusting for confounding factors, the Western Pattern food choice was found to be significantly associated with an increased risk of developing CRC (OR = 1.88; 95% CI = 1.12-3.16). The results for the Healthy and High-Sugar/High Tea Patterns showed a decrease, but the statistic was not significant for the risk of CRC development.

CONCLUSION

The Western Pattern of dietary choice was directly associated with CRC. The association between the dietary food choice in the Healthy and High-Sugar/High Tea Patterns and colorectal cancer needs further study in our Jordanian population.

Estimated daily intake of phenolics and antioxidants from green tea consumption in the Korean diet

To estimate daily intake of total phenolics and flavonoids from green tea and the contribution of green tea to the antioxidant intake from the Korean diet, 24 commercial brands of green tea were selected and analyzed. Data from the Korea National Health and Nutrition Examination Survey (KNHANES) from 2008 and 2011 indicate that the green tea consumption in these 2 years was 2.8 g/tea drinker/day and 2.9 g/tea drinker/day, respectively. Based on data derived from direct measurements of green tea phenolics and the dataset of the 2008 KNHANES, we estimated the daily per tea drinker phenolics intake to be 172 mg gallic acid equivalents (GAE), the total flavonoids to be 43 mg catechin equivalents (CE) and the total antioxidants to be 267 mg vitamin C equivalents (VCE; 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay) and 401 mg VCE (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assay). In 2011, we estimated the daily per tea drinker total phenolics intake to be 246 mg GAE, the total flavonoids to be 60 mg CE and the antioxidants to be 448 mg VCE (DPPH assay) and 630 mg VCE (ABTS assay). The daily intake of total phenolics, total flavonoids and antioxidants from green tea consumption increased from 2008 to 2011.

Reduction of hydrogen peroxide-induced erythrocyte damage by Carica papaya leaf extract

OBJECTIVE

To investigate the in vitro antioxidant potential of Carica papaya (C. papaya) leaf extract and its effect on hydrogen peroxide-induced erythrocyte damage assessed by haemolysis and lipid peroxidation.

METHODS

Hydroxyl radical scavenging activities, hydrogen ion scavenging activity, metal chelating activity, and the ferrous ion reducing ability were assessed as antioxidant indices. In the other experiment, human erythrocytes were treated with hydrogen peroxide to induce erythrocyte damage. The extract (at various concentrations) was subsequently incubated with the erythrocytes and later analysed for haemolysis and lipid peroxidation as indices for erythrocyte damage.

RESULTS

Preliminary investigation of the extract showed that the leaf possessed significant antioxidant and free radical scavenging abilities using in vitro models in a concentration dependent manner (P<0.05). The extract also reduced hydrogen peroxide induced erythrocyte haemolysis and lipid peroxidation significantly when compared with ascorbic acid (P<0.05). The IC50 values were 7.33 mg/mL and 1.58 mg/mL for inhibition of haemolysis and lipid peroxidation, respectively. In all cases, ascorbic acid (the reference antioxidant) possessed higher activity than the extract.

CONCLUSIONS

The findings show that C. papaya leaves possess significant bioactive potential which is attributed to the phytochemicals which act in synergy. Thus, the leaves can be exploited for pharmaceutical and nutritional purposes.

Epigallocatechin-3-gallate protects against cisplatin-induced nephrotoxicity by inhibiting endoplasmic reticulum stress-induced apoptosis

Cisplatin (CP)-induced nephrotoxicity hampers its application in clinic. Green tea, particularly its predominant polyphenolic constituent epigallocatechin-3-gallate (EGCG), possesses anti-inflammatory, antioxidant, and anti-apoptotic properties. The present study was designed to investigate the protective effects of EGCG against CP-induced nephrotoxicity in mice. Male C57/BL6 mice in different groups received single injection of CP (20 mg/kg) and EGCG (100 mg/kg) in various sets and kidney tissues and blood were collected after killing. Then, samples were used for biochemical and immunohistochemical assay. Our results showed EGCG decreased biochemical factors and immunohistochemical damage induced by CP. Besides, expression of phosphorylated-extracellular signal-regulated kinase (p-ERK), glucose-regulated protein 78 (GRP78), caspase-12, and apoptosis of kidney were decreased by EGCG via inhibition of endoplasmic reticulum (ER) stress-induced apoptosis.

