GREEN TEA CATECHINS ARE POTENT SENSITIZERS OF RYANODINE RECEPTOR TYPE 1 (RYR1)

PubMed Central

Feng, Wei; Cherednichenko, Gennady; Ward, Chris W.; Padilla, Isela T.; Cabrales, Elaine; Lopez, José R.; Eltit, José M.; Allen, Paul D.; Pessah, Isaac N.

2010-01-01

Catechins, polyphenols extracted from green tea leaves, have a broad range of biological activities although the specific molecular mechanisms responsible are not known. At the high experimental concentrations typically used polyphenols bind to membrane phospholipid and also are easily auto-oxidized to generate superoxide anion and semiquinones, and can adduct to protein thiols. We report that the type 1 ryanodine receptor (RyR1) is a molecular target that responds to nanomolar (−)-epigallocatechin-3-gallate (EGCG) and (−)-epicatechin-3-gallate (ECG). Single channel analyses demonstrate EGCG (5-10nM) increases channel open probability (Po) 2-fold, by lengthening open dwell time. The degree of channel activation is concentration dependent and is rapidly and fully reversible. Four related catechins, EGCG, ECG, EGC ((−)-epigallocatechin) and EC ((−)-epicatechin) showed a rank order of activity toward RyR1 (EGCG>ECG>>EGC>>>EC). EGCG and ECG enhance the sensitivity of RyR1 to activation by ≤100μM cytoplasmic Ca2+ without altering inhibitory potency by >100μM Ca2+. EGCG as high as 10μM in the extracellular medium potentiated Ca2+ transient amplitudes evoked by electrical stimuli applied to intact myotubes and adult FDB fibers, without eliciting spontaneous Ca2+ release or slowing Ca2+ transient recovery. The results identify RyR1 as a sensitive target for the major tea catechins EGCG and ECG, and this interaction is likely to contribute to their observed biological activities. PMID:20471964

The effects of co-administration of butter on the absorption, metabolism and excretion of catechins in rats after oral administration of tea polyphenols.

PubMed

Zhang, Liang; Han, Yuhui; Xu, Liwei; Liang, Yuhong; Chen, Xin; Li, Junsong; Wan, Xiaochun

2015-07-01

In Southwest China, tea polyphenols are usually utilized by way of butter tea. Tea polyphenols inhibit the absorption and biosynthesis of fatty acids in vivo, but the effects of butter on the pharmacokinetics of tea polyphenols have drawn less concern. A rapid UHPLC-MS/MS method was used to quantitatively determine the catechins in the plasma, feces and bile of rats after the oral administration of tea polyphenol or its combination with butter. In comparison with the single tea polyphenol treatment, the maximum plasma concentrations (Cmax) of the free EGCG, EGC, EC, GCG, GC and ECG significantly decreased after the co-administration of butter. The mean residence times (MRT) of the free EGCG, EGC, EC, GC and ECG were also significantly prolonged. When the plasma samples were treated with β-glucuronidase and arylsulfatase, the pharmacokinetic parameters of the total catechins (free and conjugated forms) were not affected by the co-administration of butter. These results indicated that the total absorption of catechins was not affected by butter, but the metabolism of catechins had been changed. Furthermore, the fecal catechins were significantly increased by butter. The total fecal amount and excretion ratio of all catechins were increased highly. The biliary excretion of EGCG, EGC, EC, GCG and GC was significantly increased by the co-administration of butter. To sum up, the butter changed the metabolism of catechins in vivo by decreasing the plasma concentration of the free catechins but increasing the conjugated catechins.

Molecular insights into the differences in anti-inflammatory activities of green tea catechins on IL-1β signaling in rheumatoid arthritis synovial fibroblasts.

PubMed

Fechtner, Sabrina; Singh, Anil; Chourasia, Mukesh; Ahmed, Salahuddin

2017-08-15

In this study, we found that catechins found in green tea (EGCG, EGC, and EC) differentially interfere with the IL-1β signaling pathway which regulates the expression of pro-inflammatory mediators (IL-6 and IL-8) and Cox-2 in primary human rheumatoid arthritis synovial fibroblasts (RASFs). EGCG and EGC inhibited IL-6, IL-8, and MMP-2 production and selectively inhibited Cox-2 expression. EC did not exhibit any inhibitory effects. When we looked at the expression of key signaling proteins in the IL-1β signaling pathway, we found all the tested catechins could inhibit TAK-1 activity. Therefore, the consumption of green tea offers an overall anti-inflammatory effect. Molecular docking analysis confirms that EGCG, EGC, and EC all occupy the active site of the TAK1 kinase domain. However, EGCG occupies the majority of the TAK1 active site. In addition to TAK1 inhibition, EGCG can also inhibit P38 and nuclear NF-κB expression whereas EC and EGC were not effective inhibitors. Our findings suggest one of the main health benefits associated with the consumption of green tea are due to the activity of EGCG and EGC which are both present at higher amounts. Although EGCG is the most effective catechin at inhibiting downstream inflammatory signaling, its effectiveness could be hindered by the presence of EC. Therefore, varying EC content in green tea may reduce the anti-inflammatory effects of other potential catechins in green tea. Copyright © 2017. Published by Elsevier Inc.

Analysis of some selected catechins and caffeine in green tea by high performance liquid chromatography.

PubMed

El-Shahawi, M S; Hamza, A; Bahaffi, S O; Al-Sibaai, A A; Abduljabbar, T N

2012-10-15

Green tea seems to have a positive impact on health due to the catechins-found as flavanols. Thus, the present study was aimed to develop a low cost reversed phase high performance liquid chromatographic (HPLC) method for simultaneous determination of flavanol contents, namely catechin (C), epicatechin (EC), epigallocatechin (EGC), epicatechin 3-gallate (ECG) and epigallocatechin 3-gallate (EGCG) and caffeine in 29 commercial green tea samples available in a Saudi Arabian local market. A C-18 reversed-phase column, acetonitrile-trifluoroacetic acid as a mobile phase, coupled with UV detector at 205 nm, was successfully used for precise analysis of the tested analytes in boiled water of digested tea leaves. The average values of N (No. of theoretical plates), HETP (height equivalent of theoretical plates) and R(s) (separation factor) (at 10 μg ml(-1) of the catechins EC, EGC, EGCG and ECG) were 2.6×10(3)±1.2×10(3), 1.7×10(-3)±4.7×10(-4) cm and 1.7±5.53×10(-2), respectively. The developed HPLC method demonstrated excellent performance, with low limits of detection (LOD) and quantification (LOQ) of the tested catechins of 0.004-0.05 μg ml(-1) and 0.01-0.17 μg ml(-1), respectively, and recovery percentages of 96-101%. The influence of infusion time (5-30 min) and temperature on the content of the flavanols was investigated by HPLC. After a 5 min infusion of the tea leaves, the average concentrations of caffeine, catechin, EC, EGC, ECG and EGCG were found to be in the ranges 0.086-2.23, 0.113-2.94, 0.58-10.22, 0.19-24.9, 0.22-13.9 and 1.01-43.3 mg g(-1), respectively. The contents of caffeine and catechins followed the sequence: EGCG>EGC>ECG>EC>C>caffeine. The method was applied satisfactorily for the analysis of (+)-catechin, even at trace and ultra trace concentrations of catechins. The method was rapid, accurate, reproducible and ideal for routine analysis. Copyright © 2012 Elsevier Ltd. All rights reserved.

Formulation with ascorbic acid and sucrose modulates catechin bioavailability from green tea

PubMed Central

Peters, Catrina M.; Green, Rodney J.; Janle, Elsa M.; Ferruzzi, Mario G.

2009-01-01

In order to investigate the impact of common food ingredients on catechin absorption, green tea (GT) extract (50 mg) was formulated plain, with sucrose (GT+S), with ascorbic acid (GT+AA) and with sucrose and ascorbic acid (GT+S+AA). Bioavailability and bioaccessibility were assessed in Sprague Dawley rats and an in vitro digestion/Caco-2 cell model respectively. Absorption of epigallocatechin (EGC) and epigallocatechin gallate (EGCG) was significantly (P<0.05) enhanced in GT+S+AA formulations (AUC0-6h= 3237.0 and 181.8 pmol*h/L plasma respectively) relative to GT control (AUC0-6h = 1304.1 and 61.0 pmol*h/L plasma respectively). In vitro digestive recovery was higher for EGC and epicatechin (EC) (∼51-53%) relative to EGCG and epicatechin gallate (ECG) (< 20%) and was modestly enhanced in GT+S and GT+S+AA formulations. Accumulation of EGC, EGCG and ECG by Caco-2 cells was significantly (P<0.05) higher from GT+S+AA compared to other formulations while retention of catechins was enhanced in presence of ascorbic acid. These data suggest that formulation with sucrose and ascorbic acid may improve catechin bioavailability by enhancing bioaccessibility and intestinal uptake from tea. PMID:20161530

Primary cancer prevention by green tea, and tertiary cancer prevention by the combination of green tea catechins and anticancer compounds.

PubMed

Fujiki, Hirota; Sueoka, Eisaburo; Watanabe, Tatsuro; Suganuma, Masami

2015-03-01

Green tea is a daily beverage, a non-oxidized non-fermented product containing at least four green tea catechins. Considering our first results when repeated applications of (-)-epigallocatechin gallate (EGCG) prevented tumor promotion in mouse skin, we have continued to look at green tea as a possible cancer preventive agent. 1) The 10-year prospective cohort study by Drs. K. Nakachi and K. Imai revealed that drinking 10 Japanese-size cups (120 mL/cup) of green tea per day delayed cancer onset in humans by 7.3 years among females and by 3.2 years among males. The delay of cancer onset is of course significant evidence of primary cancer prevention in humans. 2) In collaboration with Dr. H. Moriwaki's group we successfully presented a prototype of tertiary cancer prevention showing that 10 Japanese-size cups of green tea daily, supplemented with tablets of green tea extract (G.T.E), reduced recurrence of colorectal adenomas in polypectomy patients by 51.6% (from 31% to 15%). 3) In 1999, we first reported that the combination of green tea catechins and non-steroidal anti-inflammatory drugs showed synergistic anticancer effects in both in vitro and in vivo experiments, along with elucidation of the mechanism. 4) Further studies by other investigators have revealed that various combinations of EGCG or green tea extract and anticancer compounds inhibit tumor volume in xenograft mouse models implanted with various human cancer cell lines. Green tea is a cancer preventive, and green tea catechins act as synergists with anticancer compounds.

Tea Catechin Auto-oxidation Dimers are Accumulated and Retained by Caco-2 Human Intestinal Cells

PubMed Central

Neilson, Andrew P.; Song, Brian J.; Sapper, Teryn N.; Bomser, Joshua A.; Ferruzzi, Mario G.

2010-01-01

Despite the presence of bioactive catechin B-ring auto-oxidation dimers in tea, little is known regarding their absorption in humans. Our hypothesis for this research is that catechin auto-oxidation dimers are present in teas and are absorbable by human intestinal epithelial cells. Dimers [theasinensins (THSNs) and P-2 analogs) were quantified in commercial teas by HPLC-MS. (−)-Epigallocatechin (EGC) and (−)-epigallocatechin gallate (EGCG) homodimers were present at 10–43 and 0–62 µmol/g leaf, respectively. EGC-EGCG heterodimers were present at 0–79 µmol/g. The potential intestinal absorption of these dimers was assessed using Caco-2 intestinal cells. Catechin monomers and dimers were detected in cells exposed to media containing monomers and preformed dimers. Accumulation of dimers was significantly greater than monomers from test media. Three h accumulation of EGC and EGCG was 0.19– 0.55% and 1.24–1.35% respectively. Comparatively, 3h accumulation of the EGC P-2 analog, and THSNs C/E was 0.89 ± 0.28% and 1.53 ± 0.36%. Accumulation of P-2, and THSNs A/D was 6.93 ± 2.1%, and 10.1 ± 3.6%. EGCG-EGC heterodimer P-2 analog, and THSN B 3h accumulation was 4.87 ± 2.2%, and 4.65 ± 2.8% respectively. One h retention of P-2, and THSNs A/D was 171 ± 22%, and 29.6 ± 9.3% of accumulated amount suggesting intracellular oxidative conversion of THSNs to P-2. These data suggest that catechin dimers present in the gut lumen may be readily absorbed by intestinal epithelium. PMID:20579525

[Study on the analytical methods of catechins in tea and green tea polyphenol samples by high performance liquid chromatography].

PubMed

Dai, J; Wang, H X; Chen, S W; Tang, J

2001-09-01

Hypersil BDS C18 and Zorbax SB C18, suitable to separate simultaneously seven kinds of catechins and caffeine, were screened out from seven brands of reversed-phase columns. Mobile phase was a solution of methanol-water-acetic acid (or trifluoro acetic acid). Seven kinds of catechins in tea samples from six places in China and three green tea polyphenol(GTP) samples from different producers were separated and determined in 30 min by isocratic and gradient elutions. The effects of mobile phase components and temperature of column on retention parameters of catechins and caffeine are reviewed. Chromatographic conditions and pretreatment methods of samples were optimized. Gallocatechin gallate(GCG) and (-)-catechin gallate(CG) were identified by electrospray ionization mass spectrometry(ESI-MS) and prepared by high performance liquid chromatography for quantitative analysis. The other catechins, (-)-epigallocatechin (EGC), (+)-catechin (D-C), (-)-epicatechin(EC), (-)-epigallocatechin gallate(EGCG), (-)-epicatechin gallate(ECG) were identified with standards.

Effects of different brewing conditions on catechin content and sensory acceptance in Turkish green tea infusions.

PubMed

Saklar, Sena; Ertas, Erdal; Ozdemir, Ibrahim S; Karadeniz, Bulent

2015-10-01

The optimal brewing conditions for Turkish green tea were determined on the basis of extracted catechins and sensory attributes. Green tea infusions were prepared at 75, 85 and 95 °C with brewing times of 1, 2, 3, 5, 10, 20, 30 and 45 min. The amounts of epistructured catechins (EGCG, EGC, ECG, EC), non-epistructured catechins (C, GC, GCG) and caffeine in brewed tea samples were analysed. Sensory analyses were performed by nine trained panelists for infusion colour, taste, aroma and overall acceptability. Brewing at 85 °C for 3 min was found to be the optimal condition, where the EGCG content was at a maximum of 50.69 mg/100 ml with the highest sensory scores. It was observed that the yield of epistructured catechins increased rapidly for the first 3-5 min of brewing at 85 °C, and increased brewing time resulted in a decrease in the yield of epistructured catechins. The amount of nonepistructured catechins continued to increase with longer extraction times. Sensory scores for infusion colour, taste, aroma and overall acceptability were highest at 3 and 5 min brewing times at all temperatures. Sensory scores were very low for 30 and 45 min brewing at 85 and 95 °C due to the bitter taste and dark colour.

Anti-infective properties of epigallocatechin-3-gallate (EGCG), a component of green tea

PubMed Central

Steinmann, J; Buer, J; Pietschmann, T; Steinmann, E

2013-01-01

The consumption of green tea (Camellia sinensis) has been shown to have many physiological and pharmacological health benefits. In the past two decades several studies have reported that epigallocatechin-3-gallate (EGCG), the main constituent of green tea, has anti-infective properties. Antiviral activities of EGCG with different modes of action have been demonstrated on diverse families of viruses, such as Retroviridae, Orthomyxoviridae and Flaviviridae and include important human pathogens like human immunodeficiency virus, influenza A virus and the hepatitis C virus. Furthermore, the molecule interferes with the replication cycle of DNA viruses like hepatitis B virus, herpes simplex virus and adenovirus. Most of these studies demonstrated antiviral properties within physiological concentrations of EGCG in vitro. In contrast, the minimum inhibitory concentrations against bacteria were 10–100-fold higher. Nevertheless, the antibacterial effects of EGCG alone and in combination with different antibiotics have been intensively analysed against a number of bacteria including multidrug-resistant strains such as methicillin-resistant Staphylococcus aureus or Stenotrophomonas maltophilia. Furthermore, the catechin EGCG has antifungal activity against human-pathogenic yeasts like Candida albicans. Although the mechanistic effects of EGCG are not fully understood, there are results indicating that EGCG binds to lipid membranes and affects the folic acid metabolism of bacteria and fungi by inhibiting the cytoplasmic enzyme dihydrofolate reductase. This review summarizes the current knowledge and future perspectives on the antibacterial, antifungal and antiviral effects of the green tea constituent EGCG. PMID:23072320

Determination of green tea catechins in human plasma using liquid chromatography-electrospray ionization mass spectrometry.

PubMed

Masukawa, Yoshinori; Matsui, Yuji; Shimizu, Namii; Kondou, Naoki; Endou, Hidenori; Kuzukawa, Michiya; Hase, Tadashi

2006-04-13

A method for the sensitive and specific determination of eight green tea catechins, consisting of catechin (C), epicatechin (EC), gallocatechin (GC), epigallocatechin (EGC), catechin-3-gallate (CG), epicatechin-3-gallate (ECG), gallocatechin-3-gallate (GCG) and epigallocatechin-3-gallate (EGCG), in human plasma was established. For optimization of conditions for LC-ESIMS, the separation of the eight catechins was achieved chromatographically using Inertsil ODS-2 column combined with a gradient elution system of 0.1M aqueous acetic acid and 0.1M acetic acid in acetonitrile. Detection using a mass spectrometer was performed with selected ion monitoring at m/z=289 for E and EC, 305 for GC and EGC, 441 for CG and ECG, and 457 for GCG and EGCG under negative ESI. A preparative procedure, consisting of the addition of perchloric acid and acetonitrile to the plasma for deproteinizing and the subsequent addition of potassium carbonate solution to remove excess acid, was developed. In six different plasma with the eight catechins spiked at two different concentrations, the average recoveries were in the range between 72.7 and 84.1%, which resulted from the matrix effect and preparative loss, with coefficients of variance being 8.2-19.8% among individuals. The levels of the catechins in prepared plasma solutions that were kept at 5 degrees C within 24h were stable, which allows us to simply analyze many prepared plasma solutions using an autosampler overnight. When using this method to analyze the eight catechins in human plasma after oral ingestion of a commercial green tea beverage, we detected all the catechins absorbed into human blood for the first time. This also suggested that extremely small amounts of the eight catechins orally ingested may be absorbed based on each absorptive property for the catechins. The method should enable pharmacokinetic studies of green tea catechins in humans.

Physiologically based pharmacokinetic modeling of tea catechin mixture in rats and humans.

PubMed

Law, Francis C P; Yao, Meicun; Bi, Hui-Chang; Lam, Stephen

2017-06-01

Although green tea ( Camellia sinensis) (GT) contains a large number of polyphenolic compounds with anti-oxidative and anti-proliferative activities, little is known of the pharmacokinetics and tissue dose of tea catechins (TCs) as a chemical mixture in humans. The objectives of this study were to develop and validate a physiologically based pharmacokinetic (PBPK) model of tea catechin mixture (TCM) in rats and humans, and to predict an integrated or total concentration of TCM in the plasma of humans after consuming GT or Polyphenon E (PE). To this end, a PBPK model of epigallocatechin gallate (EGCg) consisting of 13 first-order, blood flow-limited tissue compartments was first developed in rats. The rat model was scaled up to humans by replacing its physiological parameters, pharmacokinetic parameters and tissue/blood partition coefficients (PCs) with human-specific values. Both rat and human EGCg models were then extrapolated to other TCs by substituting its physicochemical parameters, pharmacokinetic parameters, and PCs with catechin-specific values. Finally, a PBPK model of TCM was constructed by linking three rat (or human) tea catechin models together without including a description for pharmacokinetic interaction between the TCs. The mixture PBPK model accurately predicted the pharmacokinetic behaviors of three individual TCs in the plasma of rats and humans after GT or PE consumption. Model-predicted total TCM concentration in the plasma was linearly related to the dose consumed by humans. The mixture PBPK model is able to translate an external dose of TCM into internal target tissue doses for future safety assessment and dose-response analysis studies in humans. The modeling framework as described in this paper is also applicable to the bioactive chemical in other plant-based health products.

Green Tea Catechins Quench the Fluorescence of Bacteria-Conjugated Alexa Fluor Dyes

PubMed Central

Zhao, Lin; Li, Wei; Zhu, Shu; Tsai, Sheena; Li, Jianhua; Tracey, Kevin J.; Wang, Ping; Fan, Saijun; Sama, Andrew E.; Wang, Haichao

2013-01-01

Accumulating evidence suggests that Green tea polyphenolic catechins, especially the (-)-epigallocatechin gallate (EGCG), can be cross-linked to many proteins, and confer a wide range of anti-bacterial activities possibly by damaging microbial cytoplasmic lipids and proteins. At the doses that conferred protection against lethal polymicrobial infection (induced by cecal ligation and puncture), EGCG significantly reduced bacterial loads particularly in the liver and lung. To elucidate its bactericidal mechanisms, we determined whether EGCG affected the fluorescence intensities of bacteria-conjugated Alexa Fluor 488 or 594 dyes. When mixed with unconjugated Alexa Fluor 488 or 594 dyes, EGCG or analogs did not affect the fluorescence intensity of these dyes. In a sharp contrast, EGCG and some analogs (e.g., Catechin Gallate, CG), markedly reduced the fluorescence intensity of Gram-positive Staphylococcus aureus-conjugated Alexa 594 and Gram-negative Escherichia coli-conjugated Alexa 488. Interestingly, co-treatment with ethanol impaired the EGCG-mediated fluorescence quenching of the G+ S. aureus, but not of the G- E. coli-conjugated Alexa Flour dyes. In light of the notion that Alexa Fluor dyes can be quenched by aromatic amino acids, it is plausible that EGCG exerts anti-microbial activities possibly by altering microbial protein conformations and functions. This possibility can now be explored by screening other fluorescence-quenching agents for possible antimicrobial activities. PMID:24011199

Safety assessment of green tea based beverages and dried green tea extracts as nutritional supplements.

PubMed

Dekant, Wolfgang; Fujii, Kenkichi; Shibata, Eiichiro; Morita, Osamu; Shimotoyodome, Akira

2017-08-05

The safety of green tea infusions and green tea extract (GTE)-based products is reviewed regarding catechins. Epigallocatechin 3-gallate (EGCG), the major catechin present in green tea, is suspected of being responsible for liver toxicity reported in humans consuming food supplements. Intake of EGCG with green tea infusions and GTE-based beverages is up to about 450mg EGCG/person/day in Europe and higher in Asia. Consumption of green tea is not associated with liver damage in humans, and green tea infusion and GTE-based beverages are considered safe in the range of historical uses. In animal studies, EGCG's potency for liver effects is highly dependent on conditions of administration. Use of NOAELs from bolus administration to derive a tolerable upper intake level applying the margin of safety concept results in acceptable EGCG-doses lower than those from one cup of green tea. NOAELs from toxicity studies applying EGCG with diet/split of the daily dose are a better point of departure for risk characterization. In clinical intervention studies, liver effects were not observed after intakes below 600mg EGCG/person/day. Thus, a tolerable upper intake level of 300mg EGCG/person/day is proposed for food supplements; this gives a twofold safety margin to clinical studies that did not report liver effects and a margin of safety of 100 to the NOAELs in animal studies with dietary administration of green tea catechins. Copyright © 2017 Elsevier B.V. All rights reserved.

Green tea epigallo-catechin-galleate ameliorates the development of obliterative airway disease.

PubMed

Liang, Olin D; Kleibrink, Bjoern E; Schuette-Nuetgen, Katharina; Khatwa, Umakanth U; Mfarrej, Bechara; Subramaniam, Meera

2011-09-01

Lung transplantation has the worst outcome compared to all solid organ transplants due to chronic rejection known as obliterative bronchiolitis (OB). Pathogenesis of OB is a complex interplay of alloimmune-dependent and -independent factors, which leads to the development of inflammation, fibrosis, and airway obliteration that have been resistant to therapy. The alloimmune-independent inflammatory pathway has been the recent focus in the pathogenesis of rejection, suggesting that targeting this may offer therapeutic benefits. As a potent anti-inflammatory agent, epigallo-catechin-galleate (EGCG), a green tea catechin, has been very effective in ameliorating inflammation in a variety of diseases, providing the rationale for its use in this study in a murine heterotopic tracheal allograft model of OB. Mice treated with EGCG had reduced inflammation, with significantly less neutrophil and macrophage infiltration and significantly reduced fibrosis. On further investigation into the mechanisms, inflammatory cytokines keratinocyte (KC), interleukin-17 (IL-17), and tumor necrosis factor-α (TNF-α), involved in neutrophil recruitment, were reduced in the EGCG-treated mice. In addition, monocyte chemokine monocyte chemoattractant protein-1 (MCP-1) was significantly reduced by EGCG treatment. Antifibrotic cytokine interferon-γ-inducible protein-10 (IP-10) was increased and profibrotic cytokine transforming growth factor-β (TGF-β) was reduced, further characterizing the antifibrotic effects of EGCG. These findings suggest that EGCG has great potential in ameliorating the development of obliterative airway disease.

Simultaneous determination of twelve tea catechins by high-performance liquid chromatography with electrochemical detection.

PubMed

Sano, M; Tabata, M; Suzuki, M; Degawa, M; Miyase, T; Maeda-Yamamoto, M

2001-06-01

A high-performance liquid chromatographic method with electrochemical detection was developed for the determination of twelve tea catechins including four major catechins: epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG) and epigallocatechin gallate (EGCG); four of their epimers at the C-2 position, C, GC, CG and GCG; and four methylated catechin derivatives, epigallocatechin-3-O-(3-O-methyl)gallate, gallocatechin-3-O-(3-O-methyl)gallate, epigallocatechin-3-O-(4-O-methyl)gallate and epicatechin-3-O-(3-O-methyl)gallate. These catechins were separated on an ODS C18 reversed-phase column by isocratic elution with 0.1 M NaH2PO4 buffer (pH 2.5)-acetonitrile (87:13) containing 0.1 mM EDTA.2Na. The detection limits (S/N = 3) of these catechins were approximately 10-40 pmol ml-1 at an applied voltage of 600 mV. Extracting these catechins from tea leaf powder with H2O-acetonitrile (1:1) at 30 degrees C for 40 min inhibited the epimerization at C-2 significantly from these epicatechins compared to extraction with hot water at 90 degrees C. This analytical method is sensitive to and appropriate for the simultaneous determination of various biologically active catechins in green tea.

Quantitative comparison of cancer and normal cell adhesion using organosilane monolayer templates: an experimental study on the anti-adhesion effect of green-tea catechins.

PubMed

Sakamoto, Rumi; Kakinuma, Eisuke; Masuda, Kentaro; Takeuchi, Yuko; Ito, Kosaku; Iketaki, Kentaro; Matsuzaki, Takahisa; Nakabayashi, Seiichiro; Yoshikawa, Hiroshi Y; Yamamoto, Hideaki; Sato, Yuko; Tanii, Takashi

2016-09-01

The main constituent of green tea, (-)-Epigallocatechin-3-O-gallate (EGCG), is known to have cancer-specific chemopreventive effects. In the present work, we investigated how EGCG suppresses cell adhesion by comparing the adhesion of human pancreatic cancer cells (AsPC-1 and BxPC-3) and their counterpart, normal human embryonic pancreas-derived cells (1C3D3), in catechin-containing media using organosilane monolayer templates (OMTs). The purpose of this work is (1) to evaluate the quantitativeness in the measurement of cell adhesion with the OMT and (2) to show how green-tea catechins suppress cell adhesion in a cancer-specific manner. For the first purpose, the adhesion of cancer and normal cells was compared using the OMT. The cell adhesion in different type of catechins such as EGCG, (-)-Epicatechin-3-O-gallate (ECG) and (-)-Epicatechin (EC) was also evaluated. The measurements revealed that the anti-adhesion effect of green-tea catechins is cancer-specific, and the order is EGCG≫ECG>EC. The results agree well with the data reported to date, showing the quantitativeness of the new method. For the second purpose, the contact area of cells on the OMT was measured by reflection interference contrast microscopy. The cell-OMT contact area of cancer cells decreases with increasing EGCG concentration, whereas that of normal cells remains constant. The results reveal a twofold action of EGCG on cancer cell adhesion-suppressing cell attachment to a candidate adhesion site and decreasing the contact area of the cells-and validates the use of OMT as a tool for screening cancer cell adhesion.

Potential role of green tea catechins in the management of oxidative stress-associated infertility.

PubMed

Roychoudhury, Shubhadeep; Agarwal, Ashok; Virk, Gurpriya; Cho, Chak-Lam

2017-05-01

Reactive oxygen species (ROS) are present in low concentrations in the genital tracts of males and females. Excessive ROS lead to oxidative stress, which damages DNA, lipids and proteins. Such molecular changes result in compromised vitality, increased morphological defects and decreased sperm motility in the male. In the female, oxidative stress interferes with oocyte maturation, and may inhibit in-vitro maturation of the oocyte. Recently, green tea supplementation has been reported to possess properties that may improve the quality of male and female gametes largely due to the ability of catechin polyphenols to quench ROS. Epigallocatechin-3-gallate (EGCG) is considered the most promising bioactive compound in green tea due to its strong antioxidant activity. The unique property of green tea catechins may potentially improve reproductive health and pose an important research area. We present a comprehensive overview on the effects and potential roles of green tea catechins on oxidative stress in male and female reproduction and fertility. In this review, possible mechanisms of action are highlighted to better understand the potential use of green tea catechins in the reduction of oxidative stress and its associated beneficial effects in the clinical setting. Copyright © 2017 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Extraction and isolation of catechins from tea.

PubMed

Vuong, Quan V; Golding, John B; Nguyen, Minh; Roach, Paul D

2010-11-01

Tea is a major source of catechins, which have become well known for their antioxidant potential. Numerous human, animal, and in vitro studies have linked tea catechins with prevention of certain types of cancers, reduction of the risks for obesity, diabetes, and cardiovascular disease, and improvement of the immune system. Tea catechins are widely used in various neutraceuticals, pharmaceuticals, and cosmetics for either enhancing product shelf-life or for enhancing human health. Thus, the demand for catechins has increased considerably. Catechins have been extracted and isolated from tea leaves by numerous methods through several steps including: treatment of the tea leaves, extraction of catechins from teas into solvents, isolation of catechins from other extracted components, and drying the preparations to obtain catechin extracts in a powder form. This paper outlines the physical and chemical properties of the tea catechins and reviews the extraction steps of the various extraction methods, as a basis to improve and further develop the extraction and isolation of the tea catechins.

Rapid tea catechins and caffeine determination by HPLC using microwave-assisted extraction and silica monolithic column.

PubMed

Rahim, A A; Nofrizal, S; Saad, Bahruddin

2014-03-15

A rapid reversed-phase high performance liquid chromatographic method using a monolithic column for the determination of eight catechin monomers and caffeine was developed. Using a mobile phase of water:acetonitrile:methanol (83:6:11) at a flow rate of 1.4 mL min(-1), the catechins and caffeine were isocratically separated in about 7 min. The limits of detection and quantification were in the range of 0.11-0.29 and 0.33-0.87 mg L(-1), respectively. Satisfactory recoveries were obtained (94.2-105.2 ± 1.8%) for all samples when spiked at three concentrations (5, 40 and 70 mg L(-1)). In combination with microwave-assisted extraction (MAE), the method was applied to the determination of the catechins and caffeine in eleven tea samples (6 green, 3 black and 2 oolong teas). Relatively high levels of caffeine were found in black tea, but higher levels of the catechins, especially epigallocatechin gallate (EGCG) were found in green teas. Copyright © 2013 Elsevier Ltd. All rights reserved.

Catechin Composition and Antioxidant Activity of Black Teas in Relation to Brewing Time.

PubMed

Koch, Wojciech; Kukula-Koch, Wirginia; Głowniak, Kazimierz

2017-11-01

Black tea infusions are one of the most popular beverages across the world. Their extract composition depends on several factors, brewing time being one of the most important determinants. The aim of the present study was to determine the catechin composition of different black tea infusions using a validated LC electrospray ionization time-of-flight MS method. Additionally, total phenolic content (TPC) and antioxidant activity of infusions were evaluated using Folin-Ciocalteu reagent and stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). An optimized LC-MS method enabled the precise identification of the studied catechins [epicatechin (EC), EC gallate (ECG), epigallocatechin (EGC), and epigallocatechin-3-gallate (EGCG)] and gallic acid (GA). The major catechin in all investigated teas was EGC (25.6 mg/100 cm3 after 4 min of brewing). EC was present at the lowest concentration in all extracts. TPC and antiradical scavenging activity were in a good agreement with catechins and GA content. In general, the longer the brewing time, the higher the concentration of catechin, TPC, and antioxidant activity values. However, it should be noted that after 2 min brewing, most phenolics had already been extracted, and extract composition did not significantly change at a prolonged extraction time.

Determination of catechins in human urine subsequent to tea ingestion by high-performance liquid chromatography with electrochemical detection.

PubMed

Yang, B; Arai, K; Kusu, F

2000-07-15

The title determination was conducted by HPLC with electrochemical detection using an ODS column and a mobile phase of acetonitrile: 0.1 M phosphate buffer (pH 2.5) (15:85, v/v). The eight catechins, gallocatechin (GC), epigallocatechin (EGC), catechin (C), epicatechin (EC), epigallocatechin gallate (EGCg), gallocatechin gallate (GCg), epicatechin gallate (ECg), and catechin gallate (Cg), were detected at 0.6 V vs Ag/AgCl. Good linear relationships between current and amount were noted for 0.5-250 pmol of each catechin, with a correlation coefficient of 0.999 in each case. The detection limit for any one was 0.5 pmol (signal to noise ratio, S/N = 3). After the ingestion of 340 ml canned green tea, GC, EGC, C, and EC, mostly in conjugated form, were determined in urine samples. Conjugated catechins were hydrolyzed by enzymes using sulfatase and beta-glucuronidase. The time courses of the above four catechins showed a maxima at 1-3 h after tea ingestion. (+), (-)-EC and (+), (-)-C were present in canned tea.

Using tea stalk lignocellulose as an adsorbent for separating decaffeinated tea catechins.

PubMed

Ye, J H; Jin, J; Liang, H L; Lu, J L; Du, Y Y; Zheng, X Q; Liang, Y R

2009-01-01

Lignocelluloses prepared from woody tea stalk, pine sawdust and sugarcane bagasse were used as adsorbents to isolate decaffeinated catechins from tea extracts and compared with synthetic macroporous resin HPD 600. HPD 600 had the highest adsorption capacity to catechins, followed by tea stalk lignocellulose while lignocelluloses of pine sawdust and bagasse the least. Tea stalk lignocellulose absorbed preferentially tea catechins and showed a good selectivity. HPD 600 absorbed caffeine and tea catechins simultaneously. The kinetics data of tea stalk lignocellulose showed a good fit with the Langmuir isotherm model. It is considered that tea stalk lignocellulose is an alternative low-cost adsorbent for preparing decaffeinated tea catechins.

EPIGALLOCATECHIN-3-GALLATE (EGCG), A GREEN TEA POLYPHENOL, SUPPRESSES HEPATIC GLUCONEOGENESIS THROUGH 5′-AMP-ACTIVATED PROTEIN KINASE

PubMed Central

Collins, Qu Fan; Liu, Hui-Yu; Pi, Jingbo; Liu, Zhenqi; Quon, Michael J.; Cao, Wenhong

2008-01-01

Epigallocatechin-3-gallate (EGCG), a main catechin of green tea, has been suggested to inhibit hepatic gluconeogenesis. However, the exact role and related mechanism have not been established. In this study, we examined the role of EGCG in hepatic gluconeogenesis at concentrations that are reachable by ingestion of pure EGCG or green tea, and are not toxic to hepatocytes. Our results show in isolated hepatocytes that EGCG at relatively low concentrations (≤ 1 μM) inhibited glucose production via gluconeogenesis and expression of key gluconeogenic genes. EGCG was not toxic at these concentrations while demonstrating significant cytotoxicity at 10 μM and higher concentrations. EGCG at 1 μM or lower concentrations effective in suppressing hepatic gluconeogenesis did not activate the insulin signaling pathway, but activated 5′-AMP-activated protein kinase (AMPK). The EGCG suppression of hepatic gluconeogenesis was prevented by blockade of AMPK activity. In defining the mechanism by which EGCG activates AMPK, we found that the EGCG activation of AMPK was mediated by the Ca2+/calmodulin-dependent protein kinase kinase (CaMKK). Furthermore, our results show that the EGCG activation of AMPK and EGCG suppression of hepatic gluconeogenesis were both dependent on production of reactive oxygen species (ROS), which was a known activator of CaMKK. Together, our results demonstrate an inhibitory role for EGCG in hepatic gluconeogenesis and shed new light on the mechanism by which EGCG suppresses gluconeogenesis. PMID:17724029

Anti-proliferative and differentiation-inducing activities of the green tea catechin epigallocatechin-3-gallate (EGCG) on the human eosinophilic leukemia EoL-1 cell line.

PubMed

Lung, H L; Ip, W K; Wong, C K; Mak, N K; Chen, Z Y; Leung, K N

2002-12-06

A novel approach for the treatment of leukemia is the differentiation therapy in which immature leukemia cells are induced to attain a mature phenotype when exposed to differentiation inducers, either alone or in combinations with other chemotherapeutic or chemopreventive drugs. Over the past decade, numerous studies indicated that green tea catechins (GTC) could suppress the growth and induce apoptosis on a number of human cancer cell lines. However, the differentiation-inducing activity of GTC on human tumors remains poorly understood. In the present study, the effect of the major GTC epigallocatechin-3-gallate (EGCG) on the proliferation and differentiation of a human eosinophilc leukemic cell line, EoL-1, was examined. Our results showed that EGCG suppressed the proliferation of the EoL-1 cells in a dose-dependent manner, with an estimated IC(50) value of 31.5 microM. On the other hand, EGCG at a concentration of 40 microM could trigger the EoL-1 cells to undergo morphological differentiation into mature eosinophil-like cells. Using RT-PCR and flow cytometry, it was found that EGCG upregulated the gene and protein expression of two eosinophil-specific granule proteins, the major basic protein (MBP) and eosinophil peroxidase (EPO), in EoL-1 cells. Taken together, our findings suggest that EGCG can exhibit anti-leukemic activity on a human eosinophilic cell line EoL-1 by suppressing the proliferation and by inducing the differentiation of the leukemia cells.

Identification of epigallocatechin-3-O-(3-O-methyl)-gallate (EGCG3''Me) and amino acid profiles in various tea (Camellia sinensis L.) cultivars.

PubMed

Ji, Hyang-Gi; Lee, Yeong-Ran; Lee, Min-Seuk; Hwang, Kyeng Hwan; Kim, Eun-Hee; Park, Jun Seong; Hong, Young-Shick

2017-10-01

This article includes experimental data on the identification of epigallocatechin-3-O-(3-O-methyl)-gallate (EGCG3''Me) by 2-dimensional (2D) proton ( 1 H) NMR analysis and on the information of amino acid and catechin compound profiles by HPLC analysis in leaf extracts of various tea cultivars. These data are related to the research article " Metabolic phenotyping of various tea (Camellia sinensis L.) cultivars and understanding of their intrinsic metabolism " (Ji et al., 2017) [1]. The assignment for EGCG3x''Me by 1 H NMR analysis was also confirmed with spiking experiment of its pure chemical.

Erythrocyte membrane transporters during human ageing: modulatory role of tea catechins.

