Bioavailability of catechins from ready-to-drink tea

ObjectiveBecause consumption of teas may be associated with potential health benefits due to its content in polyphenols and in Western countries the consumption of tea is equally divided between the hot and the ready-to-drink (RTD) cold versions of this typical beverage, the aim of this work was to study the absorption and metabolism of flavan-3-ols in human volunteers after the ingestion of a commercial RTD tea.MethodsA feeding study was carried out in 20 healthy human volunteers and urine samples were collected for 24 h after tea ingestion. Flavan-3-ols–derived molecules were identified and quantified in urine samples by high-performance liquid chromatography with tandem mass spectrometric detection.ResultsEight relevant metabolites were identified in urine, all modified flavan-3-ols with the exception of unmetabolized gallic acid. The urinary excretion of flavan-3-ols was equal to 7.2% of the intake with tea. Gallic acid, which was abundant in the RTD tea used in this study, reached a 4.5% of the drunken amount.ConclusionsThe bioavailability values observed are in agreement with previous reports, although the dosage of polyphenols ingested in this study is remarkably lower. Moreover, the use of a group of 20 volunteers, more than the average number of subjects used for usual human acute-feeding studies involving polyphenols, provides additional credibility to the results. After drinking the RTD ice tea used in this study, the internal compartments are exposed to non-marginal doses of flavanols and flavanol metabolites up to 24 h.     

Effect of complex polyphenols and tannins from red wine on DNA oxidative damage of rat colon mucosa in vivo

Summary Background: Dietary polyphenols have been reported to have a variety of biological actions, including anti-carcinogenic, antioxidant and anti-inflammatory activities. Aim of the study: In the present study we have evaluated the effect of an oral treatment with complex polyphenols and tannins from red wine and tea on DNA oxidative dammage in the rat colon mucosa. Methods: Isolated colonocytes were prepared from the colon mucosa of rats treated for ten days with either wine complex polyphenols (57.2 mg/kg/d) or thearubigin (40 mg/kg/d) by oral gavage. Colonocyte oxidative DNA damage was analysed at the single cell level using a modification of the comet assay technique. Results: These results show that wine complex polyphenols and tannins induce a significant decrease (−62% for pyrimidine and −57% for purine oxidation) in basal DNA oxidative damage in colon mucosal cells without affecting the basal level of single-strand breaks. On the other hand, tea polyphenols, namely a crude extract of thearubigin, did not affect either strand breaks or pyrimidine oxidation in colon mucosal cells. Conclusions Our experiments are the first demonstration that dietary polyphenols can modulate in vivo oxidative damage in the gastrointestinal tract of rodents. These data support the hypothesis that dietary polyphenols might have both a protective and a therapeutic potential in oxidative damage-related pathologies. Received: 17 April 2000, Accepted: 27 July 2000     

Effect of green tea extract on arterial stiffness,lipid profile and sRAGE in patients with type 2 diabetes mellitus: a randomised,double-blind,placebo-controlled trial

Abstract

Type 2 diabetes mellitus (T2DM) is associated with premature atherosclerosis and arterial stiffening due to the accumulation of advanced glycation end-products in vessel walls. Green tea polyphenols are considered cardio-protective substances. In this randomised double-blind placebo-controlled trial (NCT02627898), we evaluated the effect of Green tea extract on arterial stiffness parameters, lipids, body composition and sRAGE levels. Twenty normotensive patients with T2DM treated with the standard therapy and statins, mean age 53.2?±?9.4 years and mean BMI 30.1?±?4.5?kg/m², were randomised to receive a daily dose of 400?mg of green tea extract (polyphenols ≥90%, EGCG ≥45%) or placebo for 12 weeks. Compared to placebo, administration of green tea extract decreased central augmentation index (–3.05?±?10.8% vs. 6.7?±?0.1%, p?=?.04). These findings suggest that green tea extract could be used as an adjunct to the standard therapy to improve arterial stiffness in T2DM.     