Effects of Oolong tea polyphenols, EGCG, and EGCG3″Me on pancreatic α-amylase activity in vitro

In order to investigate the inhibitory effects and possible mechanisms of Oolong tea polyphenols, (-)-epigallocatechin gallate (EGCG) and (-)-epigallocatechin 3-O-(3-O-methyl) gallate (EGCG3″Me) on pancreatic α-amylase, the inhibition, enzyme kinetics, ultraviolet (UV) absorption spectrum and fluorescence spectrum of α-amylase were investigated. The results showed that Oolong tea polyphenols, EGCG, and EGCG3″Me all exhibited inhibitory effects against α-amylase, and their half inhibitory concentration (IC50) values were 0.375, 0.350, and 0.572 mg/mL, respectively. The results of Lineweaver-Burk double reciprocal plot indicated that the inhibitory types of Oolong tea polyphenols and EGCG were competitive, whereas EGCG3″Me was in a noncompetitive pattern. Oolong tea polyphenols, EGCG, and EGCG3″Me all induced red-shift of UV absorbance and quenching of fluorescence of α-amylase, suggesting possible changes in the conformation of α-amylase. The differences of inhibitory effects and inhibition types for EGCG and EGCG3″Me might be due to their structural difference (the hydroxyl group at C-3 in D ring of EGCG substituted by methoxy group, forming EGCG3″Me).

Protective effect of theaflavin on erythrocytes subjected to in vitro oxidative stress

Antioxidant and free radical scavenging effect of black tea theaflavins has been shown in many epidemiological studies. In the present work we report the protective mechanism of tea theaflavins on biomarkers of oxidative stress, which are elevated during stress conditions. We hereby report the in vitro effect of theaflavins on erythrocyte malondialdehyde (MDA), intracellular reduced glutathione (GSH), and plasma membrane redox system (PMRS) of rats. The effect of theaflavin on PMRS has also been validated through an in silico docking simulation study using Molegro Virtual Docker (MVD). We report that theaflavins show significant protection to erythrocyte against oxidative stress induced by tert-butyl hydroperoxide (t-BHP). The findings suggest a possible protective role of theaflavins as antioxidant.

The dual action of epigallocatechin gallate (EGCG), the main constituent of green tea, against the deleterious effects of visible light and singlet oxygen-generating conditions as seen in yeast cells

Green tea extracts (GTEs) as well as their main component, the polyphenol epigallocatechin gallate (EGCG), are known for their versatile antioxidant, antimicrobial, antitumoral or anti-inflammatory effects. In spite of the huge beneficial action, there is increasing evidence that under certain conditions green tea and its components can be detrimental to living organisms. Using Saccharomyces cerevisiae strains with various defects in the response to oxidative stress, we found that GTEs or EGCG act in synergy with visible light, exhibiting either deleterious or protective effects depending on the solvent employed. Similar synergistic effects could be observed under singlet oxygen-generating conditions, such as light exposure in the presence of photosensitizers or UV-A irradiation, therefore solvent variance may represent a powerful tool to modulate the preparation of green tea extracts, depending on the intended target.

Polyphenols in brewed green tea inhibit prostate tumor xenograft growth by localizing to the tumor and decreasing oxidative stress and angiogenesis

It has been demonstrated in various animal models that the oral administration of green tea (GT) extracts in drinking water can inhibit tumor growth, but the effects of brewed GT on factors promoting tumor growth, including oxidant damage of DNA and protein, angiogenesis and DNA methylation, have not been tested in an animal model. To explore these potential mechanisms, brewed GT was administered instead of drinking water to male severe combined immunodeficiency (SCID) mice with androgen-dependent human LAPC4 prostate cancer cell subcutaneous xenografts. Tumor volume was decreased significantly in mice consuming GT, and tumor size was significantly correlated with GT polyphenol (GTP) content in tumor tissue. There was a significant reduction in hypoxia-inducible factor 1-alpha and vascular endothelial growth factor protein expression. GT consumption significantly reduced oxidative DNA and protein damage in tumor tissue as determined by 8-hydroxydeoxyguanosine/deoxyguanosine ratio and protein carbonyl assay, respectively. Methylation is known to inhibit antioxidative enzymes such as glutathione S-transferase pi to permit reactive oxygen species promotion of tumor growth. GT inhibited tumor 5-cytosine DNA methyltransferase 1 mRNA and protein expression significantly, which may contribute to the inhibition of tumor growth by reactivation of antioxidative enzymes. This study advances our understanding of tumor growth inhibition by brewed GT in an animal model by demonstrating tissue localization of GTPs in correlation with inhibition of tumor growth. Our results suggest that the inhibition of tumor growth is due to GTP-mediated inhibition of oxidative stress and angiogenesis in the LAPC4 xenograft prostate tumor in SCID mice.