PubMed

Pandey, Kanti Bhooshan; Jha, Rashmi; Rizvi, Syed Ibrahim

2013-02-01

Ageing is associated with many physiological and cellular changes, many of which are due to alterations in the plasma membrane. The functions of membrane transporter proteins are crucial for the maintenance of ionic homeostasis between the extra- and intracellular environments. The aim of the present study was to determine the status of erythrocyte membrane transporters, specifically Ca(2+) -ATPases, Na(+) /K(+) -ATPases and the Na(+) /H(+) exchanger (NHE), during ageing in humans. Furthermore, because tea catechins have been reported to possess strong anti-oxidant potential, the study was extended to evaluate the effect of (-)-epicatechin (EC), (-)-epicatechin-3-gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin-3-gallate (EGCG) on these transporters as a function of human age. The study was performed on 97 normal healthy subjects (62 men, 35 women; 16-80 years old). To investigate the effects of tea catechins, subjects were divided into three groups: young (<40 years old; n = 34); middle-aged (40-60 years old; n = 32); and old (>60 years old; n = 31). Erythrocyte ghosts/cell suspension from each group were incubated with ECG, EGCG, EGC and EC (10 μmol/L) for 30 min at 37°C prior to assay. Ageing significantly increased NHE activity and decreased Ca(2+) -ATPase activity. There were no significant changes in Na(+) /K(+) -ATPase activity during the ageing process. (-)-Epigallocatechin-3-gallate, EGC, ECG and EC effectively mitigated the changes in membrane transporter activity in erythrocytes from all age groups; however, the effect was more pronounced in the old age group. We hypothesize that impairment in -bound transporters may be one of the possible mechanisms underlying the pathological events during ageing. A higher intake of catechin-rich food may provide some protection against age-dependent diseases. © 2012 The Authors Clinical and Experimental Pharmacology and Physiology © 2012 Wiley Publishing Asia Pty Ltd.

Hyaluronic acid-green tea catechin micellar nanocomplexes: Fail-safe cisplatin nanomedicine for the treatment of ovarian cancer without off-target toxicity.

PubMed

Bae, Ki Hyun; Tan, Susi; Yamashita, Atsushi; Ang, Wei Xia; Gao, Shu Jun; Wang, Shu; Chung, Joo Eun; Kurisawa, Motoichi

2017-12-01

The green tea catechin, (-)-epigallocatechin-3-O-gallate (EGCG), has gained significant attention as a potent adjuvant to enhance the antitumor efficacy of cisplatin while mitigating its harmful side effects. Herein we report the development of a fail-safe cisplatin nanomedicine constructed with hyaluronic acid-EGCG conjugate for ovarian cancer therapy. A simple mixing of this conjugate and cisplatin induces spontaneous self-assembly of micellar nanocomplexes having a spherical core-shell structure. The surface-exposed hyaluronic acid enables efficient delivery of cisplatin into CD44-overexpressing cancer cells via receptor-mediated endocytosis whereas the internally packed EGCG moieties offer an environment favorable for the encapsulation of cisplatin. In addition, the antioxidant effect of EGCG moieties ensures fail-safe protection against off-target organ toxicity originating from cisplatin-evoked oxidative stress. Pharmacokinetic and biodistribution studies reveal the prolonged blood circulation and preferential tumor accumulation of intravenously administered nanocomplexes. Moreover, the nanocomplexes exhibit superior antitumor efficacy over free cisplatin while displaying no toxicity in both a subcutaneous xenograft model and peritoneal metastatic model of human ovarian cancer. Our findings demonstrate proof of concept for the feasibility of green tea catechin-based micellar nanocomplexes as a safe and effective cisplatin nanomedicine for ovarian cancer treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preventive effects of C-2 epimeric isomers of tea catechins on mouse type I allergy.

PubMed

Yoshino, Kyoji; Miyase, Toshio; Sano, Mitsuaki

2010-01-01

The preventive effects of C-2 epimeric isomers of (-)-epigallocatechin-3-O-gallate (EGCG) and the O-methylated derivative, (-)-epigallocatechin-3-O-(3-O-methyl)gallate (EGCG3''Me), against ovalbumin-induced type I allergy in male mice were investigated. EGCG and EGCG3''Me exhibited strong antiallergic effects by oral administration at doses of 25 and 50 mg/kg body weight. The antiallergic effects of their C-2 epimers, (-)-gallocatechin-3-O-gallate and (-)-gallocatechin-3-O-(3-O-methyl)gallate (GCG3''Me), on mouse type I allergy were almost equivalent to and/or as strong as those of the corresponding original catechins, respectively. Oral administration of these compounds at a dose of 50 mg/kg body weight tended to suppress the increases in interleukin-4 levels in the abdominal walls of allergic mice and immunoglobulin E levels in the serum of allergic mice. In particular, the administration of GCG3''Me exhibited significant effects on the production and/or release of these parameters stimulating type 2 T helper cells and mast cells in the type I allergic process. These results indicated that C-2 epimerization of tea catechins, which are produced during heat processing at high temperatures, would not be disadvantageous for preventive effects on type I allergy.

Biotransformation of catechin and extraction of active polysaccharide from green tea leaves via simultaneous treatment with tannase and pectinase.

PubMed

Baik, Joo Hyun; Shin, Kwang-Soon; Park, Yooheon; Yu, Kwang-Won; Suh, Hyung Joo; Choi, Hyeon-Son

2015-08-30

Green tea is a dietary source of bioactive compounds for human health. Enzymatic treatments induce the bioconversion of bioactive components, which can improve biological activities. In this study, we investigated the effect of simultaneous treatment with tannase and Rapidase on biotransformation of catechins and extraction of polysaccharide from green tea extract (GTE). Tannase and pectinase treatments induced the biotransformation of catechins and altered tea polysaccharide () content. The addition of GTE to the enzyme reaction resulted in a significant increase in degallated catechins, including gallic acid, a product of the tannase reaction (314.5-4076.0 µg mL(-1)) and a reduction in epigallocatechin gallate (EGCG). Biotransformation of catechins improved the radical scavenging activity of GTE. Pectinase treatment led to change of TPS composition in GTE by hydrolyzing polysaccharides. In addition, pectinase-driven hydrolysis in polysaccharides significantly increased TPS-induced Interleukin 6 (IL-6) production in macrophages. In particular, treatment of Rapidase (TPS-Ra) led to the highest IL-6 production among TPS samples, similar to treatment of highly purified pectinase (TPS-GTE), a positive control. Simultaneous processing with tannase and Rapidase can be an efficient method for the extraction of bioactive polysaccharides and biotransformation of catechins with enhanced radical scavenging activity from green tea. © 2014 Society of Chemical Industry.

Inhibitory effect of six green tea catechins and caffeine on the growth of four selected human tumor cell lines.

PubMed

Valcic, S; Timmermann, B N; Alberts, D S; Wächter, G A; Krutzsch, M; Wymer, J; Guillén, J M

1996-06-01

Green tea is an aqueous infusion of dried unfermented leaves of Camellia sinensis (family Theaceae) from which numerous biological activities have been reported including antimutagenic, antibacterial, hypocholesterolemic, antioxidant, antitumor and cancer preventive activities. From the aqueous-alcoholic extract of green tea leaves, six compounds (+)-gallocatechin (GC), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin gallate (EGCG) and caffeine, were isolated and purified. Together with (+)-catechin, these compounds were tested against each of four human tumor cells lines (MCF-7 breast carcinoma, HT-29 colon carcinoma, A-427 lung carcinoma and UACC-375 melanoma). The three most potent green tea components against all four tumor cell lines were EGCG, GC and EGC. EGCG was the most potent of the seven green tea components against three out of the four cell lines (i.e. MCF-7 breast cancer, HT-29 colon cancer and UACC-375 melanoma). On the basis of these extensive in vitro studies, it would be of considerable interest to evaluate all three of these components in comparative preclinical in vivo animal tumor model systems before final decisions are made concerning which of these potential chemopreventive drugs should be taken into broad clinical trials.

Content Variation of Catechin Markers, Total Phenolics and Caffeine in Green Tea Dietary Supplements.

PubMed

Abourashed, Ehab A; Roberson, Cindy Leslie A; Elsharkawy, Nancy

2016-01-01

Green tea (Camellia sinensis) preparations are among the top selling products in the United States dietary supplements market. Numerous manufacturers claim different levels of specific catechin markers in their products while many others use total phenolic concentration instead, or not at all. Limited quality control results have been published for green tea dietary supplements over the past seven years. Thus, the goal of this work was to correlate determined levels of phenolics, catechins, and caffeine with manufacturer label claims for selected dietary supplement products (26 total) purchased in the United States. The Folin-Ciocalteu (FC) method was used to determine the total phenolic content while reversed-phase (RP) HPLC was used to quantify the major catechins: epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG), epigallocatechin gallate (EGCG). The developed HPLC method was validated for accuracy and precision. It utilized a C8 column with gradient elution of acetonitrile in 0.1% aqueous formic acid over 11 min total run time. Peak detection was performed at 280 nm. Caffeine was also included in the HPLC method as another non-phenolic alkaloid marker commonly found in green tea. Both methods showed a good correlation between the content of catechins and polyphenolic compounds in the selected products. The ranges of total catechins and polyphenol concentrations were 3.8-70.2% and 3.6-95.8%, respectively, while that of caffeine was 0.8-11.2%. The selected products displayed a wide range of marker levels. A lack of conformity in disclosing the actual levels of marker compounds was also noticed in the labeling of many products.

Cluster analysis of the biochemical composition in 53 Sichuan EGCG3"Me tea resources

NASA Astrophysics Data System (ADS)

Li, J. H.; Chen, S. X.; Zhu, M. Z.; Meng, X. L.

2017-09-01

The EGCG3"Me contents in the young tea leaves of 102 tea resources in sichuan were analyzed accurately using HPLC-DAD. The results revealed that there was a wide variation in EGCG3"Me levels among different tea resources. The EGCG3"Me content in different tea resources was in a range from 0 to 11.04 mg/g, mean was 2.33 mg/g.53 tea resources contained EGCG3"Me, accounting for 51.96% of the total number of resources survey. Shucha5, Jinguanyin, Chengxi11, Fenghuang-dancong, Chongpi 71-1 were found to contain higher EGCG3"Me content (>10mg/g).Cluster analysis showed that: 53 Sichuan EGCG3"Me tea resources were divided into six groups and the difference was obvious between their biochemical composition; tea resources rich in EGCG3"Me were mainly distributed in Sichuan, Chongqing and Fujian Province, mostly were shrub and mid-leaf, mainly existed in tea resources which were suitable to make green tea, oolong tea. The morphological and biochemical distribution provided a good theoretical basis for selecting and utilizing higher EGCG3"Me resources.

Bioavailability of catechins from tea: the effect of milk.

PubMed

van het Hof, K H; Kivits, G A; Weststrate, J A; Tijburg, L B

1998-05-01

To assess the blood concentration of catechins following green or black tea ingestion and the effect of addition of milk to black tea. Twelve volunteers received a single dose of green tea, black tea and black tea with milk in a randomized cross-over design with one-week intervals. Blood samples were drawn before and up to eight hours after tea consumption. The study was performed at the Unilever Research Vlaardingen in The Netherlands. Twelve healthy adult volunteers (7 females, 5 males) participated in the study. They were recruited among employees of Unilever Research Vlaardingen. Green tea, black tea and black tea with semi-skimmed milk (3 g tea solids each). Consumption of green tea (0.9 g total catechins) or black tea (0.3 g total catechins) resulted in a rapid increase of catechin levels in blood with an average maximum change from baseline (CVM) of 0.46 micromol/l (13%) after ingestion of green tea and 0.10 micromol/l (13%) in case of black tea. These maximum changes were reached after (mean (s.e.m.)) t=2.3 h (0.2) and t=2.2 h (0.2) for green and black tea respectively. Blood levels rapidly declined with an elimination rate (mean (CVM)) of t1/2=4.8 h (5%) for green tea and t1/2=6.9 h (8%) for black tea. Addition of milk to black tea (100 ml in 600 ml) did not significantly affect the blood catechin levels (areas under the curves (mean (CVM) of 0.53 h. micromol/l (11%) vs 0.60 h. micromol/l (9%) for black tea and black tea with milk respectively. Catechins from green tea and black tea are rapidly absorbed and milk does not impair the bioavailability of tea catechins.

Green tea polyphenol epigallocatechin-3-gallate (EGCG) as adjuvant in cancer therapy.

PubMed

Lecumberri, Elena; Dupertuis, Yves Marc; Miralbell, Raymond; Pichard, Claude

2013-12-01

Green tea catechins, especially epigallocatechin-3-gallate (EGCG), have been associated with cancer prevention and treatment. This has resulted in an increased number of studies evaluating the effects derived from the use of this compound in combination with chemo/radiotherapy. This review aims at compiling latest literature on this subject. Keywords including EGCG, cancer, chemotherapy, radiotherapy and side effects, were searched using PubMed and ScienceDirect databases to identify, analyze, and summarize the research literature on this topic. Most of the studies on this subject up to date are preclinical. Relevance of the findings, impact factor, and date of publication were critical parameters for the studies to be included in the review. Additive and synergistic effects of EGCG when combined with conventional cancer therapies have been proposed, and its anti-inflammatory and antioxidant activities have been related to amelioration of cancer therapy side effects. However, antagonistic interactions with certain anticancer drugs might limit its clinical use. The use of EGCG could enhance the effect of conventional cancer therapies through additive or synergistic effects as well as through amelioration of deleterious side effects. Further research, especially at the clinical level, is needed to ascertain the potential role of EGCG as adjuvant in cancer therapy. Copyright © 2013 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Tea-induced improvement of endothelial function in humans: No role for epigallocatechin gallate (EGCG).

PubMed

Lorenz, Mario; Rauhut, Franziska; Hofer, Christine; Gwosc, Stefanie; Müller, Eda; Praeger, Damaris; Zimmermann, Benno F; Wernecke, Klaus-Dieter; Baumann, Gert; Stangl, Karl; Stangl, Verena

2017-05-23

Consumption of tea is inversely associated with cardiovascular diseases. However, the active compound(s) responsible for the protective effects of tea are unknown. Although many favorable cardiovascular effects in vitro are mediated by epigallocatechin gallate (EGCG), its contribution to the beneficial effects of tea in vivo remains unresolved. In a randomised crossover study, a single dose of 200 mg EGCG was applied in three different formulas (as green tea beverage, green tea extract (GTE), and isolated EGCG) to 50 healthy men. Flow-mediated dilation (FMD) and endothelial-independent nitro-mediated dilation (NMD) was measured before and two hours after ingestion. Plasma levels of tea compounds were determined after each intervention and correlated with FMD. FMD significantly improved after consumption of green tea containing 200 mg EGCG (p < 0.01). However, GTE and EGCG had no significant effect on FMD. NMD did not significantly differ between interventions. EGCG plasma levels were highest after administration of EGCG and lowest after consumption of green tea. Plasma levels of caffeine increased after green tea consumption. The results show that EGCG is most likely not involved in improvement of flow-mediated dilation by green tea. Instead, other tea compounds, metabolites or combinations thereof may play a role.

Bactericidal catechins damage the lipid bilayer.

PubMed

Ikigai, H; Nakae, T; Hara, Y; Shimamura, T

1993-04-08

The mode of antibacterial action of, the green tea (Camellia sinensis) extracts, (-)-epigallocatechin gallate (EGCg) and (-)-epicatechin (EC) was investigated. Strong bactericidal EGCg caused leakage of 5,6-carboxyfluorescein from phosphatidylcholine liposomes (PC), but EC with very weak bactericidal activity caused little damage to the membrane. Phosphatidylserine and dicetyl phosphate partially protected the membrane from EGCg-mediated damage when reconstituted into the liposome membrane with PC. EGCg, but not EC, caused strong aggregation and NPN-fluorescence quenching of PC-liposomes and these actions were markedly lowered in the presence of negatively charged lipids. These results show that bactericidal catechins primarily act on and damage bacterial membranes. The observation that Gram-negative bacteria are more resistant to bactericidal catechins than Gram-positive bacteria can be explained to some extent by the presence of negatively charged lipopolysaccharide.

EGCG inhibit chemical reactivity of iron through forming an Ngal-EGCG-iron complex.

PubMed

Bao, Guan-Hu; Xu, Jie; Hu, Feng-Lin; Wan, Xiao-Chun; Deng, Shi-Xian; Barasch, Jonathan

2013-12-01

Accumulated evidence indicates that the interconversion of iron between ferric (Fe(3+)) and ferrous (Fe(2+)) can be realized through interaction with reactive oxygen species in the Fenton and Haber-Weiss reactions and thereby physiologically effects redox cycling. The imbalance of iron and ROS may eventually cause tissue damage such as renal proximal tubule injury and necrosis. Many approaches were exploited to ameliorate the oxidative stress caused by the imbalance. (-)-Epigallocatechin-3-gallate, the most active and most abundant catechin in tea, was found to be involved in the protection of a spectrum of renal injuries caused by oxidative stress. Most of studies suggested that EGCG works as an antioxidant. In this paper, Multivariate analysis of the LC-MS data of tea extracts and binding assays showed that the tea polyphenol EGCG can form stable complex with iron through the protein Ngal, a biomarker of acute kidney injury. UV-Vis and Luminescence spectrum methods showed that Ngal can inhibit the chemical reactivity of iron and EGCG through forming an Ngal-EGCG-iron complex. In thinking of the interaction of iron and ROS, we proposed that EGCG may work as both antioxidant and Ngal binding siderphore in protection of kidney from injuries.

Green tea catechins: defensive role in cardiovascular disorders.

PubMed

Bhardwaj, Pooja; Khanna, Deepa

2013-07-01

Green tea, Camellia sinensis (Theaceae), a major source of flavonoids such as catechins, has recently shown multiple cardiovascular health benefits through various experimental and clinical studies. These studies suggest that green tea catechins prevent the incidence of detrimental cardiovascular events, and also lower the cardiovascular mortality rate. Catechins present in green tea have the ability to prevent atherosclerosis, hypertension, endothelial dysfunction, ischemic heart diseases, cardiomyopathy, cardiac hypertrophy and congestive heart failure by decreasing oxidative stress, preventing inflammatory events, reducing platelet aggregation and halting the proliferation of vascular smooth muscle cells. Catechins afford an anti-oxidant effect by inducing anti-oxidant enzymes, inhibiting pro-oxidant enzymes and scavenging free radicals. Catechins present anti-inflammatory activity through the inhibition of transcriptional factor NF-κB-mediated production of cytokines and adhesion molecules. Green tea catechins interfere with vascular growth factors and thus inhibit vascular smooth muscle cell proliferation, and also inhibit thrombogenesis by suppressing platelet adhesion. Additionally, catechins could protect vascular endothelial cells and enhance vascular integrity and regulate blood pressure. In this review various experimental and clinical studies suggesting the role of green tea catechins against the markers of cardiovascular disorders and the underlying mechanisms for these actions are discussed. Copyright © 2013 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Green tea (Camellia sinensis) catechins and vascular function.

PubMed

Moore, Rosalind J; Jackson, Kim G; Minihane, Anne M

2009-12-01

The health benefits of green tea (Camellia sinensis) catechins are becoming increasingly recognised. Amongst the proposed benefits are the maintenance of endothelial function and vascular homeostasis and an associated reduction in atherogenesis and CVD risk. The mounting evidence for the influential effect of green tea catechins on vascular function from epidemiological, human intervention and animal studies is subject to review together with exploration of the potential mechanistic pathways involved. Epigallocatechin-3-gallate, one of the most abundant and widely studied catechin found in green tea, will be prominent in the present review. Since there is a substantial inconsistency in the published data with regards to the impact of green tea catechins on vascular function, evaluation and interpretation of the inter- and intra-study variability is included. In conclusion, a positive effect of green tea catechins on vascular function is becoming apparent. Further studies in animal and cell models using physiological concentrations of catechins and their metabolites are warranted in order to gain some insight into the physiology and molecular basis of the observed beneficial effects.

Effect of girdling at various positions of 'Huang Zhi Xiang' tea tree (Camellia sinensis) on the contents of catechins and starch in fresh leaf.

PubMed

Chen, Yulong; Jiang, Yueming; Shi, John; Xu, Xinlan; Yang, Shaoyu; Duan, Jun

2011-06-01

The contents of starch and catechins in the fresh leaf of 'Huang Zhi Xiang' Oolong tea trees girdled at the bottom, middle (on the big branches) and top (on the small branches) were determined. The study demonstrated that the starch contents from girdled trees were significantly higher (p<0.05) than that from non-girdled ones. Furthermore, the contents of (-)-epicatechin (EC), (-)-epigallocatechin (EGC), total catechins (TC) and simple catechins (SC) from girdled trees were significantly higher (p<0.05) than those from non-girdled ones. Especially, the contents of (-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG) and catechin gallate (CG) from girdled at the middle were also significantly higher (p<0.05) than those from the non-girdled. The starch contents were negatively correlated with the contents of (-)-gallocatechin (GC), EC, SC, TC and EGC, while positively correlated with the contents of EGCG and CG in fresh shoots.

Comparison of effects of green tea catechins on apicomplexan hexose transporters and mammalian orthologues.

PubMed

Slavic, Ksenija; Derbyshire, Elvira T; Naftalin, Richard J; Krishna, Sanjeev; Staines, Henry M

2009-11-01

Here we have investigated the inhibitory properties of green tea catechins on the Plasmodium falciparum hexose transporter (PfHT), the Babesia bovis hexose transporter 1 (BboHT1) and the mammalian facilitative glucose transporters, GLUT1 and GLUT5, expressed in Xenopus laevis oocytes. (-)-Epicatechin-gallate (ECG) and (-)-epigallocatechin-gallate (EGCG) inhibited D-glucose transport by GLUT1 and PfHT, and D-fructose transport by GLUT5, with apparent K(i) values between 45 and 117 microM. BboHT1 was more potently inhibited by the ungallated catechins (-)-epicatechin (EC) and (-)-epigallocatechin (EGC), with apparent K(i) values of 108 and 168 microM, respectively. Site-directed mutagenesis experiments provided little further support for previously reported models of catechin binding to hexose transporters. Furthermore, P. falciparum growth inhibition by catechins was not affected by the external D-glucose concentration. Our results provide new data on the inhibitory action of catechins against sugar transporters but were unable to elucidate the antimalarial mechanism of action of these agents.

Comparison of effects of green tea catechins on apicomplexan hexose transporters and mammalian orthologues

PubMed Central

Slavic, Ksenija; Derbyshire, Elvira T.; Naftalin, Richard J.; Krishna, Sanjeev; Staines, Henry M.

2009-01-01

Here we have investigated the inhibitory properties of green tea catechins on the Plasmodium falciparum hexose transporter (PfHT), the Babesia bovis hexose transporter 1 (BboHT1) and the mammalian facilitative glucose transporters, GLUT1 and GLUT5, expressed in Xenopus laevis oocytes. (−)-Epicatechin-gallate (ECG) and (−)-epigallocatechin-gallate (EGCG) inhibited d-glucose transport by GLUT1 and PfHT, and d-fructose transport by GLUT5, with apparent Ki values between 45 and 117 μM. BboHT1 was more potently inhibited by the ungallated catechins (−)-epicatechin (EC) and (−)-epigallocatechin (EGC), with apparent Ki values of 108 and 168 μM, respectively. Site-directed mutagenesis experiments provided little further support for previously reported models of catechin binding to hexose transporters. Furthermore, P. falciparum growth inhibition by catechins was not affected by the external d-glucose concentration. Our results provide new data on the inhibitory action of catechins against sugar transporters but were unable to elucidate the antimalarial mechanism of action of these agents. PMID:19577593

In Vitro and In Silico Studies of the Molecular Interactions of Epigallocatechin-3-O-gallate (EGCG) with Proteins That Explain the Health Benefits of Green Tea.

PubMed

Saeki, Koichi; Hayakawa, Sumio; Nakano, Shogo; Ito, Sohei; Oishi, Yumiko; Suzuki, Yasuo; Isemura, Mamoru

2018-05-28

Green tea has been shown to have beneficial effects on many diseases such as cancer, obesity, inflammatory diseases, and neurodegenerative disorders. The major green tea component, epigallocatechin-3- O -gallate (EGCG), has been demonstrated to contribute to these effects through its anti-oxidative and pro-oxidative properties. Furthermore, several lines of evidence have indicated that the binding affinity of EGCG to specific proteins may explain its mechanism of action. This review article aims to reveal how EGCG-protein interactions can explain the mechanism by which green tea/EGCG can exhibit health beneficial effects. We conducted a literature search, using mainly the PubMed database. The results showed that several methods such as dot assays, affinity gel chromatography, surface plasmon resonance, computational docking analyses, and X-ray crystallography have been used for this purpose. These studies have provided evidence to show how EGCG can fit or occupy the position in or near functional sites and induce a conformational change, including a quaternary conformational change in some cases. Active site blocking, steric hindrance by binding of EGCG near an active site or induced conformational change appeared to cause inhibition of enzymatic activity and other biological activities of proteins, which are related to EGCG's biological oligomer and formation of their toxic aggregates, leading to the prevention of neurodegenerative diseases and amyloidosis. In conclusion, these studies have provided useful information on the action of green tea/catechins and would lead to future studies that will provide further evidence for rational EGCG therapy and use EGCG as a lead compound for drug design.

Metabolic phenotyping of various tea (Camellia sinensis L.) cultivars and understanding of their intrinsic metabolism.

PubMed

Ji, Hyang-Gi; Lee, Yeong-Ran; Lee, Min-Seuk; Hwang, Kyeong Hwan; Kim, Eun-Hee; Park, Jun Seong; Hong, Young-Shick

2017-10-15

Recently, we selected three tea (Camellia sinensis) cultivars that are rich in taste, epigallocatechin-3-O-gallate (EGCG) and epigallocatechin-3-O-(3-O-methyl)-gallate (EGCG3″Me) and then cultivated them through asexual propagation by cutting in the same region. In the present study, proton nuclear magnetic resonance ( 1 H NMR)-based metabolomics was applied to characterize the metabotype and to understand the metabolic mechanism of these tea cultivars including wild type tea. Of the tea leaf metabolite variations, reverse associations of amino acid metabolism with catechin compound metabolism were found in the rich-taste, and EGCG- and EGCG3″Me-rich tea cultivars. Indeed, the metabolism of individual catechin compounds in the EGCG3″Me-rich cultivar differed from those of other tea cultivars. The current study highlights the distinct metabolism of various tea cultivars newly selected for cultivation and the important role of metabolomics in understanding the metabolic mechanism. Thus, comprehensive metabotyping is a useful method to assess and then develop a new plant cultivar. Copyright © 2017 Elsevier Ltd. All rights reserved.

'Benifuuki' green tea containing o-methylated catechin reduces symptoms of Japanese cedar pollinosis: a randomized, double-blind, placebo-controlled trial.

PubMed

Masuda, Sawako; Maeda-Yamamoto, Mari; Usui, Satoko; Fujisawa, Takao

2014-06-01

Methylated catechin, one of the active ingredients in green tea, has been reported to ameliorate allergic reactions. We evaluated the efficacy of 'Benifuuki' green tea, which contains O-methylated epigallocatechin-3-O-[3-O-methyl] gallate (O-methylated EGCG), in alleviating Japanese cedar pollinosis (JCP). The study was a double-blind, randomized, placebo-controlled trial. The subjects with JCP were randomly assigned to drink 700ml of 'Benifuuki' green tea containing O-methylated EGCG or 'Yabukita' green tea (not containing O-methylated EGCG) as a placebo every day from December 2007 through March 2008, which includes the pollen season. The primary outcome was the area under the curve (AUC) of symptom scores during the peak pollen season. Fifty-one adults with JCP participated in the study. Twenty-six subjects were assigned to 'Benifuuki' and 25 to 'Yabukita'. The AUC of symptom score during the peak pollen season in the 'Benifuuki' group was significantly smaller than in the 'Yabukita' group for each of runny nose, itchy eyes, tearing, total nasal symptom score, total ocular symptom score, nasal symptom-medication score and ocular symptom-medication score. The total QOL-related questionnaire score for one week in the peak pollen season was significantly better in the 'Benifuuki' group. Increase in the peripheral eosinophil count in response to pollen exposure was suppressed in the 'Benifuuki' group. No adverse events were reported in either group. 'Benifuuki' green tea containing a large amount of O-methylated EGCG reduced the symptoms of JCP and has potential as a complementary/alternative medicine for treating seasonal allergic rhinitis.

Using Defatted Rice Bran as a Bioadsorbent for Carrying Tea Catechins.

PubMed

Shi, Meng; Yang, Ya-Ping; Jin, Jing; Huang, Long-Yue; Ye, Jian-Hui; Liang, Yue-Rong

2015-10-01

The potential of rice bran as a bioabsorbent for tea catechins was examined. Defatted rice bran had the highest adsorption capacity for tea catechins and the best selectivity for (-)-epigallocatechin gallate over total catechins among water-washed rice bran and untreated rice bran. The adsorption characteristics of tea catechins onto defatted rice bran were determined over a range of concentration (0.5 to 2.5 g/L) and temperatures (10, 25, and 45 °C). The adsorption of tea catechins onto defatted rice bran showed excellent fitness with the pseudo-second-order model at different temperature. Both the Langmuir and Freundlich models adequately describe the isothermal adsorption of tea catechins onto defatted rice bran. The adsorption of total catechins on rice bran decreased from 10 to 25 °C, whereas was greatly enhanced at 45 °C. The adsorption system of bioadsorbent with multiconstituents may not be as simple as the single-force-driving adsorption system. Protein and cellulose are the main contributors to the adsorption of tea catechins on defatted rice bran. Rice bran is regarded as a good fibre source that can be added to various food products and health supplements, which is a potential biocarrier for bioactives. Our study showed that defatted rice bran had a high affinity for tea catechins but caffeine, and provided a promising way for selective enrichment of catechins on defatted rice bran under practical condition. Protein and cellulose are the main contributors to the adsorption of tea catechins on defatted rice bran. © 2015 Institute of Food Technologists®

The safety of green tea and green tea extract consumption in adults - Results of a systematic review.

PubMed

Hu, Jiang; Webster, Donna; Cao, Joyce; Shao, Andrew

2018-06-01

A systematic review of published toxicology and human intervention studies was performed to characterize potential hazards associated with consumption of green tea and its preparations. A review of toxicological evidence from laboratory studies revealed the liver as the target organ and hepatotoxicity as the critical effect, which was strongly associated with certain dosing conditions (e.g. bolus dose via gavage, fasting), and positively correlated with total catechin and epigallocatechingallate (EGCG) content. A review of adverse event (AE) data from 159 human intervention studies yielded findings consistent with toxicological evidence in that a limited range of concentrated, catechin-rich green tea preparations resulted in hepatic AEs in a dose-dependent manner when ingested in large bolus doses, but not when consumed as brewed tea or extracts in beverages or as part of food. Toxico- and pharmacokinetic evidence further suggests internal dose of catechins is a key determinant in the occurrence and severity of hepatotoxicity. A safe intake level of 338 mg EGCG/day for adults was derived from toxicological and human safety data for tea preparations ingested as a solid bolus dose. An Observed Safe Level (OSL) of 704 mg EGCG/day might be considered for tea preparations in beverage form based on human AE data. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

A History of Catechin Chemistry with Special Reference to Tea Leaves

NASA Astrophysics Data System (ADS)

Ryoyasu, Saijo; Katoh, Miyuki

This review describes the history of the discovery of catechins, i.e., flavan 3-ols in the flavonoid compounds, with a special reference to tea leaves. 1. Catechin was first separated from gambier catechu and acacia catechu, and its molecular weight and chemical structure were proposed in 1902. By 1948 the six catechins,(+)-catechin,(-)-epicatechin,(-)-epicatechin 3-O-gallate,(-)-epigallocatechin,(+)-gallocatechin, and(-)-epigallocatechin 3-O-gallate, as shown in Table 1, had been found in a variety of plants, including tea. Table 1 summarizes each catechin, the plant associated with it, and the year and authorship of each first reporting.(-)-Epigallocatechin 3-gallate was isolated from tea leaves in 1948 as the last compound of the six catechins, even though it accounted for the largest proportion of total catechin content. The compound was not isolated and purified by traditional separation methods, such as the ethyl acetate extraction and lead acetate precipitation methods; instead, silica gel column chromatography was the key technique used to succeed in the separation and purification of the compound, from which the determination of the chemical structure followed. 2. The six catechins in fresh tea leaves are easily epimerized by heat treatment to form the corresponding epimerized catechins, as shown in Table 2. Observation indicates that the six natural and six epimerized catechins can be present in heat-treated dried tea leaves or green teas. 3. The chemical structures of the ten catechins, which include the compounds in Table 1, are shown in Table 3. As the contents of the catechins in fresh tea leaves have been reported many times in the literature, it is certain that these compounds are naturally present in tea leaves. 4. Table 4 summarizes the chemical structures of eight minor catechin derivatives found in tea leaves and oolong teas, the first reporting authors, and the year reported. Because the presence of these catechin derivatives in fresh tea

Augmented cellular uptake of nanoparticles using tea catechins: effect of surface modification on nanoparticle-cell interaction

NASA Astrophysics Data System (ADS)

Lu, Yi-Ching; Luo, Pei-Chun; Huang, Chun-Wan; Leu, Yann-Lii; Wang, Tzu-Hao; Wei, Kuo-Chen; Wang, Hsin-Ell; Ma, Yunn-Hwa

2014-08-01

Nanoparticles may serve as carriers in targeted therapeutics; interaction of the nanoparticles with a biological system may determine their targeting effects and therapeutic efficacy. Epigallocatechin-3-gallate (EGCG), a major component of tea catechins, has been conjugated with nanoparticles and tested as an anticancer agent. We investigated whether EGCG may enhance nanoparticle uptake by tumor cells. Cellular uptake of a dextran-coated magnetic nanoparticle (MNP) was determined by confocal microscopy, flow cytometry or a potassium thiocyanate colorimetric method. We demonstrated that EGCG greatly enhanced interaction and/or internalization of MNPs (with or without polyethylene glycol) by glioma cells, but not vascular endothelial cells. The enhancing effects are both time- and concentration-dependent. Such effects may be induced by a simple mix of MNPs with EGCG at a concentration as low as 1-3 μM, which increased MNP uptake 2- to 7-fold. In addition, application of magnetic force further potentiated MNP uptake, suggesting a synergetic effect of EGCG and magnetic force. Because the effects of EGCG were preserved at 4 °C, but not when EGCG was removed from the culture medium prior to addition of MNPs, a direct interaction of EGCG and MNPs was implicated. Use of an MNP-EGCG composite produced by adsorption of EGCG and magnetic separation also led to an enhanced uptake. The results reveal a novel interaction of a food component and nanocarrier system, which may be potentially amenable to magnetofection, cell labeling/tracing, and targeted therapeutics.

Antioxidative capacity and binding affinity of the complex of green tea catechin and beta-lactoglobulin glycated by the Maillard reaction.

PubMed

Perusko, Marija; Al-Hanish, Ayah; Mihailovic, Jelena; Minic, Simeon; Trifunovic, Sara; Prodic, Ivana; Cirkovic Velickovic, Tanja

2017-10-01

Major green tea catechin, epigallocatechin-3-gallate (EGCG), binds non-covalently to numerous dietary proteins, including beta-lactoglobulin of cow's milk. The effects of glycation of proteins via Maillard reaction on the binding capacity for polyphenols and the antiradical properties of the formed complexes have not been studied previously. Binding constant of BLG glycated by milk sugar lactose to EGCG was measured by the method of fluorophore quenching. Binding of EGCG was confirmed by CD and FTIR. The antioxidative properties of the complexes were examined by measuring ABTS radical scavenging capacity, superoxide anion scavenging capacity and total reducing power assay. Glycation of BLG does not significantly influence the binding constant of EGCG for the protein. Conformational changes were observed for both native and glycated BLG upon complexation with EGCG. Masking effect of polyphenol complexation on the antioxidative potential of the protein was of the similar degree for both glycated BLG and native BLG. Copyright © 2017 Elsevier Ltd. All rights reserved.

Green Tea Catechin-Based Complex Micelles Combined with Doxorubicin to Overcome Cardiotoxicity and Multidrug Resistance

PubMed Central

Cheng, Tangjian; Liu, Jinjian; Ren, Jie; Huang, Fan; Ou, Hanlin; Ding, Yuxun; Zhang, Yumin; Ma, Rujiang; An, Yingli; Liu, Jianfeng; Shi, Linqi

2016-01-01

Chemotherapy for cancer treatment has been demonstrated to cause some side effects on healthy tissues and multidrug resistance of the tumor cells, which greatly limits therapeutic efficacy. To address these limitations and achieve better therapeutic efficacy, combination therapy based on nanoparticle platforms provides a promising approach through delivering different agents simultaneously to the same destination with synergistic effect. In this study, a novel green tea catechin-based polyion complex (PIC) micelle loaded with doxorubicin (DOX) and (-)-Epigallocatechin-3-O-gallate (EGCG) was constructed through electrostatic interaction and phenylboronic acid-catechol interaction between poly(ethylene glycol)-block-poly(lysine-co-lysine-phenylboronic acid) (PEG-PLys/PBA) and EGCG. DOX was co-loaded in the PIC micelles through π-π stacking interaction with EGCG. The phenylboronic acid-catechol interaction endowed the PIC micelles with high stability under physiological condition. Moreover, acid cleavability of phenylboronic acid-catechol interaction in the micelle core has significant benefits for delivering EGCG and DOX to same destination with synergistic effects. In addition, benefiting from the oxygen free radicals scavenging activity of EGCG, combination therapy with EGCG and DOX in the micelle core could protect the cardiomyocytes from DOX-mediated cardiotoxicity according to the histopathologic analysis of hearts. Attributed to modulation of EGCG on P-glycoprotein (P-gp) activity, this kind of PIC micelles could effectively reverse multidrug resistance of cancer cells. These results suggested that EGCG based PIC micelles could effectively overcome DOX induced cardiotoxicity and multidrug resistance. PMID:27375779

Green Tea Catechin-Based Complex Micelles Combined with Doxorubicin to Overcome Cardiotoxicity and Multidrug Resistance.

PubMed

Cheng, Tangjian; Liu, Jinjian; Ren, Jie; Huang, Fan; Ou, Hanlin; Ding, Yuxun; Zhang, Yumin; Ma, Rujiang; An, Yingli; Liu, Jianfeng; Shi, Linqi

2016-01-01

Chemotherapy for cancer treatment has been demonstrated to cause some side effects on healthy tissues and multidrug resistance of the tumor cells, which greatly limits therapeutic efficacy. To address these limitations and achieve better therapeutic efficacy, combination therapy based on nanoparticle platforms provides a promising approach through delivering different agents simultaneously to the same destination with synergistic effect. In this study, a novel green tea catechin-based polyion complex (PIC) micelle loaded with doxorubicin (DOX) and (-)-Epigallocatechin-3-O-gallate (EGCG) was constructed through electrostatic interaction and phenylboronic acid-catechol interaction between poly(ethylene glycol)-block-poly(lysine-co-lysine-phenylboronic acid) (PEG-PLys/PBA) and EGCG. DOX was co-loaded in the PIC micelles through π-π stacking interaction with EGCG. The phenylboronic acid-catechol interaction endowed the PIC micelles with high stability under physiological condition. Moreover, acid cleavability of phenylboronic acid-catechol interaction in the micelle core has significant benefits for delivering EGCG and DOX to same destination with synergistic effects. In addition, benefiting from the oxygen free radicals scavenging activity of EGCG, combination therapy with EGCG and DOX in the micelle core could protect the cardiomyocytes from DOX-mediated cardiotoxicity according to the histopathologic analysis of hearts. Attributed to modulation of EGCG on P-glycoprotein (P-gp) activity, this kind of PIC micelles could effectively reverse multidrug resistance of cancer cells. These results suggested that EGCG based PIC micelles could effectively overcome DOX induced cardiotoxicity and multidrug resistance.

[Determination of catechins and caffeine in tea and tea beverages by high-performance liquid chromatography].