Effect of domestic cooking on human bioavailability of naringenin,chlorogenic acid,lycopene and β-carotene in cherry tomatoes

Summary Background Epidemiological data showed that tomato and tomato product (sauce, paste) consumption is associated with a protective effect against the development of some chronic-degenerative diseases. Tomato antioxidant bioactive molecules such as carotenoids and polyphenols could be responsible, at least in part, for the healthy effect observed. The bioavailability of these compounds is an essential requirement to sustain their in vivo role. While it is well known that many factors can influence the bioaccessibility of carotenoids from the food matrix, there is little information about the factors affecting phenolic compounds bioaccessibility. Aim of the study This investigation was carried out to evaluate the effect of domestic cooking on the bioavailability in humans of antioxidant molecules after the administration of a test meal containing cherry tomatoes. Methods A cross-over design was conducted. Subjects (3 females and 2 males) consumed experimental meals containing fresh and cooked cherry tomatoes. Blood collection was performed at different time intervals (0, 2, 4, 6, 8 and 24 h). Results Carotenoid and phenol plasma concentrations were measured. Plasma levels of lycopene and -carotene were not significantly different with respect to the baseline after ingestion of both the test meals, while plasma concentrations of naringenin and chlorogenic acid increased significantly with respect to the baseline (P<0.05) after administration of cooked cherry tomatoes, but not after administration of fresh cherry tomatoes. Conclusions The present study indicated that domestically cooked tomatoes significantly increase naringenin and chlorogenic acid plasma levels. Considering that both naringenin and chlorogenic acid are widely studied for their potential healthy properties, evidence of their bioavailability and of the factors influencing their bioaccessibility is an important tool to sustain the possibility that these polyphenols play a biological role in human physiology.     

Estimated dietary intake and major food sources of polyphenols in the Polish arm of the HAPIEE study

ObjectiveThe aim of this study was to estimate the intake of known individual polyphenols and their major dietary sources in the Polish arm of the HAPIEE (Health, Alcohol and Psychosocial factors In Eastern Europe) study.MethodsA total of 10,477 random sample (45–69 y) of urban population of Krakow, Poland, completed a validated 148-item food frequency questionnaire. Polyphenol intake was calculated by matching food consumption data with the recently developed Phenol-Explorer database.ResultsThe mean intake of polyphenols was 1756.5 ± 695.8 mg/d (median = 1662.5 mg/d). The main polyphenol groups were flavonoids (897 mg/d) and phenolic acids (800 mg/d). A total of 347 polyphenols from 19 polyphenol subclasses were found. The individual compounds with the highest intakes were isomers of chlorogenic acid (i.e., 5-caffeoylquinic acid and 4-caffeoylquinic acid) among hydroxycinnamic acids (average intake 150 mg/d), that largely originated from coffee, and compounds belonging to the catechin chemical family (i.e., [+]-gallocatechin, [-]-epigallocatechin 3-O-gallate, and [-]-epicatechin) among flavanols (average intake 50 mg/d), that mostly originated from tea and cocoa products.ConclusionsThe current study provides the most updated data for individual polyphenols intake in the diet of a well-established nutritional cohort. These findings will be useful to assess potential beneficial role on health of specific foods with high polyphenol content and characterize the effects of individual phenolic compounds.     

Effect of different additives on antiooxidant capacity of black tea

ABSTRACT

The aim of this work was the study of effects of different additives on antioxidative potential of tea. Brewing additives including; clove, cinnamon, cardamom, saffron, and ginger, and nonbrewing additives such as milk, sugar, and honey were added to tea at 0.25:1, 0.5:1, and 1:1 ratio of additive to tea. Antioxidant activity (ferric iron reducing antioxidant power), total phenolic, and flavonoid content were determined. The highest antioxidant activity was seen for clove. The highest and lowest phenolic compounds were found with honey and clove, respectively. The tea containing saffron and control sample had the highest and the least flavonoids, respectively. Totally, the brewing additives had more effect on antioxidant activity of tea beverage in comparison with non-brewing additives. In relation to polyphenols content, nonbrewing additives had more influence on polyphenols in comparison with the brewing additives. No defined trend was seen in flavonoid content in the light of classification of additives.     