Supplementation with green tea polyphenols improves bone microstructure and quality in aged, orchidectomized rats

Recent studies show that green tea polyphenols (GTPs) attenuate bone loss and microstructure deterioration in ovariectomized aged female rats, a model of postmenopausal osteoporosis. This study evaluated the efficacy of GTPs at mitigating bone loss and microstructure deterioration along with related mechanisms in androgen-deficient aged rats, a model of male osteoporosis. A 2 (sham vs. orchidectomy) × 2 (no GTP and 0.5% GTP in drinking water) factorial design was studied for 16 weeks using 40 aged male rats. An additional 10 rats (baseline group) were killed at the beginning of study to provide baseline parameters. There was no difference in femoral mineral density between baseline and the sham only group. Orchidectomy suppressed serum testosterone and tartrate-resistant acid phosphatase concentrations, liver glutathione peroxidase activity, bone mineral density, and bone strength. Orchidectomy also decreased trabecular bone volume, number, and thickness in the distal femur and proximal tibia and bone-formation rate in trabecular bone of proximal tibia but increased serum osteocalcin concentrations and bone-formation rates in the endocortical tibial shaft. GTP supplementation resulted in increased serum osteocalcin concentrations, bone mineral density, and trabecular volume, number, and strength of femur; increased trabecular volume and thickness and bone formation in both the proximal tibia and periosteal tibial shaft; decreased eroded surface in the proximal tibia and endocortical tibial shaft; and increased liver glutathione peroxidase activity. We conclude that GTP supplementation attenuates trabecular and cortical bone loss through increasing bone formation while suppressing bone resorption due to its antioxidant capacity.

A novel dietary supplement containing multiple phytochemicals and vitamins elevates hepatorenal and cardiac antioxidant enzymes in the absence of significant serum chemistry and genomic changes

A novel dietary supplement composed of three well-known phytochemicals, namely, Salvia officinalis (sage) extract, Camellia sinensis (oolong tea) extract, and Paullinia cupana (guarana) extract, and two prominent vitamins (thiamine and niacin) was designed to provide nutritional support by enhancing metabolism and maintaining healthy weight and energy. The present study evaluated the safety of this dietary supplement (STG; S=sage; T=tea; G=guarana) and assessed changes in target organ antioxidant enzymes (liver, kidneys and heart), serum chemistry profiles and organ histopathology in Fisher 344 rats. Adult male and female Fisher 344 rats were fed control (no STG) or STG containing (1X and 7X, 1X=daily human dose) diets and sacrificed after 2 and 4 months. Serum chemistry analysis and histopathological examination of three vital target organs disclosed no adverse influence on protein, lipid and carbohydrate profiles, genomic integrity of the liver and/or the tissue architecture. However, analysis of the most important antioxidant components in the liver, kidney and heart homogenates revealed a dramatic increase in total glutathione concentrations, glutathione peroxidase and superoxide dismutase enzyme activities. Concomitantly, oxidative stress levels (malondialdehyde accumulation) in these three organs were less than control. Organ specific serum markers (ALT/AST for the liver; CPK/AST for the heart; BUN/creatinine for kidneys) and the genomic integrity disclosed no STG-induced alteration. Some of the serum components (lipid and protein) showed insignificant changes. Overall, STG-exposed rats were more active, and the results suggest that STG exposure produces normal serum chemistry coupled with elevated antioxidant capacity in rats fed up to seven times the normal human dose and does not adversely influence any of the vital target organs. Additionally, this study reiterates the potential benefits of exposure to a pharmacologically relevant combination of phytochemicals compared to a single phytochemical entity.

Intracellular uptake of (-)epicatechin by human erythrocytes as a function of human age

The present studies were carried out to determine the intracellular uptake of (-)epicatechin by erythrocytes during aging in humans. (-)Epicatechin uptake was estimated by performing ethyl acetate extraction while the total antioxidant potential of the (-)epicatechin was estimated in terms of FRAP (ferric reducing ability of plasma) values. A significant (p < 0.001) decrease in (-)epicatechin uptake by human erythrocytes was observed as a function of age. It is hypothesized that the uptake of (-)epicatechin in human erythrocytes has an important role in the regulation of PMRS (plasma membrane redox system) activity during normal human aging.

The antioxidant and pro-oxidant activities of green tea polyphenols: a role in cancer prevention

Green tea (Camellia sinensis) is rich in catechins, of which (-)-epigallocatechin-3-gallate (EGCG) is the most abundant. Studies in animal models of carcinogenesis have shown that green tea and EGCG can inhibit tumorigenesis during the initiation, promotion and progression stages. Many potential mechanisms have been proposed including both antioxidant and pro-oxidant effects, but questions remain regarding the relevance of these mechanisms to cancer prevention. In the present review, we will discuss the redox chemistry of the tea catechins and the current literature on the antioxidant and pro-oxidative effects of the green tea polyphenols as they relate to cancer prevention. We report that although the catechins are chemical antioxidants which can quench free radical species and chelate transition metals, there is evidence that some of the effects of these compounds may be related to induction of oxidative stress. Such pro-oxidant effects appear to be responsible for the induction of apoptosis in tumor cells. These pro-oxidant effects may also induce endogenous antioxidant systems in normal tissues that offer protection against carcinogenic insult. This review is meant point out understudied areas and stimulate research on the topic with the hope that insights into the mechanisms of cancer preventive activity of tea polyphenols will result.