PubMed

Ling, Yun; Zhao, Yun-feng; Li, Zhi-jun; Zhang, Gong; Wu, Yongning

2005-03-01

A high-performance liquid chromatography method was developed for the determination of total tea catechin and caffeine. The catechins needed to be determined are: (-)-catechin, (-)-epigallocatechin, (-)-epigallocatechin gallate, (-)-epicatechin, (-)-epicatechin gallate, (-)-gallocatechin, (-)-gallocatechin gallate, (-)-catechin gallate and caffeine. The catechins in the tea was extracted with water:ethanol (3:7) by sonication for 20 min. After the extraction solution was centrifuged, it was analyzed by HPLC. The column used was a CAPCELL PAK C18 MG (4.6mm I.D. x 150mm) and gradient elution at constant column temperature with 30 degrees C under UV detector with 210nm. Mobile phase A was 0.1% H3PO4 in water, mobile phase B was 0.1% H3PO4 in methanol with the flow rate 1ml/min. The results showed that the concentration of the catechins and caffeine and their peak areas achieved good linear relation, r > 0.999. The recoveries were between 61.7%-117.3%. RSD was below 10%. With this method, some tea samples were determined, the results were favorable. The method can be applied for determination of catechin and caffeine in tea and tea beverages.

Antimutagenicity and catechin content of soluble instant teas.

PubMed

Constable, A; Varga, N; Richoz, J; Stadler, R H

1996-03-01

The antimutagenic properties of soluble instant teas were examined using the bacterial Ames assay. Inhibition of the numbers of revertants induced from a number of known mutagens indicates that aqueous extracts of instant teas have antimutagenic activity and antioxidative properties, and can inhibit nitrosation reactions. Despite a significant reduction in the amounts of major green tea catechins, quantified using reversed-phase HPLC with electro-chemical detection, no differences in antimutagenicity were observed between the instant teas, a black fermented tea and a green tea. Oxidation of polyphenolic compounds which occurs during the production of instant tea does not therefore decrease the antioxidant, free radical scavenging and antimutagenic properties. This suggests that catechins are not the only compounds responsible for the protective effects of teas.

Application of Green Tea Catechin for Inducing the Osteogenic Differentiation of Human Dedifferentiated Fat Cells in Vitro

PubMed Central

Kaida, Koji; Honda, Yoshitomo; Hashimoto, Yoshiya; Tanaka, Masahiro; Baba, Shunsuke

2015-01-01

Despite advances in stem cell biology, there are few effective techniques to promote the osteogenic differentiation of human primary dedifferentiated fat (DFAT) cells. We attempted to investigate whether epigallocatechin-3-gallate (EGCG), the main component of green tea catechin, facilitates early osteogenic differentiation and mineralization on DFAT cells in vitro. DFAT cells were treated with EGCG (1.25–10 μM) in osteogenic medium (OM) with or without 100 nM dexamethasone (Dex) for 12 days (hereafter two osteogenic media were designated as OM(Dex) and OM). Supplementation of 1.25 μM EGCG to both the media effectively increased the mRNA expression of collagen 1 (COL1A1) and runt-related transcription factor 2 (RUNX2) and also increased proliferation and mineralization. Compared to OM(Dex) with EGCG, OM with EGCG induced earlier expression for COL1A1 and RUNX2 at day 1 and higher mineralization level at day 12. OM(Dex) with 10 μM EGCG remarkably hampered the proliferation of the DFAT cells. These results suggest that OM(without Dex) with EGCG might be a preferable medium to promote proliferation and to induce osteoblast differentiation of DFAT cells. Our findings provide an insight for the combinatory use of EGCG and DFAT cells for bone regeneration and stem cell-based therapy. PMID:26602917

Determination of catechins and flavonol glycosides in Chinese tea varieties.

PubMed

Wu, Chunyan; Xu, Hairong; Héritier, Julien; Andlauer, Wilfried

2012-05-01

A standardised profiling method based on high performance liquid chromatography combined with ultraviolet (UV) and mass spectrometric detection (MS) was established to analyse the phenolic compounds of selected tea varieties used for manufacturing of green, black and oolong teas. The composition and content of 24 tea constituents were analysed, including catechins, flavonol and flavones glycosides, phenolic acids and purine alkaloids. Each tea variety had a unique chemical profile. The compositions of catechins were lower in the tea varieties for green tea manufacturing, while the content of myricetin glycosides was the lowest in the tea variety for oolong tea manufacturing. The content of individual phenolic compounds in the selected tea varieties is highly variable. However, the content of total catechins is proposed to be helpful to classify tea according to the future application as non fermented green and fermented oolong or black tea. Copyright © 2011 Elsevier Ltd. All rights reserved.

[Antibacterial and anti-hemolysin activities of tea catechins and their structural relatives].

PubMed

Toda, M; Okubo, S; Ikigai, H; Shimamura, T

1990-03-01

Among catechins tested, (-)epigallocatechin (EGC), (-)epicatechin gallate (ECg), (-) epigallocatechin gallate (EGCg) inhibited the growth of Staphylococcus aureus, Vibrio cholerae O1 classical Inaba 569B and El Tor Inaba V86. S. aureus was more sensitive than V. cholerae O1 to these compounds. EGCg showed also a bactericidal activity against V. cholerae O1 569B. Pyrogallol showed a stronger antibacterial activity against S. aureus and V. cholerae O1 than tannic and gallic acid. Rutin or caffein had no effect on them. ECg and EGCg showed the most potent anti-hemolysin activity against S. aureus alpha-toxin, Vibrio parahaemolyticus thermostable direct hemolysin (Vp-TDH) and cholera hemolysin. Among catechin relatives, only tannic acid had a potent anti-hemolysin activity against alpha-toxin. These results suggest that the catechol and pyrogallol groups are responsible for the antibacterial and bactericidal activities, while the conformation of catechins might play an important role in the anti-hemolysin activity.

Regulation of matrix metalloproteinase secretion by green tea catechins in a three-dimensional co-culture model of macrophages and gingival fibroblasts.

PubMed

Morin, Marie-Pierre; Grenier, Daniel

2017-03-01

Elevated levels of matrix metalloproteinases (MMPs) have been associated with the active phases of tissue and bone destruction in periodontitis, an inflammatory disease characterized by a significant breakdown of tooth support. In the present study, we used a three-dimensional (3D) co-culture model of macrophages and gingival fibroblasts to investigate the ability of a green tea extract and its major constituent epigallocatechin-3-gallate (EGCG) to regulate the secretion of MMP-3, -8, and -9. The 3D co-culture model was composed of gingival fibroblasts embedded in a type I collagen matrix overlaid with macrophages. Two arbitrary ratios were tested. The ratio composed of 1 macrophage to 10 fibroblasts was used to mimic a slightly inflamed periodontal site while the ratio composed of 10 macrophages to 1 fibroblast was used to mimic a severely inflamed periodontal site. The 3D co-culture model was pre-treated for 2h with either the green tea extract or EGCG. It was then stimulated with Aggregatibacter actinomycetemcomitans lipopolysaccharide (LPS). The model was also first stimulated with LPS for 2h and then incubated with the green tea extract or EGCG. The concentrations of secreted MMP-3, -8, and -9 were quantified by enzyme-linked immunoassays. When the 3D co-culture model was stimulated with A. actinomycetemcomitans LPS, the 10:1 ratio of macrophages to gingival fibroblasts was associated with a highest secretion of MMP-3 and -9 and, to a lesser extent, MMP-8, than the 1:10 ratio. Non-cytotoxic concentrations of the green tea extract or EGCG reduced the basal secretion levels of all three MMPs. A 2-h treatment with the green tea extract or EGCG prior to the stimulation with LPS resulted in a dose-dependent decrease in MMP secretion, with MMP-9 showing the most significant decrease. A decrease in MMP secretion was also observed when the green tea extract or EGCG was added following a 2-h stimulation with LPS. Our results suggested that green tea catechins, and more

The Green Tea Polyphenol Epigallocatechin-3-Gallate (EGCg) Attenuates Skeletal Muscle Atrophy in a Rat Model of Sarcopenia.

PubMed

Meador, B M; Mirza, K A; Tian, M; Skelding, M B; Reaves, L A; Edens, N K; Tisdale, M J; Pereira, S L

2015-01-01

Sarcopenia-the loss of muscle mass and functionality occurring with age-is a pervasive problem with few effective treatments beyond exercise. We examined the ability of the green tea catechin, epigallocatechin-3-gallate (EGCg), to impact muscle mass and the molecular pathway involved in muscle atrophy in a rat model of sarcopenia. 20-month-old Sprague-Dawley rats were treated for 8 weeks with control diet or control plus 200mg/kg body weight of EGCg diet. EGCg-supplemented animals had significantly greater gastrocnemius muscle mass than the aged controls, and showed a trend for increased muscle fiber cross-sectional areas (CSA) (p=0.06). These changes were associated with significantly lower protein expressions of the intramuscular 19S and 20S proteasome subunits and the MuRF1 and MAFbx ubiquitin ligases in the EGCg-treated animals. Proteasome activity as determined by 'Chymotrypsin-like' enzyme activity was also significantly reduced by EGCg. Muscle mRNA expression of IL-15 and IGF-1 were significantly increased in the EGCg group vs. the aged controls. In comparison to younger adult animals (6 month), the protein expression of 19S, 20S, MuRF1, MAFbx, and myostatin were increased between approximately 4- and 12-fold in the aged controls, but only up to ~2-fold in the aged EGCg animals. EGCg supplementation was able to preserve muscle in sarcopenic rats, partly through attenuating protein degradation via the ubiquitin-proteasome pathway, together with increased expression of anabolic factors.

The Powdering Process with a Set of Ceramic Mills for Green Tea Promoted Catechin Extraction and the ROS Inhibition Effect.

PubMed

Fujioka, Kouki; Iwamoto, Takeo; Shima, Hidekazu; Tomaru, Keiko; Saito, Hideki; Ohtsuka, Masaki; Yoshidome, Akihiro; Kawamura, Yuri; Manome, Yoshinobu

2016-04-11

For serving green tea, there are two prominent methods: steeping the leaf or the powdered leaf (matcha style) in hot water. The purpose of the present study was to reveal chemical and functional differences before and after the powdering process of green tea leaf, since powdered green tea may contribute to expanding the functionality because of the different ingesting style. In this study, we revealed that the powdering process with a ceramic mill and stirring in hot water increased the average extracted concentration of epigallocatechin gallate (EGCG) by more than three times compared with that in leaf tea using high-performance liquid chromatography (HPLC) and liquid chromatography-tandem mass Spectrometry (LC-MS/MS) analyses. Moreover, powdered green tea has a higher inhibition effect of reactive oxygen species (ROS) production in vitro compared with the same amount of leaf tea. Our data suggest that powdered green tea might have a different function from leaf tea due to the higher catechin contents and particles.

Anti-Fatigue Effect of Green Tea Polyphenols (-)-Epigallocatechin-3-Gallate (EGCG).

PubMed

Teng, Yu-Song; Wu, Di

2017-01-01

(-)-Epigallocatechin-3-gallate (EGCG) is the most abundant of the green tea polyphenols that exhibit a variety of bioactivities. The objective of this study was to evaluate the anti-fatigue effect of EGCG by forced swimming exercise. The mice were divided into one control group and three EGCG-treated groups. The control group was administered with distilled water and EGCG-treated groups were administered with different dose of EGCG (50, 100, and 200 mg/kg) by oral gavage for 28 days. On the last day of experiment, the forced swimming exercise was performed and corresponding biochemical parameters were measured. The data showed that EGCG prolonged exhaustive swimming time, decreasing the levels of blood lactic acid, serum urea nitrogen, serum creatine kinase and malondialdehyde, which were accompanied by corresponding increase in liver and muscle glycogen contents, and superoxide dismutase, catalase, and glutathione peroxidase activities. This study indicated that EGCG had an anti-fatigue effect. EGCG significantly prolonged exhaustive swimming time and decreased the levels of BLA, SUN, SCK and MDA, which were accompanied by corresponding increases in liver and muscle glycogen contents, and SOD, CAT, and GPx activities.EGCG can be used to design nutraceutical supplements aimed to facilitate recovery from fatigue and attenuate exhaustive exercise-induced oxidative damage. Abbreviations used: EGCG: (-)-Epigallocatechin-3-gallate, ROS: reactive oxygen species, BLA: blood lactic acid, SUN: serum urea nitrogen, SOD: superoxide dismutase, GPx: glutathione peroxidase, CAT: catalase, SCK: serum creatine kinase, MDA: malondialdehyde, C: control, LET: Low-dose EGCG-treated, MET: Middle-dose EGCG-treated, HET: High-dose EGCG-treated, GTE: green tea extract.

Inhibition of pectin methyl esterase activity by green tea catechins.

PubMed

Lewis, Kristin C; Selzer, Tzvia; Shahar, Chen; Udi, Yael; Tworowski, Dmitry; Sagi, Irit

2008-10-01

Pectin methyl esterases (PMEs) and their endogenous inhibitors are involved in the regulation of many processes in plant physiology, ranging from tissue growth and fruit ripening to parasitic plant haustorial formation and host invasion. Thus, control of PME activity is critical for enhancing our understanding of plant physiological processes and regulation. Here, we report on the identification of epigallocatechin gallate (EGCG), a green tea component, as a natural inhibitor for pectin methyl esterases. In a gel assay for PME activity, EGCG blocked esterase activity of pure PME as well as PME extracts from citrus and from parasitic plants. Fluorometric tests were used to determine the IC50 for a synthetic substrate. Molecular docking analysis of PME and EGCG suggests close interaction of EGCG with the catalytic cleft of PME. Inhibition of PME by the green tea compound, EGCG, provides the means to study the diverse roles of PMEs in cell wall metabolism and plant development. In addition, this study introduces the use of EGCG as natural product to be used in the food industry and agriculture.

Effect of Tea Theaflavins and Catechins on Microvascular Function

PubMed Central

Fuchs, Dagmar; de Graaf, Young; van Kerckhoven, Roeland; Draijer, Richard

2014-01-01

Beneficial effects of flavonoid-rich black and green tea on macrocirculation have been well established. Theaflavins are unique to black tea as they are formed from catechins during the enzymatic oxidation of tea leaves. The study was performed to gain more insight into the effects of theaflavins on microcirculation and to compare effects with another important flavonoid class, the green tea derived catechins, which have been reported to improve vascular function. Twenty-four healthy subjects were included in a double-blind, placebo-controlled, randomised, cross-over study. On six different days, subjects received capsules with a single dose of catechins (500 mg), four varying doses of theaflavins (100 to 500 mg) or placebo. Microcirculation was assessed after each treatment by Pulse Amplitude Tonometry (EndoPAT) at baseline and 2, 4 and 6 h after test product intake. The EndoPAT reactive hyperemia response was improved by 500 mg catechins (reactive hyperemia index (RHI): 0.2; p = 0.04) and by 500 mg theaflavins (RHI: 0.19; p = 0.06) compared to placebo. Also, 300 mg theaflavins increased the RHI (0.28; p = 0.02), but no effects were observed at lower doses. The study suggests moderate effects of single doses of catechins and theaflavins on peripheral microcirculation. PMID:25514559

Anti-Fatigue Effect of Green Tea Polyphenols (-)-Epigallocatechin-3-Gallate (EGCG)

PubMed Central

Teng, Yu-song; Wu, Di

2017-01-01

Background: (-)-Epigallocatechin-3-gallate (EGCG) is the most abundant of the green tea polyphenols that exhibit a variety of bioactivities. The objective of this study was to evaluate the anti-fatigue effect of EGCG by forced swimming exercise. Materials and Methods: The mice were divided into one control group and three EGCG-treated groups. The control group was administered with distilled water and EGCG-treated groups were administered with different dose of EGCG (50, 100, and 200 mg/kg) by oral gavage for 28 days. On the last day of experiment, the forced swimming exercise was performed and corresponding biochemical parameters were measured. Results: The data showed that EGCG prolonged exhaustive swimming time, decreasing the levels of blood lactic acid, serum urea nitrogen, serum creatine kinase and malondialdehyde, which were accompanied by corresponding increase in liver and muscle glycogen contents, and superoxide dismutase, catalase, and glutathione peroxidase activities. Conclusions: This study indicated that EGCG had an anti-fatigue effect. SUMMARY EGCG significantly prolonged exhaustive swimming time and decreased the levels of BLA, SUN, SCK and MDA, which were accompanied by corresponding increases in liver and muscle glycogen contents, and SOD, CAT, and GPx activities.EGCG can be used to design nutraceutical supplements aimed to facilitate recovery from fatigue and attenuate exhaustive exercise-induced oxidative damage. Abbreviations used: EGCG: (-)-Epigallocatechin-3-gallate, ROS: reactive oxygen species, BLA: blood lactic acid, SUN: serum urea nitrogen, SOD: superoxide dismutase, GPx: glutathione peroxidase, CAT: catalase, SCK: serum creatine kinase, MDA: malondialdehyde, C: control, LET: Low-dose EGCG-treated, MET: Middle-dose EGCG-treated, HET: High-dose EGCG-treated, GTE: green tea extract. PMID:28539729

New insights into the mechanisms of polyphenols beyond antioxidant properties; lessons from the green tea polyphenol, epigallocatechin 3-gallate☆

PubMed Central

Kim, Hae-Suk; Quon, Michael J.; Kim, Jeong-a

2014-01-01

Green tea is rich in polyphenol flavonoids including catechins. Epigallocatechin 3-gallate (EGCG) is the most abundant and potent green tea catechin. EGCG has been extensively studied for its beneficial health effects as a nutriceutical agent. Based upon its chemical structure, EGCG is often classified as an antioxidant. However, treatment of cells with EGCG results in production of hydrogen peroxide and hydroxyl radicals in the presence of Fe (III). Thus, EGCG functions as a pro-oxidant in some cellular contexts. Recent investigations have revealed many other direct actions of EGCG that are independent from anti-oxidative mechanisms. In this review, we discuss these novel molecular mechanisms of action for EGCG. In particular, EGCG directly interacts with proteins and phospholipids in the plasma membrane and regulates signal transduction pathways, transcription factors, DNA methylation, mitochondrial function, and autophagy to exert many of its beneficial biological actions. PMID:24494192

Quantitative proteomic analysis reveals the role of tea polyphenol EGCG in egg whites in response to vanadium stress.

PubMed

Wang, Jianping; Bai, Xue; Ding, Xuemei; Bai, Shiping; Zeng, Qiufeng; Mao, Xiangbing; Zhang, Keying

Tea polyphenol (TP) epigallo-catechin-3-gallate (EGCG) can alleviate vanadium (V) stress in laying hens; however, our understanding of the molecular mechanisms and proteomic changes occurring in the egg albumen remains limited. The aim of the present study is to better understand the response in layers under V challenge and mechanism of EGCG detoxification. We divided 120 layers into four treatments in the absence and presence of 130 mg/kg EGCG, supplemented with either 0 or 5 mg/kg V. The Haugh unit (HU) was decreased and the apoptosis rate of magnum and V residual in egg was increased by the effect of vanadium and EGCG alleviated the detrimental effect in HU and apoptosis rate induced by vanadium (interactive effect, P < 0.05). In all, 379 proteins were identified and 28 differential proteins were observed with and without EGCG and V. Eight proteins, which respond to stress stimuli (five immune response proteins [F1P3B2, P21760, A2N881, F2Z4L6, and P02789], and one cell redox homeostasis protein [Q5F472] were presented in the albumen of laying hens with EGCG administration. Proteins involved in heavy metal binding (E1C5J4) and cell proliferation (F1NX05 and E1BT2) also were changed in EGCG-treated albumen. The detoxification mechanism of EGCG under V stress may act through regulating metal-binding mediation, cell proliferation, and immune function-related proteins. Copyright © 2017 Elsevier Inc. All rights reserved.

Randomized, Placebo-Controlled Trial of Green Tea Catechins for Prostate Cancer Prevention

PubMed Central

Kumar, Nagi B.; Pow-Sang, Julio; Egan, Kathleen M.; Spiess, Philippe E.; Dickinson, Shohreh; Salup, Raoul; Helal, Mohamed; McLarty, Jerry; Williams, Christopher R.; Schreiber, Fred; Parnes, Howard L.; Sebti, Said; Kazi, Aslam; Kang, Loveleen; Quinn, Gwen; Smith, Tiffany; Yue, Binglin; Diaz, Karen; Chornokur, Ganna; Crocker, Theresa; Schell, Michael J.

2015-01-01

Preclinical, epidemiological and prior clinical trial data suggest that green tea catechins (GTCs) may reduce prostate cancer (PCa) risk. We conducted a placebo-controlled, randomized clinical trial of Polyphenon E® (PolyE), a proprietary mixture of GTCs, containing 400 mg (–)-epigallocatechin-3-gallate (EGCG) per day, in 97 men with high-grade prostatic intraepithelial neoplasia (HGPIN) and/or atypical small acinar proliferation (ASAP). The primary study endpoint was a comparison of the cumulative one-year PCa rates on the two study arms. No differences in the number of PCa cases were observed: 5/49 (PolyE) versus 9/48 (placebo), P=0.25. A secondary endpoint comparing the cumulative rate of PCa plus ASAP among men with HGPIN without ASAP at baseline, revealed a decrease in this composite endpoint: 3/26 (PolyE) versus 10/25 (placebo), P<0.024. This finding was driven by a decrease in ASAP diagnoses on the Poly E (0/26) compared to the placebo arm (5/25). A decrease in serum prostate specific antigen (PSA) was observed on the PolyE arm [−0.87 ng/ml (95%CI: −1.66, −0.09)]. Adverse events related to the study agent did not significantly differ between the two study groups. Daily intake of a standardized, decaffeinated catechin mixture containing 400 mg EGCG per day for 1 year accumulated in plasma and was well tolerated but did not reduce the likelihood of PCa in men with baseline HGPIN or ASAP. PMID:25873370

Total polyphenols, catechin profiles and antioxidant activity of tea products from purple leaf coloured tea cultivars.

PubMed

Kerio, L C; Wachira, F N; Wanyoko, J K; Rotich, M K

2013-02-15

Black (aerated) and green (unaerated) tea products, processed from 10 green and 18 purple leaf coloured cultivars of Kenyan origin, and two tea products, from the Japanese cultivars, Yabukita and Yutakamidori, were assayed for total polyphenols (TP) content, individual catechin profiles and in vitro antioxidant capacity (AA). In addition, the phenolic content of the tea products was determined using the Folin-Ciocalteu phenol reagent. Catechin fractions were identified using reverse phase high performance liquid chromatography (HPLC) with a binary gradient elution system. The AA% of the tea products was determined using a 2,2'-diphenyl picrylhydrazyl (DPPH) radical assay method. The results showed that TPs, catechin profiles and antioxidant activities were significantly (p≤0.05) higher in unaerated than in aerated teas. Tea products from the purple leaf coloured tea cultivars had levels of TPs, total catechin (TC) and antioxidant activities similar to those from the green leaf coloured cultivars, except for teas from the Japanese cultivars that were very low in the assayed parameters. Caffeine content was significantly (p≤0.05) lower in products from the purple leaf coloured cultivars than in those from the green leaf coloured tea cultivars. Antioxidant activity (%) was higher in tea products from the Kenyan germplasm than in those from the Japanese cultivars. Antioxidant potency of tea products was significantly (r=0.789(∗∗), p≤0.01) influenced by the total anthocyanin content of the purple leaf coloured cultivars. Cyanidin-3-O-glucoside was the anthocyanin most highly correlated with AA% (r=0.843(∗∗), p≤0.01 in unaerated tea). Total catechins in the unaerated products from the green leaf coloured tea cultivars were also significantly correlated with antioxidant capacity (r=0.818(∗∗), p≤0.01). Results from this study suggest that the antioxidant potency of teas is dependent on the predominant flavonoid compound, the type of tea cultivar and

Population nutrikinetics of green tea extract.

PubMed

Scholl, Catharina; Lepper, Anna; Lehr, Thorsten; Hanke, Nina; Schneider, Katharina Luise; Brockmöller, Jürgen; Seufferlein, Thomas; Stingl, Julia Carolin

2018-01-01

Green tea polyphenols may contribute to the prevention of cancer and other diseases. To learn more about the pharmacokinetics and interindividual variation of green tea polyphenols after oral intake in humans we performed a population nutrikinetic study of standardized green tea extract. 84 healthy participants took green tea extract capsules standardized to 150 mg epigallocatechin-gallate (EGCG) twice a day for 5 days. On day 5 catechin plasma concentrations were analyzed using non-compartmental and population pharmacokinetic methods. A strong between-subject variability in catechin pharmacokinetics was found with maximum plasma concentrations varying more than 6-fold. The AUCs of EGCG, EGC and ECG were 877.9 (360.8-1576.5), 35.1 (8.0-87.4), and 183.6 (55.5-364.6) h*μg/L respectively, and the elimination half lives were 2.6 (1.8-3.8), 3.9 (0.9-10.7) and 1.8 (0.8-2.9) h, respectively. Genetic polymorphisms in genes of the drug transporters MRP2 and OATP1B1 could at least partly explain the high variability in pharmacokinetic parameters. The observed variability in catechin plasma levels might contribute to interindividual variation in benefical and adverse effects of green tea polyphenols. Our data could help to gain a better understanding of the causes of variability of green tea effects and to improve the design of studies on the effects of green tea polyphenols in different health conditions. ClinicalTrials.gov: NCT01360320.

Carboxymethyl- and carboxyl-catechins from ripe Pu-er tea.

PubMed

Tian, Li-Wen; Tao, Mu-Ke; Xu, Min; Hu, Jing; Zhu, Hong-Tao; Xiong, Wen-Yong; Wang, Dong; Yang, Chong-Ren; Zhang, Ying-Jun

2014-12-17

Ripe Pu-er tea, a special microbial postfermented tea originated from Yunnan Province, China, since ancient times, is made from green Pu-er tea prepared from the leaves of Camellia sinensis var. assamica (Theaceae). Chemical investigation on thearubigin (n-BuOH-soluble) fraction of the commercial ripe Pu-er tea, led to the identification of four new flavan-3-ol derivatives, 8-carboxymethyl-(+)-catechin (1), 8-carboxymethyl-(+)-catechin methyl ester (2), 6-carboxymethyl-(+)-catechin (3), and 6-carboxyl-(-)-gallocatechin (4), together with 18 known compounds, including other three flavan-3-ol derivatives (5-7), 10 flavonoid glycosides (8-17), two hydrolyzable tannins (18 and 19), two quinic acid derivatives (20-21), and a purine alkaloid (22). Flavonoid glycosides 8-11 are reported from tea plants for the first time. The thearubigin fraction of ripe Pu-er tea was qualitatively analyzed by HPLC, and gallic acid was found to be the major component. Compounds 4, 6-17, 21 and 22 were tested for their acute activities on insulin sensitivity in differentiated 3T3-L1 adipocytes, but none of them showed significant bioactivity at a concentration of 10 μM.

Preparation of tea catechins using polyamide.

PubMed

Ye, Jian-Hui; Wang, Liu-Xiang; Chen, Hao; Dong, Jun-Jie; Lu, Jian-Liang; Zheng, Xin-Qiang; Wu, Ming-Yan; Liang, Yue-Rong

2011-02-01

An adsorption separation method using Polyamide-6 (PA) as an adsorbent was developed to separate catechins from green tea extract. The adsorption capacity of total catechins for PA was 193.128 mg g⁻¹ with an adsorption selectivity coefficient K(A)(B) of total catechins over caffeine 21.717, which was better than macroporous resin model HPD 600. The Langmuir model and the pseudo-second order mode were primely fitted to describe its equilibrium data and adsorption kinetics, respectively. PA column separation by two-step elution using water and 80% (v/v) aqueous ethanol was established to prepare catechins complex which contained 670.808 mg g⁻¹ total catechins and 1.828 mg g⁻¹ caffeine. It is considered that PA was a promising adsorbent for selective isolation of catechins. Copyright © 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Bioefficacy of tea catechins encapsulated in casein micelles tested on a normal mouse cell line (4D/WT) and its cancerous counterpart (D/v-src) before and after in vitro digestion.

PubMed

Haratifar, Sanaz; Meckling, Kelly A; Corredig, Milena

2014-06-01

Numerous studies have demonstrated that tea catechins form complexes with milk proteins, especially caseins. Much less work has been conducted to understand the metabolic conversions of tea-milk complexes during gastro-duodenal digestion. The objective of this study was to determine the significance of this association on the digestibility of the milk proteins and on the bioaccessibility of the tea polyphenol epigallocatechin gallate (EGCG). An in vitro digestion model mimicking the gastric and duodenal phases of the human gastrointestinal tract was employed to follow the fate of the milk proteins during digestion and determine the bioefficacy of EGCG isolated or encapsulated with the caseins. The samples, before and after digestion, were tested using two parallel colonic epithelial cell lines, a normal line (4D/WT) and its cancerous transformed counterpart (D/v-src). EGCG caused a decrease in proliferation of cancer cells, while in normal cells, neither isolated nor encapsulated EGCG affected cell proliferation, at concentrations <0.15 mg ml(-1). At higher concentrations, both isolated and encapsulated produced similar decreases in proliferation. On the other hand, the bioefficacy on the cancer cell line showed some differences at lower concentrations. The results demonstrated that regardless of the extent of digestion of the nanoencapsulated EGCG, the bioefficacy of EGCG was not diminished, confirming that casein micelles are an appropriate delivery system for polyphenols.

Green tea polyphenol EGCG blunts androgen receptor function in prostate cancer

PubMed Central

Siddiqui, Imtiaz A.; Asim, Mohammad; Hafeez, Bilal B.; Adhami, Vaqar M.; Tarapore, Rohinton S.; Mukhtar, Hasan

2011-01-01

Androgen deprivation therapy is the major treatment for advanced prostate cancer (PCa). However, it is a temporary remission, and the patients almost inevitably develop hormone refractory prostate cancer (HRPC). HRPC is almost incurable, although most HRPC cells still express androgen receptor (AR) and depend on the AR for growth, making AR a prime drug target. Here, we provide evidence that epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, is a direct antagonist of androgen action. In silico modeling and FRET-based competition assay showed that EGCG physically interacts with the ligand-binding domain of AR by replacing a high-affinity labeled ligand (IC50 0.4 μM). The functional consequence of this interaction was a decrease in AR-mediated transcriptional activation, which was due to EGCG mediated inhibition of interdomain N-C termini interaction of AR. Treatment with EGCG also repressed the transcriptional activation by a hotspot mutant AR (T877A) expressed ectopically as well as the endogenous AR mutant. As the physiological consequence of AR antagonism, EGCG repressed R1881-induced PCa cell growth. In a xenograft model, EGCG was found to inhibit AR nuclear translocation and protein expression. We also observed a significant down-regulation of androgen-regulated miRNA-21 and up-regulation of a tumor suppressor, miRNA-330, in tumors of mice treated with EGCG. Taken together, we provide evidence that EGCG functionally antagonizes androgen action at multiple levels, resulting in inhibition of PCa growth.—Siddiqui, I. A., Asim, M., Hafeez, B. B., Adhami, V. M., Tarapore, R. S., Mukhtar, H. Green tea polyphenol EGCG blunts androgen receptor function in prostate cancer. PMID:21177307

Synthesis and Biological Testing of Novel Glucosylated Epigallocatechin Gallate (EGCG) Derivatives.

PubMed

Zhang, Xin; Wang, Jing; Hu, Jiang-Miao; Huang, Ye-Wei; Wu, Xiao-Yun; Zi, Cheng-Ting; Wang, Xuan-Jun; Sheng, Jun

2016-05-11

Epigallocatechin gallate (EGCG) is the most abundant component of green tea catechins and has strong physiological activities. In this study, two novel EGCG glycosides (EGCG-G1 and EGCG-G2) were chemoselectively synthesized by a chemical modification strategy. Each of these EGCG glycosides underwent structure identification, and the structures were assigned as follows: epigallocatechin gallate-4''-O-β-d-glucopyranoside (EGCG-G1, 2) and epigallocatechin gallate-4',4''-O-β-d-gluco-pyranoside (EGCG-G2, 3). The EGCG glycosides were evaluated for their anticancer activity in vitro against two human breast cell lines (MCF-7 and MDA-MB-231) using MTT assays. The inhibition rate of EGCG glycosides (EGCG-G1 and EGCG-G2) is not obvious. The EGCG glycosides are more stable than EGCG in aqueous solutions, but exhibited decreasing antioxidant activity in the DPPH radical-scavenging assay (EGCG > EGCG-G2 > EGCG-G1). Additionally, the EGCG glycosides exhibited increased water solubility: EGCG-G2 and EGCG-G1 were 15 and 31 times as soluble EGCG, respectively. The EGCG glycosides appear to be useful, and further studies regarding their biological activity are in progress.

Novel acetylcholinesterase inhibitors from Zijuan tea and biosynthetic pathway of caffeoylated catechin in tea plant.

PubMed

Wang, Wei; Fu, Xi-Wen; Dai, Xin-Long; Hua, Fang; Chu, Gang-Xiu; Chu, Ming-Jie; Hu, Feng-Lin; Ling, Tie-Jun; Gao, Li-Ping; Xie, Zhong-Wen; Wan, Xiao-Chun; Bao, Guan-Hu

2017-12-15

Zijuan tea is a special cultivar of Yunnan broad-leaf tea (Camellia sinensis var. assamica) with purple buds, leaves, and stems. Phytochemical study on this tea led to the discovery of three hydroxycinnamoylated catechins (HCCs) (1-3), seven other catechins (4-10), three proanthocyanidins (11-13), five flavones and flavone glycosides (14-18), two alkaloids (19, 20), one steroid (21), and one phenylpropanoid glycoside (22). The isolation and structural elucidation of the caffeoylated catechin (1) by means of spectroscopic techniques were described. We also provide the first evidence that 1 is synthesized via a two-step pathway in tea plant. The three HCCs (1-3) were investigated on their bioactivity through molecular modeling simulation and biochemical experiments. Our results show that they bind acetylcholinesterase (AChE) tightly and have strong AChE inhibitory activity with IC 50 value at 2.49, 11.41, 62.26μM, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simultaneous preparation of naturally abundant and rare catechins by tannase-mediated biotransformation combining high speed counter current chromatography.

PubMed

Xia, Guobin; Hong, Shan; Liu, Songbai

2014-05-15

Simultaneous preparation of naturally rare catechins, EGC and EC, has been realized by tannase-mediated biotransformation combining high speed counter current chromatography. In addition, simultaneous preparation of the four catechins, EGCG, ECG, EGC, and EC in green tea extract has also been achieved by HSCCC under the normal phase and the reversed phase modes. The identity of the catechins was determined by HPLC-DAD-ESI-MS and quantification of the catechins was performed by HPLC-DAD. In a typical HSCCC separation, 27.2 mg 98.8% EGCG, 14.1 mg 94.7% EGC, and 9.3 mg 97.5% EC were obtained. This new method is efficient, time-saving and valuable for biological studies. Copyright © 2013 Elsevier Ltd. All rights reserved.

In vitro electrocardiographic and cardiac ion channel effects of (-)-epigallocatechin-3-gallate, the main catechin of green tea.

PubMed

Kang, Jiesheng; Cheng, Hsien; Ji, Junzhi; Incardona, Josephine; Rampe, David

2010-08-01

Epigallocatechin-3-gallate (EGCG) is the major catechin found in green tea. EGCG is also available for consumption in the form of concentrated over-the-counter nutritional supplements. This compound is currently undergoing clinical trials for the treatment of a number of diseases including multiple sclerosis, and a variety of cancers. To date, few data exist regarding the effects of EGCG on the electrophysiology of the heart. Therefore, we examined the effects of EGCG on the electrocardiogram recorded from Langendorff-perfused guinea pig hearts and on cardiac ion channels using patch-clamp electrophysiology. EGCG had no significant effects on the electrocardiogram at concentrations of 3 and 10 microM. At 30 microM, EGCG prolonged PR and QRS intervals, slightly shortened the QT interval, and altered the shape of the ST-T-wave segment. The ST segment merged with the upstroke of the T wave, and we noted a prolongation in the time from the peak of the T wave until the end. Patch-clamp studies identified the KvLQT1/minK K(+) channel as a target for EGCG (IC(50) = 30.1 microM). In addition, EGCG inhibited the cloned human cardiac Na(+) channel Na(v)1.5 in a voltage-dependent fashion. The L-type Ca(2+) channel was inhibited by 20.8% at 30 microM, whereas the human ether-a-go-go-related gene and Kv4.3 cardiac K(+) channels were less sensitive to inhibition by EGCG. ECGC has a number of electrophysiological effects in the heart, and these effects may have clinical significance when multigram doses of this compound are used in human clinical trials or through self-ingestion of large amounts of over-the-counter products enriched in EGCG.

Epigallocatechin gallate (EGCG) suppresses lipopolysaccharide-induced inflammatory bone resorption, and protects against alveolar bone loss in mice.

PubMed

Tominari, Tsukasa; Matsumoto, Chiho; Watanabe, Kenta; Hirata, Michiko; Grundler, Florian M W; Miyaura, Chisato; Inada, Masaki

2015-01-01

Epigallocatechin gallate (EGCG), a major polyphenol in green tea, possesses antioxidant properties and regulates various cell functions. Here, we examined the function of EGCG in inflammatory bone resorption. In calvarial organ cultures, lipopolysaccharide (LPS)-induced bone resorption was clearly suppressed by EGCG. In osteoblasts, EGCG suppressed the LPS-induced expression of COX-2 and mPGES-1 mRNAs, as well as prostaglandin E2 production, and also suppressed RANKL expression, which is essential for osteoclast differentiation. LPS-induced bone resorption of mandibular alveolar bones was attenuated by EGCG in vitro, and the loss of mouse alveolar bone mass was inhibited by the catechin in vivo.

The protective activity of tea catechins against experimental infection by Vibrio cholerae O1.

PubMed

Toda, M; Okubo, S; Ikigai, H; Suzuki, T; Suzuki, Y; Hara, Y; Shimamura, T

1992-01-01

Tea catechins inhibited the fluid accumulation induced by cholera toxin in sealed adult mice. The catechins also reduced fluid accumulation by Vibrio cholerae O1 in ligated intestinal loops of rabbits. These findings suggest that tea catechins may possess protective activity against V. cholerae O1.

Chemopreventive potential of the tannase-mediated biotransformation of green tea.

PubMed

Macedo, J A; Ferreira, L R; Camara, L E; Santos, J C; Gambero, A; Macedo, G A; Ribeiro, M L

2012-07-15

Green tea (Camellia sinensis) is one of the most widely consumed beverages in the world. The cancer chemopreventive qualities of green tea have been well documented. Epigallocatechin gallate (EGCG) is often described as the most potently chemopreventive green tea catechin; however, the low bioavailability of EGCG is a limiting factor for its biological effect. Thus, the aim of this work was to test the chemopreventive potential of green tea extract and EGCG after tannase-mediated hydrolysis. The results showed that the biotransformed compounds retained most of the beneficial properties of the original compounds, and some beneficial properties were improved in the biotransformed compounds. Biotransformation of EGCG decreased its toxicity without affecting its antiproliferative effects. Furthermore, human cells gene expression profiling showed that the biotransformed compounds modulated the expression of several genes related to carcinogenesis. These results demonstrate the benefits of the biotechnological modification of natural food molecules, allowing the improvement of the nutraceutical potential of a beverage as green tea. Copyright © 2012 Elsevier Ltd. All rights reserved.

Green tea and its major polyphenol EGCG increase the activity of oral peroxidases.