Effet de la digestion gastro-intestinale in vitro sur les composés phénoliques et l’activité antioxydante du thé vert Camellia sinensis L. issu de l’agriculture biologique

ObjectivesThe aim of this work is to study the effect of in vitro digestion on the contents of total polyphenols and flavonoids and the antioxidant activity of green tea (Camellia sinensis L.) from organic farming.Material and methodsOptimization of the tea cooking conditions was carried out by a central composite design. The contents of total polyphenols and flavonoids of the undigested and digested plants were determined by spectrophotometric methods. Phenolic extracts of green tea and digested lyophilizes were analysed by Attenuated total reflection-Fourier transform infrared. Evaluation of the antioxidant activity was carried out by three methods: DPPH, ABTS, and CUPRAC.ResultsDigestion causes a decrease in the levels of total polyphenols and flavonoids. The spectra obtained during the ATR-FTIR analysis showed intense bands corresponding to the O-H bonds, and C = C, C-H, C-O, and C = C bonds confirmed the presence of the polyphenols. A gradual decrease in the intensity of the absorption bands was observed during the three phases of digestion. The study of the effect of in vitro digestion on antioxidant activity indicates decreased antioxidant activity during two digestive phases (salivary and intestinal) and a marked increase during the gastric phase compared to the extract of the undigested plant.ConclusionThis study shows that the three phases of digestion reduce the levels of total polyphenols and flavonoids. Two phases of digestion (salivary and intestinal) cause a decrease in antioxidant activity, while an increase in this activity was observed in the gastric phase.     

Short-term Effects of Green Tea on Blood Pressure,Endothelial Function,and Metabolic Profile in Obese Prehypertensive Women: A Crossover Randomized Clinical Trial

Background: Green tea consumption has been inversely associated with cardiovascular disease (CVD) in epidemiological studies. Although some interventional trials suggest that green tea has beneficial effects on CVD risk factors, such as hypertension and obesity, others have failed to show such benefits.

Aims: To evaluate the short-term effects of green tea on blood pressure, endothelial function, metabolic profile, and inflammatory activity in obese prehypertensive women.

Methods: This study was a crossover, randomized, double-blind, placebo-controlled clinical trial. Participants were randomly allocated to receive daily 3 capsules containing either 500 mg of green tea extract (GTE) or a matching placebo for 4 weeks, with a washout period of 2 weeks between treatments. Each GTE capsule contained 260 mg of polyphenols. At the beginning and at the end of each treatment, participants were submitted to evaluation of blood pressure (ambulatory blood pressure monitoring, ABPM), endothelial function (Endo-PAT 2000 and cellular adhesion molecules), nutritional parameters, metabolic profile, and biomarkers of inflammation.

Results: Twenty women age 41.1 ± 8.4 years completed the study. After 4 weeks of GTE supplementation in comparison with placebo, there was a significant decrease (p < 0.05) in systolic blood pressure at 24 hours (?3.61 ± 1.23 vs 1.05 ± 1.34 mmHg), daytime (?3.61 ± 1.26 vs 0.80 ± 1.57 mmHg), and nighttime (?3.94 ± 1.70 vs 1.90 ± 1.66 mmHg). Changes in diastolic blood pressure and in all other parameters did not present a significant difference between GTE and placebo.

Conclusion: The findings of this study suggest that in obese prehypertensive women, short-term daily intake of GTE may decrease blood pressure.     

Effect of Green Tea on Plasma Adiponectin Levels: A Systematic Review and Meta-analysis of Randomized Controlled Clinical Trials

Objective: Our objective was to perform a systematic review and meta-analysis on randomized controlled trials (RCTs) assessing the effect of green tea on serum adiponectin concentration.