Neuroprotective herbs and foods from different traditional medicines and diets

Plant secondary metabolites include an array of bioactive constituents form both medicinal and food plants able to improve human health. The exposure to these phytochemicals, including phenylpropanoids, isoprenoids and alkaloids, through correct dietary habits, may promote health benefits, protecting against the chronic degenerative disorders mainly seen in Western industrialized countries, such as cancer, cardiovascular and neurodegenerative diseases. In this review, we briefly deal with some plant foods and herbs of traditional medicines and diets, focusing on their neuroprotective active components. Because oxidative stress and neuroinflammation resulting from neuroglial activation, at the level of neurons, microglial cells and astrocytes, are key factors in the etiopathogenesis of both neurodegenerative and neurological diseases, emphasis will be placed on the antioxidant and anti-inflammatory activity exerted by specific molecules present in food plants or in remedies prescribed by herbal medicines.

Application of metabolomics in the analysis of manufacturing type of pu-erh tea and composition changes with different postfermentation year

Liquid chromatography-mass and multivariate analyses were employed to measure the composition of pu-erh teas and to determine the general changes in the compositional patterns of pu-erh teas during postfermentation. Principle component analysis of pu-erh teas indicated two large distinct clusters in the score plot: ripened pu-erh teas and raw pu-erh teas. The raw pu-erh teas contained more antioxidant compounds compared to ripened pu-erh teas. As a result, the raw pu-erh teas showed significantly higher antioxidant activities than the ripened pu-erh teas in the 1,1-diphenyl-2-picrylhydrazyl, Trolox equivalent antioxidant capacity, and ferric reducing antioxidant power assays. In addition, raw pu-erh teas showed significantly higher NO inhibitory and cell protective activities than the ripened pu-erh teas. Significant correlations between compounds and postfermentation year were observed in raw pu-erh teas; epigallocatechin-3-gallate, epigallocatechin, epicatechin-3-gallate, and quinic acid were decreased and gallic acid was increased in a year-dependent manner. The antioxidant activity was shown to decrease as the number of antioxidant compounds in raw pu-erh tea decreased. These findings indicate that a metabolomic approach is a useful tool for analyzing manufacturing type, postfermentation year, and antioxidant activity of pu-erh tea.

EGCG enhances TRAIL-mediated apoptosis in human melanoma A375 cell line

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anti-cancer agent. Epigallocatechin-3-gallate (EGCG) is a polyphenolic constituent of green tea. In this study, inhibitory effect of combined use of EGCG and TRAIL on human melanoma A375 cells was examined and the possible mechanism investigated. The cells were divided into 4 groups: control group, EGCG group (EGCG: 10, 20 mug/mL), TRAIL group (TRAIL: 25 ng/mL) and EGCG+TRAIL group (combined group). The growth inhibition was measured in the A375 cells treated with different concentrations of TRAIL ((25, 50, 75, 100, 125, 150 ng/mL) by MTT assay. The apoptosis was assessed by flow cytometry. The expressions of DR4 and DR5 were detected by flow cytometry and western blotting. The activities of caspase-8 and caspase-3 were determined by colorimetric assay. The results showed that TRAIL could dose-dependently inhibit the growth of A375 cells and the IC(50) of TRAIL was 150 ng/mL. The apoptosis rate was 11.8% in the TRAIL group, 5%-7% in the EGCG group and 48.9%-59.1% in the combined group. Significant difference was found in the apoptosis rate between the combined group and the EGCG or TRAIL group (P<0.05 for each). The expression of DR4 instead of DR5 was significantly increased in the EGCG group. The activity of caspase-3 rather than caspase-8 was substantially enhanced in the EGCG group. These results suggest that EGCG is useful for the TRAIL-based treatment for melanoma.

Polyphenols from green tea and pomegranate for prevention of prostate cancer

Prostate cancer (PCa) is the most common non-cutaneous cancer diagnosed in North America with similar trends in many Western countries. Geographic, epidemiological and laboratory studies suggest a role for dietary constituents in the etiology as well as prevention of PCa. The rising incidence of PCa in several countries appears to be coincidental with adoption of western lifestyle. Increase in the incidence of PCa has also been found in Asian populations migrating to the west. These facts give numerous leads to explore testable PCa prevention strategies. There is growing evidence in support of use of dietary ingredients in prevention and treatment of PCa. While substantial data exists in favor of use of polyphenols from tea as PCa chemopreventive agent, interest in anti-cancer properties of polyphenols from pomegranate has recently emerged. This review summarizes current literature on the effects of polyphenols from green tea and pomegranate against PCa.