PubMed

Narotzki, Baruch; Levy, Yishai; Aizenbud, Dror; Reznick, Abraham Z

2013-01-01

Oral peroxidases (OPO) consist mainly of salivary peroxidase and myeloperoxidase and are involved in oral defense mechanisms. Salivary peroxidase is synthesized and secreted by salivary glands, whereas myeloperoxidase is found in polymorphonuclear leukocytes, which migrate into the oral cavity at gingival crevices. Green tea is the world's second most popular drink after water. Polyphenols are the most biologically active group of tea components. The purpose of our study was to elucidate the interaction between green tea & EGCG (Epigallocatechin 3-gallate), its main polyphenol and OPO. In previous studies we have shown that elderly trained people who drink green tea for 3 months, have a higher level of OPO activity compared to non-drinkers. Thus, we decided to extend our project in order to understand the above observations by studying the interaction of green tea and OPO both in vitro and in vivo. Addition of green tea and black tea infusions (50 μl/ml) and EGCG (50 μM) to saliva, resulted in a sharp rise of OPO activity +280% (p = 0.009), 54% (p = 0.04) and 42% (p = 0.009), respectively. The elevation of OPO activity due to addition of green tea and EGCG was in a dose dependent manner: r = 0.91 (p = 0.001) and r = 0.637 (p = 0.019), respectively. Also, following green tea infusion mouth rinsing, a rise of OPO activity was observed: +268% (p = 0.159). These results may be of great clinical importance, as tea consumer's oral epithelium may have better protection against the deleterious effects of hydroxyl radicals, produced by not removed hydrogen peroxides in the presence of metal ions. Higher OPO activity upon green tea drinking may provide an extra protection against oxidative stress in the oral cavity.

Nutraceuticals for body-weight management: The role of green tea catechins.

PubMed

Janssens, Pilou L H R; Hursel, Rick; Westerterp-Plantenga, Margriet S

2016-08-01

Green tea catechins mixed with caffeine have been proposed as adjuvants for maintaining or enhancing energy expenditure and for increasing fat oxidation, in the context of prevention and treatment of obesity. These catechins-caffeine mixtures seem to counteract the decrease in metabolic rate that occurs during weight loss. Their effects are of particular importance during weight maintenance after weight loss. Other metabolic targets may be fat absorption and the gut microbiota composition, but these effects still need further investigation in combination with weight loss. Limitations for the effects of green tea catechins are moderating factors such as genetic predisposition related to COMT-activity, habitual caffeine intake, and ingestion combined with dietary protein. In conclusion, a mixture of green tea catechins and caffeine has a beneficial effect on body-weight management, especially by sustained energy expenditure, fat oxidation, and preservation of fat free body-mass, after energy restriction induced body-weight loss, when taking the limitations into account. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of gut microbiota and time of treatment on tissue levels of green tea polyphenols in mice.

PubMed

Liu, Anna B; Tao, Siyao; Lee, Mao-Jung; Hu, Qi; Meng, Xiaofeng; Lin, Yong; Yang, Chung S

2018-05-08

The previous studies have shown that tea polyphenols are metabolized by gut microbiota. This study investigated the effect of gut microbiota on the bioavailability, tissue levels, and degradation of tea polyphenols. Mice were treated with antibiotics (ampicillin/sulfamethoxazole/trimethoprim) in drinking water and the control mice received water for 11 days, and they were given an AIN93M diet enriched with 0.32% of Polyphenon E. The levels of catechins and their metabolites (if present) in the serum, liver, urine, and fecal samples were determined by high-performance liquid chromatography. The results showed that treatment with antibiotics significantly increased the levels of the major polyphenol, (-)-epigallocatechin-3-gallate (EGCG), in serum and liver samples. Antibiotics also raised the levels of some catechins in urine and fecal samples but decreased the levels of their metabolites. These results suggest that antibiotics eliminated gut microbes and increased the bioavailabilities of these tea catechins. In a second study, mice were given different concentrations of green tea infusions as the drinking fluid. The plasma levels of EGCG and (-)-epicatechin-3-gallate (ECG) at day 112 were significantly lower than those at day 5. The urine levels of EGCG and ECG increased in the first 4 or 5 days, and then decreased to much lower levels at day 23 and beyond. In contrast, the levels of (-)-epigallocatechin and (-)-epicatechin showed a trend of increase during the 112-day experiment, likely owing to microbial hydrolysis of EGCG and ECG. Both sets of experiments support the idea that the degradation of EGCG and ECG by gut microbiota decreases their bioavailabilities. © 2018 BioFactors, 2018. © 2018 International Union of Biochemistry and Molecular Biology.

Green Tea as Inhibitor of the Intestinal Absorption of Lipids: Potential Mechanism for its Lipid-Lowering Effect1

PubMed Central

Koo, Sung I.; Noh, Sang K.

2007-01-01

Animal and epidemiological studies suggest that green tea catechins may reduce the risk of cardiovascular diseases (CHD). The health benefit of green tea has been attributed to its antioxidant and anti-inflammatory properties; however, considerable evidence suggests that green tea and its catechins may reduce the risk of CHD by lowering the plasma levels of cholesterol and triglyceride. Although the mechanism underlying such effect of green tea is yet to be determined, it is evident from in vitro and in vivo studies that green tea or catechins inhibit the intestinal absorption of dietary lipids. Studies in vitro indicate that green tea catechins, particularly EGCG, interfere with the emulsification, digestion, and micellar solubilization of lipids, critical steps involved in the intestinal absorption of dietary fat, cholesterol, and other lipids. Based on the observations, it is likely that green tea or its catechins lower the absorption and tissue accumulation of other lipophilic organic compounds. The available information strongly suggests that green tea or its catechins may be used as safe and effective lipid-lowering therapeutic agents. PMID:17296491

Green and black tea inhibit cytokine-induced IL-8 production and secretion in AGS gastric cancer cells via inhibition of NF-κB activity.

PubMed

Gutierrez-Orozco, Fabiola; Stephens, Brian R; Neilson, Andrew P; Green, Rodney; Ferruzzi, Mario G; Bomser, Joshua A

2010-10-01

Consumption of tea is associated with a reduced risk for several gastrointestinal cancers. Inflammatory processes, such as secretion of IL-8 from the gastric epithelium in response to chronic chemokine or antigen exposure, serve both as a chemoattractant for white blood cells and a prerequisite for gastric carcinogenesis. In this study, the gastric adenocarcinoma cell line AGS was used to investigate the effect of green tea extract, black tea extract, and epigallocatechin gallate (EGCG), the most abundant catechin in tea, on cytokine-induced inflammation. AGS cells were stimulated with interleukin-1β (IL-1β) to initiate inflammation, followed by exposure to either tea extracts or EGCG. We found that both green and black tea extracts at concentrations of 20 and 2 µM total catechins, respectively, significantly (p < 0.05) inhibited IL-1β-induced IL-8 production and secretion to a similar extent. Treatment of AGS cells with EGCG (8 µM) produced similar reductions in IL-1β-induced IL-8 production and secretion. Inhibition of NF-κB activity was found to be responsible, in part, for these observed effects. Our findings demonstrate that both green and black tea extracts with distinctly different catechin profiles, are capable of disrupting the molecular link between inflammation and carcinogenesis via inhibition of NF-κB activity in AGS cells. © Georg Thieme Verlag KG Stuttgart · New York.

Factors influencing the antifolate activity of synthetic tea-derived catechins.

PubMed

Sáez-Ayala, Magalí; Fernández-Pérez, María Piedad; Chazarra, Soledad; Mchedlishvili, Nani; Tárraga-Tomás, Alberto; Rodríguez-López, José Neptuno

2013-07-16

Novel tea catechin derivatives have been synthesized, and a structure-activity study, related to the capacity of these and other polyphenols to bind dihydrofolate reductase (DHFR), has been performed. The data showed an effective binding between all molecules and the free enzyme, and the dissociation constants of the synthetic compounds and of the natural analogues were on the same order. Polyphenols with a catechin configuration were better DHFR inhibitors than those with an epicatechin configuration. Antiproliferative activity was also studied in cultured tumour cells, and the data showed that the activity of the novel derivatives was higher in catechin isomers. Derivatives with a hydroxyl group para on the ester-bonded gallate moiety presented a high in vitro binding to DHFR, but exhibited transport problems in cell culture due to ionization at physiologic pHs. The impact of the binding of catechins to serum albumin on their biological activity was also evaluated. The information provided in this study could be important for the design of novel medicinal active compounds derived from tea catechins. The data suggest that changes in their structure to avoid serum albumin interactions and to facilitate plasmatic membrane transport are essential for the intracellular functions of catechins.

The anti-hyperuricemic effect of epigallocatechin-3-gallate (EGCG) on hyperuricemic mice.

PubMed

Zhu, Chuang; Xu, Yan; Liu, Zeng-Hui; Wan, Xiao-Chun; Li, Da-Xiang; Tai, Ling-Ling

2018-01-01

Epigallocatechin-3-gallate (EGCG), a major constituent of green tea catechin, has been used for antioxidant. This study aimed to evaluate the antihyperuricemic activity of EGCG on hyperuricemic mice. We demonstrated that serum uric acid (UA) level was decreased significantly with dose-dependence by EGCG treated with 10, 20, and 50mg/kg. Compared with the model, data on blood urea nitrogen (BUN) supported that there was significance with high dose of EGCG (50mg/kg). Levels of serum creatinine (Cr) in each EGCG-treated group were decreased but not significant; the activities of hepatic xanthine oxidase (XOD) and adenosine deaminase (ADA) in high dose groups' EGCG were notably lower than those of model group. EGCG could downregulate the renal mRNA expression levels of glucose transporter 9 (GLUT9) and urate transporter 1 (URAT1) on hyperuricemic mice. These results presented that EGCG had obvious hypouricemic and renal protective effects on hyperuricemic mice. Our data may have a potential value in clinical practice in the treatment of hyperuricemia. Copyright © 2017. Published by Elsevier Masson SAS.

Application of a functional mathematical index for antibacterial and anticarcinogenic effects of tea catechins.

PubMed

Finotti, Enrico; Bersani, Enrico; Friedman, Mendel

2011-02-09

Tea leaves produce secondary metabolites that are involved in the defense of the plants against invading pathogens. In the case of green teas, these metabolites are polyphenolic compounds called catechins. Previous studies developed a mathematical formula called functional mathematical index (FMI) that was used to describe the quality of different olive oils and potatoes in terms of compositional parameters and antioxidative properties of individual components. This study extends the development of the FMI concept to define an "optimum tea" based on reported relationships between the content of structurally different catechins of a large number of teas and their dual beneficial effects: antimicrobial activities against a foodborne pathogen and inhibition of human cancer cell lines. The described mathematical approach may be useful for predicting relative beneficial effects of new teas based on their catechin content.

Accumulation of catechins in tea in relation to accumulation of mRNA from genes involved in catechin biosynthesis.

PubMed

Eungwanichayapant, P D; Popluechai, S

2009-02-01

Catechins are a group of polyphenols found in tea (Camellia sinensis var. sinensis) at high levels. They are beneficial for health. From the study on accumulation of catechins in shoots and mature leaves of a tea cultivar, Oolong No. 17, using high-performance liquid chromatography (HPLC), it was found that the amounts of most catechins in the shoots were higher than those in the mature leaves, with an exception of catechins gallate (CG) that was found in trace amounts in both the shoots and mature leaves. mRNA accumulation of genes involved in catechin synthesis was studied using reverse transcriptase-polymerase chain reaction (RT-PCR). The results showed that the mRNA accumulation of the genes were higher in the shoots than in the mature leaves. These genes included genes of phenylalanine ammonia-lyase 1 (PAL1; EC 4.3.1.5), chalcone synthase (CHS; EC 2.3.1.74), dihydroflavonol 4-reductase (DFR; EC 1.1.1.219), leucoanthocyanidin reductase (LCR; EC 1.17.1.3), and flavanone 3-hydroxylase (F3H; EC 1.14.11.9).

Prooxidant property of green tea polyphenols epicatechin and epigallocatechin-3-gallate: implications for anticancer properties.

PubMed

Azam, S; Hadi, N; Khan, N U; Hadi, S M

2004-10-01

It is believed that anticancer and apoptosis inducing properties of green tea are mediated by it's polyphenolic constituents particularly catechins. A number of reports have shown that green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) is among the most effective chemopreventive and apoptosis-inducing agents present in the beverage. Plant polyphenols are naturally occurring antioxidants but they also exhibit prooxidant properties. Over the last several years we have shown that various classes of plant polyphenols including flavonoids, curcuminoids and tannins are capable of catalyzing oxidative DNA cleavage particularly in the presence of transition metal ions such as copper and iron. With a view to understand the chemical basis of various pharmacological properties of green tea, in this paper we have compared the prooxidant properties of green tea polyphenols--EGCG and EC ((-)-epicatechin). The rate of oxidative DNA degradation as well as hydroxyl radical and superoxide anion formation was found to be greater in the case of EGCG as compared with EC. It was also shown that copper mediated oxidation of EC and EGCG possibly leads to the formation of polymerized polyphenols. Further, it was indicated that copper oxidized catechins were more efficient prooxidants as compared with their unoxidized forms. These results correlate with the observation by others that EGCG is the most effective apoptosis inducing polyphenol present in green tea. They are also in support of our hypothesis that prooxidant action of plant polyphenols may be an important mechanism of their anticancer properties. A model for binding of Cu(II) to EC has been presented where the formation of quinone and a quinone methide has been proposed.

Green tea catechins and their metabolites in human skin before and after exposure to ultraviolet radiation.

PubMed

Clarke, Kayleigh A; Dew, Tristan P; Watson, Rachel E B; Farrar, Mark D; Osman, Joanne E; Nicolaou, Anna; Rhodes, Lesley E; Williamson, Gary

2016-01-01

Dietary flavonoids may protect against sunburn inflammation in skin. Preliminary reports using less complete analysis suggest that certain catechins and their metabolites are found in skin biopsies and blister fluid after consumption of green tea; however, it is not known if they are affected by solar-simulated ultraviolet radiation (UVR) or whether conjugated forms, with consequently altered bioactivity, are present. The present study tested the hypothesis that UVR affects the catechin levels in the skin of healthy volunteers after consumption of green tea and how catechins in the plasma are related to their presence in skin tissue samples. In an open oral intervention study, 11 subjects consumed green tea and vitamin C supplements daily for 3months. Presupplementation and postsupplementation plasma samples, suction blister fluid and skin biopsies were collected; the latter two samples were collected both before and after UVR. A sensitive high-performance liquid chromatography/mass spectrometric assay was used to measure the intact catechin metabolites, conjugates and free forms. Seven green tea catechins and their corresponding metabolites were identified postsupplementation in skin biopsies, 20 in blister fluid and 26 in plasma, with 15 green tea catechin metabolites present in both blister fluid and plasma. The valerolactone, O-methyl-M4-O-sulfate, a gut microbiota metabolite of catechins, was significantly increased 1.6-fold by UVR in blister fluid samples. In conclusion, there were some common catechin metabolites in the plasma and blister fluid, and the concentration was always higher in plasma. The results suggest that green tea catechins and metabolites are bioavailable in skin and provide a novel link between catechin metabolites derived from the skin and gut microbiota. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Metabolic dependence of green tea on plucking positions revisited: a metabolomic study.

PubMed

Lee, Jang-Eun; Lee, Bum-Jin; Hwang, Jeong-Ah; Ko, Kwang-Sup; Chung, Jin-Oh; Kim, Eun-Hee; Lee, Sang-Jun; Hong, Young-Shick

2011-10-12

The dependence of global green tea metabolome on plucking positions was investigated through (1)H nuclear magnetic resonance (NMR) analysis coupled with multivariate statistical data set. Pattern recognition methods, such as principal component analysis (PCA) and orthogonal projection on latent structure-discriminant analysis (OPLS-DA), were employed for a finding metabolic discrimination among fresh green tea leaves plucked at different positions from young to old leaves. In addition to clear metabolic discrimination among green tea leaves, elevations in theanine, caffeine, and gallic acid levels but reductions in catechins, such as epicatechin (EC), epigallocatechin (EGC), epicatechin-3-gallate (ECG), and epigallocatechin-3-gallate (EGCG), glucose, and sucrose levels were observed, as the green tea plant grows up. On the other hand, the younger the green tea leaf is, the more theanine, caffeine, and gallic acid but the lesser catechins accumlated in the green tea leaf, revealing a reverse assocation between theanine and catechins levels due to incorporaton of theanine into catechins with growing up green tea plant. Moreover, as compared to the tea leaf, the observation of marked high levels of theanine and low levels of catechins in green tea stems exhibited a distinct tea plant metabolism between the tea leaf and the stem. This metabolomic approach highlights taking insight to global metabolic dependence of green tea leaf on plucking position, thereby providing distinct information on green tea production with specific tea quality.

Inhibition of proliferation of human lung cancer cells by green tea catechins is mediated by upregulation of let-7

PubMed Central

ZHONG, ZHIWEI; DONG, ZHUO; YANG, LIHUA; CHEN, XIAOQIANG; GONG, ZHAOHUI

2012-01-01

Green tea catechins are known to function as anticancer agents via inhibition of carcinogenesis during the initiation, promotion and progression stages. Many potential mechanisms have been proposed, yet the precise mechanism of lung cancer prevention by green tea catechins remains unclear. microRNAs (miRs) are a class of 21–24 nucleotide small non-coding RNAs and play critical roles throughout cellular development and regulation. Emerging evidence demonstrates that tea catechins influence the expression of miRs in human cancer cells to inhibit tumorigenesis. Both let-7a-1 and let-7g were detected in the human lung cancer cells treated with tea catechins. The cell viability and cell cycle were analyzed after tea catechins treatment. In the present study, we found that tea catechins upregulated the tumor-suppressor miRs, let-7a-1 and let-7g, in lung cancer cell lines. The upregulation of let-7a/7g repressed the expression of their targets, C-MYC and the regulatory protein of LIN-28, at the mRNA and protein levels. Moreover, the cell growth assay indicated that tea catechins significantly inhibited cell proliferation, and the flow cytometric analysis revealed an increase in the number of cells in the G2/M phase and a decrease in the number of cells in the S phase after treatment with tea catechins. These observations suggest that green tea catechins mediate the inhibition of proliferation of lung cancer cells through the let-7 signaling pathway. PMID:22970031

The green tea catechin epigallocatechin gallate induces cell cycle arrest and shows potential synergism with cisplatin in biliary tract cancer cells.

PubMed

Mayr, Christian; Wagner, Andrej; Neureiter, Daniel; Pichler, Martin; Jakab, Martin; Illig, Romana; Berr, Frieder; Kiesslich, Tobias

2015-06-23

The green tea catechin epigallocatechin gallate (EGCG) was shown to effectively inhibit tumor growth in various types of cancer including biliary tract cancer (BTC). For most BTC patients only palliative therapy is possible, leading to a median survival of about one year. Chemoresistance is a major problem that contributes to the high mortality rates of BTC. The aim of this study was to investigate the cytotoxic effect of EGCG alone or in combination with cisplatin on eight BTC cell lines and to investigate the cellular anti-cancer mechanisms of EGCG. The effect of EGCG treatment alone or in combination with the standard chemotherapeutic cisplatin on cell viability was analyzed in eight BTC cell lines. Additionally, we analyzed the effects of EGCG on caspase activity, cell cycle distribution and gene expression in the BTC cell line TFK-1. EGCG significantly reduced cell viability in all eight BTC cell lines (p < 0.05 or p < 0.01, respectively, for most cell lines and EGCG concentrations > 5 μM). Combined EGCG and cisplatin treatment showed a synergistic cytotoxic effect in five cell lines and an antagonistic effect in two cell lines. Furthermore, EGCG reduced the mRNA levels of various cell cycle-related genes, while increasing the expression of the cell cycle inhibitor p21 and the apoptosis-related death receptor 5 (p < 0.05). This observation was accompanied by an increase in caspase activity and cells in the sub-G1 phase of the cell cycle, indicating induction of apoptosis. EGCG also induced a down-regulation of expression of stem cell-related genes and genes that are associated with an aggressive clinical character of the tumor, such as cd133 and abcg2. EGCG shows various anti-cancer effects in BTC cell lines and might therefore be a potential anticancer drug for future studies in BTC. Additionally, EGCG displays a synergistic cytotoxic effect with cisplatin in most tested BTC cell lines. Graphical abstract Summary illustration.

The effects of tea catechins on fecal conditions of elderly residents in a long-term care facility.

PubMed

Goto, K; Kanaya, S; Ishigami, T; Hara, Y

1999-01-01

This study was carried out to evaluate the effects of tea catechins on fecal contents and metabolites of elderly people who were on a diet of solid food. The subjects were 35 residents in a long-term care facility who were all on the same diet, consisting of rice gruel and minced food. Tea catechins (300 mg), which were divided into 3 doses a day, were a meal supplement every day for 6 weeks. Fecal specimens were collected by the nursing staff, and their moisture content, pH, ammonia, sulfide, and oxidation-reduction potential (ORP) were determined before, during, and after the administration of tea catechins. In a comparison of values before the administration, all these fecal parameters decreased significantly during the tea catechin administration. After termination of the administration, these data tended to return toward the levels before administration. The reduction of such fecal parameters as moisture, pH, ammonia, sulfide, and ORP by tea catechin administration indicated very favorable improvements of the subjects' bowel conditions.

Effect of emulsification on the skin permeation and UV protection of catechin.

PubMed

Yoshino, Sachie; Mitoma, Tomoaki; Tsuruta, Keiko; Todo, Hiroaki; Sugibayashi, Kenji

2014-06-01

An anti-aging effect may be obtained by skin application of tea catechins (Camellia sinensis) since they have high ultraviolet (UV)-protection activity. In this study, the skin permeation of catechin (C), epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECg) and epigallocatechin gallate (EGCg) was determined and compared, and the effect of emulsification on the skin permeation of C was measured. The UV-protective effect of C was also determined. The in vitro skin permeability of each catechin derivative was determined using side-by-side diffusion of cells. The UV-protective effect of C was determined by applying different concentrations of C to the solution or emulsion on a three-dimensional cultured human skin model or normal human epidermal keratinocytes with UV-irradiation. ECg and EGCg with gallate groups showed lower skin permeability than C, EC and EGC without gallate groups, suggesting that the skin permeability of catechin derivatives may be dependent on the existence of a gallate group. Interestingly, the skin permeation of C was increased by an o/w emulsification. In addition, the C emulsion showed a significantly higher UV-protective effect by C than that with its aqueous solution. These results suggest that the o/w emulsion of catechin derivatives is probably useful as a cosmetic formulation with anti-aging efficacy.

UHPLC determination of catechins for the quality control of green tea.

PubMed

Naldi, Marina; Fiori, Jessica; Gotti, Roberto; Périat, Aurélie; Veuthey, Jean-Luc; Guillarme, Davy; Andrisano, Vincenza

2014-01-01

An ultra-high performance liquid chromatography (UHPLC) with UV detection method was developed for the fast quantitation of the most represented and biologically important green tea catechins and caffeine. UHPLC system was equipped with C18 analytical column (50mm×2.1mm, 1.8μm), utilizing a mobile phase composed of pH 2.5 triethanolamine phosphate buffer (0.1M) and acetonitrile in a gradient elution mode; under these conditions six major catechins and caffeine were separated in a 3min run. The method was fully validated in terms of precision, detection and quantification limits, linearity, accuracy, and it was applied to the identification and quantification of catechins and caffeine present in green tea infusions. In particular, commercially available green tea leaves samples of different geographical origin (Sencha, Ceylon Green and Lung Ching) were used for infusion preparations (water at 85°C for 15min). The selectivity of the developed UHPLC method was confirmed by comparison with UHPLC-MS/MS analysis. The recovery of the main six catechins and caffeine on the three analyzed commercial tea samples ranged from 94 to 108% (n=3). Limits of detection (LOD) were comprised in the range 0.1-0.4μgmL(-1). An orthogonal micellar electrokinetic (MEKC) method was applied for comparative purposes on selectivity and quantitative data. The combined use of the results obtained by the two techniques allowed for a fast confirmation on quantitative characterization of commercial samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Lack of pharmacokinetic interaction between fluvastatin and green tea in healthy volunteers.

PubMed

Misaka, Shingen; Abe, Osamu; Sato, Hideyuki; Ono, Tomoyuki; Shikama, Yayoi; Onoue, Satomi; Yabe, Hirooki; Kimura, Junko

2018-05-01

The objective of this study is to assess the effects of green tea and its major catechin component, (-)-epigallocatechin gallate (EGCG), on CYP2C9-mediated substrate metabolism in vitro, and the pharmacokinetics of fluvastatin in healthy volunteers. The metabolism of diclofenac and fluvastatin in human recombinant CYP2C9 was investigated in the presence of EGCG. In a randomized three-phase crossover study, 11 healthy volunteers ingested a single 20-mg dose of fluvastatin with green tea extract (GTE), containing 150 mg of EGCG, along with water (300 mL), brewed green tea (300 mL), or water (300 mL) after overnight fasting. Plasma concentrations of fluvastatin and EGCG were measured by ultra-performance liquid chromatography with fluorescence detection and a single mass spectrometer. EGCG inhibited diclofenac 4'-hydroxylation and fluvastatin degradation with IC 50 of 2.23 and 48.04 μM, respectively. Brewed green tea used in the clinical study also dose-dependently inhibited the metabolism of diclofenac and fluvastatin in vitro. However, no significant effects of GTE and brewed green tea were observed in plasma concentrations of fluvastatin. The geometric mean ratios with 90% CI for area under the plasma concentration-time curve (AUC 0-∞ ) of fluvastatin were 0.993 (0.963-1.024, vs. brewed green tea) and 0.977 (0.935-1.020, vs. GTE). Although in vitro studies indicated that EGCG and brewed green tea produce significant inhibitory effects on CYP2C9 activity, the concomitant administration of green tea and fluvastatin in healthy volunteers did not influence the pharmacokinetics of fluvastatin.

Plasma appearance and correlation between coffee and green tea metabolites in human subjects.

PubMed

Renouf, Mathieu; Guy, Philippe; Marmet, Cynthia; Longet, Karin; Fraering, Anne-Lise; Moulin, Julie; Barron, Denis; Dionisi, Fabiola; Cavin, Christophe; Steiling, Heike; Williamson, Gary

2010-12-01

Coffee and green tea are two of the most widely consumed hot beverages in the world. Their respective bioavailability has been studied separately, but absorption of their respective bioactive phenolics has not been compared. In a randomised cross-over design, nine healthy subjects drank instant coffee and green tea. Blood samples were collected over 12 h and at 24 h to assess return to baseline. After green tea consumption, (-)-epigallocatechin (EGC) was the major catechin, appearing rapidly in the plasma; (-)-EGC gallate (EGCg) and (-)-epicatechin (EC) were also present, but (-)-EC gallate and C were not detected. Dihydroferulic acid and dihydrocaffeic acid were the major metabolites that appeared after coffee consumption with a long time needed to reach maximum plasma concentration, suggesting metabolism and absorption in the colon. Other phenolic acid equivalents (caffeic acid (CA), ferulic acid (FA) and isoferulic acid (iFA)) were detected earlier, and they peaked at lower concentrations. Summations of the plasma area under the curves (AUC) for the measured metabolites showed 1.7-fold more coffee-derived phenolic acids than green tea-derived catechins (P = 0.0014). Furthermore, we found a significant correlation between coffee metabolites based on AUC. Inter-individual differences were observed, but individuals with a high level of CA also showed a correspondingly high level of FA. However, no such correlation was observed between the tea catechins and coffee phenolic acids. Correlation between AUC and maximum plasma concentration was also significant for CA, FA and iFA and for EGCg. This implies that the mechanisms of absorption for these two classes of compounds are different, and that a high absorber of phenolic acids is not necessarily a high absorber of catechins.

Green tea and its anti-angiogenesis effects.

PubMed

Rashidi, Bahman; Malekzadeh, Mehrnoush; Goodarzi, Mohammad; Masoudifar, Aria; Mirzaei, Hamed

2017-05-01

The development of new blood vessels from a pre-existing vasculature (also known as angiogenesis) is required for many physiological processes including embryogenesis and post-natal growth. However, pathological angiogenesis is also a hallmark of cancer and many ischaemic and inflammatory diseases. The pro-angiogenic members of the VEGF family (vascular endothelial growth factor family), VEGF-A, VEGF-B, VEGF-C, VEGF-D and placental growth factor (PlGF), and the related receptors, VEGFR-1, VEGFR-2 and VEGFR-3 have a central and decisive role in angiogenesis. Indeed, they are the targets for anti-angiogenic drugs currently approved. Green tea (from the Camellia sinensis plant) is one of the most popular beverages in the world. It is able to inhibit angiogenesis by different mechanisms such as microRNAs (miRNAs). Green tea and its polyphenolic substances (like catechins) show chemo-preventive and chemotherapeutic features in various types of cancer and experimental models for human cancers. The tea catechins, including (-)-epigallocatechin-3-gallate (EGCG), have multiple effects on the cellular proteome and signalome. Note that the polyphenolic compounds from green tea are able to change the miRNA expression profile associated with angiogenesis in various cancer types. This review focuses on the ability of the green tea constituents to suppress angiogenesis signaling and it summarizes the mechanisms by which EGCG might inhibit the VEGF family. We also highlighted the miRNAs affected by green tea which are involved in anti-angiogenesis. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Inhibitory effect of the green tea molecule EGCG against dengue virus infection.

PubMed

Raekiansyah, Muhareva; Buerano, Corazon C; Luz, Mark Anthony D; Morita, Kouichi

2018-06-01

Dengue virus (DENV) infection is a major public health problem worldwide; however, specific antiviral drugs against it are not available. Hence, identifying effective antiviral agents for the prevention of DENV infection is important. In this study, we showed that the reportedly highly biologically active green-tea component epigallocatechin gallate (EGCG) inhibited dengue virus infection regardless of infecting serotype, but no or minimal inhibition was observed with other flaviviruses, including Japanese encephalitis virus, yellow fever virus, and Zika virus. EGCG exerted its antiviral effect mainly at the early stage of infection, probably by interacting directly with virions to prevent virus infection. Our results suggest that EGCG specifically targets DENV and might be used as a lead structure to develop an antiviral drug for use against the virus.

The antioxidant effect of Green Tea Mega EGCG against electromagnetic radiation-induced oxidative stress in the hippocampus and striatum of rats.

PubMed

Ahmed, Nawal A; Radwan, Nasr M; Aboul Ezz, Heba S; Salama, Noha A

2017-01-01

Electromagnetic radiation (EMR) of cellular phones may affect biological systems by increasing free radicals and changing the antioxidant defense systems of tissues, eventually leading to oxidative stress. Green tea has recently attracted significant attention due to its health benefits in a variety of disorders, ranging from cancer to weight loss. Thus, the aim of the present study was to investigate the effect of EMR (frequency 900 MHz modulated at 217 Hz, power density 0.02 mW/cm 2 , SAR 1.245 W/kg) on different oxidative stress parameters in the hippocampus and striatum of adult rats. This study also extends to evaluate the therapeutic effect of green tea mega EGCG on the previous parameters in animals exposed to EMR after and during EMR exposure. The experimental animals were divided into four groups: EMR-exposed animals, animals treated with green tea mega EGCG after 2 months of EMR exposure, animals treated with green tea mega EGCG during EMR exposure and control animals. EMR exposure resulted in oxidative stress in the hippocampus and striatum as evident from the disturbances in oxidant and antioxidant parameters. Co-administration of green tea mega EGCG at the beginning of EMR exposure for 2 and 3 months had more beneficial effect against EMR-induced oxidative stress than oral administration of green tea mega EGCG after 2 months of exposure. This recommends the use of green tea before any stressor to attenuate the state of oxidative stress and stimulate the antioxidant mechanism of the brain.

Quantitative analysis of major constituents in green tea with different plucking periods and their antioxidant activity.

PubMed

Lee, Lan-Sook; Kim, Sang-Hee; Kim, Young-Boong; Kim, Young-Chan

2014-07-01

The objective of this study was to determine the relationship between the plucking periods and the major constituents and the antioxidant activity in green tea. Green tea was prepared from leaves plucked from the end of April 2013 to the end of May 2013 at intervals of one week or longer. The contents of theanine, theobromine, caffeine, catechin (C), and gallocatechin gallate (GCg) were significantly decreased, whereas those of epicatechin (EC), epigallocatechin gallate (EGCg) and epigallocatechin (EGC) were significantly increased along with the period of tea leaf plucking. In addition, antioxidant activity of green tea and standard catechins was investigated using ABTS, FRAP and DPPH assays. The highest antioxidant activity was observed in relatively the oldest leaf, regardless of the assay methods used. Additionally, the order of antioxidant activity of standard catechins was as follows: EGCg≥GCg≥ECg>EGC≥GC≥EC≥C. Moreover, the cis-catechins contents were the key factor affecting the antioxidant activity of green tea in all assays employed (ABTS, r=0.731, p<0.01; FRAP, r=0.886, p<0.01; DPPH, r=0.778, p<0.01).

Green tea catechins and their metabolites in human skin before and after exposure to ultraviolet radiation☆☆☆★

PubMed Central

Clarke, Kayleigh A.; Dew, Tristan P.; Watson, Rachel E.B.; Farrar, Mark D.; Osman, Joanne E.; Nicolaou, Anna; Rhodes, Lesley E.; Williamson, Gary

2016-01-01

Dietary flavonoids may protect against sunburn inflammation in skin. Preliminary reports using less complete analysis suggest that certain catechins and their metabolites are found in skin biopsies and blister fluid after consumption of green tea; however, it is not known if they are affected by solar-simulated ultraviolet radiation (UVR) or whether conjugated forms, with consequently altered bioactivity, are present. The present study tested the hypothesis that UVR affects the catechin levels in the skin of healthy volunteers after consumption of green tea and how catechins in the plasma are related to their presence in skin tissue samples. In an open oral intervention study, 11 subjects consumed green tea and vitamin C supplements daily for 3 months. Presupplementation and postsupplementation plasma samples, suction blister fluid and skin biopsies were collected; the latter two samples were collected both before and after UVR. A sensitive high-performance liquid chromatography/mass spectrometric assay was used to measure the intact catechin metabolites, conjugates and free forms. Seven green tea catechins and their corresponding metabolites were identified postsupplementation in skin biopsies, 20 in blister fluid and 26 in plasma, with 15 green tea catechin metabolites present in both blister fluid and plasma. The valerolactone, O-methyl-M4-O-sulfate, a gut microbiota metabolite of catechins, was significantly increased 1.6-fold by UVR in blister fluid samples. In conclusion, there were some common catechin metabolites in the plasma and blister fluid, and the concentration was always higher in plasma. The results suggest that green tea catechins and metabolites are bioavailable in skin and provide a novel link between catechin metabolites derived from the skin and gut microbiota. PMID:26454512

Plasma pharmacokinetics of catechin metabolite 4'-O-Me-EGC in healthy humans.

PubMed

Renouf, Mathieu; Redeuil, Karine; Longet, Karin; Marmet, Cynthia; Dionisi, Fabiola; Kussmann, Martin; Williamson, Gary; Nagy, Kornél

2011-10-01

Tea is an infusion of the leaves of the Camellia sinensis plant and is the most widely consumed beverage in the world after water. Green tea contains significant amounts of polyphenol catechins and represents a promising dietary component to maintain health and well-being. Epidemiological studies indicate that polyphenol intake may have potential health benefits, such as, reducing the incidence of coronary heart disease, diabetes and cancer. While bioavailability of green tea bioactives is fairly well understood, some gaps still remain to be filled, especially the identification and quantification of conjugated metabolites in plasma, such as, sulphated, glucuronidated or methylated compounds. In the present study, we aimed to quantify the appearance of green tea catechins in plasma with particular emphasis on their methylated forms. After feeding 400 mL of green tea, 1.25% infusion to 9 healthy subjects, we found significant amounts of EC, EGC and EGCg in plasma as expected. EGC was the most bioavailable catechin, and its methylated form (4'-O-Me-EGC) was also present in quantifiable amounts. Its kinetics followed that of its parent compound. However, the relative amount of the methylated form of EGC was lower than that of the parent compound, an important aspect which, in the literature, has been controversial so far. The quantitative results presented in our study were confirmed by co-chromatography and accurate mass analysis of the respective standards. We show that the relative abundance of 4'-O-Me-EGC is ~40% compared to the parent EGC. 4'-O-Me-EGC is an important metabolite derived from catechin metabolism. Its presence in significant amounts should not be overlooked when assessing human bioavailability of green tea.

Topical application of ointment containing 0.5% green tea catechins suppresses tongue oxidative stress in 5-fluorouracil administered rats.

PubMed

Miyai, Hisataka; Maruyama, Takayuki; Tomofuji, Takaaki; Yoneda, Toshiki; Azuma, Tetsuji; Mizuno, Hirofumi; Sugiura, Yoshio; Kobayashi, Terumasa; Ekuni, Daisuke; Morita, Manabu

2017-10-01

The purpose of this study was to investigate the preventive effects of topical application of green tea catechins on tongue oxidative stress induced by 5-fluorouracil (5-FU) administration in rats. Male Wistar rats (n=28, 8 weeks old) were divided into four groups of seven rats each: a negative control group (saline administration and application of ointment without green tea catechins), a positive control group (5-FU administration and application of ointment without green tea catechins), and two experimental groups (5-FU administration and application of ointment containing 0.1% or 0.5% green tea catechins). Topical application of each ointment to the ventral surface of the tongue was performed once a day for 5days. The level of 8-hydroxydeoxyguanosine (8-OHdG) was determined to evaluate oxidative stress. Fluorescence staining was also performed to confirm nuclear factor erythroid 2-related factor 2 (Nrf2) translocation to the nucleus. After the experimental period, the ratios of 8-OHdG-positive cells in the ventral tongue tissue were higher in the positive control group than in the negative control group (P<0.05). On the other hand, those in the 0.5% green tea catechin group, but not in the 0.1% green tea catechin group, were lower than the positive control group (P<0.05). In addition, Nrf2 translocation to the nucleus was greater in the 0.5% green tea catechin group than in the positive control group (P<0.05). Topical application of ointment containing 0.5% green tea catechins could prevent tongue oxidative stress in 5-FU administered rats, via up-regulation of the Nrf2 signaling pathway. Copyright © 2017 Elsevier Ltd. All rights reserved.

Epigallocatechin-3-gallate (EGCG), a green tea polyphenol, stimulates hepatic autophagy and lipid clearance.

PubMed

Zhou, Jin; Farah, Benjamin Livingston; Sinha, Rohit Anthony; Wu, Yajun; Singh, Brijesh Kumar; Bay, Boon-Huat; Yang, Chung S; Yen, Paul Michael

2014-01-01

Epigallocatechin gallate (EGCG) is a major polyphenol in green tea that has been shown to have anti-inflammatory, anti-cancer, anti-steatotic effects on the liver. Autophagy also mediates similar effects; however, it is not currently known whether EGCG can regulate hepatic autophagy. Here, we show that EGCG increases hepatic autophagy by promoting the formation of autophagosomes, increasing lysosomal acidification, and stimulating autophagic flux in hepatic cells and in vivo. EGCG also increases phosphorylation of AMPK, one of the major regulators of autophagy. Importantly, siRNA knockdown of AMPK abrogated autophagy induced by EGCG. Interestingly, we observed lipid droplet within autophagosomes and autolysosomes and increased lipid clearance by EGCG, suggesting it promotes lipid metabolism by increasing autophagy. In mice fed with high-fat/western style diet (HFW; 60% energy as fat, reduced levels of calcium, vitamin D3, choline, folate, and fiber), EGCG treatment reduces hepatosteatosis and concomitantly increases autophagy. In summary, we have used genetic and pharmacological approaches to demonstrate EGCG induction of hepatic autophagy, and this may contribute to its beneficial effects in reducing hepatosteatosis and potentially some other pathological liver conditions.

Separation and identification of twelve catechins in tea using liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry.

PubMed

Zeeb, D J; Nelson, B C; Albert, K; Dalluge, J J

2000-10-15

A method has been developed for the direct microscale determination of 12 catechins in green and black tea infusions. The method is based on liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (LC/APCI-MS). Standard catechin mixtures and tea infusions were analyzed by LC/APCI-MS with detection of protonated molecular ions and characteristic fragment ions for each compound. The identities of eight major catechins and caffeine in tea were established based on LC retention times and simultaneously recorded mass spectra. In addition, monitoring of the catechin-specific retro Diels-Alder fragment ion at m/z 139 throughout the chromatogram provided a unique fingerprint for catechin content in the samples that led to the identification of four minor chemically modified catechin derivatives in the infusions. This report is the first to describe the comprehensive determination of all 12 reported catechins in a single analysis. The utility of LC/APCI-MS for providing routine separation and identification of catechins at femtomole to low-picomole levels without extraction or sample pretreatment, and its potential as a standard analytical tool for the determination of polyphenols in natural products and biological fluids, are discussed.