Method: We searched PubMed, ISI Web of Science, Scopus, and the Google Scholar databases up to November 2016. RCTs conducted among human adults studied the effects of green tea and green tea extract on serum adiponectin concentrations as an outcome variable was included. The weighted mean differences and standard deviations (SD) of change in serum adiponectin levels were calculated. The random effects model was used for deriving a summary of mean estimates with their corresponding SDs. The protocol was registered with PROSPERO (No. CRD42017057716).

Result: Fourteen RCTs were eligible to be included in the systematic review and the meta-analysis. Our analysis showed that green tea did not significantly affect adiponectin concentrations in comparison with placebo (weighted mean difference = ?0.02 µg/ml, 95% confidence interval [CI], ?0.41, 0.38; p = 0.936). There was a substantial heterogeneity between studies (I² = 91.7%; p < 0.0001). Subgroup analyses based on sex, type of intervention, continent, and body mass index (BMI) could not explain the sources of heterogeneity. Metaregression analyses revealed that the dose and duration of green tea ingestion did not have any effect on adiponectin concentrations.

Conclusion: Green tea could not change the circulatory adiponectin levels. The dose and duration of green tea could not change the result. RCTs with longer follow-up periods and higher doses are needed to replicate our results.     

Consumption of black tea elicits an increase in plasma antioxidant potential in humans

Epidemiological studies suggest that the consumption of tea flavonoids may be associated with reduced risk of coronary heart disease, stroke and cancer-related deaths. The flavonoids are polyphenols which in vitro exhibit antioxidant properties. Tea flavonoids are known to be rapidly absorbed into the circulation following oral ingestion. To date few studies have demonstrated that these bioavailable flavonoids retain antioxidant properties in vivo. Nine healthy subjects aged between 26 and 59 (one male and eight females) took part in 3 study days. On 1 day subjects consumed no tea and on the other 2 days subjects drank either black tea with milk, or black tea alone at hourly intervals between 9.00 a.m. and 14.00 p.m. Blood was sampled at 9.00 a.m. and at 12.00 p.m. and 15.00 p.m. The antioxidant potential of plasma was determined using the ferric reducing antioxidant power (FRAP) assay. Subjects consuming no tea exhibited no significant change in FRAP across the 6 hours of the study day. Similarly consumption of milky tea produced no change in FRAP between 9.00 a.m. and 12.00 p.m. and the 50% increase in FRAP noted between 12.00 p.m. and 15.00 p.m. was not statistically significant. When the subjects consumed black tea without milk FRAP increased by 65% between 9.00 a.m. and 12.00 p.m. (P = 0.02) and at 15.00 p.m. was 76% higher than at 9.00 a.m. (P = 0.002). Heavy consumption of black tea thus appears to elevate circulating antioxidant potentials in vivo. This is an effect which appears to be totally negated by the drinking of tea with milk. Although tea may thus represent an important source of dietary antioxidants in many societies, the role of tea in reducing risk of major disease states needs to be investigated in more detail.     

中国成年双生子饮茶行为分布特征

目的 描述中国双生子登记系统（CNTR）成年双生子饮茶行为的分布特征,探索饮茶行为在双生子人群中的分布规律,为探究遗传和环境因素对饮茶行为的影响提供线索。方法 样本选自2010-2018年在CNTR进行登记的双生子,纳入≥18岁且具有饮茶信息的双生子共25 264对进行分析,描述双生子中饮茶行为的人群、地区分布特征,以及不同卵型双生子饮茶行为一致率和对内饮茶量差异分布情况。结果 研究对象年龄（35.38±12.45）岁,每周饮茶者占比17.0%,饮茶量（3.36±2.44）杯/d。男性、50~59岁、南方、城镇、文化程度高、双生子中先出生的个体中每周饮茶者比例较高（P<0.05）,未婚者中比例较低（P<0.001）。双生子对内分析发现同卵饮茶行为一致率均大于异卵,饮茶遗传度为13.45%（11.38%~15.51%）,除女性亚组外,不同性别、年龄、地区间饮茶一致率差异有统计学意义（均P<0.05）;根据性别、年龄、地区分层后仅男性同卵一致率始终呈大于异卵趋势。同性别双生子对内饮茶量差异在男性中呈现同卵小于异卵的特征（P<0.05）,而女性中差异不明显。结论 本研究双生子人群饮茶行为的分布存在人群和地区差异,饮茶行为主要受环境因素影响,遗传因素影响较弱,且遗传效应大小在不同性别、年龄、地区间不尽相同,性别可修饰这一遗传作用。     