Simultaneous analysis of tea catechins, caffeine, gallic acid, theanine and ascorbic acid by micellar electrokinetic capillary chromatography.

PubMed

Aucamp, J P; Hara, Y; Apostolides, Z

2000-04-21

A micellar electrokinetic capillary chromatography (MEKC) method for the simultaneous analysis of five tea catechins, theanine, caffeine, gallic acid and ascorbic acid has been developed. The catechins are (-)-epicatechin, (+)-catechin, (-)-epigallocatechin, (-)-epicatechin gallate and (-)-epigallocatechin gallate. p-Nitrophenol serves as both reference and internal standard. All the components are separated within 13 min with a 57 cm uncoated fused-silica column. On-column detection was carried out at 200 nm. This method has been used to measure these compounds in fresh tea leaves and tea liquor. The limit of detection for all analytes ranged from 1 to 20 microg/ml.

Analytical separation of tea catechins and food-related polyphenols by high-speed counter-current chromatography.

PubMed

Yanagida, Akio; Shoji, Atsushi; Shibusawa, Yoichi; Shindo, Heisaburo; Tagashira, Motoyuki; Ikeda, Mitsuo; Ito, Yoichiro

2006-04-21

High-speed counter-current chromatography (HSCCC) using the type-J coil planet centrifuge was applied to compositional analysis of tea catechins and separation of other food-related polyphenols. The HSCCC separation of nine different standard compounds and those from extracts of commercial tea leaves was performed with a two-phase solvent system composed of tert-butyl methyl ether-acetonitrile-0.1% aqueous trifluoroacetic acid (TFA) (2:2:3, v/v/v) by eluting the upper organic phase at a flow rate of 2 ml/min. The main compounds in the extract of non-fermented green tea were found to be monomeric catechins, their galloylated esters and caffeine. In addition to these compounds, oxidized pigments, such as hydrophobic theaflavins (TFs) and polar thearubigins (TRs) were also separated and detected from the extracts of semi-fermented oolong tea and fermented black tea. Furthermore, several food-related polyphenols, such as condensed catechin oligomers (procyanidins), phenolic acids and flavonol glycosides were clearly separated under the same HSCCC condition. These separation profiles of HSCCC provide useful information about the hydrophobic diversity of these bioactive polyphenols present in various types of teas and food products.

Epigallocatechin gallate (EGCG) inhibits adhesion and migration of neural progenitor cells in vitro.

PubMed

Barenys, Marta; Gassmann, Kathrin; Baksmeier, Christine; Heinz, Sabrina; Reverte, Ingrid; Schmuck, Martin; Temme, Thomas; Bendt, Farina; Zschauer, Tim-Christian; Rockel, Thomas Dino; Unfried, Klaus; Wätjen, Wim; Sundaram, Sivaraj Mohana; Heuer, Heike; Colomina, Maria Teresa; Fritsche, Ellen

2017-02-01

Food supplements based on herbal products are widely used during pregnancy as part of a self-care approach. The idea that such supplements are safe and healthy is deeply seated in the general population, although they do not underlie the same strict safety regulations than medical drugs. We aimed to characterize the neurodevelopmental effects of the green tea catechin epigallocatechin gallate (EGCG), which is now commercialized as high-dose food supplement. We used the "Neurosphere Assay" to study the effects and unravel underlying molecular mechanisms of EGCG treatment on human and rat neural progenitor cells (NPCs) development in vitro. EGCG alters human and rat NPC development in vitro. It disturbs migration distance, migration pattern, and nuclear density of NPCs growing as neurospheres. These functional impairments are initiated by EGCG binding to the extracellular matrix glycoprotein laminin, preventing its binding to β1-integrin subunits, thereby prohibiting cell adhesion and resulting in altered glia alignment and decreased number of migrating young neurons. Our data raise a concern on the intake of high-dose EGCG food supplements during pregnancy and highlight the need of an in vivo characterization of the effects of high-dose EGCG exposure during neurodevelopment.

Effect of catechin and its derivatives on inhibition of polyphenoloxidase and melanosis of Pacific white shrimp.

PubMed

Sae-Leaw, Thanasak; Benjakul, Soottawat; Simpson, Benjamin K

2017-04-01

This study aimed to investigate the effect of tea catechin (C) and 4 of its derivatives on the Pacific white shrimp PPO inhibition and melanosis during refrigerated storage. Epigallocatechin gallate (EGCG) exhibited the highest inhibition towards PPO, followed by C. Inhibitory activity of all compounds tested was in a dose dependent manner (0.1-2.0 mM). Based on activity staining, EGCG most effectively inhibited PPO. For inhibition kinetic studies, C and epicatechin (EC) showed uncompetitive type, whereas epicatechin gallate (ECG), epigallocatechin (EGC) and EGCG exhibited mixed type inhibition. When whole shrimps were treated with EGCG solution at various concentrations (0.25-0.75%), those treated with 0.5 or 0.75% EGCG had lower melanosis scores throughout storage for 10 days at 4 °C, compared with the control and the 1.25% sodium metabisulfite treated samples ( P  < 0.05). Therefore, EGCG could be used as a potential inhibitor for melanosis in raw Pacific white shrimp during refrigerated storage.

Catechins activate muscle stem cells by Myf5 induction and stimulate muscle regeneration.

PubMed

Kim, A Rum; Kim, Kyung Min; Byun, Mi Ran; Hwang, Jun-Ha; Park, Jung Il; Oh, Ho Taek; Kim, Hyo Kyeong; Jeong, Mi Gyeong; Hwang, Eun Sook; Hong, Jeong-Ho

2017-07-22

Muscle weakness is one of the most common symptoms in aged individuals and increases risk of mortality. Thus, maintenance of muscle mass is important for inhibiting aging. In this study, we investigated the effect of catechins, polyphenol compounds in green tea, on muscle regeneration. We found that (-)-epicatechin gallate (ECG) and (-)-epigallocatechin-3-gallate (EGCG) activate satellite cells by induction of Myf5 transcription factors. For satellite cell activation, Akt kinase was significantly induced after ECG treatment and ECG-induced satellite cell activation was blocked in the presence of Akt inhibitor. ECG also promotes myogenic differentiation through the induction of myogenic markers, including Myogenin and Muscle creatine kinase (MCK), in satellite and C2C12 myoblast cells. Finally, EGCG administration to mice significantly increased muscle fiber size for regeneration. Taken together, the results suggest that catechins stimulate muscle stem cell activation and differentiation for muscle regeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

Anti-stress effects of drinking green tea with lowered caffeine and enriched theanine, epigallocatechin and arginine on psychosocial stress induced adrenal hypertrophy in mice.

PubMed

Unno, Keiko; Hara, Ayane; Nakagawa, Aimi; Iguchi, Kazuaki; Ohshio, Megumi; Morita, Akio; Nakamura, Yoriyuki

2016-11-15

Theanine, an amino acid in tea, has significant anti-stress effects on animals and humans. However, the anti-stress effects of drinking green tea have not yet been elucidated. The present study aimed to explore anti-stress effects of green tea and roles of tea components in a mouse model of psychosocial stress. We examined anti-stress effects of three types of green teas, theanine-rich "Gyokuro", standard "Sencha", and Sencha with lowered caffeine (low-caffeine green tea). Furthermore, the roles of tea components such as caffeine, catechins, and other amino acids in anti-stress effects were examined. To prepare low-caffeine green tea, plucked new tea leaves were treated with a hot-water spray. Mice were psychosocially stressed from a conflict among male mice under confrontational housing. Mice consumed each tea that was eluted with room temperature water ad libitum. As a marker for the stress response, adrenal hypertrophy was compared with mice that ingested water. Caffeine was significantly lowered by spraying hot-water on tea leaves. While epigallocatechin gallate (EGCG) is the main catechin in tea leaves, epigallocatechin (EGC) was mainly infused into water at room temperature. Adrenal hypertrophy was significantly suppressed in mice that ingested theanine-rich and low-caffeine green tea that were eluted with water at room temperature. Caffeine and EGCG suppressed the anti-stress effects of theanine while EGC and arginine (Arg) retained these effects. These results suggest that drinking green tea exhibits anti-stress effects, where theanine, EGC and Arg cooperatively abolish the counter-effect of caffeine and EGCG on psychosocial stress induced adrenal hypertrophy in mice. Copyright © 2016 Elsevier GmbH. All rights reserved.

28-Day oral (gavage) toxicity studies of green tea catechins prepared for beverages in rats.

PubMed

Chengelis, Christopher P; Kirkpatrick, Jeannie B; Regan, Karen S; Radovsky, Ann E; Beck, Melissa J; Morita, Osamu; Tamaki, Yasushi; Suzuki, Hiroyuki

2008-03-01

The beneficial health effects associated with drinking green tea are widely considered to be due primarily to tea catechins. Heat treatment of marketed green tea beverages for sterilization causes epimerization and/or polymerization of tea catechins. Safety studies on heat-treated tea catechins are limited. The objective of the present study was to evaluate potential adverse effects, if any, of two standardized green tea catechin (GTC) preparations: one that underwent heat sterilization (GTC-H) and one that was not heat-sterilized (GTC-UH). A decaffeinated preparation of the GTC-H (GTC-HDC) was also evaluated to ascertain if any effects were due to caffeine. The GTC preparations were administered to rats once daily at levels up to 2000 mg/kg/day for 28 days. There were no deaths attributable to the GTC preparations. The clinical condition of the animals, functional observational battery, motor activity, clinical pathology evaluations, organ weights, and gross necropsy findings were unaffected by any of the GTC preparations. GTC-HDC or GTC-UH dosing had no effects on body weights or microscopic findings, whereas lower body weights and food consumption were observed in the 1000 and 2000 mg/kg/day GTC-H group males. The no observed-adverse-effect level (NOAEL) for localized gastric effects for GTC-H was 1000 mg/kg/day. No other target organs were identified. Thus, the NOAEL for systemic toxicity following oral administration was 2000 mg/kg/day for GTC-H, GTC HDC, and GTC-UH under the conditions of this study.

Simultaneous Determination of Black Tea-Derived Catechins and Theaflavins in Tissues of Tea Consuming Animals Using Ultra-Performance Liquid-Chromatography Tandem Mass Spectrometry

PubMed Central

Ganguly, Souradipta; G., Taposh Kumar; Mantha, Sudarshan

2016-01-01

The bioavailability, tissue distribution and metabolic fate of the major tea polyphenols, catechins and theaflavins as well as their gallated derivatives are yet to be precisely elucidated on a single identification platform for assessment of their relative bioefficacy in vivo. This is primarily due to the lack of suitable analytical tools for their simultaneous determination especially in an in vivo setting, which continues to constrain the evaluation of their relative health beneficiary potential and therefore prospective therapeutic application. Herein, we report a rapid and sensitive Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS) based method for the simultaneous determination of the major catechins and theaflavins in black tea infusions as well as in different vital tissues and body fluids of tea-consuming guinea pigs. This method allowed efficient separation of all polyphenols within seven minutes of chromatographic run and had a lower limit of quantification (LLOQ) of ~5 ng/ml. Using this method, almost all bioactive catechins and theaflavins could be simultaneously detected in the plasma of guinea pigs orally administered 5% black tea for 14 days. Our method could further detect the majority of these polyphenols in the lung and kidney as well as identify the major catechin metabolites in the urine of the tea-consuming animals. Overall, our study presents a novel tool for simultaneous detection and quantitation of both catechins and theaflavins in a single detection platform that could potentially enable precise elucidation of their relative bioavailability and bioefficacy as well as true health beneficiary potential in vivo. Such information would ultimately facilitate the accurate designing of therapeutic strategies utilizing high efficacy formulations of tea polyphenols for effective mitigation of oxidative damage and inflammation in humans as well as prevention of associated diseases. PMID:27695123

In vitro and in vivo anti-allergic effects of ‘benifuuki’ green tea containing O-methylated catechin and ginger extract enhancement

PubMed Central

Ema, Kaori; Shibuichi, Ikuo

2007-01-01

‘Benifuuki’, a tea (Camellia Sinensis L.) cultivar in Japan, is rich in anti-allergic epigallocatechin-3-O-(3-O-methyl) gallate (EGCG3″Me). ‘Benifuuki’ green tea and simultaneous addition of ginger extract remarkably suppressed cytokine (TNF-α and MIP-1α) secretion from mouse bone marrow-derived mast cells after antigen stimulation and, as expected, suppressed delay-type allergy. After drinking ‘benifuuki’ green tea containing 43.5 mg of EGCG and 8.5 mg of EGCG3″Me, the AUC (area under the drug concentration time curve; min μg/ml) of EGCG was 6.72 ± 2.87 and EGCG3″Me was 8.48 ± 2.54 in healthy human volunteers. Though the dose of EGCG was 5.1 times the dose of EGCG3″Me, the AUC of EGCG3″Me was higher than that of EGCG. A double blind clinical study on subjects with Japanese cedar pollinosis was carried out. At the 11th week after starting the study, in the most severe cedar pollen scattering period, symptoms, i.e., blowing the nose and itching eyes, were significantly relieved in the ‘benifuuki’ intake group compared with the placebo group, and blowing the nose, itching eyes and nasal symptom score, and at the 11th and 13th weeks, stuffy nose, throat pain and the nasal symptom medication score were significantly relieved in the ‘benifuuki’ containing ginger extract group compared with the placebo group. These results suggested that over one consecutive month, drinking ‘benifuuki’ green tea was useful to reduce some of the symptoms from Japanese cedar pollinosis, and did not affect any normal immune response in subjects with seasonal rhinitis, and the ginger extract enhanced the effect of ‘benifuuki’ green tea. PMID:19003003

Effect of Catechins, Green tea Extract and Methylxanthines in Combination with Gentamicin Against Staphylococcus aureus and Pseudomonas aeruginosa

PubMed Central

Fazly Bazzaz, Bibi Sedigheh; Sarabandi, Sahar; Khameneh, Bahman; Hosseinzadeh, Hossein

2016-01-01

Objectives: Bacterial resistant infections have become a global health challenge and threaten the society’s health. Thus, an urgent need exists to find ways to combat resistant pathogens. One promising approach to overcoming bacterial resistance is the use of herbal products. Green tea catechins, the major green tea polyphenols, show antimicrobial activity against resistant pathogens. The present study aimed to investigate the effect of catechins, green tea extract, and methylxanthines in combination with gentamicin against standard and clinical isolates of Staphylococcus aureus (S. aureus) and the standard strain of Pseudomonas aeruginosa (P. aeruginosa). Methods: The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values of different agents against bacterial strains were determined. The interactions of green tea extract, epigallate catechin, epigallocatechin gallate, two types of methylxanthine, caffeine, and theophylline with gentamicin were studied in vitro by using a checkerboard method and calculating the fraction inhibitory concentration index (FICI). Results: The MICs of gentamicin against bacterial strains were in the range of 0.312 - 320 μg/mL. The MIC values of both types of catechins were 62.5 - 250 μg/ mL. Green tea extract showed insufficient antibacterial activity when used alone. Methylxanthines had no intrinsic inhibitory activity against any of the bacterial strains tested. When green tea extract and catechins were combined with gentamicin, the MIC values of gentamicin against the standard strains and a clinical isolate were reduced, and synergistic activities were observed (FICI < 1). A combination of caffeine with gentamicin did not alter the MIC values of gentamicin. Conclusion: The results of the present study revealed that green tea extract and catechins potentiated the antimicrobial action of gentamicin against some clinical isolates of S. aureus and standard P. aeruginosa strains. Therefore

Crystal Engineering of Green Tea Epigallocatechin-3-gallate (EGCg) Cocrystals and Pharmacokinetic Modulation in Rats

PubMed Central

2013-01-01

The most abundant polyphenol in green tea, epigallocatechin-3-gallate (EGCg), has recently received considerable attention due to the discovery of numerous health-promoting bioactivities. Despite reports of its poor oral bioavailability, EGCg has been included in many dietary supplement formulations. Conventional preformulation methods have been employed to improve the bioavailability of EGCg. However, these methods have limitations that hinder the development of EGCg as an effective therapeutic agent. In this study, we have utilized the basic concepts of crystal engineering and several crystallization techniques to screen for various solid crystalline forms of EGCg and evaluated the efficacy of crystal engineering for modulating the pharmacokinetics of EGCg. We synthesized and characterized seven previously undescribed crystal forms of EGCg including the pure crystal structure of EGCg. The aqueous solubility profiles of four new EGCg cocrystals were determined. These cocrystals were subsequently dosed at 100 mg EGCg per kg body weight in rats, and the plasma levels were monitored over the course of eight hours following the single oral dose. Two of the EGCg cocrystals were found to exhibit modest improvements in relative bioavailability. Further, cocrystallization resulted in marked effects on pharmacokinetic parameters including Cmax, Tmax, area under curve, relative bioavailability, and apparent terminal half-life. Our findings suggest that modulation of the pharmacokinetic profile of EGCg is possible using cocrystallization and that it offers certain opportunities that could be useful during its development as a therapeutic agent. PMID:23730870

Inhibition of FLT3 Expression by Green Tea Catechins in FLT3 Mutated-AML Cells

PubMed Central

Ly, Bui Thi Kim; Chi, Hoang Thanh; Yamagishi, Makoto; Kano, Yasuhiko; Hara, Yukihiko; Nakano, Kazumi; Sato, Yuko; Watanabe, Toshiki

2013-01-01

Acute myeloid leukemia (AML) is a heterogeneous disease characterized by a block in differentiation and uncontrolled proliferation. FLT3 is a commonly mutated gene found in AML patients. In clinical trials, the presence of a FLT3-ITD mutation significantly correlates with an increased risk of relapse and dismal overall survival. Therefore, activated FLT3 is a promising molecular target for AML therapies. In this study, we have shown that green tea polyphenols including (−)-epigallocatechin-3-gallate (EGCG), (−)-epigallocatechin (EGC), and (−)-epicatechin-3-gallate (ECG) suppress the proliferation of AML cells. Interestingly, EGCG, EGC and ECG showed the inhibition of FLT3 expression in cell lines harboring FLT3 mutations. In the THP-1 cells harboring FLT3 wild-type, EGCG showed the suppression of cell proliferation but did not suppress the expression of FLT3 even at the concentration that suppress 100% cell proliferation. Moreover, EGCG-, EGC-and ECG-treated cells showed the suppression of MAPK, AKT and STAT5 phosphorylation. Altogether, we suggest that green tea polyphenols could serve as reagents for treatment or prevention of leukemia harboring FLT3 mutations. PMID:23840454

Green Tea Catechin Consumption Enhances Exercise-Induced Abdominal Fat Loss

USDA-ARS?s Scientific Manuscript database

Aim: This study evaluated the influence of a green tea catechin beverage on body composition and fat distribution in overweight and obese adults during exercised-induced weight loss. Methods: Participants (N=132) were randomly assigned to receive a 500 mL beverage containing approximately 625 mg of...

Inhibition of green tea polyphenol EGCG((-)-epigallocatechin-3-gallate) on the proliferation of gastric cancer cells by suppressing canonical wnt/β-catenin signalling pathway.

PubMed

Yang, Chenggang; Du, Wenfeng; Yang, Daogui

2016-11-01

(-)-Epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, could affect carcinogenesis and development of many cancers. However, the effects and underlying mechanisms of EGCG on gastric cancer remain unclear. We found that EGCG significantly inhibited proliferation and increased apoptosis of SGC-7901 cells in vitro. The decreased expressions of p-β-catenin(Ser552), p-GSK3β(S9) and β-catenin target genes were detected in SGC-7901 cells after treated by EGCG. XAV939 and β-catenin plasmid were further used to demonstrate the inhibition of EGCG on canonical Wnt/β-catenin signalling. Moreover, EGCG significantly inhibited gastric tumour growth in vivo by inhibiting Wnt/β-catenin signalling. Taken together, our findings establish that EGCG suppressed gastric cancer cell proliferation and demonstrate that this inhibitory effect is related to canonical Wnt/β-catenin signalling. This study raises a new insight into gastric cancer prevention and therapy, and provides evidence that green tea could be used as a nutraceutical beverage.

[Separation of catechins and caffeine in tea polyphenol by isocratic elution high performance liquid chromatography].

PubMed

Tang, G Y; Wu, H J; Wu, L; Li, Z J; Yao, Y G

2001-05-01

The catechins, particularly in green tea, have been found to possess anti-mutagenic and anti-tumorigenic properties. As each catechin possesses distinct properties, a simple and rapid method that could be used for analysis of individual catechins in a complex mixture would be necessary. A relatively simple and rapid method for simultaneous separation of five catechins and caffeine in tea polyphenol by isocratic elution high performance liquid chromatography has been developed. The analysis could be finished within 30 min. They were measured using Resolve C18 column (at 43 degrees C) and UV detector (at 280 nm), water-85% phosphoric acid aqueous solution-acetonitrile-dimethyl formamide(DMF) (859:1:120:20, V/V) as mobile phase. There was a good linear relationship between the content of component and its peak area for catechins and caffeine, with the correlation coefficients of 0.9992-0.9999. The average recoveries (n = 5) were 83.33%-104.42%, and the relative standard deviations (n = 6) were 0.74%-1.43%. The effect of concentration of DMF in mobile phase was studied.

Grape seed and tea extracts and catechin 3-gallates are potent inhibitors of α-amylase and α-glucosidase activity.

PubMed

Yilmazer-Musa, Meltem; Griffith, Anneke M; Michels, Alexander J; Schneider, Erik; Frei, Balz

2012-09-12

This study evaluated the inhibitory effects of plant-based extracts (grape seed, green tea, and white tea) and their constituent flavan-3-ol monomers (catechins) on α-amylase and α-glucosidase activity, two key glucosidases required for starch digestion in humans. To evaluate the relative potency of extracts and catechins, their concentrations required for 50 and 90% inhibition of enzyme activity were determined and compared to the widely used pharmacological glucosidase inhibitor, acarbose. Maximum enzyme inhibition was used to assess relative inhibitory efficacy. Results showed that grape seed extract strongly inhibited both α-amylase and α-glucosidase activity, with equal and much higher potency, respectively, than acarbose. Whereas tea extracts and catechin 3-gallates were less effective inhibitors of α-amylase, they were potent inhibitors of α-glucosidase. Nongallated catechins were ineffective. The data show that plant extracts containing catechin 3-gallates, in particular epigallocatechin gallate, are potent inhibitors of α-glucosidase activity and suggest that procyanidins in grape seed extract strongly inhibit α-amylase activity.

Elevated plasma and urinary concentrations of green tea catechins associated with improved plasma lipid profile in healthy Japanese women.

PubMed

Takechi, Ryusuke; Alfonso, Helman; Hiramatsu, Naoko; Ishisaka, Akari; Tanaka, Akira; Tan, La'Belle; Lee, Andy H

2016-03-01

This study investigated green tea catechins in plasma and urine and chronic disease biomarkers. We hypothesized that plasma and urinary concentration of green tea catechins are associated with cardiovascular disease and diabetes biomarkers. First void urine and fasting plasma samples were collected from 57 generally healthy females aged 38 to 73 years (mean, 52 ± 8 years) recruited in Himeji, Japan. The concentrations of plasma and urinary green tea catechins were determined by liquid chromatography coupled with mass tandem spectrometer. Low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglyceride, glucose, insulin, glycated hemoglobin, and C-reactive protein in plasma/serum samples were analyzed by a commercial diagnostic laboratory. Statistical associations were assessed using Spearman correlation coefficients. The results showed weak associations between plasma total catechin and triglyceride (r = -0.30) and LDL cholesterol (r = -0.28), whereas plasma (-)-epigallocatechin-3-gallate, (-)-epigallocatechin, (-)-epicatechin-3-gallate, and (-)-epicatechin exhibited weak to moderate associations with triglyceride or LDL cholesterol, but little associations with HDL cholesterol, body fat, and body mass index were evident. Urinary total catechin was weakly associated with triglyceride (r = -0.19) and LDL cholesterol (r = -0.15), whereas urinary (-)-epigallocatechin-3-gallate (r = -0.33), (-)-epigallocatechin (r = -0.23), and (-)-epicatechin-3-gallate (r = -0.33) had weak to moderate correlations with triglyceride and similarly with body fat and body mass index. Both plasma (r = -0.24) and urinary (r = -0.24) total catechin, as well as individual catechins, were weakly associated with glycated hemoglobin. Plasma total and individual catechins were weakly to moderately associated with C-reactive protein, but not the case for urinary catechins. In conclusion, we found weak to moderate associations between plasma and urinary green tea

Dietary catechins and procyanidins modulate zinc homeostasis in human HepG2 cells.

PubMed

Quesada, Isabel M; Bustos, Mario; Blay, Mayte; Pujadas, Gerard; Ardèvol, Anna; Salvadó, M Josepa; Bladé, Cinta; Arola, Lluís; Fernández-Larrea, Juan

2011-02-01

Catechins and their polymers procyanidins are health-promoting flavonoids found in edible vegetables and fruits. They act as antioxidants by scavenging reactive oxygen species and by chelating the redox-active metals iron and copper. They also behave as signaling molecules, modulating multiple cell signalling pathways and gene expression, including that of antioxidant enzymes. This study aimed at determining whether catechins and procyanidins interact with the redox-inactive metal zinc and at assessing their effect on cellular zinc homeostasis. We found that a grape-seed procyanidin extract (GSPE) and the green tea flavonoid (-)-epigallocatechin-3-gallate (EGCG) bind zinc cations in solution with higher affinity than the zinc-specific chelator Zinquin, and dose-dependently prevent zinc-induced toxicity in the human hepatocarcinoma cell line HepG2, evaluated by the lactate dehydrogenase test. GSPE and EGCG hinder intracellular accumulation of total zinc, measured by atomic flame absorption spectrometry, concomitantly increasing the level of cytoplasmic labile zinc detectable by Zinquin fluorescence. Concurrently, GSPE and EGCG inhibit the expression, evaluated at the mRNA level by quantitative reverse transcriptase-polymerase chain reaction, of zinc-binding metallothioneins and of plasma membrane zinc exporter ZnT1 (SLC30A1), while enhancing the expression of cellular zinc importers ZIP1 (SLC39A1) and ZIP4 (SLC39A4). GSPE and EGCG also produce all these effects when HepG2 cells are stimulated to import zinc by treatment with supplemental zinc or the proinflammatory cytokine interleukin-6. We suggest that extracellular complexation of zinc cations and the elevation of cytoplasmic labile zinc may be relevant mechanisms underlying the modulation of diverse cell signaling and metabolic pathways by catechins and procyanidins. Copyright © 2011 Elsevier Inc. All rights reserved.

Construction of a SSR-Based Genetic Map and Identification of QTLs for Catechins Content in Tea Plant (Camellia sinensis)

PubMed Central

Ma, Chun-Lei; Wang, Xin-Chao; Jin, Ji-Qiang; Wang, Xue-Min; Chen, Liang

2014-01-01

Catechins are the most important bioactive compounds in tea, and have been demonstrated to possess a wide variety of pharmacological activities. To characterize quantitative trait loci (QTLs) for catechins content in the tender shoots of tea plant, we constructed a moderately saturated genetic map using 406 simple sequence repeat (SSR) markers, based on a pseudo-testcross population of 183 individuals derived from an intraspecific cross of two Camellia sinensis varieties with diverse catechins composition. The map consisted of fifteen linkage groups (LGs), corresponding to the haploid chromosome number of tea plant (2n = 2x = 30). The total map length was 1,143.5 cM, with an average locus spacing of 2.9 cM. A total of 25 QTLs associated with catechins content were identified over two measurement years. Of these, nine stable QTLs were validated across years, and clustered into four main chromosome regions on LG03, LG11, LG12 and LG15. The population variability explained by each QTL was predominantly at moderate-to-high levels and ranged from 2.4% to 71.0%, with an average of 17.7%. The total number of QTL for each trait varied from four to eight, while the total population variability explained by all QTLs for a trait ranged between 38.4% and 79.7%. This is the first report on the identification of QTL for catechins content in tea plant. The results of this study provide a foundation for further cloning and functional characterization of catechin QTLs for utilization in improvement of tea plant. PMID:24676054

Green-Tea and Epigallocatechin-3-Gallate are Bactericidal against Bacillus anthracis

DTIC Science & Technology

2017-06-13

EGCG, catechins such 245 as epigallocatechin and epicatechin gallate are also antibacterial agents. Moreover, the 246 bactericidal activity of green...Sharma A, Gupta S, Sarethy IP, Dang S, Gabrani R. 2012. Green tea extract: possible mechanism 285 and antibacterial activity on skin pathogens. Food...was shown to be responsible for this activity , against 30 both the attenuated B. anthracis ANR and the virulent, encapsulated strain B. anthracis

Validation of AN Hplc-Dad Method for the Classification of Green Teas

NASA Astrophysics Data System (ADS)

Yu, Jingbo; Ye, Nengsheng; Gu, Xuexin; Liu, Ni

A reversed phase high performance liquid chromatography (RP-HPLC) separation coupled with diode array detection (DAD) and electrospray ionization mass spectrometer (ESI/MS) was developed and optimized for the classification of green teas. Five catechins [epigallocatechin (EGC), epigallocatechin gallate (EGCG), epicatechin (EC), gallocatechin gallate (GCG), epicatechin gallate (ECG)] had been identified and quantified by the HPLC-DAD-ESI/MS/MS method. The limit of detection (LOD) of five catechins was within the range of 1.25-15 ng. All the analytes exhibited good linearity up to 2500 ng. These compounds were considered as chemical descriptors to define groups of green teas. Chemometric methods including principal component analysis (PCA) and hierarchical cluster analysis (HCA) were applied for the purpose. Twelve green tea samples originating from different regions were subjected to reveal the natural groups. The results showed that the analyzed green teas were differentiated mainly by provenance; HCA afforded an excellent performance in terms of recognition and prediction abilities. This method was accurate and reproducible, providing a potential approach for authentication of green teas.

A novel functional full-fat hard cheese containing liposomal nanoencapsulated green tea catechins: manufacture and recovery following simulated digestion.

PubMed

Rashidinejad, Ali; Birch, E John; Everett, David W

2016-07-13

(+)-Catechin or green tea extract were encapsulated in soy lecithin nanoliposomes and incorporated into a full-fat cheese, then ripened at 8 °C for 90 days. Cheese samples were subjected to simulated gastrointestinal digestion to measure total phenolic content (TPC) and antioxidant activity of the cheese digesta, and to determine the catechin recovery after digestion by high performance liquid chromatography (HPLC). Addition of catechin or green tea extract significantly (P ≤ 0.05) increased TPC and antioxidant activity (measured by ferric reducing antioxidant power and oxygen radical absorbance capacity) of the full-fat cheese without affecting pH or proximate composition. HPLC analysis confirmed retention of encapsulated catechins in the cheese curd; however, individual catechins were recovered in differing amounts (15-52%) from cheese digesta after 6 h of digestion. Transmission electron microscopy and Fourier transform infrared spectroscopy provided evidence for association of nanoliposomes with the surface of milk fat globules inside the cheese matrix. The study shows the potential for using cheese as a delivery vehicle for green tea antioxidants.

ORAC and DPPH assay comparison to assess antioxidant capacity of tea infusions: relationship between total polyphenol and individual catechin content.

PubMed

Roy, Molay K; Koide, Motoki; Rao, Theertham P; Okubo, Tsutomu; Ogasawara, Yutaka; Juneja, Lekh R

2010-03-01

Commercially available tea infusions are the major source of catechins for preparing bottled tea beverages and tea supplements available in the market today. In the present study, we analyzed five tea infusions to measure the total antioxidant capacity (TAC) by oxygen radical absorbance capacity (ORAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity (DRSC) assays, total polyphenol content by the colorimetric method and individual catechin content by high-performance liquid chromatography. Four major tea catechins were also analyzed for their TAC to reveal differential antioxidant behavior of the tea infusions, resulting in the ORAC and DRSC methods. The correlation coefficients between DRSC and the total polyphenol or total catechin content of the tea infusions were 1.0 and 0.99. However, the values fall to 0.73 and 0.69, respectively, while the ORAC activity was correlated with total polyphenol and total catechin content. Determining the TAC of individual tea catechins showed that ORAC of epicatechin was seven-fold higher than that of epigallocatechin gallate; on the contrary, epigallocatechin gallate showed significantly (P < 0.05) stronger DRSC activity than epicatechin. By evaluating the structure-activity relationship, this study further revealed that OH substitution at the 3' position in pyrogallol moieties contributes to the lower ORAC value of epigallocatechin and epigallocatechin gallate comparing with their non-3'-OH counterparts, such as epicatechin and epicatechin gallate, respectively. Also, numbers of OH substitutions were poorly correlated with the observed ORAC value unlike the DRSC. Overall, results of this study enabled us to hypothesize that substances having a lower TAC value in the ORAC assay compared with that in DPPH assays may pertain to a pro-oxidant effect by generating reactive oxygen species in an aqueous buffer, at a physiological pH. We also propose that substances exhibiting lower TAC value in the ORAC assay

Biochemical evaluation of triploid progenies of diploid × tetraploid breeding populations of Camellia for genotypes rich in catechin and caffeine.

PubMed

Das, Sourabh Kumar; Sabhapondit, Santanu; Ahmed, Giasuddin; Das, Sudripta

2013-06-01

To verify the quality of triploid varieties of Camellia tea species at the secondary metabolite level, we tested caffeine and catechin profiles of 97 F(1) segregating progenies in two breeding populations with a common tetraploid parent and diploid parents of two geographic and varietal origins. Catechin and caffeine levels of the triploid progenies were quantified and compared against their diploid parent. Some of the progenies showed better performance than their diploid parent. Most of the progenies of the diploid C. sinensis × tetraploid cross showed heterosis for caffeine and EGCG. Progenies of the C. assamica subsp. lasiocalyx × tetraploid cross showed heterosis for +C, EC, EGC, and TC. The genomic contributions of the diploid parent seem to be the main factor in the variation between the two populations. Our studies showed quantitative enhancement of some of the quality-related parameters in tea, providing a platform to refocus on this classical breeding approach for developing quality cultivars in tea.

Acute EGCG Supplementation Reverses Endothelial Dysfunction in Patients with Coronary Artery Disease

PubMed Central

Widlansky, Michael E.; Hamburg, Naomi M.; Anter, Elad; Holbrook, Monika; Kahn, David F.; Elliott, James G.; Keaney, John F.; Vita, Joseph A.

2013-01-01

Background Epidemiological studies demonstrate an inverse relation between dietary flavonoid intake and cardiovascular risk. Recent studies with flavonoid-containing beverages suggest that the benefits of these nutrients may relate, in part, to improved endothelial function. Objective We hypothesized that dietary supplementation with epigallocatechin gallate (EGCG), a major catechin in tea, would improve endothelial function in humans. Design We examined the effects of EGCG on endothelial function in a double blind, placebo-controlled, crossover design study. We measured brachial artery flow-mediated dilation by vascular ultrasound at six time points: prior to treatment with EGCG or placebo, two hours after an initial dose of EGCG (300 mg) or placebo, and after two weeks of treatment with EGCG (150 mg twice daily) or placebo. The order of treatments (EGCG or placebo) was randomized and there was a one-week washout period between treatments. Results A total of 42 subjects were enrolled, and brachial artery flow-mediated dilation improved from 7.1±4.1 to 8.6±4.7% two hours after the first dose of 300mg of EGCG (P=0.01), but was similar to baseline (7.8±4.2%, P=0.12) after two weeks of treatment with the final measurements made approximately 14 hours after the last dose. Placebo treatment had no significant effect, and there were no changes in reactive hyperemia or the response to sublingual nitroglycerin. The changes in vascular function paralleled plasma EGCG concentrations, which increased from 2.6±10.9 to 92.8±78.7 ng/ml after acute EGCG (P<0.001), but were unchanged from baseline after two weeks of treatment (3.4±13.1 ng/ml). Conclusion EGCG acutely improves endothelial function in humans with coronary artery disease, and may account for a portion of the beneficial effects of flavonoid-rich food on endothelial function. PMID:17536120

Acute EGCG supplementation reverses endothelial dysfunction in patients with coronary artery disease.

PubMed

Widlansky, Michael E; Hamburg, Naomi M; Anter, Elad; Holbrook, Monika; Kahn, David F; Elliott, James G; Keaney, John F; Vita, Joseph A

2007-04-01

Epidemiological studies demonstrate an inverse relation between dietary flavonoid intake and cardiovascular risk. Recent studies with flavonoid-containing beverages suggest that the benefits of these nutrients may relate, in part, to improved endothelial function. We hypothesized that dietary supplementation with epigallocatechin gallate (EGCG), a major catechin in tea, would improve endothelial function in humans. We examined the effects of EGCG on endothelial function in a double blind, placebo-controlled, crossover design study. We measured brachial artery flow-mediated dilation by vascular ultrasound at six time points: prior to treatment with EGCG or placebo, two hours after an initial dose of EGCG (300 mg) or placebo, and after two weeks of treatment with EGCG (150 mg twice daily) or placebo. The order of treatments (EGCG or placebo) was randomized and there was a one-week washout period between treatments. A total of 42 subjects completed the study, and brachial artery flow-mediated dilation improved from 7.1 +/- 4.1 to 8.6 +/- 4.7% two hours after the first dose of 300 mg of EGCG (P = 0.01), but was similar to baseline (7.8 +/- 4.2%, P = 0.12) after two weeks of treatment with the final measurements made approximately 14 hours after the last dose. Placebo treatment had no significant effect, and there were no changes in reactive hyperemia or the response to sublingual nitroglycerin. The changes in vascular function paralleled plasma EGCG concentrations, which increased from 2.6 +/- 10.9 to 92.8 +/- 78.7 ng/ml after acute EGCG (P < 0.001), but were unchanged from baseline after two weeks of treatment (3.4 +/- 13.1 ng/ml). EGCG acutely improves endothelial function in humans with coronary artery disease, and may account for a portion of the beneficial effects of flavonoid-rich food on endothelial function.

Role of catechins in the antioxidant capacity of an active film containing green tea, green coffee, and grapefruit extracts.

PubMed

Colon, M; Nerin, C

2012-10-03

The oxygen radical absorbance capacity (ORAC) method was used to characterize the antioxidant capacity of natural extracts of green tea, green coffee, and grapefruit. These natural extracts were incorporated into a plastic film layer, which was subsequently subjected to a free radical gas stream in order to determine the antioxidant capacity directly in the active film. The green tea extract (GTE) afforded the strongest antioxidant activity. To identify the active compounds in the extract, concentration of the diverse catechins in samples were determined by HPLC-UV analysis. The results showed that the content of catechins in the GTE is around 77% (w/w), the major components being (-)-epigallocatechin gallate, (-)-epicatechin gallate, and (-)-epicatechin. A variation in the concentration profile of catechins was detected during the oxidation process. The chromatographic study demonstrated that (-)-gallocatechin, (-)- epigallocatechin, (+)-catechin, and (-)-catechin gallate exhibited the most radical scavenging.

New Drugs for Prevention of Breast Cancer Metastases

DTIC Science & Technology

1999-07-01

the principal anticancer catechin, epigallocatechin gallate ( EGCg ). A 3-way mixture of epicatechin (EC), EGCg and glaucarubolone was more effective...DAPI, 4’,6-diamidino-2-phenylindole; DMSO, dimethyl sulfoxide; EGF, epidermal growth factor; EGCg , epigallocatechin gallate . ABSTRACT A drug...preferentially in HeLa and human and mouse mammary adenocarcinoma by the naturally-occurring catechin of green tea, epigallocatechin gallate ( EGCg ). With

GPCR6A Is a Molecular Target for the Natural Products Gallate and EGCG in Green Tea.

PubMed

Pi, Min; Kapoor, Karan; Ye, Ruisong; Smith, Jeremy C; Baudry, Jerome; Quarles, Leigh D

2018-04-01

The molecular mechanisms whereby gallates in green tea exert metabolic effects are poorly understood. We found that GPRC6A, a multi-ligand-sensing G-protein-coupled receptor that regulates energy metabolism, sex hormone production, and prostate cancer progression, is a target for gallates. Sodium gallate (SG), gallic acid (GA) > ethyl gallate (EG) > octyl gallate (OG) dose dependently activated ERK in HEK-293 cells transfected with GPRC6A but not in non-transfected controls. SG also stimulated insulin secretion in β-cells isolated from wild-type mice similar to the endogenous GPRC6A ligands, osteocalcin (Ocn) and testosterone (T). Side-chain additions to create OG resulted in loss of GPRC6A agonist activity. Another component of green tea, epigallocatechin 3-gallate (EGCG), dose-dependently inhibited Ocn activation of GPRC6A in HEK-293 cells transfected with GPRC6A and blocked the effect of Ocn in stimulating glucose production in CH10T1/2 cells. Using structural models of the venus fly trap (VFT) and 7-transmembrane (7-TM) domains of GPRC6A, calculations suggest that l-amino acids and GA bind to the VFT, whereas EGCG is calculated to bind to sites in both the VFT and 7-TM. GA and EGCG have offsetting agonist and antagonist effects on GPRC6A that may account for the variable metabolic effect of green tea consumption. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Separation of major catechins from green tea by ultrahigh pressure extraction.

PubMed

Jun, Xi; Shuo, Zhao; Bingbing, Lu; Rui, Zhang; Ye, Li; Deji, Shen; Guofeng, Zhou

2010-02-15

This study presents a novel extraction technique, ultrahigh pressure extraction, to obtain major catechins from green tea leaves. The effects of various high pressure level (100, 200, 300, 400, 500, 600 MPa) on the extract are examined. HPLC chromatographic analyses determine the concentration of four major catechins and caffeine. The extraction yields of active ingredients with ultrahigh pressure extraction (400 MPa pressure) for only 15 min were given the same as those of organic solvent extraction for 2h. These excellent results for the ultrahigh pressure extraction are promising for the future separation of active ingredients from traditional Chinese herbal medicine. Copyright 2009 Elsevier B.V. All rights reserved.

Antioxidative activity of green tea treated with radical initiator 2, 2'-azobis(2-amidinopropane) dihydrochloride.

PubMed

Yokozawa, T; Cho, E J; Hara, Y; Kitani, K

2000-10-01

This study investigated the antioxidative activity of green tea extract, and a green tea tannin mixture and its components, under conditions of radical generation using the hydrophilic azo compound, 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) to generate peroxyl radicals at a constant and measurable rate in the cultured renal epithelial cell line, LLC-PK(1), which is susceptible to oxidative damage. Treatment with AAPH decreased cell viability and increased the formation of thiobarbituric acid-reactive substances. However, green tea extract, and the tannin mixture and its components, comprising (-)-epigallocatechin 3-O-gallate (EGCg), (-)-gallocatechin 3-O-gallate (GCg), (-)-epicatechin 3-O-gallate (ECg), (-)-epigallocatechin (EGC), (+)-gallocatechin (GC), (-)-epicatechin (EC), and (+)-catechin (C), showed protective activity against AAPH-induced cellular damage. The tannin mixture and its components exhibited higher antioxidative activity than the green tea extract. Furthermore, EGCg and GCg had higher activity than EGC and GC, respectively. In particular, EGCg exerted the most significant cellular protective activity against AAPH. These results indicate that green tea tannin may inhibit cellular loss and lipid peroxidation resulting from the peroxyl radical generated by AAPH, and that the chemical structure of tannin is also involved in the activity, suggesting that the O-dihydroxy structure in the B ring and the galloyl groups are important determinants for radical scavenging and antioxidative potential.

Chiral analysis of theanine and catechin in characterization of green tea by cyclodextrin-modified micellar electrokinetic chromatography and high performance liquid chromatography.

PubMed

Fiori, Jessica; Pasquini, Benedetta; Caprini, Claudia; Orlandini, Serena; Furlanetto, Sandra; Gotti, Roberto

2018-08-10

Monomeric catechins are important compounds in green tea accounting for potential bioactivity against a wide range of diseases. Besides catechins, l-Theanine (γ-glutamylethylamide), a characteristic amino acid in tea leaves, has become a further focus of the phytochemical research for the reported beneficial effects mainly on cognitive performance, emotional state and sleep quality. In the present study has been developed a CD-MEKC method based on sodium dodecyl sulfate (SDS) and Heptakis (2,6-di-O-methyl)-β-cyclodextrin for the separation of six major green tea catechins and enantiomers of theanine. The latter, because of the poor detectability was derivatized prior analysis by o-phthaldialdehyde in the presence of N-acetyl-l-cysteine which, under mild conditions (neutral pH, in two minutes) allowed two diastereomers isoindole derivatives to be obtained. The derivatization reaction was directly carried out on tea infusion and derivatized samples were analysed by CD-MEKC involving 65 mM SDS and 28 mM cyclodextrin in acidic buffer (pH 2.5). The separation of six major green tea catechins including enantioresolution of (±)-Catechin and d/l-Theanine was obtained in about 5 min allowing d-Theanine to be quantified at least at 0.5% m/m level with respect to l-Theanine. Since (-)-Catechin and d-Theanine can be considered as non-native enantiomers (distomers), their presence in real samples provides an indication of tea leaves treatments (thermal treatment, fermentation, etc.) and could represent an opportunity for grading tea. The obtained results were confirmed by a RP-HPLC approach; even though the chromatography was developed in achiral conditions, the derivatization approach applied to theanine (diastereomers formation), allowed for d/l-Theanine chiral analysis. Copyright © 2018 Elsevier B.V. All rights reserved.

EGCG in Green Tea Induces Aggregation of HMGB1 Protein through Large Conformational Changes with Polarized Charge Redistribution

NASA Astrophysics Data System (ADS)

Meng, Xuan-Yu; Li, Baoyu; Liu, Shengtang; Kang, Hongsuk; Zhao, Lin; Zhou, Ruhong

2016-02-01

As a major effective component in green tea, (-)-epigallocatechin-3-gallate (EGCG)’s potential benefits to human health have been widely investigated. Recent experimental evidences indicate that EGCG can induce the aggregation of HMGB1 protein, a late mediator of inflammation, which subsequently stimulates the autophagic degradation and thus provides protection from lethal endotoxemia and sepsis. In this study, we use molecular dynamics (MD) simulations to explore the underlying molecular mechanism of this aggregation of HMGB1 facilitated by EGCG. Our simulation results reveal that EGCG firmly binds to HMGB1 near Cys106, which supports previous preliminary experimental evidence. A large HMGB1 conformational change is observed, where Box A and Box B, two homogenous domains of HMGB1, are repositioned and packed together by EGCG. This new HMGB1 conformation has large molecular polarity and distinctive electrostatic potential surface. We suggest that the highly polarized charge distribution leads to the aggregation of HMGB1, which differs from the previous hypothesis that two HMGB1 monomers are linked by the dimer of EGCG. Possible aggregating modes have also been investigated with potential of mean force (PMF) calculations. Finally, we conclude that the conformation induced by EGCG is more aggregation-prone with higher binding free energies as compared to those without EGCG.

On-chip sample pretreatment using a porous polymer monolithic column for solid-phase microextraction and chemiluminescence determination of catechins in green tea.

PubMed

Lin, Ling; Chen, Hui; Wei, Huibin; Wang, Feng; Lin, Jin-Ming

2011-10-21

A porous polymer monolithic column for solid-phase microextraction and chemiluminescence detection was integrated into a simple microfluidic chip for the extraction and determination of catechins in green tea. The porous polymer was prepared by poly(glycidyl methacrylate-co-ethylene dimethacrylate) and modified with ethylenediamine. Catechins can be concentrated in the porous polymer monolithic column and react with potassium permanganate to give chemiluminescence. The microfluidic chip is reusable with high sensitivity and very low reagent consumption. The on-line preconcentration and detection can be realized without an elution step. The enrichment factor was calculated to be about 20 for catechins. The relative chemiluminescence intensity increased linearly with concentration of catechin from 5.0 × 10(-9) to 1.0 × 10(-6) M and the limit of detection was 1.0 × 10(-9) M. The proposed method was applied to determine catechin in green tea. The recoveries are from 90% to 110% which benefits the actual application for green tea samples.

Investigation of epigallocatechin-3-O-caffeoate and epigallocatechin-3-O-p-coumaroate in tea leaves by LC/MS-MS analysis.

PubMed

Umehara, Masahiro; Yanae, Koji; Maruki-Uchida, Hiroko; Sai, Masahiko

2017-12-01

(-)-Epigallocatechin-3-O-gallate (EGCG), the major catechin present in green tea, exhibits potent antioxidant activity. We thereby investigated the presence of unknown components bearing the (-)-epigallocatechin (EGC) moiety in fresh tea leaf samples. Initially, liquid chromatography tandem mass spectrometry (LC-MS/MS) was employed to examine fresh tea leaves of the Yabukita, the most popular tea cultivar in Japan, which suggested the presence of the EGC phenylpropanoid derivatives, (-)-epigallocatechin-3-O-p-coumaroate (EGCpCA) and (-)-epigallocatechin-3-O-caffeoate (EGCCA). The structures of the detected EGCpCA and EGCCA were then confirmed by LC-MS/MS using synthesized EGCpCA and EGCCA as standards. In addition, EGCpCA and EGCCA were evaluated for their antioxidant activity in the ORAC (oxygen radical antioxidant capacity) and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assays, where EGCCA (8.60μmolTE/μmol, TE=Trolox equivalents) exhibited a stronger antioxidant activity than EGCG (5.52μmolTE/μmol) in the ORAC assay. Finally, EGCpCA and EGCCA were quantitated in several tea leaf samples using LC-MS/MS, and it was found that these compounds were present in lower quantities (EGCpCA, 16.8-345.8μg/g, EGCCA, 4.3-75.1μg/g in the dry tea leaves) than the major catechins. In this study, we found the potent antioxidant EGCCA using LC-MS/MS and revealed its wide existence in various tea leaves. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of epigallocatechin-3-gallate (EGCG) on human alveolar bone cells both in vitro and in vivo.

PubMed

Mah, Yon-Joo; Song, Je Seon; Kim, Seong-Oh; Lee, Jae-Ho; Jeon, Mijeong; Jung, Ui-Won; Moon, Seok Jun; Kim, Jeong-Hee; Choi, Hyung-Jun

2014-05-01

The effects of epigallocatechin-3-gallate (EGCG), a major catechin in green tea, on human and mouse osteoblasts remain controversial. This study investigated the direct effects of EGCG on human alveolar bone-derived cells (hABCs) both in vitro and in vivo. hABCs which were collected from eight children (aged 7-9 years, seven males and one female) were treated with EGCG at various concentrations (1, 5, 10, 25, and 50μM), and a proliferation assay, flow cytometric analysis for apoptosis evaluation, migration assay, and in vitro osteogenic differentiation were performed. hABCs that were pretreated with 10μM EGCG and mixed with calcium phosphate carrier combined with EGCG (0.1, 0.5, or 1.5mg) in vivo were transplanted into immunodeficient mouse. Histological staining, quantitative gene expressions, and alkaline phosphatase activity were evaluated in the retrieved transplants. The proliferation and migration were decreased when EGCG was present at over 25μM. The osteogenic differentiation increased slightly when EGCG was present at up to 10μM, and clearly decreased for higher concentrations of EGCG. In vivo, the potential for hard-tissue formation was slightly higher for the group with 0.1mg of EGCG than for the control group, and decreased sharply for higher concentrations of EGCG. The present observations suggest that EGCG at a low concentration can slightly enhance the osteogenic effect in vivo, whereas at a higher concentration it can prevent the osteogenic differentiation of hABCs both in vitro and in vivo. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preparative separation and purification of epigallocatechin gallate from green tea extracts using a silica adsorbent containing β-cyclodextrin.

PubMed

Lai, Shih-Ming; Gu, Jhe-Yu; Huang, Bing-Hao; Chang, Chieh-Ming J; Lee, Wen-Lung

2012-03-01

A silica adsorbent containing β-cyclodextrin (β-CD) has been developed and used for the separation and purification of epigallocatechin gallate (EGCG) from the green tea extracts. The batch adsorption experiments demonstrated that, the β-CD bonded silica adsorbent possessed excellent adsorption equilibrium capacity (> 55 mg/g adsorbent) and adsorption ratio (>95%) for EGCG compared to the other tea catechins and caffeine. The excellent adsorption capacity and selectivity for EGCG are attributed to the specific interactions between β-CD and EGCG. The preparative separation and purification performance of EGCG on the β-CD bonded silica column (220 mm L × 15 mm i.d., 40-63 μm) was then evaluated. The column was operated in the polar organic mode using methanol/acetonitrile/acetic acid as the mobile phase and eluted under a three-step gradient elution program. The sample was dissolved in acetonitrile and loaded on a preparative scale of about 0.8 mg/g adsorbent. Under the optimal chromatographic conditions, the target compound, EGCG, being the most retained species, was obtained at a purity of about 90% with a recovery of about 90%. The productivity of EGCG was about 6 mg per injection, which can be further increased by scaling-up the chromatographic system. Copyright © 2012 Elsevier B.V. All rights reserved.

Role of (-)-epigallocatechin gallate in the pharmacokinetic interaction between nadolol and green tea in healthy volunteers.

PubMed

Abe, Osamu; Ono, Tomoyuki; Sato, Hideyuki; Müller, Fabian; Ogata, Hiroshi; Miura, Itaru; Shikama, Yayoi; Yabe, Hirooki; Onoue, Satomi; Fromm, Martin F; Kimura, Junko; Misaka, Shingen

2018-06-01

The aim of the present study is to investigate a possible role of a single dose of (-)-epigallocatechin gallate (EGCG), the major catechin in green tea, for the pharmacokinetic interaction between green tea and nadolol in humans. In a randomized three-phase crossover study, 13 healthy volunteers received single doses of 30 mg nadolol orally with water (control), or an aqueous solution of EGCG-concentrated green tea extract (GTE) at low or high dose. Plasma concentrations and urinary excretion of nadolol were determined up to 48 h. In addition, blood pressure and pulse rate were monitored. In vitro transport kinetic experiments were performed using human embryonic kidney 293 cells stably expressing organic anion transporting polypeptide (OATP)1A2 to evaluate the inhibitory effect of EGCG on OATP1A2-mediated substrate transport. Single coadministration of low and high dose GTE significantly reduced the plasma concentrations of nadolol. The geometric mean ratios with 90% CI for area under the plasma concentration-time curves from 0 to infinity of nadolol were 0.72 (0.56-0.87) for the low and 0.60 (0.51-0.69) for the high dose. There were no significant differences in T max , elimination half-life, and renal clearance between GTE and water phases. No significant changes were observed for blood pressure and pulse rate between phases. EGCG competitively inhibited OATP1A2-mediated uptake of sulphobromophthalein and nadolol with K i values of 21.6 and 19.4 μM, respectively. EGCG is suggested to be a key contributor to the interaction of green tea with nadolol. Moreover, even a single coadministration of green tea may significantly affect nadolol pharmacokinetics.

Interaction of Environmental Moisture with Powdered Green Tea Formulations: Relationship between Catechin Stability and Moisture-Induced Phase Transformations

PubMed Central

Ortiz, Julieta; Kestur, Umesh S.; Taylor, Lynne S.; Mauer, Lisa J.

2009-01-01

This study investigated the effect of phase transformations of amorphous and deliquescent ingredients on catechin stability in green tea powder formulations. Blends of amorphous green tea and crystalline sucrose, citric acid, and/or ascorbic acid were analyzed by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), dynamic water vapor sorption, water activity measurements, and high-performance liquid chromatography (HPLC) after storage for up to 12 weeks at 0–75% relative humidity (RH) and 22 °C. The glass transition temperature (Tg) of green tea was reduced to below room temperature (<22 °C) at 68% RH. Dissolution of deliquescent ingredients commenced at RH values below deliquescence points in blends with amorphous green tea, and these blends had greater water uptake than predicted by an additive model of individual ingredient moisture sorption. Catechin degradation was affected by Tg of green tea powder and both dissolution and deliquescence of citric and ascorbic acids. PMID:19489621

Microwave-assisted water extraction of green tea polyphenols.

PubMed

Nkhili, Ezzohra; Tomao, Valerie; El Hajji, Hakima; El Boustani, Es-Seddik; Chemat, Farid; Dangles, Olivier

2009-01-01

Green tea, a popular drink with beneficial health properties, is a rich source of specific flavanols (polyphenols). There is a special interest in the water extraction of green tea polyphenols since the composition of the corresponding extracts is expected to reflect the one of green tea infusions consumed worldwide. To develop a microwave-assisted water extraction (MWE) of green tea polyphenols. MWE of green tea polyphenols has been investigated as an alternative to water extraction under conventional heating (CWE). The experimental conditions were selected after consideration of both temperature and extraction time. The efficiency and selectivity of the process were determined in terms of extraction time, total phenolic content, chemical composition (HPLC-MS analysis) and antioxidant activity of the extracts. By MWE (80 degrees C, 30 min), the flavanol content of the extract reached 97.46 (+/- 0.08) mg of catechin equivalent/g of green tea extract, vs. only 83.06 (+/- 0.08) by CWE (80 degrees C, 45 min). In particular, the concentration of the most bioactive flavanol EGCG was 77.14 (+/- 0.26) mg of catechin equivalent/g of green tea extract obtained by MWE, vs 64.18 (+/- 0.26) mg/g by CWE. MWE appears more efficient than CWE at both 80 and 100 degrees C, particularly for the extraction of flavanols and hydroxycinnamic acids. Although MWE at 100 degrees C typically affords higher yields in total phenols, MWE at 80 degrees C appears more convenient for the extraction of the green tea-specific and chemically sensitive flavanols.

Preparation of catechin extracts and nanoemulsions from green tea leaf waste and their inhibition effect on prostate cancer cell PC-3

PubMed Central

Tsai, Yin-Jieh; Chen, Bing-Huei

2016-01-01

Green tea is one of the most commonly consumed natural health beverages in Taiwan’s market, with the major functional component catechin being shown to possess several biological activities such as antioxidation, anticancer, and prevention of cardiovascular disease. The objectives of this study were to develop a high-performance liquid chromatography–mass spectrometry method to determine the variety and content of catechins in green tea leaf waste, a by-product obtained during processing of tea beverage. In addition, catechin nanoemulsion was prepared to study its inhibition effect on prostate cancer cell PC-3. Results showed that a total of eight catechin standards were separated within 25 minutes by using a Gemini C18 column and a gradient mobile phase of 0.1% formic acid (A) and acetonitrile (B) with flow rate at 1 mL/min, column temperature at 30°C, and detection wavelength at 280 nm. Among various extraction solvents, 50% ethanol generated the highest yield of total catechins from tea leaf waste, of which five catechins were identified and quantified. The catechin nanoemulsion was composed of catechin extract, lecithin, Tween 80, and deionized water in an appropriate proportion, with the mean particle size being 11.45 nm, encapsulation efficiency 88.1%, and zeta potential −66.3 mV. A high stability of catechin nanoemulsion was shown over a storage period of 120 days at 4°C. Both catechin extract and nanoemulsion could inhibit growth of PC-3 tumor cells, with the half maximal inhibitory concentration being 15.4 μg/mL and 8.5 μg/mL, respectively. The PC-3 cell cycle was arrested at S phase through elevation of P27 expression and decline of cyclin A, cyclin B, cyclin-dependent kinase 2, and cyclin-dependent kinase 1 expression. In addition, both catechin extract and nanoemulsion could induce apoptosis of PC-3 cells through decrease in B-cell lymphoma 2 (bcl-2) expression and increase in cytochrome c expression for activation of caspase-3, caspase-8, and

Determination of volatile organic compounds, catechins, caffeine and theanine in Jukro tea at three growth stages by chromatographic and spectrometric methods.

PubMed

Jeon, Dong Bok; Hong, Young Shin; Lee, Ga Hyun; Park, Yu Min; Lee, Cheong Mi; Nho, Eun Yeong; Choi, Ji Yeon; Jamila, Nargis; Khan, Naeem; Kim, Kyong Su

2017-03-15

Tea contains characteristic volatile organic compounds, polyphenols, caffeine and catechins, and is therefore among the most widely consumed beverages all over the world. In this study, fresh Jukro tea leaves collected from Damyang-gun (Jeollanam-do) at 40, 60 and 90day growth stages, were semi-fermented. The volatile organic compounds (VOCs) were extracted by simultaneous distillation-solvent extraction (SDE) and analyzed by gas chromatography/mass spectrometry (GC/MS). Catechins, caffeine and theanine were analyzed by high performance liquid chromatography (HPLC). A total of 159 VOCs were identified in the analyzed Jukro tea leaves. Comparatively, the increase in the concentrations of VOCs was high in 60day leaves. The content of catechins increased along the three growth stages, whereas caffeine, compared to 90day leaves, was higher for 40 and 60day leaves. Based on the results, the 60day leaves were found to be the most suitable and useful for making semi-fermented Jukro tea. Copyright © 2016 Elsevier Ltd. All rights reserved.

Self-assembled micellar nanocomplexes comprising green tea catechin derivatives and protein drugs for cancer therapy

NASA Astrophysics Data System (ADS)

Chung, Joo Eun; Tan, Susi; Gao, Shu Jun; Yongvongsoontorn, Nunnarpas; Kim, Soon Hee; Lee, Jeong Heon; Choi, Hak Soo; Yano, Hirohisa; Zhuo, Lang; Kurisawa, Motoichi; Ying, Jackie Y.

2014-11-01

When designing drug carriers, the drug-to-carrier ratio is an important consideration, because the use of high quantities of carriers can result in toxicity as a consequence of poor metabolism and elimination of the carriers. However, these issues would be of less concern if both the drug and carrier had therapeutic effects. (-)-Epigallocatechin-3-O-gallate (EGCG), a major ingredient of green tea, has been shown, for example, to possess anticancer effects, anti-HIV effects, neuroprotective effects and DNA-protective effects. Here, we show that sequential self-assembly of the EGCG derivative with anticancer proteins leads to the formation of stable micellar nanocomplexes, which have greater anticancer effects in vitro and in vivo than the free protein. The micellar nanocomplex is obtained by complexation of oligomerized EGCG with the anticancer protein Herceptin to form the core, followed by complexation of poly(ethylene glycol)-EGCG to form the shell. When injected into mice, the Herceptin-loaded micellar nanocomplex demonstrates better tumour selectivity and growth reduction, as well as longer blood half-life, than free Herceptin.

Functional Characterization of Epitheaflagallin 3-O-Gallate Generated in Laccase-Treated Green Tea Extracts in the Presence of Gallic Acid.

PubMed

Itoh, Nobuya; Kurokawa, Junji; Isogai, Yasuhiro; Ogasawara, Masaru; Matsunaga, Takayuki; Okubo, Tsutomu; Katsube, Yuji

2017-12-06

Epitheaflagallin (ETFG) and epitheaflagallin 3-O-gallate (ETFGg) are minor polyphenols in black tea extract that are enzymatically synthesized from epigallocatechin (EGC) and epigallocatechin gallate (EGCg), respectively, in green tea extract via laccase oxidation in the presence of gallic acid. The constituents of laccase-treated green tea extract in the presence of gallic acid are thus quite different from those of nonlaccase-treated green tea extract: EGC and EGCg are present in lower concentrations, and ETFG and ETFGg are present in higher concentrations. Additionally, laccase-treated green tea extract contains further polymerized catechin derivatives, comparable with naturally fermented teas such as oolong tea and black tea. We found that ETFGg and laccase-treated green tea extracts exhibit versatile physiological functions in vivo and in vitro, including antioxidative activity, pancreatic lipase inhibition, Streptococcus sorbinus glycosyltransferase inhibition, and an inhibiting effect on the activity of matrix metalloprotease-1 and -3 and their synthesis by human gingival fibroblasts. We confirmed that these inhibitory effects of ETFGg in vitro match well with the results obtained by docking simulations of the compounds with their target enzymes or noncatalytic protein. Thus, ETFGg and laccase-treated green tea extracts containing ETFGg are promising functional food materials with potential antiobesity and antiperiodontal disease activities.

Systemic Absorption of Catechins after Intraruminal or Intraduodenal Application of a Green Tea Extract in Cows

PubMed Central

Wein, Silvia; Beyer, Birgit; Gohlke, Annika; Blank, Ralf; Metges, Cornelia C.; Wolffram, Siegfried

2016-01-01

Green tea catechins have various potential health benefits in humans including anti-inflammatory, anti-oxidative and hepato-protective effects. If present in the circulation, they might have similar effects in ruminants, which are exposed to oxidative stress and fatty liver disease such as dairy cows during the periparturient phase. However, the bioavailability of a substance is a prerequisite for any post absorptive effect in vivo. This study aimed to investigate the appearance of catechins from a green tea extract (GTE) in cattle plasma after intraruminal and intraduodenal administration because absorption is of major importance regarding the bioavailability of catechins. The studies were performed in 5 rumen-fistulated non-lactating heifers and 6 duodenally fistulated lactating dairy cows, respectively, equipped with indwelling catheters placed in a jugular vein. The GTE was applied intraruminally (10 and 50 mg/kg BW, heifers) or duodenally (10, 20 and 30 mg/kg BW, dairy cows) in a cross‐over design with a 2 d washout period between different dosages. Blood samples were drawn following the GTE administration at various pre-defined time intervals. The concentration of the major GTE catechins (gallocatechin, epigallocatechin, catechin, epicatechin, epigallocatechin-gallate, epicatechin-gallate) in plasma samples were analysed by HPLC with electrochemical detection. Irrespective of the dose, almost none of the catechins originally contained in the GTE were detected in plasma samples after intraruminal application. In contrast, intraduodenal administration of GTE resulted in increased plasma concentrations of epicatechin, epigallocatechin, epigallocatechin gallate in a dose‐dependent manner. Thus, we can conclude that intraruminally or orally administered catechins are intensively metabolized by ruminal microorganisms. PMID:27427946

Recent advances on tea polyphenols

PubMed Central

Kanwar, Jyoti; Taskeen, Mujtaba; Mohammad, Imthiyaz; Huo, Congde; Chan, Tak Hang; Dou, Qing Ping

2012-01-01

Over the past decade many scientific and medical studies have focused on green tea for its long-purported health benefits. There is convincing evidence that tea is a cup of life. It has multiple preventive and therapeutic effects. This review thus focuses on the recent advances of tea polyphenols and their applications in the prevention and treatment of human cancers. Of the various polyphenols in tea, (−)-Epigallocatechin-3-gallate (EGCG) is the most abundant, and active compound studied in tea research. EGCG inhibits several molecular targets to inhibit cancer initiation and modulates several essential survival pathways to block cancer progression. Herein, we describe the various mechanisms of action of EGCG and also discuss previous and current ongoing clinical trials of EGCG and green tea polyphenols in different cancer types. PMID:22201858

[Study on extraction process of available components of tea].

PubMed

Bai, Qing-Qing; Liu, Yong-Feng; Guo, Mei; Zhao, Jian-Xi; Zhang, Tian-Cai; Di, Duo-Long

2011-09-01

To investigate the optimum ethanol extraction process conditions for the available components in the tea - Catechines (CT) including Epigallo catechin gallate (EGCG) and Caffeine (CF). The content of EGCG, CT and CF, extraction rate, DPPH * Free radical scavenging capacity were chosen as the assessment indexes. With the alcohol ratio (A), solid-liquid ratio (B) and reflux time (C) as investigation factors, the optimum ethanol extraction process of the available components from tea was determined by L9 (3(4)) orthogonal experimental design. It would obtain different extraction conditions to analyze the assessment indexes depending on the different extraction purposes. For the purpose of CT, the contents of EGCG and CT, extraction rate and DPPH * Free radical scavenging capacity were chosen as the assessment indexes, the optimum extraction conditions were selected as follows: the ratio of raw material to 75% alcohol was 1: 12, the reflux time was 30 minutes and extraction times were three; For the purpose of CF, the content of CF and extraction rate were chosen as the assessment indexes, the optimum extraction conditions were selected as follows: the ratio of raw material to 60% alcohol was 1: 12, the reflux time was 30 minutes and extraction times were three; For the purpose of integrated extraction, the contents of CT and CF, extraction rate and DPPH * Free radical scavenging capacity were chosen as the assessment indexes, the optimum extraction conditions were selected as follows: the ratio of raw material to 60% alcohol was 1: 8, the reflux time was 30 minutes and extraction times were three. The optimum extraction process in order to attain different purposes can give a reference to the research of a new medicine and industry production.

Y-27632 Increases Sensitivity of PANC-1 Cells to EGCG in Regulating Cell Proliferation and Migration.

PubMed

Liu, Xing; Bi, Yongyi

2016-10-03

BACKGROUND The study aimed to investigate the inhibitory effect of (1R,4r)-4-((R)-1-aminoethyl)-N-(pyridin-4-yl) cyclohexanecarboxamide (Y-27632) and (-)-epigallocatechin-3-gallate (EGCG) on the proliferation and migration of PANC-1 cells. EGCG, found in green tea, has been previously shown to be one of the most abundant and powerful catechins in cancer prevention and treatment. Y-27632, a selective inhibitor of rho-associated protein kinase 1, is widely used in treating cardiovascular disease, inflammation, and cancer. MATERIAL AND METHODS PANC-1 cells, maintained in Dulbecco's Modified Eagle's Medium, were treated with dimethyl sulfoxide (control) as well as different concentrations (20, 40, 60, and 80 μg/mL) of EGCG for 48 h. In addition, PANC-1 cells were treated separately with 60 μg/mL EGCG, 20 μM Y-27632, and EGCG combined with Y-27632 (60 μg/mL EGCG + 20 μM Y-27632) for 48 h. The effect of EGCG and Y-27632 on the proliferation and migration of PANC-1 cells was evaluated using Cell Counting Kit-8 and transwell migration assays. The expression of peroxisome proliferator-activated receptor alpha (PPARα) and Caspase-3 mRNA was determined by Quantitative real-time polymerase chain reaction (RT-qPCR). RESULTS EGCG (20-80 μg/mL) inhibited cell viability in a dose-dependent manner. Y-27632 enhanced the sensitivity of PANC-1 cells to EGCG (by increasing the expression of PPARa and Caspase-3 mRNA) and suppressed cell proliferation. PANC-1 cell migration was inhibited by treatment with a combination of EGCG and Y-27632. CONCLUSIONS Y-27632 increases the sensitivity of PANC-1 cells to EGCG in regulating cell proliferation and migration, which is likely to be related to the expression of PPARa mRNA and Caspase-3 mRNA.

Effect of (-)-epigallocatechin gallate (EGCG) extracted from green tea in reducing the formation of acrylamide during the bread baking process.

PubMed

Fu, Zhengjie; Yoo, Michelle J Y; Zhou, Weibiao; Zhang, Lei; Chen, Yutao; Lu, Jun

2018-03-01

This is the first study to investigate the extent of reduction in acrylamide formation during baking with the addition of (-)-epigallocatechin gallate (EGCG) extracted from green tea, and to determine whether EGCG influences the texture and colour attributes of bread, or interacts with other ingredients. EGCG powders were added to white bread formulations at the concentrations of 3.3, 6.6 and 9.9g·kg -1 . The amount of acrylamide in the bread was analysed using liquid chromatography-mass spectrometry. EGCG addition significantly reduced the acrylamide formation by 37% compared to the control and decreased the moisture content of the bread by 6%. It did not affect its texture attribute, but increased the lightness and the yellowness and decreased the redness of bread crust (with contrasting results in crumb). It also decreased granule size and porosity. In conclusion, EGCG fortification is a feasible method to decrease acrylamide formation in baked bread. Copyright © 2017 Elsevier Ltd. All rights reserved.

Separation and purification of epigallocatechin-3-gallate (EGCG) from green tea using combined macroporous resin and polyamide column chromatography.

PubMed

Jin, Xin; Liu, Mingyan; Chen, Zaixing; Mao, Ruikun; Xiao, Qinghuan; Gao, Hua; Wei, Minjie

2015-10-01

Epigallocatechin-3-gallate (EGCG) is a major bioactive ingredient of green tea that produces beneficial neuroprotective effects. In this paper, to optimize the EGCG enrichment, thirteen macroporous resins with different chemical and physical properties were systemically evaluated. Among the thirteen tested resins, the H-bond resin HPD826 exhibited best adsorption/desorption capabilities and desorption ratio, as well as weakest affinity for caffeine. The absorption of EGCG on the HPD826 resin followed the pseudo-second-order kinetics and Langmuir isotherm model. The separation parameters of EGCG were optimized by dynamic adsorption/desorption experiments with the HPD826 resin column. Under the optimal condition, the content of EGCG in the 30% ethanol eluent increased by 5.8-fold from 7.7% to 44.6%, with the recovery yield of 72.1%. After further purification on a polyamide column, EGCG with 74.8% purity was obtained in the 40-50% ethanol fraction with a recovery rate of 88.4%. In addition, EGCG with 95.1% purity could be easily obtained after one-step crystallization in distilled water. Our study suggests that the combined macroporous resin and polyamide column chromatography is a simple method for large-scale separation and purification of EGCG from natural plants for food and pharmaceutical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Implications of Green Tea and Its Constituents in the Prevention of Cancer via the Modulation of Cell Signalling Pathway

PubMed Central

Rahmani, Arshad H.; Al shabrmi, Fahad M.; Allemailem, Khaled S.; Aly, Salah M.; Khan, Masood A.

2015-01-01

Green tea is commonly used as a beverage worldwide, especially in China, Japan, Morocco, and Saudi Arabia. Green tea and its constituents have been considered very effective in the prevention and treatment of various diseases. It contains a variety of catechins, which show a pivotal role in the modulation of biological activities and also act as chemopreventive agents. Earlier studies have confirmed that green tea and its chief constituent epigallocatechin gallate (EGCG) have a potential role in the management of cancer through the modulation of cell signaling pathways. In this review, we focused on the beneficial effects of green tea and its constituents in the cancer prevention and treatment and its impact on modulation of molecular pathways. PMID:25977926

Laboratory Studies on Weight Control and Prevention of Metabolic Syndrome by Green Tea1

PubMed Central

Sudathip, Sae-tan; Grove, Kimberly A.; Lambert, Joshua D.

2011-01-01

Green tea (Camellia sinensis, Theaceace) is the second most popular beverage in the world and has been extensively studied for its putative disease preventive effects. Green tea is characterized by the presence of a high concentrations of polyphenolic compounds known as catechins, with (−)-epigallocatechin-3-gallate (EGCG) being the most abundant and most well-studied. Metabolic syndrome (MetS) is a complex condition that is defined by the presence of elevated waist circumference, dysglycemia, elevated blood pressure, decrease serum high density lipoprotein-associated cholesterol, and increased serum triglycerides. Studies in both in vitro and laboratory animal models have examined the preventive effects of green tea and EGCG against the symptoms of MetS. Overall, the results of these studies have been promising and demonstrate that green tea and EGCG have preventive effects in both genetic and dietary models of obesity, insulin resistance, hypertension, and hypercholesterolemia. Various mechanisms have been proposed based on these studies and include: modulation of dietary fat absorption and metabolism, increased glucose utilization, decreased de novo lipogenesis, enhanced vascular responsiveness, and antioxidative effects. In the present review, we discuss the current state of the science with regard to laboratory studies on green tea and MetS. We attempt to critically evaluate the available data and point out areas for future research. Although there is a considerable amount of data available, questions remain in terms of the primary mechanism(s) of action, the dose-response relationships involved, and the best way to translate the results to human intervention studies. PMID:21193040

Combination of curcumin and green tea catechins prevents dimethylhydrazine-induced colon carcinogenesis.

PubMed

Xu, Gang; Ren, Guijie; Xu, Xia; Yuan, Huiqing; Wang, Zhenzheng; Kang, Ludong; Yu, Wenguang; Tian, Keli

2010-01-01

The chemopreventive effects of curcumin and green tea catechins individually and in combination on 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis were studied in male Wister rats following 32 weeks of dietary treatment. The incidence, number and size of colorectal cancer were measured. Colorectal aberrant crypt foci (ACF) were analyzed by methylene blue staining. Proliferation indices and apoptotic indices were determined by PCNA immunostaining and TUNEL assay, respectively. The results showed that dietary curcumin, catechins and combination administration significantly inhibited the total number of ACF per rat. The combination treatment displayed the most potent inhibitory effect, while there was no difference of inhibition between curcumin and catechins-treated groups. The incidence of colorectal cancer in the treated groups was significantly lower than that of positive control group. Compared with the positive control group, the proliferation index was significantly decreased and the apoptotic index was significantly increased in all treatment groups, while the effect of the combination was the greatest among the treated groups. Our findings suggest that the combination of curcumin and catechins may produce a synergistic colon cancer-preventative effect that would be more potent than each of the compounds alone. Copyright 2009 Elsevier Ltd. All rights reserved.

EGCG inhibits Cd(2+)-induced apoptosis through scavenging ROS rather than chelating Cd(2+) in HL-7702 cells.

PubMed

An, Zhen; Qi, Yongmei; Huang, Dejun; Gu, Xueyan; Tian, Yihong; Li, Ping; Li, Hui; Zhang, Yingmei

2014-05-01

Epigallocatechin-3-gallat (EGCG), the major catechin in green tea, shows a potential protective effect against heavy metal toxicity to humans. Apoptosis is one of the key events in cadmium (Cd(2+))-induced cytotoxicity. Nevertheless, the study of EGCG on Cd(2+)-induced apoptosis is rarely reported. The objective of this study was to clarify the effect and detailed mechanism of EGCG on Cd(2+)-induced apoptosis. Normal human liver cells (HL-7702) were treated with Cd(2+) for 21 h, and then co-treated with EGCG for 3 h. Cell viability, apoptosis, intracellular reactive oxygen species (ROS), malondialdehyde (MDA), mitochondrial membrane potential (MMP) and caspase-3 activity were detected. On the other hand, the chelation of Cd(2+) with EGCG was tested by UV-Vis spectroscopy analysis and Nuclear Magnetic Resonance ((1)H NMR) spectroscopy under neutral condition (pH 7.2). Cd(2+) significantly decreased the cell viability and induced apoptosis in HL-7702 cells. Conversely, EGCG co-treatment resulted in significant inhibition of Cd(2+)-induced reduction of cell viability and apoptosis, implying a rescue effect of EGCG against Cd(2+) poisoning. The protective effect most likely arises from scavenging ROS and maintaining redox homeostasis, as the generation of intracellular ROS and MDA is significantly reduced by EGCG, which further prevents MMP collapse and suppresses caspase-3 activity. However, no evidence is observed for the chelation of EGCG with Cd(2+) under neutral condition. Therefore, a clear conclusion from this work can be made that EGCG could inhibit Cd(2+)-induced apoptosis by acting as a ROS scavenger rather than a metal chelating agent.

Protective effect of green tea polyphenol EGCG against neuronal damage and brain edema after unilateral cerebral ischemia in gerbils.