Comparative activity of antioxidants from wheat sprouts,Morinda citrifolia,fermented papaya and white tea

Hydroalcoholic extracts from wheat sprouts, white tea, Morinda citrifolia and fermented papaya were analysed to determine their reducing power and antioxidant activity. The results show that the micromoles of potassium ferricyanide reduced by a quantity of extract corresponding to 1 g of the various dehydrated starting tissues are: 12.91±0.83 (wheat sprouts), 10.66±1.22 (M. citrifolia), 17.06±1.24 (white tea), and 1.05±0.09 (fermented papaya). In addition the results show a strong oxygen superoxide scavenging activity in the extracts from white tea, M. citrifolia and wheat sprouts. The activity of the fermented papaya extract is the lowest. The thin-layer chromatography and UV spectrophotometry of the extracts show in each source a mixture of antioxidant compounds probably belonging to the families of reducing glycosides and polyphenols. The chromatographic pattern of the antioxidant compounds and the UV spectrum are quite different in the various sources.     

Both aluminum and polyphenols in green tea decoction (<Emphasis Type="Italic">Camellia sinensis</Emphasis>) affect iron status and hematological parameters in rats

Background Green tea leaves naturally contain high levels of polyphenols and aluminum (Al). Polyphenols in green tea decoction are considered to be one of the major factors responsible of low iron status. However, the effects of Al from green tea decoction on iron status and hematological parameters remained unclear. Aim of the study The objective was to investigate the Al absorption from green tea decoction and studied its influence on iron status and hematological parameters in rats. Methods During the experiment period, rats were given the experimental diet + a simple dose of Al sulfate with or without graded doses of green tea decoction (25, 50 and 100 g/l). The Al absorption was evaluated in the serum; however, iron status was evaluated by the iron concentration in the liver, kidney, spleen and femur. In addition, the hemoglobin and hematocrit were evaluated. Results Our results showed that the serum Al significantly increased between 61.5 and 342%, as tea doses-dependant. The Al sulfate significantly decreased the reserve of iron in all studied organs between 21.7 and 17% (P < 0.05). In groups receiving green tea decoction alone or Al + graded doses of tea, the reserve of iron significantly decreased in all studied organs between 59.4 and 18.5% (P < 0.01). Al alone or associated with drinking doses of tea significantly decreased hemoglobin concentration between 23.6 and 9% (P < 0.05) and hematocrit between 12.7 and 7% (P < 0.01). Conclusion Our data showed that Al from green tea decoction was more absorbed in the serum than Al sulfate. Al absorption was associated with low iron status and reduction of hemoglobin and hematocrit. Considering that Al competes with iron in different stage of erythropoiesis including transferrin binding, so we could assume that the negative effect of tea on iron status arises not only from polyphenols iron complexes but also from Al released in tea decoction.     

Consumption of polyphenol-rich juar tea increases endothelium-bound extracellular superoxide dismutase levels in men with metabolic syndrome: link with LDL oxidizability

Endothelium-bound extracellular superoxide dismutase (eEC-SOD), a major antioxidative enzyme in the vasculature, is involved in anti-atherogenesis by inhibiting low-density lipoprotein (LDL) oxidation. The objective was to investigate whether the polyphenol-rich juar tea had beneficial effects on LDL oxidation and eEC-SOD levels in patients with metabolic syndrome (MetS). A total of 20 men with MetS participated in a randomized cross-over trial, comparing consumption of five cups/day of juar tea with that of a polyphenol-poor tea, barley tea, for 4 weeks. Although there was no change in LDL oxidizability after consumption of either tea, juar tea significantly increased eEC-SOD levels by 16% (p < 0.05), whereas barley tea significantly decreased levels by 15% (p < 0.05). It is noteworthy that the changes in eEC-SOD were positively associated with those in LDL oxidizability after tea consumption (r ² = 0.11, p < 0.05). Tea polyphenols may provide anti-atherosclerotic effects by inhibiting LDL oxidation through EC-SOD bound to the endothelium.     