PubMed

Lee, Hyung; Bae, Jae Hoon; Lee, Seong-Ryong

2004-09-15

Previous studies have demonstrated that a green tea polyphenol, (-)-epigallocatechine gallate (EGCG), has a potent free radical scavenging and antioxidant effect. Glutamate leads to excitotoxicity and oxidative stress, which are important pathophysiologic responses to cerebral ischemia resulting in brain edema and neuronal damage. We investigated the effect of EGCG on excitotoxic neuronal damage in a culture system and the effect on brain edema formation and lesion after unilateral cerebral ischemia in gerbils. In vitro, excitotoxicity was induced by 24-hr incubation with N-methyl-D-aspartate (NMDA; 10 microM), AMPA (10 microM), or kainate (20 microM). EGCG (5 microM) was added to the culture media alone or with excitotoxins. We examined malondialdehyde (MDA) level and neuronal viability to evaluate the effect of EGCG. In vivo, unilateral cerebral ischemia was induced by occlusion of the right common carotid artery for 30, 60, or 90 min and followed by reperfusion of 24 hr. Brain edema, MDA, and infarction were examined to evaluate the protective effect of EGCG. EGCG (25 or 50 mg/kg, intraperitoneally) was administered twice, at 30 min before and immediately after ischemia. EGCG reduced excitotoxin-induced MDA production and neuronal damage in the culture system. In the in vivo study, treatment of gerbils with the lower EGCG dose failed to show neuroprotective effects; however, the higher EGCG dose attenuated the increase in MDA level caused by cerebral ischemia. EGCG also reduced the formation of postischemic brain edema and infarct volume. These results demonstrate EGCG may have future possibilities as a neuroprotective agent against excitotoxicity-related neurologic disorders such as brain ischemia.

Assessment of DNA damage and lipid peroxidation in diabetic mice: effects of propolis and epigallocatechin gallate (EGCG).

PubMed

Oršolić, Nada; Sirovina, Damir; Gajski, Goran; Garaj-Vrhovac, Vera; Jazvinšćak Jembrek, Maja; Kosalec, Ivan

2013-09-18

There is growing recognition that polyphenolic compounds present in many plants and natural products may have beneficial effects on human health. Propolis - a substance produced by honeybees - and catechins in tea, in particular (-)-epigallocatechin gallate (EGCG), are strong antioxidants that appear to have anti-obesity and anti-diabetic effects. The present study was designed to elucidate the anti-diabetic effect of the water-soluble derivative of propolis (WSDP), which contains phenolic acids as the main compounds, and EGCG in alloxan-induced (75mg/kg, iv) diabetes in mice. Intraperitoneal administration of EGCG or propolis at doses of 50mg/kg body weight (bw) to diabetic mice for a period of 7 days resulted in a significant increase in body weight and in haematological/immunological blood parameters, as well as in 100% survival of the mice. A significant decrease in lipid peroxidation in liver, kidney and brain tissue was also observed in diabetic mice treated with these two agents. Additionally, EGCG and propolis clearly reduced DNA damage in peripheral lymphocytes of diabetic mice. Our studies demonstrate the anti-oxidative and anti-inflammatory potential of WSDP and EGCG, which could exert beneficial effects against diabetes and the associated consequences of free-radical formation in kidney, liver, spleen and brain tissue. The results suggest that dietary supplementation with WSDP or EGCG could potentially contribute to nutritional strategies for the prevention and treatment of diabetes mellitus. Copyright © 2013 Elsevier B.V. All rights reserved.

Designed polar cosolvent-modified supercritical CO2 removing caffeine from and retaining catechins in green tea powder using response surface methodology.

PubMed

Huang, Kuo-Jong; Wu, Jia-Jiuan; Chiu, Yung-Ho; Lai, Cheng-Yung; Chang, Chieh-Ming J

2007-10-31

This study examines cosolvent-modified supercritical carbon dioxide (SC-CO2) to remove caffeine from and to retain catechins in green tea powder. The response surface method was adopted to determine the optimal operation conditions in terms of the extraction efficiencies and concentration factors of caffeine and catechins during the extractions. When SC-CO2 was used at 333 K and 300 bar, 91.5% of the caffeine was removed and 80.8% of catechins were retained in the tea: 3600 g of carbon dioxide was used in the extraction of 4 g of tea soaked with 1 g of water. Under the same extraction conditions, 10 g of water was added to <800 g of carbon dioxide in an extraction that completely removed caffeine (that is, the caffeine extraction efficiency was 100%). The optimal result as predicted by three-factor response surface methodology and supported by experimental data was that in 1.5 h of extraction, 640 g of carbon dioxide at 323 K and 275 bar with the addition of 6 g of water extracted 71.9% of the caffeine while leaving 67.8% of the catechins in 8 g of tea. Experimental data indicated that supercritical carbon dioxide decaffeination increased the concentrations of caffeine in the SC-CO2 extracts at 353 K.

(-)Epigallocatechin-3-gallate decreases the stress-induced impairment of learning and memory in rats.

PubMed

Soung, Hung-Sheng; Wang, Mao-Hsien; Tseng, Hsiang-Chien; Fang, Hsu-Wei; Chang, Kuo-Chi

2015-08-18

Stress induces reactive oxygen species (ROS) and causes alterations in brain cytoarchitecture and cognition. Green tea has potent antioxidative properties especially the tea catechin (-) epigallocatechin-3-gallate (EGCG). These powerful antioxidative properties are able to protect against various oxidative damages. In this study we investigated the impact of stress on rats' locomotor activity, learning and memory. Many tea catechins, including EGCG, were examined for their possible therapeutic effects in treating stress-induced impairment. Our results indicated that locomotor activity was decreased, and the learning and memory were impaired in stressed rats (SRs). EGCG treatment was able to prevent the decreased locomotor activity as well as improve the learning and memory in SRs. EGCG treatment was also able to reduce the increased oxidative status in SRs' hippocampi. The above results suggest a therapeutic effect of EGCG in treating stress-induced impairment of learning and memory, most likely by means of its powerful antioxidative properties. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Attenuated migration by green tea extract (-)-epigallocatechin gallate (EGCG): involvement of 67 kDa laminin receptor internalization in macrophagic cells.

PubMed

Ren, Xuezhi; Guo, Xingzhi; Chen, Li; Guo, Minxia; Peng, Ning; Li, Rui

2014-08-01

Excessive activation of the microglia in the brain is involved in the development of several neurodegenerative diseases. Previous studies have indicated that (-)-epigallocatechin gallate (EGCG), a major active constituent of green tea, exhibits potent suppressive effects on the activation of microglia. As the 67 kDa laminin receptor (67LR) is a key element in cellular activation and migration, we investigated the effect of EGCG on cell migration and 67LR in lipopolysaccharide (LPS)-activated macrophagic RAW264.7 cells. The presence of EGCG (1-25 μM) markedly attenuated LPS-induced cell migration in a dose-dependent manner. However, the total amount of 67LR protein in the RAW264.7 cells was unaffected by EGCG, as revealed by Western blot analysis. In addition, confocal immunofluorescence microscopy indicated that EGCG caused a marked membrane translocation of 67LR from the membrane surface towards the cytoplasm. Cell-surface biotinylation analysis confirmed that EGCG induced a significant internalization of 67LR by 24-68% in a dose-dependent manner. This study helps to explain the pharmacological action of EGCG on 67LR, suggesting its potential use in the treatment of diseases associated with macrophage/microglia activation, such as neurodegenerative diseases and cancer.

A prodrug of green tea polyphenol (-)-epigallocatechin-3-gallate (Pro-EGCG) serves as a novel angiogenesis inhibitor in endometrial cancer.

PubMed

Wang, Jianzhang; Man, Gene Chi Wai; Chan, Tak Hang; Kwong, Joseph; Wang, Chi Chiu

2018-01-01

Anti-angiogenesis effect of a prodrug of green tea polyphenol (-)-epigallocatechin-3-gallate (Pro-EGCG) in malignant tumors is not well studied. Here, we investigated how the treatment with Pro-EGCG inhibited tumor angiogenesis in endometrial cancer. Tumor xenografts of human endometrial cancer were established and subjected to microarray analysis after Pro-EGCG treatment. First, we showed Pro-EGCG inhibited tumor angiogenesis in xenograft models through down-regulation of vascular endothelial growth factor A (VEGFA) and hypoxia inducible factor 1 alpha (HIF1α) in tumor cells and chemokine (C-X-C motif) ligand 12 (CXCL12) in host stroma by immunohistochemical staining. Next, we investigated how HIF1α/VEGFA was down-regulated and how the reduction of CXCL12 inhibited tumor angiogenesis. We found that VEGFA secretion from endometrial cancer cells was decreased by Pro-EGCG treatment through inhibiting PI3K/AKT/mTOR/HIF1α pathway. Furthermore, the down-regulation of CXCL12 in stromal cells by Pro-EGCG treatment restricted migration and differentiation of macrophages thereby inhibited infiltration of VEGFA-expressing tumor-associated macrophages (TAMs). Taken together, we demonstrated that treatment with Pro-EGCG not only decreases cancer cell-secreted VEGFA but also inhibits TAM-secreted VEGFA in endometrial cancer. These findings demonstrate that Pro-EGCG is a novel angiogenesis inhibitor for endometrial cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

The activity of catechol-O-methyltransferase (COMT) is not impaired by high doses of epigallocatechin-3-gallate (EGCG) in vivo.

PubMed

Lorenz, Mario; Paul, Friedemann; Moobed, Minoo; Baumann, Gert; Zimmermann, Benno F; Stangl, Karl; Stangl, Verena

2014-10-05

Catechol-O-methyltransferase (COMT) inactivates many endogenous and exogenous compounds by O-methylation. Therefore, it represents a major enzyme of the metabolic pathway with important biological functions in hormonal and drug metabolism. The tea catechin epigallocatechin-3-gallate (EGCG) is known to inhibit COMT enzymatic activity in vitro. Based on beneficial in vitro results, EGCG is extensively used in human intervention studies in a variety of human diseases. Owing to its low bioavailability, rather high doses of EGCG are frequently applied that may impair COMT activity in vivo. Enzymatic activities of four functional COMT single-nucleotide polymorphisms (SNPs) were determined in red blood cells (RBCs) in 24 healthy human volunteers (14 women, 10 men). The subjects were supplemented with 750 mg of EGCG and EGCG plasma levels and COMT enzyme activities in erythrocytes were measured before and 2 h after intervention. The homozygous Val→Met substitution in the SNP rs4680 resulted in significantly decreased COMT activity. Enzymatic COMT activities in RBCs were also affected by the other three COMT polymorphisms. EGCG plasma levels significantly increased after intervention. They were not influenced by any of the COMT SNPs and different enzyme activities. Ingestion of 750 mg EGCG did not result in impairment of COMT activity. However, COMT activity was significantly increased by 24% after EGCG consumption. These results indicate that supplementation with a high dose of EGCG does not impair the activity of COMT. Consequently, it may not interfere with COMT-mediated metabolism and elimination of exogenous and endogenous COMT substrates. Copyright © 2014 Elsevier B.V. All rights reserved.

Persistence of thiacloprid and deltamethrin residues in tea grown at different locations of North-East India.

PubMed

Sharma, Nitesh; Banerjee, Hemanta; Pal, Srikumar; Sharma, K K

2018-07-01

In order to examine the residues of thiacloprid (90 and 180 g a.i./ha) and deltamethrin (10 and 20 g a.i./ha) in fresh tea leaves, made tea and tea infusion, field experiments were conducted at three different locations viz. Kamalpur tea estate, Darjeeling; West Bengal, Teok tea Estate and AAU, Jorhat; Assam in India. Regardless of location and doses, residues of both the insecticides dissipated following first order kinetics. The half-life of Thiacloprid (4.93-5.38 days) was longer than that of deltamethrin (1.78-1.94 days). Processing of green tea leaves reduced the residue level of thiacloprid and deltamethrin in made tea. No residues of both these insecticides could be detected in tea infusion. With respect to the phenolic distribution in tea, a marked increase in total catechin monomers with thiacloprid and greater accumulation of EGCG and ECG (indices of phenol quality) with deltamethrin were observed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Reduction in Autophagy by (-)-Epigallocatechin-3-Gallate (EGCG): a Potential Mechanism of Prevention of Mitochondrial Dysfunction After Subarachnoid Hemorrhage.

PubMed

Chen, Ying; Huang, Liyong; Zhang, Huiyong; Diao, Xiling; Zhao, Shuyang; Zhou, Wenke

2017-01-01

Mitochondrial dysfunction and subsequent autophagy, which are common features in central nervous system (CNS) disorders, were found to contribute to neuronal cell injury after subarachnoid hemorrhage (SAH). (-)-Epigallocatechin-3-gallate (EGCG), the main biological active of tea catechin, is well known for its beneficial effects in the treatment of CNS diseases. Here, the ability of EGCG to rescue cellular injury and mitochondrial function following the improvement of autophagic flux after SAH was investigated. As expected, EGCG-protected mitochondrial function depended on the inhibition of cytosolic Ca 2+ concentration ([Ca 2+ ] i ) influx via voltage-gated calcium channels (VGCCs) and, consequently, mitochondrial Ca 2+ concentration ([Ca 2+ ] m ) overload via mitochondrial Ca 2+ uniporter (MCU). The attenuated [Ca 2+ ] i and [Ca 2+ ] m levels observed in the EGCG-treated group likely lessened oxyhemoglobin (OxyHb)-induced mitochondrial dysfunction, including mitochondrial membrane potential depolarization, mitochondrial membrane permeability transition pore (mPTP) opening, reactive oxygen species (ROS), and cytochrosome c (cyt c) releasing. Subsequently, EGCG can restore the disrupted autophagy flux after SAH both at the initiation and formation stages by regulating Atg5, LC3B, and Becn-1 (Beclin-1) mRNA expressions. Thus, precondition EGCG resulted in autophagosomes and more autolysosomes compared with SAH group. As a result, EGCG pre-treatment increased the neurological score and decreased cell death. This study suggested that the mitochondrial dysfunction and abnormal autophagy flux synergistically contribute to SAH pathogenesis. Thus, EGCG can be regarded as a new pharmacological agent that targets both mitochondria and altered autophagy in SAH therapy.

Comparison of (-)-epigallocatechin-3-O-gallate (EGCG) and O-methyl EGCG bioavailability in rats.

PubMed

Oritani, Yukihiro; Setoguchi, Yuko; Ito, Ryouichi; Maruki-Uchida, Hiroko; Ichiyanagi, Takashi; Ito, Tatsuhiko

2013-01-01

(-)-Epigallocatechin-3-O-(3-O-methyl)gallate (EGCG3″Me) and (-)-epigallocatechin-3-O-(4-O-methyl)gallate (EGCG4″Me) are O-methyl derivatives of (-)-epigallocatechin-3-O-gallate (EGCG) present in tea cultivars such as Benifuuki. Although O-methyl EGCGs have various bioactivities, their bioavailabilities have not been determined. In this study, we compared the bioavailability of EGCG and O-methyl EGCGs in rats, and clarified the pharmacokinetics of O-methyl EGCGs. Following oral administration (100 mg/kg), the areas under the concentration-time curves (AUCs) for EGCG, EGCG3″Me, and EGCG4″Me were 39.6 ± 14.2 µg·h/L, 317.2 ± 43.7 µg·h/L, and 51.9 ± 11.0 µg·h/L, respectively. The AUC after intravenous administration (10 mg/kg) was 2772 ± 480 µg·h/L for EGCG, 8209 ± 549 µg·h/L for EGCG3″Me, and 2465 ± 262 µg·h/L for EGCG4″Me. The bioavailability of EGCG3″Me (0.38%) was the highest (EGCG: 0.14% and EGCG4″Me: 0.21%). The distribution volume of EGCG3″Me (0.26 ± 0.02 L/kg) was the lowest (EGCG: 0.94 ± 0.16 L/kg and EGCG4″Me: 0.93 ± 0.14 L/kg). These results suggested that the higher AUC of EGCG3″Me after oral administration was related to its high bioavailability and low distribution volume. These findings supported the stronger bioactivity of EGCG3″Me in vivo.

Certain (-)-epigallocatechin-3-gallate (EGCG) auto-oxidation products (EAOPs) retain the cytotoxic activities of EGCG.

PubMed

Wei, Yaqing; Chen, Pingping; Ling, Tiejun; Wang, Yijun; Dong, Ruixia; Zhang, Chen; Zhang, Longjie; Han, Manman; Wang, Dongxu; Wan, Xiaochun; Zhang, Jinsong

2016-08-01

(-)-Epigallocatechin-3-gallate (EGCG) from green tea has anti-cancer effect. The cytotoxic actions of EGCG are associated with its auto-oxidation, leading to the production of hydrogen peroxide and formation of numerous EGCG auto-oxidation products (EAOPs), the structures and bioactivities of them remain largely unclear. In the present study, we compared several fundamental properties of EGCG and EAOPs, which were prepared using 5mg/mL EGCG dissolved in 200mM phosphate buffered saline (pH 8.0 at 37°C) and normal oxygen partial pressure for different periods of time. Despite the complete disappearance of EGCG after the 4-h auto-oxidation, 4-h EAOPs gained an enhanced capacity to deplete cysteine thiol groups, and retained the cytotoxic effects of EGCG as well as the capacity to produce hydrogen peroxide and inhibit thioredoxin reductase, a putative target for cancer prevention and treatment. The results indicate that certain EAOPs possess equivalent cytotoxic activities to EGCG, while exhibiting simultaneously enhanced capacity for cysteine depletion. These results imply that EGCG and EAOPs formed extracellularly function in concert to exhibit cytotoxic effects, which previously have been ascribed to EGCG alone. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Presurgical Study of Lecithin Formulation of Green Tea Extract in Women with Early Breast Cancer.

PubMed

Lazzeroni, Matteo; Guerrieri-Gonzaga, Aliana; Gandini, Sara; Johansson, Harriet; Serrano, Davide; Cazzaniga, Massimiliano; Aristarco, Valentina; Macis, Debora; Mora, Serena; Caldarella, Pietro; Pagani, Gianmatteo; Pruneri, Giancarlo; Riva, Antonella; Petrangolini, Giovanna; Morazzoni, Paolo; DeCensi, Andrea; Bonanni, Bernardo

2017-06-01

Epidemiologic data support an inverse association between green tea intake and breast cancer risk. Greenselect Phytosome (GSP) is a lecithin formulation of a caffeine-free green tea catechin extract. The purpose of the study was to determine the tissue distribution of epigallocatechin-3-O-gallate (EGCG) and its effect on cell proliferation and circulating biomarkers in breast cancer patients. Twelve early breast cancer patients received GSP 300 mg, equivalent to 44.9 mg of EGCG, daily for 4 weeks prior to surgery. The EGCG levels were measured before (free) and after (total) enzymatic hydrolysis by HPLC-MS/MS in plasma, urine, breast cancer tissue, and surrounding normal breast tissue. Fasting blood samples were taken at baseline, before the last administration, and 2 hours later. Repeated administration of GSP achieved levels of total EGCG ranging from 17 to 121 ng/mL in plasma. Despite a high between-subject variability, total EGCG was detectable in all tumor tissue samples collected up to 8 ng/g. Median total EGCG concentration was higher in the tumor as compared with the adjacent normal tissue (3.18 ng/g vs. 0 ng/g, P = 0.02). Free EGCG concentrations ranged from 8 to 65.8 ng/mL in plasma ( P between last administration and 2 hours after <0.001). Free EGCG plasma levels showed a significant positive correlation with the Ki-67 decrease in tumor tissue ( P = 0.02). No change in any other biomarkers was noted, except for a slight increase in testosterone levels after treatment. Oral GSP increases bioavailability of EGCG, which is detectable in breast tumor tissue and is associated with antiproliferative effects on breast cancer tissue. Cancer Prev Res; 10(6); 363-9. ©2017 AACR . ©2017 American Association for Cancer Research.

Interaction between Ester-Type Tea Catechins and Neutrophil Gelatinase-Associated Lipocalin: Inhibitory Mechanism.

PubMed

Zhang, Wei; Li, Xiao; Hua, Fang; Chen, Wei; Wang, Wei; Chu, Gang-Xiu; Bao, Guan-Hu

2018-02-07

Tea is thought to alleviate neurotoxicity due to the antioxidative effect of ester-type tea catechins (ETC). Neutrophil gelatinase-associated lipocalin (NGAL) can sensitize β-amyloid (Aβ) induced neurotoxicity, and inhibitors of NGAL may relieve associated symptoms. As such, the interactions of ETC with NGAL were investigated by fluorescence spectrometry and molecular simulation. NGAL fluorescence is quenched regularly when being added with six processing types of tea infusion (SPTT) and ETC. Thermodynamic analyses suggest that ETC with more catechol moieties has a stronger binding capacity with NGAL especially in the presence of Fe 3+ . (-)-Epicatechin 3-O-caffeoate (ECC), a natural product isolated from Zijuan green tea, shows the strongest binding ability with NGAL (K d = 15.21 ± 8.68 nM in the presence of Fe 3+ ). All ETC are effective in protecting nerve cells against H 2 O 2 or Aβ 1-42 induced injury. The inhibitory mechanism of ETC against NGAL supports its potential use in attenuation of neurotoxicity.

Effects of (-)-epigallocatechin gallate (EGCG) on DNA strand breaks as evaluated by single-cell gel electrophoresis (SCG) in human lymphocytes.

PubMed

Yuquan, L; Takeshita, T; Morimoto, K

2001-01-01

(-)-Epigallocatechin gallate (EGCG), a catechin polyphenol component, is the main ingredient of green tea extract. Although the anti-carcinogenic and cancer inhibitory effects of EGCG have been widely reported, its genotoxicity is not clear and seldom reported. In this study, we examined the effects of EGCG on DNA strand breaks in the isolated lymphocytes and whole blood lymphocytes obtained from two smoking subjects and a nonsmoking healthy subject using a single cell gel electrophoresis (SCG) assay. The results showed that after 2 hrs of treating the isolated lymphocytes from the smokers, EGCG induced a significant, increase in DNA strand breaks at concentrations from 2.5×10(-5) M to 2.0×10(-4) M, while after 2 hrs of treating the whole blood obtained from the same smokers, EGCG suppressed the DNA strand breaks in the lymphocytes at concentrations of 1.0×10(-4) M and 2.0×10(-4) M. A similar suppressive result was also shown in the whole blood lymphocytes from the nonsmoker at nearly the same concentrations, while at concentrations of 1.0×10(-3) M or 2.0×10(-3) M, EGCG induced a significant increase in DNA strand breaks in the whole blood lymphocytes from the nonsmoker. This result suggests that EGCG is not only inhibitory against DNA strand breaks in whole blood, but also genotoxic to the isolated or whole blood lymphocytes at high concentrations. Thus, more research is needed to comprehensively assess the effects of EGCG on genetic materials.

Effects of green tea catechin extract on serum lipids in postmenopausal women: a randomized, placebo-controlled clinical trial12

PubMed Central

Samavat, Hamed; Newman, April R; Wang, Renwei; Yuan, Jian-Min; Wu, Anna H; Kurzer, Mindy S

2016-01-01

Background: Green tea has been suggested to improve cardiovascular disease risk factors, including circulating lipid variables. However, current evidence is predominantly based on small, short-term randomized controlled trials conducted in diverse populations. Objective: The aim of this study was to examine the efficacy and impact of green tea extract (GTE) supplementation high in epigallocatechin gallate (EGCG) on blood lipids in healthy postmenopausal women. Design: This was an ancillary study of a double-blind, randomized, placebo-controlled, parallel-arm trial investigating the effects of a GTE supplement containing 1315 mg catechins (843 mg EGCG) on biomarkers of breast cancer risk. Participants were randomly assigned to receive GTE (n = 538) or placebo (n = 537) and were stratified by catechol-O-methyltransferase (COMT) genotype activity (high COMT compared with low or intermediate COMT genotype activity). They consumed either 4 GTE or identical placebo capsules daily for 12 mo. A total of 936 women completed this substudy. Circulating lipid panels including total cholesterol (TC), HDL cholesterol, and triglycerides were measured at baseline and at months 6 and 12. Results: Compared with placebo, 1-y supplementation with GTE capsules resulted in a significant reduction in circulating TC (−2.1% compared with 0.7%; P = 0.0004), LDL cholesterol (−4.1% compared with 0.9%; P < 0.0001) and non-HDL cholesterol (−3.1% compared with 0.4%; P = 0.0032). There was no change in HDL-cholesterol concentration, but triglyceride concentrations increased by 3.6% in the GTE group, whereas they decreased by 2.5% in the placebo group (P = 0.046). A significant reduction in TC was observed only among women with high (i.e., ≥200 mg/dL) baseline TC concentrations (P-interaction = 0.01) who consumed GTE capsules. The effect of GTE on the increase in triglycerides was mainly observed among obese women and statin users (P-interaction = 0.06). Conclusion: Supplementation with

Effect of particle size in preparative reversed-phase high-performance liquid chromatography on the isolation of epigallocatechin gallate from Korean green tea.

PubMed

Kim, Jung Il; Hong, Seung Bum; Row, Kyung Ho

2002-03-08

To isolate epigallocatechin gallate (EGCG) of catechin compounds from Korean green tea (Bosung, Chonnam), a C18 reversed-phase preparative column (250x22 mm) packed with packings of three different sizes (15, 40-63, and 150 microm) was used. The sample extracted with water was partitioned with chloroform and ethyl acetate to remove the impurities including caffeine. The mobile phases in this experiment were composed of 0.1% acetic acid in water, acetonitrile, methanol and ethyl acetate. The injection volume was fixed at 400 microl and the flow rate was increased as the particle size becomes larger. The isolation of EGCG with particle size was compared at a preparative scale and the feasibility of separation of EGCG at larger particle sizes was confirmed. The optimum mobile phase composition for separating EGCG was experimentally obtained at the particle sizes of 15 and 40-63 microm in the isocratic mode, but EGCG was not purely separated at the particle size of 150 microm.

Green tea supplementation affects body weight, lipids, and lipid peroxidation in obese subjects with metabolic syndrome.

PubMed

Basu, Arpita; Sanchez, Karah; Leyva, Misti J; Wu, Mingyuan; Betts, Nancy M; Aston, Christopher E; Lyons, Timothy J

2010-02-01

To compare the effects of supplementation of green tea beverage or green tea extracts with controls on body weight, glucose and lipid profile, biomarkers of oxidative stress, and safety parameters in obese subjects with metabolic syndrome. Randomized, controlled prospective trial. General Clinical Research Center (GCRC) at University of Oklahoma Health Sciences Center (OUHSC). Thirty-five subjects with obesity and metabolic syndrome were recruited in age- and gender-matched trios and were randomly assigned to the control (4 cups water/d), green tea (4 cups/d), or green tea extract (2 capsules and 4 cups water/d) group for 8 weeks. The tea and extract groups had similar dosing of epiogallocatechin-3-gallate (EGCG), the active compound in green tea. Anthropometrics, blood pressure, fasting glucose and lipids, nuclear magnetic resonance (NMR)-based lipid particle size, safety parameters, biomarkers of oxidative stress (oxidized low-density lipoprotein [LDL], myeloperoxidase [MPO], malondialdehyde and hydroxynonenals [MDA and HNE]), and free catechins were analyzed at screen and at 4 and 8 weeks of the study. Pairwise comparisons showed green tea beverage and green tea extracts caused a significant decrease in body weight and body mass index (BMI) versus controls at 8 weeks (-2.5 +/- 0.7 kg, p < 0.01, and -1.9 +/- 0.6, p < 0.05, respectively). Green tea beverage showed a decreasing trend in LDL-cholesterol and LDL/high-density lipoprotein (HDL) versus controls (p < 0.1). Green tea beverage also significantly decreased MDA and HNE (-0.39 +/- 0.06 microM, p < 0.0001) versus controls. Plasma free catechins were detectable in both beverage and extract groups versus controls at screen and at 8 weeks, indicating compliance and bioavailability of green tea catechins. Green tea beverage consumption (4 cups/d) or extract supplementation (2 capsules/d) for 8 weeks significantly decreased body weight and BMI. Green tea beverage further lowered lipid peroxidation versus age- and

Absorption, metabolism, anti-cancer effect and molecular targets of epigallocatechin gallate (EGCG): An updated review.

PubMed

Gan, Ren-You; Li, Hua-Bin; Sui, Zhong-Quan; Corke, Harold

2018-04-13

Green tea is one of the most popular beverages in the world, especially in Asian countries. Consumption of green tea has been demonstrated to possess many health benefits, which mainly attributed to the main bioactive compound epigallocatechin gallate (EGCG), a flavone-3-ol polyphenol, in green tea. EGCG is mainly absorbed in the intestine, and gut microbiota play a critical role in its metabolism prior to absorption. EGCG exhibits versatile bioactivities, with its anti-cancer effect most attracting due to the cancer preventive effect of green tea consumption, and a great number of studies intensively investigated its anti-cancer effect. In this review, we therefore, first stated the absorption and metabolism process of EGCG, and then summarized its anti-cancer effect in vitro and in vivo, including its manifold anti-cancer actions and mechanisms, especially its anti-cancer stem cell effect, and next highlighted its various molecular targets involved in cancer inhibition. Finally, the anti-cancer effect of EGCG analogs and nanoparticles, as well as the potential cancer promoting effect of EGCG were also discussed. Understanding of the absorption, metabolism, anti-cancer effect and molecular targets of EGCG can be of importance to better utilize it as a chemopreventive and chemotherapeutic agent.

Prevention of carcinogenesis of mouse mammary epithelial cells RIII/MG by epigallocatechin gallate.

PubMed

Yanaga, Hiroshi; Fujii, Teruhiko; Koga, Toshihiro; Araki, Ruriko; Shirouzu, Kazuo

2002-09-01

The chemopreventive effect of the polyphenols abundant in green tea on carcinogenesis has been attracting attention in recent years. Among tea polyphenols, epigallocatechin gallate (EGCG) has been studied as a preventive substance for carcinogenesis. We investigated the chemopreventive effect in a group treated with EGCG in vitro and in vivo using mouse mammary epithelial cells RIII/MG. In the in vitro experiment, crude catechin (catechin) containing 50% or more EGCG significantly inhibited the growth of RIII/MG cells, which were precancerous cultured cells. Many cells died, and a DNA ladder was observed. In the in vivo experiment, RIII/MG cells formed a tumor after 13 weeks in a group without catechin treatment, and the tumor formation rate in the 20th week was 40%. In a group treated with 0.1% catechin, a tumor began to grow in the 13th week, and the tumor formation rate in the 20th week was 20%. In a group treated with 1% catechin, no tumor was detected even in the 20th week. There was no significant difference in the change in body weight between the catechin treatment groups and the non-treatment group during the observation period. Tissue samples were stained by the nick-end-labeling method and apoptosis was observed in many cells. Based on the above findings, EGCG inhibited growth in the mouse viral mammary epithelial carcinogenesis model RIII/MG, and induced apoptosis, suggesting a clinical usefulness of EGCG as a chemopreventive substance.

Effect of green tea catechins and hydrolyzable tannins on benzo[a]pyrene-induced DNA adducts and structure-activity relationship.

PubMed

Cao, Pengxiao; Cai, Jian; Gupta, Ramesh C

2010-04-19

Green tea catechins and hydrolyzable tannins are gaining increasing attention as chemopreventive agents. However, their mechanism of action is poorly understood. We investigated the effects of four green tea catechins and two hydrolyzable tannins on microsome-induced benzo[a]pyrene (BP)-DNA adducts and the possible structure-activity relationship. BP (1 microM) was incubated with rat liver microsomes and DNA in the presence of the test compound (1-200 microM) or vehicle. The purified DNA was analyzed by (32)P-postlabeling. The inhibitory activity of the catechins was in the following descending order: epigallocatechin gallate (IC(50) = 16 microM) > epicatechin gallate (24 microM) > epigallocatechin (146 microM) > epicatechin (462 microM), suggesting a correlation between the number of adjacent aromatic hydroxyl groups in the molecular structure and their potencies. Tannic acid (IC(50) = 4 microM) and pentagalloglucose (IC(50) = 26 microM) elicited as much DNA adduct inhibitory activity as the catechins or higher presumably due to the presence of more functional hydroxyl groups. To determine if the activity of these compounds was due to direct interaction of phenolic groups with electrophilic metabolite(s) of BP, DNA was incubated with anti-benzo[a]pyrene-7,8-diol-9,10-epoxide (anti-BPDE) (0.5 microM) in the presence of test compounds (200 microM) or vehicle. Significant inhibition of DNA adduct formation was found (tannic acid > pentagalloglucose > epigallocatechin gallate > epicatechin gallate). This notion was confirmed by analysis of the reaction products of anti-BPDE with the catechins and pentagalloglucose by electrospray ionization mass spectrometry and liquid chromatography-mass spectrometry. In conclusion, our data demonstrate that green tea catechins and the hydrolyzable tannins are highly effective in inhibiting BP-DNA adduct formation at least, in part, due to direct interaction of adjacent hydroxyl groups in their structures and that the activity is

Effect of Green Tea Catechins and Hydrolyzable Tannins on Benzo[a]pyrene-Induced DNA Adducts and Structure–Activity Relationship

PubMed Central

Cao, Pengxiao; Cai, Jian; Gupta, Ramesh C.

2016-01-01

Green tea catechins and hydrolyzable tannins are gaining increasing attention as chemopreventive agents. However, their mechanism of action is poorly understood. We investigated the effects of four green tea catechins and two hydrolyzable tannins on microsome-induced benzo[a]pyrene (BP)–DNA adducts and the possible structure–activity relationship. BP (1 μM) was incubated with rat liver microsomes and DNA in the presence of the test compound (1–200 μM) or vehicle. The purified DNA was analyzed by 32P-postlabeling. The inhibitory activity of the catechins was in the following descending order: epigallocatechin gallate (IC50 = 16 μM) > epicatechin gallate (24 μM) > epigallocatechin (146 μM) > epicatechin (462 μM), suggesting a correlation between the number of adjacent aromatic hydroxyl groups in the molecular structure and their potencies. Tannic acid (IC50 = 4 μM) and pentagalloglucose (IC50 = 26 μM) elicited as much DNA adduct inhibitory activity as the catechins or higher presumably due to the presence of more functional hydroxyl groups. To determine if the activity of these compounds was due to direct interaction of phenolic groups with electrophilic metabolite(s) of BP, DNA was incubated with anti-benzo[a]pyrene-7,8-diol-9,10-epoxide (anti-BPDE) (0.5 μM) in the presence of test compounds (200 μM) or vehicle. Significant inhibition of DNA adduct formation was found (tannic acid > pentagalloglucose > epigallocatechin gallate > epicatechin gallate). This notion was confirmed by analysis of the reaction products of anti-BPDE with the catechins and pentagalloglucose by electrospray ionization mass spectrometry and liquid chromatography–mass spectrometry. In conclusion, our data demonstrate that green tea catechins and the hydrolyzable tannins are highly effective in inhibiting BP–DNA adduct formation at least, in part, due to direct interaction of adjacent hydroxyl groups in their structures and that the activity is higher with an increasing

Enhanced uptake and transport of (+)-catechin and (−)-epigallocatechin gallate in niosomal formulation by human intestinal Caco-2 cells

PubMed Central

Song, Qinxin; Li, Danhui; Zhou, Yongzhi; Yang, Jie; Yang, Wanqi; Zhou, Guohua; Wen, Jingyuan

2014-01-01

The aim of this study was to evaluate (+)-catechin and (−)-epigallocatechin gallate (EGCG) cellular uptake and transport across human intestinal Caco-2 cell monolayer in both the absence and presence of niosomal carrier in variable conditions. The effect of free drugs and drug-loaded niosomes on the growth of Caco-2 cells was studied. The effects of time, temperature, and concentration on drug cellular uptake in the absence or presence of its niosomal delivery systems were investigated. The intestinal epithelial membrane transport of the drug-loaded niosomes was examined using the monolayer of the human Caco-2 cells. The kinetics of transport, and the effect of temperature, adenosine triphosphate inhibitor, permeability glycoprotein inhibitor, multidrug resistance-associated protein 2 inhibitor, and the absorption enhancer on transport mechanism were investigated. It was found that the uptake of catechin, EGCG, and their niosomes by Caco-2 cells was 1.22±0.16, 0.90±0.14, 3.25±0.37, and 1.92±0.22 μg/mg protein, respectively (n=3). The apparent permeability coefficient values of catechin, EGCG, and their niosomes were 1.68±0.16, 0.88±0.09, 2.39±0.31, and 1.42±0.24 cm/second (n=3) at 37°C, respectively. The transport was temperature- and energy-dependent. The inhibitors of permeability glycoprotein and multidrug resistance-associated protein 2 and the absorption enhancer significantly enhanced the uptake amount. Compared with the free drugs, niosomal formulation significantly enhanced drug absorption. Additionally, drug-loaded niosomes exhibited stronger stability and lower toxicity. These findings showed that the oral absorption of tea flavonoids could be improved by using the novel drug delivery systems. PMID:24855353

Green tea component EGCG, insulin and IGF-1 promote nuclear efflux of atrophy-associated transcription factor Foxo1 in skeletal muscle fibers.

PubMed

Wimmer, Robert J; Russell, Sarah J; Schneider, Martin F

2015-12-01

Prevention and slowing of skeletal muscle atrophy with nutritional approaches offers the potential to provide far-reaching improvements in the quality of life for our increasingly aging population. Here we show that polyphenol flavonoid epigallocatechin 3-gallate (EGCG), found in the popular beverage green tea (Camellia sinensis), demonstrates similar effects to the endogenous hormones insulin-like growth factor 1 (IGF-1) and insulin in the ability to suppress action of the atrophy-promoting transcription factor Foxo1 through a net translocation of Foxo1 out of the nucleus as monitored by nucleo-cytoplasmic movement of Foxo1-green fluorescent protein (GFP) in live skeletal muscle fibers. Foxo1-GFP nuclear efflux is rapid in IGF-1 or insulin, but delayed by an additional 30 min for EGCG. Once activated, kinetic analysis with a simple mathematical model shows EGCG, IGF-1 and insulin all produce similar apparent rate constants for Foxo1-GFP unidirectional nuclear influx and efflux. Interestingly, EGCG appears to have its effect at least partially via parallel signaling pathways that are independent of IGF-1's (and insulin's) downstream PI3K/Akt/Foxo1 signaling axis. Using the live fiber model system, we also determine the dose-response curve for both IGF-1 and insulin on Foxo1 nucleo-cytoplasmic distribution. The continued understanding of the activation mechanisms of EGCG could allow for nutritional promotion of green tea's antiatrophy skeletal muscle benefits and have implications in the development of a clinically significant parallel pathway for new drugs to target muscle wasting and the reduced insulin receptor sensitivity which causes type II diabetes mellitus. Copyright © 2015 Elsevier Inc. All rights reserved.

Anticandidal synergistic activity of green tea catechins, antimycotics and copper sulphate as a mean of combinational drug therapy against candidiasis.

PubMed

Anand, J; Rai, N

2017-03-01

The present investigation aims at evaluating synergistic herbal based composition of purified catechins with fluconazole, amphotericin B and copper sulphate against Candida albicans (MTCC 3017) and Candida glabrata (MTCC 3019). The catechins were isolated from green tea leaves of Assam, Himachal Pradesh and Uttarakhand regions of India. The synergistic activity of combinations against Candida species was assessed following microdilution checkerboard technique and time kill assay. The inhibitory action of most significant combination on treated Candida cells was assessed by scanning electron microscopy. Cytotoxicity of synergistic compositions was further analyzed by performing MTT assay on Vero cell lines. Purified catechins of Assam and Himachal Pradesh green tea showed synergistic activity with fluconazole and amphotericin B against Candida species. Time kill assay depicted synergistic activity at minimum inhibitory concentration and twice of minimum inhibitory concentration of purified catechins and antimycotics. Further, Copper sulphate increased anticandidal efficacy of synergistic combinations by 0.4% to 6.63%. SEM analysis revealed morphological distortions of treated Candida cells. Cytotoxicity analysis of synergistic composition depicted high percentage viability (≥91.4% to≥100%) of Vero cell line, which suggests non-cytotoxic activity of proposed composition on healthy cells. It can be inferred that present evaluated synergistic composition can confer promising anticandidal efficacy and requires further investigation of safety and translational guidelines for effective and safer green tea based potent therapeutic drug. Copyright © 2016. Published by Elsevier Masson SAS.