Identification of microbial metabolites derived from in vitro fecal fermentation of different polyphenolic food sources

ObjectiveThe biological effects of dietary polyphenols are linked to their bioavailability and catabolism in humans. The colon, with its symbiotic microbiota, is an active site where complex polyphenolic compounds are possibly modified to smaller and more absorbable molecules. The aim of this study was to identify the major metabolites derived from microbial colonic fermentation of some common polyphenol-rich foods.MethodsAn in vitro fecal fermentation model was applied to 16 polyphenol-rich foods and polyphenolic precursors. Phenolic metabolites were identified by high-performance liquid chromatography coupled with tandem mass spectrometric detection.ResultsTwenty-four phenolic fermentation metabolites were characterized. Some metabolites were common to several polyphenol-rich foods, whereas others were characteristic of specific sources.ConclusionThe metabolites identified in vitro likely are generated in the human colon after consumption of polyphenol-rich foods. Their occurrence in plasma and/or urine should be considered when evaluating the bioavailability of polyphenols from specific food groups in humans and in the definition of markers of exposure to specific foods or food groups in epidemiologic studies. However, the search for these and other microbial metabolites after a feeding study in vivo should consider their possible further conjugation at the level of the liver.     

Improvement of blood lipid profiles by Goishi tea polyphenols in a randomised,double-blind,placebo-controlled clinical study

Dyslipidaemia is a risk factor for arteriosclerosis. Recent studies have shown that dyslipidaemia is effectively prevented by various polyphenols. In this clinical study (UMIN trial: 000024028), we evaluated the beneficial effects of polyphenols contained in Goishi tea on blood lipid profiles. Seventy-seven subjects with LDL cholesterol (CHO) ≧120?mg/mL were randomly divided into two groups for 12 weeks of polyphenol intake as follows: the Goishi tea group for daily consumption of Goishi tea containing 122?mg of polyphenols and the placebo group for the corresponding consumption of a placebo drink containing 12.2?mg of polyphenols. Intake of Goishi tea polyphenols tended to increase HDL CHO and suppress the elevation of triglycerides. These effects were particularly notable among the subjects with a body mass index <25?kg/m². These findings suggest that Goishi tea polyphenols may suppress arteriosclerosis and reduce cardiovascular event risk by improving blood lipid profiles and thereby preventing dyslipidaemia.     

Green Tea Consumption and Serum Malondialdehyde-Modified LDL Concentrations in Healthy Subjects

Objective: Green tea was shown to inhibit LDL oxidation, platelet aggregation, and matrix metalloproteinases (MMPs) activities in vitro. We tried to elucidate whether or not green tea consumption may have these effects in vivo, which may be protective against atherosclerotic disease.

Methods: We measured serum malondialdehyde-modified LDL (MDA-LDL) concentrations and urine 8-epi-prostaglandin (PG) F_2α in 22 healthy male nonsmokers. They drank 7 cups/day of water for 2 weeks and drank 7 cups/day of green tea for the next 2 weeks. Regarding platelet aggregation, plasma thromboxane B₂ (TXB₂) and 6-keto-PGF_1α concentrations and ex vivo platelet aggregation were evaluated. Plasma MMP-2 and -9 concentrations were also measured.

Results: Of the 22 subjects, 20 had been in the habit of drinking green tea before the study. Plasma catechins concentrations significantly decreased at the end of the water period and then increased at the end of the green tea period. Although no change in plasma LDL-cholesterol concentrations (110 ± 33 vs. 113 ± 28 mg/dL, p = NS) was found, MDA-LDL concentrations (84 ± 45 vs. 76 ± 40 IU/L, p < 0.05) and the ratio of MDA-LDL/LDL-cholesterol (0.74 ± 0.21 vs. 0.65 ± 0.20, p < 0.02) significantly decreased at the end of the green tea period. However, no significant changes were observed in urine 8-epi-PGF_2α concentrations, in platelet aggregation, nor in plasma TXB₂, 6-keto-PGF_1α or MMP concentrations.

Conclusion: Daily consumption of green tea decreased serum MDA-LDL concentrations, but it had no significant effects on platelet aggregation, platelet TX production or plasma MMPs concentrations. Our results suggest that green tea consumption may inhibit LDL oxidation in vivo.     

Apoptosis Inducing Effects of Kuding Tea Polyphenols in Human Buccal Squamous Cell Carcinoma Cell Line BcaCD885

Tea polyphenols are functional substances present in tea. Kuding tea as a traditional drink also contains these compounds. After 25, 50 and 100 μg/mL of Kuding tea polyphenol treatment for 48 h, cell proliferation of human buccal squamous cell carcinoma cell line BcaCD885 was inhibited, and the 100 μg/mL of Kuding tea polyphenol showed the highest inhibitory rate at 72.3%. Compared to the lower concentration, the 100 μg/mL of Kuding tea polyphenols significantly (p < 0.05) induced apoptosis as determined by flow cytometry analysis, the content of sub-G1 cancer cells was 32.7%. By RT-PCR and western blot assays, Kuding tea polyphenol significantly induced apoptosis in BcaCD885 cancer cells (p < 0.05) by upregulating caspase-3, caspase-8, caspase-9, Fas/FasL, Bax, p53, p21, E2F1, p73 and downregulating Bcl-2, Bcl-xL, HIAP-1, and HIAP-2 mRNA and protein expressions. Kuding tea polyphenols thus present apoptosis inducing effects in vitro.     

一起由呋喃丹引起的急性中毒事件的调查分析

目的 分析一起由呋喃丹引起的酥油茶急性中毒事件的流行特征和处置过程，为今后类似事件的调查处置提供科学依据。方法 对2018年丹巴县梭坡乡发生的一起急性中毒事件开展现场流行病学调查、动物实验和实验室检测，采用描述性流行病学方法对该起疫情资料进行分析。结果 本次疫情共有病例26例，涉及3个村的村民，总罹患率为41.27%，无死亡病例。26例病例均于饮用酥油茶后数分钟发病，主要临床表现为呕吐、头晕、瞳孔缩小、恶心等。现场1只犬饮用样品酥油茶后发病。实验室在所采集的样品酥油茶、呕吐物、糌粑中同时检出呋喃丹。结论 本起疫情是呋喃丹引起的急性中毒事件，为点源传播模式。应急处置中有效流行病学调查，简易的动物实验可为快速采样检测、病例救治提供方向；病例及时送医救治，严格落实源头控制措施是降低伤亡，防止事件扩大的关键环节。     

Tea Polyphenols as Prospective Natural Attenuators of Brain Aging

No organism can avoid the process of aging, which is often accompanied by chronic disease. The process of biological aging is driven by a series of interrelated mechanisms through different signal pathways, including oxidative stress, inflammatory states, autophagy and others. In addition, the intestinal microbiota play a key role in regulating oxidative stress of microglia, maintaining homeostasis of microglia and alleviating age-related diseases. Tea polyphenols can effectively regulate the composition of the intestinal microbiota. In recent years, the potential anti-aging benefits of tea polyphenols have attracted increasing attention because they can inhibit neuroinflammation and prevent degenerative effects in the brain. The interaction between human neurological function and the gut microbiota suggests that intervention with tea polyphenols is a possible way to alleviate brain-aging. Studies have been undertaken into the possible mechanisms underpinning the preventative effect of tea polyphenols on brain-aging mediated by the intestinal microbiota. Tea polyphenols may be regarded as potential neuroprotective substances which can act with high efficiency and low toxicity.