Direct scavenging of nitric oxide and superoxide by green tea.

PubMed

Nakagawa, T; Yokozawa, T

2002-12-01

In the present study, we investigated the free radical scavenging effects of green tea extract and green tea tannin mixture and its components using a nitric oxide (NO) and superoxide (O(2)(-)) generating system in vitro. Green tea extract showed direct scavenging activity against NO and O(2)(-) and green tea tannin mixture, at the same concentration, showed high scavenging activity. Comparison of the activities of seven pure compounds isolated from green tea tannin mixture showed that (-)-epigallocatechin 3-O-gallate (EGCg), (-)-gallocatechin 3-O-gallate (GCg) and (-)-epicatechin 3-O-gallate (ECg) had higher scavenging activities than (-)-epigallocatechin (EGC), (+)-gallocatechin (GC), (-)-epicatechin (EC) and (+)-catechin (C), showing the importance of the structure of flavan-3-ol linked to gallic acid for this activity. Among the gallate-free tannins, EGC and GC were more effective O(2)(-) scavengers than EC and C, indicating the O-trihydroxy structure in the B ring is an important determinant of such activity. However, this structure did not affect the NO scavenging activity. These findings confirm that green tea tannin has excellent antioxidant properties, which may be involved in the beneficial effect of this compound.

Y-27632 Increases Sensitivity of PANC-1 Cells to Epigallocatechin Gallate (EGCG) in Regulating Cell Proliferation and Migration

PubMed Central

Liu, Xing; Bi, Yongyi

2016-01-01

Background The study aimed to investigate the inhibitory effect of (1R,4r)-4-((R)-1-aminoethyl)-N-(pyridin-4-yl) cyclohexanecarboxamide (Y-27632) and (−)-epigallocatechin-3-gallate (EGCG) on the proliferation and migration of PANC-1 cells. EGCG, found in green tea, has been previously shown to be one of the most abundant and powerful catechins in cancer prevention and treatment. Y-27632, a selective inhibitor of rho-associated protein kinase 1, is widely used in treating cardiovascular disease, inflammation, and cancer. Material/Methods PANC-1 cells, maintained in Dulbecco’s Modified Eagle’s Medium, were treated with dimethyl sulfoxide (control) as well as different concentrations (20, 40, 60, and 80 μg/mL) of EGCG for 48 h. In addition, PANC-1 cells were treated separately with 60 μg/mL EGCG, 20 μM Y-27632, and EGCG combined with Y-27632 (60 μg/mL EGCG + 20 μM Y-27632) for 48 h. The effect of EGCG and Y-27632 on the proliferation and migration of PANC-1 cells was evaluated using Cell Counting Kit-8 and transwell migration assays. The expression of peroxisome proliferator–activated receptor alpha (PPARα) and Caspase-3 mRNA was determined by Quantitative real-time polymerase chain reaction (RT-qPCR). Results EGCG (20–80 μg/mL) inhibited cell viability in a dose-dependent manner. Y-27632 enhanced the sensitivity of PANC-1 cells to EGCG (by increasing the expression of PPARα and Caspase-3 mRNA) and suppressed cell proliferation. PANC-1 cell migration was inhibited by treatment with a combination of EGCG and Y-27632. Conclusions Y-27632 increases the sensitivity of PANC-1 cells to EGCG in regulating cell proliferation and migration, which is likely to be related to the expression of PPARα mRNA and Caspase-3 mRNA. PMID:27694793

Investigate the Binding of Catechins to Trypsin Using Docking and Molecular Dynamics Simulation

PubMed Central

Cui, Fengchao; Yang, Kecheng; Li, Yunqi

2015-01-01

To explore the inhibitory mechanism of catechins for digestive enzymes, we investigated the binding mode of catechins to a typical digestive enzyme-trypsin and analyzed the structure-activity relationship of catechins, using an integration of molecular docking, molecular dynamics simulation and binding free energy calculation. We found that catechins with different structures bound to a conservative pocket S1 of trypsin, which is comprised of residues 189–195, 214–220 and 225–228. In the trypsin-catechin complexes, Asp189 by forming strong hydrogen bonding, and Gln192, Trp215 and Gly216 through hydrophobic interactions, all significantly contribute to the binding of catechins. The number and the position of hydroxyl and aromatic groups, the structure of stereoisomers, and the orientation of catechins in the binding pocket S1 of trypsin all affect the binding affinity. The binding affinity is in the order of Epigallocatechin gallate (EGCG) > Epicatechin gallate (ECG) > Epicatechin (EC) > Epigallocatechin (EGC), and 2R-3R EGCG shows the strongest binding affinity out of other stereoisomers. Meanwhile, the synergic conformational changes of residues and catechins were also analyzed. These findings will be helpful in understanding the knowledge of interactions between catechins and trypsin and referable for the design of novel polyphenol based functional food and nutriceutical formulas. PMID:25938485

An in vitro evaluation of epigallocatechin gallate (eGCG) as a biocompatible inhibitor of ricin toxin.

PubMed

Dyer, Paul D R; Kotha, Arun K; Gollings, Alex S; Shorter, Susan A; Shepherd, Thomas R; Pettit, Marie W; Alexander, Bruce D; Getti, Giulia T M; El-Daher, Samer; Baillie, Les; Richardson, Simon C W

2016-07-01

The catechin, epigallocatechin gallate (eGCG), found in green tea, has inhibitory activity against a number of protein toxins and was investigated in relation to its impact upon ricin toxin (RT) in vitro. The IC(50) for RT was 0.08±0.004 ng/mL whereas the IC(50) for RT+100 μM eGCG was 3.02±0.572 ng/mL, indicating that eGCG mediated a significant (p<0.0001) reduction in ricin toxicity. This experiment was repeated in the human macrophage cell line THP-1 and IC(50) values were obtained for RT (0.54±0.024 ng/mL) and RT+100 μM eGCG (0.68±0.235 ng/mL) again using 100 μM eGCG and was significant (p=0.0013). The documented reduction in ricin toxicity mediated by eGCG was found to be eGCG concentration dependent, with 80 and 100 μg/mL (i.e. 178 and 223 μM respectively) of eGCG mediating a significant (p=0.0472 and 0.0232) reduction in ricin toxicity at 20 and 4 ng/ml of RT in Vero and THP-1 cells (respectively). When viability was measured in THP-1 cells by propidium iodide exclusion (as opposed to the MTT assays used previously) 10 ng/mL and 5 ng/mL of RT was used. The addition of 1000 μM and 100 μM eGCG mediated a significant (p=0.0015 and <0.0001 respectively) reduction in ricin toxicity relative to an identical concentration of ricin with 1 μg eGCG. Further, eGCG (100 μM) was found to reduce the binding of RT B chain to lactose-conjugated Sepharose as well as significantly (p=0.0039) reduce the uptake of RT B chain in Vero cells. This data suggests that eGCG may provide a starting point to refine biocompatible substances that can reduce the lethality of ricin. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Assessment of the polyphenolic composition of the organic extracts of Mauritian black teas: a potential contributor to their antioxidant functions.

PubMed

Luximon-Ramma, Amitabye; Neergheen, Vidushi S; Bahorun, Theeshan; Crozier, Alan; Zbarsky, Virginia; Datla, Krishna P; Dexter, David T; Aruoma, Okezie I

2006-01-01

There is increasing interest in the emerging view that tea improves the antioxidant status in vivo and thereby helps to lower risk of certain types of cancer, coronary heart disease and stroke and its component biofactors could provide prophylactic potential for these diseases. The polyphenolic composition and the antioxidant properties of organic extracts (acetone/methanol) of Mauritian commercial black teas were evaluated. HPLC data of the individual compounds revealed remarkably high levels (+)-Catechin ((+)-C), (-)-epicatechin ((-)-EC), (-)-epicatechin 3-gallate ((-)-ECG), (-)-epigallocatechin ((-)-EGC), (-)-epigallocatechin 3-gallate ((-)-EGCG) and gallic acid. Analysis of hydrolysed extracts indicated that quercetin was the dominant flavonol aglycone with traces of myricetin and kaempferol. Based on the Ferric Reducing Antioxidant Power (FRAP) and the Trolox Equivalent Antioxidant Capacity (TEAC) assays Extra tea from Bois Chéri exhibited the highest antioxidant potential. Linear regression analyses showed that the antioxidant capacities of the organic extracts are strongly influenced by total phenols (TEAC: r=0.95 and FRAP: r=0.96) and to a lesser extent by total proanthocyanidin and total flavonoid contents. Catechins and gallic acid seem to add up to the overall antioxidant capacity of black tea extracts. The fresh tea leaves had high levels of total phenols, total flavonoids, total proanthocyanidin and exhibited greater antioxidant potential when compared with black teas. Organic extracts of endemic teas represent useful source of phenolic antioxidants supplements for prophylactic use.

Effects of water-soluble natural antioxidants on photosensitized oxidation of conjugated linoleic acid in an oil-in-water emulsion system.

PubMed

Liu, T-T; Yang, T-S

2008-05-01

The effect of photosensitized oxidation of conjugated linoleic acid in an oil-in-water (o/w) emulsion system was studied. Water-soluble natural antioxidants, including apple polyphenols from apple extract, green tea extract, 4-hydroxy-2(or 5)-ethyl-5(or2)-methyl-3(2H)-furanone(HEMF), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), and ascorbic acid, were tested for antioxidant activity in this system. The green tea extract showed the highest antioxidant activity followed by ascorbic acid. Apple polyphenols did not give significant antioxidant activity. HEMF and HDMF exhibited a prooxidant effect. The antioxidant activity of tea catechins was also investigated. Of them, EGCG and ECG exhibited antioxidant activity at 50 ppm, but the antioxidant activity between them was not significantly different (P < 0.05). Comparatively, EC, EGC, and GCG showed no significant antioxidative effect at 50 ppm. When the concentration increased to 100 ppm, the antioxidant activity of ECG and EGCG significantly increased compared with that at 50 ppm, and EGCG had higher antioxidant activity than ECG. GCG also showed significant antioxidant activity at 100 ppm. EGCG exhibited the highest antioxidant activity among the tea catechins in the emulsion system at 100 ppm.

Epigallocatechin-3-gallate (EGCG) as a pro-osteogenic agent to enhance osteogenic differentiation of mesenchymal stem cells from human bone marrow: an in vitro study.

PubMed

Jin, Pan; Wu, Huayu; Xu, Guojie; Zheng, Li; Zhao, Jinmin

2014-05-01

The proliferation and osteogenic capacity of mesenchymal stem cells (MSCs) needs to be improved for their use in cell-based therapy for osteoporosis. (-)-Epigallocatechin-3-gallate (EGCG), one of the green tea catechins, has been widely investigated in studies of osteoblasts and osteoclasts. However, no consensus on its role as an osteogenic inducer has been reached, possibly because of the various types of cell lines examined and the range of concentrations of EGCG used. In this study, the osteogenic effects of EGCG are studied in primary human bone-marrow-derived MSCs (hBMSCs) by detecting cell proliferation, alkaline phosphatase (ALP) activity and the expression of relevant osteogenic markers. Our results show that EGCG has a strong stimulatory effect on hBMSCs developing towards the osteogenic lineage, especially at a concentration of 5 μM, as evidenced by an increased ALP activity, the up-regulated expression of osteogenic genes and the formation of bone-like nodules. Further exploration has indicated that EGCG directes osteogenic differentiation via the continuous up-regulation of Runx2. The underlying mechanism might involve EGCG affects on osteogenic differentiation through the modulation of bone morphogenetic protein-2 expression. EGCG has also been found to promote the proliferation of hBMSCs in a dose-dependent manner. This might be associated with its antioxidative effect leading to favorable amounts of reactive oxygen species in the cellular environment. Our study thus indicates that EGCG can be used as a pro-osteogenic agent for the stem-cell-based therapy of osteoporosis.

Direct enantioseparation of catechin and epicatechin in tea drinks by 6-O-alpha-D-glucosyl-beta-cyclodextrin-modified micellar electrokinetic chromatography.

PubMed

Kodama, Shuji; Yamamoto, Atsushi; Matsunaga, Akinobu; Yanai, Hiroko

2004-08-01

Cyclodextrin-modified micellar electrokinetic chromatography was applied to the enantioseparation of catechin and epicatechin using 6-O-alpha-D-glucosyl-beta-cyclodextrin together with sodium dodecyl sulfate and borate-phosphate buffer. Factors affecting chiral resolution and migration time of catechin and epicatechin were studied. The optimum running conditions were found to be 200 mM borate-20 mM phosphate buffer (pH 6.4) containing 25 mM 6-O-alpha-D-glucosyl-beta-cyclodextrin and 240 mM sodium dodecyl sulfate with an effective voltage of +25 kV at 20 degrees C using direct detection at 210 nm. Under these conditions, the resolution (Rs) of racemic catechin and epicatechin were 4.15 and 1.92, respectively. With this system, catechin and epicatechin enantiomers along with other four catechins ((-)-catechin gallate, (-)-epicatechin gallate, (-)-epigallocatechin, (-)-epigallocatechin gallate) and caffeine in tea samples were analyzed successfully. The difference of migration time between catechin and epicatechin is discussed.

Mechanism for the antibacterial action of epigallocatechin gallate (EGCg) on Bacillus subtilis.

PubMed

Nakayama, Motokazu; Shimatani, Kanami; Ozawa, Tadahiro; Shigemune, Naofumi; Tomiyama, Daisuke; Yui, Koji; Katsuki, Mao; Ikeda, Keisuke; Nonaka, Ai; Miyamoto, Takahisa

2015-01-01

Catechins are a class of polyphenols and have high anti-bacterial activity against various microorganisms. Here, we report the mechanism for antibacterial activity of epigallocatechin gallate (EGCg) against Gram-positive bacteria Bacillus subtilis, which is highly sensitive to EGCg. Transmission electron microscope analysis revealed that deposits containing EGCg were found throughout the cell envelope from the outermost surface to the outer surface of cytoplasmic membrane. Aggregating forms of proteins and EGCg were identified as spots that disappeared or showed markedly decreased intensity after the treatment with EGCg compared to the control by two-dimensional electrophoresis. Among the identified proteins included 4 cell surface proteins, such as oligopeptide ABC transporter binding lipoprotein, glucose phosphotransferase system transporter protein, phosphate ABC transporter substrate-binding protein, and penicillin-binding protein 5. Observations of glucose uptake of cells and cell shape B. subtilis after the treatment with EGCg suggested that EGCg inhibits the major functions of these proteins, leading to growth inhibition of B. subtilis.

Improving the effectiveness of (-)-epigallocatechin gallate (EGCG) against rabbit atherosclerosis by EGCG-loaded nanoparticles prepared from chitosan and polyaspartic acid.

PubMed

Hong, Zhiyong; Xu, Yongquan; Yin, Jun-Feng; Jin, Jianchang; Jiang, Yongwen; Du, Qizhen

2014-12-31

(-)-Epigallocatechin gallate (EGCG) is the major bioactive compound in green tea. Its effect is limited by the harsh environment of the gastrointestinal tract. The present study investigates how the effectiveness of EGCG is influenced by its encapsulation into self-assembled nanoparticles of chitosan (CS) and aspartic acid (PAA). Blank nanoparticles with a mean diameter of ca. 93 nm were prepared from 30-50 kDa PAA and 3-5 kDa CS with a mass rate of 1:1. EGCG was loaded in the nanoparticles to yield EGCG-CS-PAA nanoparticles with an average diameter of 102 nm, which were pH-responsive and demonstrated different EGCG release profiles in simulated gastrointestinal tract media. The average ratio (%) of lipid deposition for EGCG-CS-PAA nanoparticles administered orally to rabbits was 16.9 ± 5.8%, which was close to that of oral simvastatin (15.6 ± 4.1%). Orally administered EGCG alone yielded an average ratio of lipid deposit area of 42.1 ± 4.0%, whereas this value was 65.3 ± 10.8% for the blank nanoparticles. The effectiveness of EGCG against rabbit atherosclerosis was significantly improved by incorporating EGCG into the nanoformulation.

Catechin prodrugs and analogs: a new array of chemical entities with improved pharmacological and pharmacokinetic properties.

PubMed

Bansal, Sumit; Vyas, Sandeep; Bhattacharya, Shoumyo; Sharma, Manu

2013-10-11

Extensive research on tea catechins, mainly (-)-epigallocatechin gallate, has shown numerous health promoting effects. However, various clinical studies demonstrated several issues associated with tea catechins which account for their poor systemic bioavailability. In order to improve pharmacological activity and bioavailability of natural tea catechins, two major strategies have been adopted to date which include synthesizing catechin analogs/prodrugs and the development of novel drug delivery systems. In this review, we provide a detailed account of novel synthetic analogs/prodrugs as well as novel drug delivery approaches used for natural tea catechins to make them therapeutically potent drug-like molecules.

EGCG assisted green synthesis of ZnO nanopowders: Photodegradative, antimicrobial and antioxidant activities

NASA Astrophysics Data System (ADS)

Suresh, D.; Udayabhanu; Nethravathi, P. C.; Lingaraju, K.; Rajanaika, H.; Sharma, S. C.; Nagabhushana, H.

2015-02-01

Zinc oxide nanopowders were synthesized by solution combustion method using Epigallocatechin gallate (EGCG) a tea catechin as fuel. The structure and morphology of the product was characterized by Powder X-ray Diffraction, Scanning Electron Microscopy, photoluminescence and UV-Visible spectroscopy. The nanopowders (Nps) were subjected to photocatalytic and biological activities such as antimicrobial and antioxidant studies. PXRD patterns demonstrate that the formed product belongs to hexagonal wurtzite system. SEM images show that the particles are agglomerated to form sponge like structure and the average crystallite sizes were found to be ∼10-20 nm. PL spectra exhibit broad and strong peak at 590 nm due to the Zn-vacancies, and O-vacancies. The prepared ZnO Nps exhibit excellent photocatalytic activity for the photodegradation of malachite green (MG) and methylene blue (MB) indicating that the ZnO NPs are potential photocatalytic semiconductor materials. ZnO NPs exhibit significant bactericidal activity against Klebsiella aerogenes, Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus using the agar well diffusion method. Furthermore, the ZnO nano powders show good antioxidant activity by potentially scavenging DPPH radicals. The study successfully demonstrates synthesis of ZnO NPs by simple ecofriendly route employing EGCG as fuel that exhibit superior photodegradative, antibacterial and antioxidant activities.

Green tea extract for periodontal health

PubMed Central

Venkateswara, Babu; Sirisha, K.; Chava, Vijay K.

2011-01-01

Tea, the commonly consumed beverage, is gaining increased attention in promoting overall health. In specific, green tea is considered a healthful beverage due to the biological activity of its polyphenols namely catechins. Among the polyphenols Epigallo catechin 3 gallate and Epicatechin 3 Gallate are the most predominant catechins. The antioxidant, antimicrobial, anticollagenase, antimutagenic, and c hemopreventive properties of these catechins proved to be helpful in the treatment of chronic diseases like periodontal disease. Studies have demonstrated that the type of processing mainly effects the concentration of catechins. Several epidemiological studies have proved that green tea also has some general health benefitting properties like antihypertensive, reduction of cardiovascular risk, antibacterial, antiviral, and antifungal activity. The present review concentrates on the effects of green tea in periodontal and general health. PMID:21772716

Polyphenols and Prostate Cancer Chemoprevention

DTIC Science & Technology

2005-03-01

ABSTRACT (Maximum 200 Words) The goal of this research is to Investigate the potential of (-)- epigallocatechin -3- gallate ( EGCG ), genistein and resveratrol...prostate chemoprevention are the soy isoflavone, genistein, and the tea catechin, (-)- epigallocatechin -3- gallate ( EGCG ). Another polyphenol that has...adenocarcinoma (TRAMP)). The specific aims are 1) to investigate the potential of genistein, EGCG and resveratrol, alone and in combination, to

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

PubMed

Liao, Zih-Hui; Chen, Ying-Jie; Tzen, Jason Tze-Cheng; Kuo, Ping-Chung; Lee, Maw-Rong; Mai, Fu-Der; Rairat, Tirawat; Chou, Chi-Chung

2018-01-01

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. 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. 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. © 2017 Society of Chemical Industry.

The efficacy of early treatment of seasonal allergic rhinitis with benifuuki green tea containing O-methylated catechin before pollen exposure: an open randomized study.

PubMed

Maeda-Yamamoto, Mari; Ema, Kaori; Monobe, Manami; Shibuichi, Ikuo; Shinoda, Yuki; Yamamoto, Tomohiro; Fujisawa, Takao

2009-09-01

We previously reported that 'benifuuki' green tea containing O-methylated catechin significantly relieved the symptoms of perennial or seasonal rhinitis compared with a placebo green tea that did not contain O-methylated catechin in randomized double-blind clinical trials. In this study we assessed the effects of 'benifuuki' green tea on clinical symptoms of seasonal allergic rhinitis. An open-label, single-dose, randomized, parallel-group study was performed on 38 subjects with Japanese cedar pollinosis. The subjects were randomly assigned to long-term (December 27, 2006-April 8, 2007, 1.5 months before pollen exposure) or short-term (February 15, 2007: after cedar pollen dispersal--April 8, 2007) drinking of a 'benifuuki' tea drink containing 34 mg O-methylated catechin per day. Each subject recorded their daily symptom scores in a diary. The primary efficacy variable was the mean weekly nasal symptom medication score during the study period. The nasal symptom medication score in the long-term intake group was significantly lower than that of the short-term intake group at the peak of pollen dispersal. The symptom scores for throat pain, nose-blowing, tears, and hindrance to activities of daily living were significantly better in the long-term group than the short-term group. In particular, the differences in the symptom scores for throat pain and nose-blowing between the 2 groups were marked. We conclude that drinking 'benifuuki' tea for 1.5 months prior to the cedar pollen season is effective in reducing symptom scores for Japanese cedar pollinosis.

[Protection and its mechanism of catechin morphon on hypoxia-reoxygenation [corrected] induced injury in myocardial cells].

PubMed

Ye, Jin-Xia; Wang, Lan; Liang, Ri-Xin; Yang, Bin

2008-04-01

To observe the protective effects of catechin morphon (GCG and EGCG) on hypoxia-reoxygenation induced injury in myocardial cells and to explore the mechanisms. In cultured neonatal rat cardiomyocytes, we investigated the preconditioning protection by GCG and EGCG on the spontaneous beating, the survival rate, the release of LDH, MDA, SOD, GSH-Px and the ATP enzyme activity of cardiomyocyte cellular membrane in cultured rat cardiomyocytes treated during the reoxygenation 1h following hypoxia 3 h. The blocking agent of protien kinase C staurosporine (10 nmol x L(-1)) or the deactivator of Gi/o protein pertussis toxin (PTX, 200 microg x mL(-1)) were added before the catechin treatment. Preconditioning by GCG and EGCG increased the spontaneous beating and the survival rate, and decreased the release of LDH and MDA with the rise of SOD and ATP enzyme activity. Inhibition of PKC by staurosporine and Gi/o protein by PTX abolished the protection by catechin with the reduction of the beating, survival rate and activity of SOD, and the increase of the release of LDH and MDA. The results indicated that the activation of signal transduction pathway from PKC and Gi/o protein seemed to be involved in the cardioprotection of preconditioning by GCG and EGCG. The protection by GCG and EGCG on hypoxia-reoxygenation injury in cultured neonatal rat cardiomyocytes is found, which is related with scavenging of free radicals, and PKC Gi/o signal transduction pathway.

Protection of brain and pancreas from high-fat diet: effects of catechin and caffeine.

PubMed

Unno, Keiko; Yamamoto, Hiroyuki; Maeda, Ken-Ichi; Takabayashi, Fumiyo; Yoshida, Hirotoshi; Kikunaga, Naomi; Takamori, Nina; Asahina, Shunsuke; Iguchi, Kazuaki; Sayama, Kazutoshi; Hoshino, Minoru

2009-02-16

To investigate the effect of a high-fat diet on brain and pancreas functions, we used SAMP10 mice that have characteristics of brain atrophy and cognitive dysfunction with aging. Simultaneously, we investigated the effect of green tea catechin consumption on high-fat diet feeding, because green tea catechin has been reported to improve brain atrophy, brain dysfunction and obesity. The body weight of mice fed a high-fat diet from 2 to 12 months was higher than that of the control, although the calorie intake was not. The high-fat diet also increased insulin secretion; however, the hypersecretion of insulin and obesity were suppressed when mice were fed a high-fat diet with green tea catechin and caffeine. Furthermore, brain atrophy was suppressed and the working memory, tested using Y-maze, improved in mice fed a high-fat diet containing green tea catechin and caffeine. The secretion of insulin might affect both obesity and brain function. A strong correlation was found between working memory and insulin release in mice fed a high-fat diet with green tea catechin and/or caffeine. The results indicate the protective effect of green tea catechin and caffeine on the functions of brain and pancreas in mice fed a high-fat diet.

Green Tea Polyphenols and Metabolites in Prostatectomy Tissue: Implications for Cancer Prevention

PubMed Central

Wang, Piwen; Aronson, William J.; Huang, Min; Zhang, Yanjun; Lee, Ru-Po; Heber, David; Henning, Susanne M.

2011-01-01

Epidemiologic, preclinical, and clinical trials suggest that green tea (GT) consumption may prevent prostate cancer via the action of green tea polyphenols including (-)-epigallocatechin-3-gallate (EGCG). In order to study the metabolism and bioactivity of green tea polyphenols in human prostate tissue, men with clinically localized prostate cancer consumed 6 cups of GT (n=8) daily or water (n=9) for 3-6 weeks prior to undergoing radical prostatectomy. Using high performance liquid chromatography 4″-O-methyl EGCG (4″-MeEGCG) and EGCG were identified in comparable amounts, and (-)-epicatechin-3-gallate (ECG) in lower amounts in prostatectomy tissue from men consuming GT (38.9 ± 19.5, 42.1 ± 32.4, and 17.8 ± 10.1 pmol/g tissue, respectively). The majority of EGCG and other green tea polyphenols were not conjugated. Green tea polyphenols were not detected in prostate tissue or urine from men consuming water preoperatively. In the urine of men consuming GT, 50-60% of both (-)-epigallocatechin (EGC) and (-)-epicatechin were present in methylated form with 4′-O-MeEGC being the major methylated form of EGC. When incubated with EGCG LNCaP prostate cancer cells were able to methylate EGCG to 4″-MeEGCG. The capacity of 4″-MeEGCG to inhibit proliferation and NF-κB activation and induce apoptosis in LNCaP cells was decreased significantly compared to EGCG. In summary, methylated and non-methylated forms of EGCG are detectable in prostate tissue following a short-term GT intervention and the methylation status of EGCG may potentially modulate its preventive impact on prostate cancer, possibly based on genetic polymorphisms of catechol O-methyltransferase. PMID:20628004

Effect of green tea catechin, a local drug delivery system as an adjunct to scaling and root planing in chronic periodontitis patients: A clinicomicrobiological study

PubMed Central

Kudva, Praveen; Tabasum, Syeda Tawkhira; Shekhawat, Nirmal Kanwar

2011-01-01

Background: Evaluate the adjunctive use of locally delivered green tea catechin with scaling and root planing, as compared to scaling and root planing alone in the management of chronic periodontitis. Materials and Methods: Fourteen patients with two sites in the contralateral quadrants with probing pocket depth of 5–8mm were selected. Each of the sites was assessed for the plaque index, gingival index, and probing pocket depth at baseline and 21 days and for microbiological analysis at baseline, 1 week and 21 days. Test sites received scaling and root planing along with green tea catechin strips and control sites received scaling and root planning alone. Results: The result showed intercomparison of the plaque index and gingival index for test and control groups at 21 days was not significant with P>0.05, whereas the probing depth at 21 days was significant with P<0.001. Intercomparison between microbial results demonstrated a considerable reduction of occurrence of Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Fusobacterium species and Capnocytophaga in test. Conclusion: Green tea catechin local delivery along with scaling and root planing is more effective than scaling and root planing alone. PMID:21772720

Self-assembly of green tea catechin derivatives in nanoparticles for oral lycopene delivery.

PubMed

Li, Weikun; Yalcin, Murat; Lin, Qishan; Ardawi, Mohammed-Salleh M; Mousa, Shaker A

2017-02-28

Lycopene is a natural anti-oxidant that has attracted much attention due to its varied applications such as protection against loss of bone mass, chronic diseases, skin cancer, prostate cancer, and cardiovascular disease. However, high instability and extremely low oral bioavailability limit its further clinical development. We selected a green tea catechin derivative, oligomerized (-)-epigallocatechin-3-O-gallate (OEGCG) as a carrier for oral lycopene delivery. Lycopene-loaded OEGCG nanoparticles (NPs) were prepared by a nano-precipitation method, followed by coating with chitosan to form a shell. This method not only can easily control the size of the NP to be around 200nm to improve its bioavailability, but also can effectively protect the lycopene against degradation due to EGCG's anti-oxidant property. OEGCG was carefully characterized with nuclear magnetic resonance spectroscopy and mass spectrometry. Lycopene-loaded polylactic-co-glycolic acid (PLGA) NPs were prepared by the same method. Chitosan-coated OEGCG/lycopene NPs had a diameter of 152±32nm and a ζ-potential of 58.3±4.2mv as characterized with transmission electron microscopy and dynamic light scattering. The loading capacity of lycopene was 9% and encapsulation efficiency was 89%. FT-IR spectral analysis revealed electrostatic interaction between OEGCG and chitosan. Freeze drying of the NPs was also evaluated as a means to improve shelf life. Dynamic light scattering data showed that no aggregation occurred, and the size of the NP increased 1.2 times (S f /S i ratio) in the presence of 10% sucrose after freeze drying. The in vitro release study showed slow release of lycopene in simulated gastric fluid at acidic pH and faster release in simulated intestinal fluid. In an in vivo study in mice, lycopene pharmacokinetic parameters were improved by lycopene/OEGCG/chitosan NPs, but not improved by lycopene/PLGA/chitosan NPs. The self-assembled nanostructure of OEGCG combined with lycopene may be a

Dynamic calibration approach for determining catechins and gallic acid in green tea using LC-ESI/MS.

PubMed

Bedner, Mary; Duewer, David L

2011-08-15

Catechins and gallic acid are antioxidant constituents of Camellia sinensis, or green tea. Liquid chromatography with both ultraviolet (UV) absorbance and electrospray ionization mass spectrometric (ESI/MS) detection was used to determine catechins and gallic acid in three green tea matrix materials that are commonly used as dietary supplements. The results from both detection modes were evaluated with 14 quantitation models, all of which were based on the analyte response relative to an internal standard. Half of the models were static, where quantitation was achieved with calibration factors that were constant over an analysis set. The other half were dynamic, with calibration factors calculated from interpolated response factor data at each time a sample was injected to correct for potential variations in analyte response over time. For all analytes, the relatively nonselective UV responses were found to be very stable over time and independent of the calibrant concentration; comparable results with low variability were obtained regardless of the quantitation model used. Conversely, the highly selective MS responses were found to vary both with time and as a function of the calibrant concentration. A dynamic quantitation model based on polynomial data-fitting was used to reduce the variability in the quantitative results using the MS data.

Physiological effects of epigallocatechin-3-gallate (EGCG) on energy expenditure for prospective fat oxidation in humans: A systematic review and meta-analysis.

PubMed

Kapoor, Mahendra P; Sugita, Masaaki; Fukuzawa, Yoshitaka; Okubo, Tsutomu

2017-05-01

Green tea catechins (GTCs) are known to improve fat oxidation (FOX) during fasted, rested and exercise conditions wherein epigallocatechin-3-gallate (EGCG) is thought to be the most pharmacologically active and has been studied extensively. From the available data of randomized controlled trials (RCTs) on EGCG, we carried out a systematic review and meta-analysis to elucidate whether EGCG consumption indeed increase energy expenditure (EE) and promote FOX. A systematic review of the literature was conducted using electronic databases (PubMed, Embase, Cochrane Library, CINAHL, JICST, JSTPLUS, and JMEDPLUS and others) and eight RCTs were included. RCTs were reviewed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and methodological quality was assessed. After data extraction, results were aggregated using fixed- and random-effect approaches and expressed to quantify the relationship between the dose of EGCG for respiratory quotient (RQ), EE and rate of FOX to compare the EGCG and placebo treatments. The meta-analysis results of verities of studies in terms of dose and length of duration revealed that EGCG supplementation provided significant mean difference (MD) when compared with placebo for RQ [MD: -0.02; 95% confidence intervals (95% CI), -0.04 to 0.00; I 2 =67%; P=.01] and EE [MD: 158.05 kJ/day; 95% CI, 4.72 to 311.38; I 2 =0%; P=.04] in fixed-effect approach. Changes in FOX did not reach the level of statistical significance. Meta-analyses of EGCG influence on the body mass index, waist circumference and total body fat mass (TBFM) were also examined and their impact on the promotion of FOX is reported. Effect of EGCG doses was also systematically reviewed. Finding showed that EGCG intake moderately accelerates EE and reduces RQ. The analyses revealed that the EGCG resulted in difference in RQ and EE but the effect on the other measures of energy metabolism was relatively mild. Possibly, EGCG alone has the potential to increase

Biophysical characteristics of proteins and living cells exposed to the green tea polyphenol epigallocatechin-3-gallate (EGCg): review of recent advances from molecular mechanisms to nanomedicine and clinical trials.

PubMed

Peter, Beatrix; Bosze, Szilvia; Horvath, Robert

2017-01-01

Herbs and traditional medicines have been applied for thousands of years, but researchers started to study their mode of action at the molecular, cellular and tissue levels only recently. Nowadays, just like in ancient times, natural compounds are still determining factors in remedies. To support this statement, the recently won Nobel Prize for an anti-malaria agent from the plant sweet wormwood, which had been used to effectively treat the disease, could be mentioned. Among natural compounds and traditional Chinese medicines, the green tea polyphenol epigallocatechin gallate (EGCg) is one of the most studied active substances. In the present review, we summarize the molecular scale interactions of proteins and EGCg with special focus on its limited stability and antioxidant properties. We outline the observed biophysical effects of EGCg on various cell lines and cultures. The alteration of cell adhesion, motility, migration, stiffness, apoptosis, proliferation as well as the different impacts on normal and cancer cells are all reviewed. We also handle the works performed using animal models, microbes and clinical trials. Novel ways to develop its utilization for therapeutic purposes in the future are discussed too, for instance, using nanoparticles and green tea polyphenols together to cure illnesses and the combination of EGCg and anticancer compounds to intensify their effects. The limitations of the employed experimental models and criticisms of the interpretation of the obtained experimental data are summarized as well.

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

PubMed

Sapper, Teryn N; Mah, Eunice; Ahn-Jarvis, Jennifer; McDonald, Joshua D; Chitchumroonchokchai, Chureeporn; Reverri, Elizabeth J; Vodovotz, Yael; Bruno, Richard S

2016-09-14

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.

Human clinical studies of tea polyphenols in allergy or life style-related diseases.

PubMed

Maeda-Yamamoto, Mari

2013-01-01

Many previous epidemiological studies have revealed that green tea or green tea catechins contributed to the preveintion of lifestyle-related diseases. Several cohort studies on the relationship between green tea consumption and cardiovascular disease (CVD) risk/type 2 diabetes mellitus risk have been conducted. The results showed that green tea consumption (5 or more cups/day) was inversely associated with mortality from CVD and all causes. Within CVD mortality, the strongest inverse association was observed for stroke mortality. Furthermore, consumption of green tea, coffee, and total caffeine was associated with a reduced risk for type 2 diabetes. On the other hand, the analysis of randomized clinical trial (RCT) studies showed that the administration of green tea beverages or extracts resulted in significant reductions in serum total cholesterol and LDL-cholesterol concentrations, but had no apparent effect on HDL-cholesterol. Green tea reduced fasting blood glucose levels in a small intervention trial, although no improvements in HbA1c levels were seen. Continuous intake of green tea containing catechins and caffeine (5 or more cups per day) may be beneficial for body weight management, vascular disease risk reduction via LDL-cholesterol improvement, and type 2 diabetes risk reduction through the lowering of fasting blood glucose levels. Epigallocatechin-3-O-(3-O-methyl) gallate (EGCG3"Me) isolated from cv. "Benifuuki" green tea has been shown to strongly inhibit mast cell activation and histamine release after FcepsilonRI cross-linking through the suppression of tyrosine phosphorylation (Lyn) of cellular protein kinase, and the suppression of myosin light chain phosphorylation and high-affinity IgE receptor expression via the binding to 67 kDa laminin receptors. A double-blind clinical study on subjects with Japanese cedar pollinosis was carried out. At the eleventh week after starting intake, which was coincident with the most severe period of cedar pollen

Epigallocatechin-3-gallate(EGCG) : mechanisms and the combined applications.

PubMed

Song, Xuekun; Du, Juan; Zhao, Wenyuan; Guo, Zheng

2017-12-17

EGCG is the most important pharmacological component in tea. Researches have confirmed its effects, including anti-tumor, anti-inflammation, anti-aging, anti-obesity, anti-diabetic, cardiovascular disease prevention and protection, immunoregulation and neuroprotection. Paradoxically, the clinical application of EGCG is very rare. One of the most important reasons is its poor stability and low bioavailability. Excepting for altering the dosage form or synthesizing the analogues to overcome the loss during absorption, an increasing number of studies indicate that EGCG can exert certain auxiliary effect and enhance chemosensitivity in combined medication. The pharmacological action, the pharmacology network including mutation of signaling receptor and modulation of intracellular signaling pathway, and the combination treatment strategy of EGCG are clarified and sorted out, both the possible targets and combinatorial applications based on the characteristics of EGCG are systematically summarized. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Beneficial effects of dietary EGCG and voluntary exercise on behavior in an Alzheimer's disease mouse model.

PubMed

Walker, Jennifer M; Klakotskaia, Diana; Ajit, Deepa; Weisman, Gary A; Wood, W Gibson; Sun, Grace Y; Serfozo, Peter; Simonyi, Agnes; Schachtman, Todd R

2015-01-01

Alzheimer's disease (AD) is a progressive, age-dependent neurodegenerative disorder affecting specific brain regions that control memory and cognitive functions. Epidemiological studies suggest that exercise and dietary antioxidants are beneficial in reducing AD risk. To date, botanical flavonoids are consistently associated with the prevention of age-related diseases. The present study investigated the effects of 4 months of wheel-running exercise, initiated at 2-months of age, in conjunction with the effects of the green tea catechin (-)-epigallocatechin-3-gallate (EGCG) administered orally in the drinking water (50 mg/kg daily) on: (1) behavioral measures: learning and memory performance in the Barnes maze, nest building, open-field, anxiety in the light-dark box; and (2) soluble amyloid-β (Aβ) levels in the cortex and hippocampus in TgCRND8 (Tg) mice. Untreated Tg mice showed hyperactivity, relatively poor nest building behaviors, and deficits in spatial learning in the Barnes maze. Both EGCG and voluntary exercise, separately and in combination, were able to attenuate nest building and Barnes maze performance deficits. Additionally, these interventions lowered soluble Aβ1-42 levels in the cortex and hippocampus. These results, together with epidemiological and clinical studies in humans, suggest that dietary polyphenols and exercise may have beneficial effects on brain health and slow the progression of AD.

Differential prooxidative effects of the green tea polyphenol, (-)-epigallocatechin-3-gallate, in normal and oral cancer cells are related to differences in sirtuin 3 signaling.

PubMed

Tao, Ling; Park, Jong-Yung; Lambert, Joshua D

2015-02-01

We have previously reported that the green tea catechin, (-)-epigallocatechin-3-gallate (EGCG), can induce oxidative stress in oral cancer cells but exerts antioxidant effects in normal cells. Here, we report that these differential prooxidative effects are associated with sirtuin 3 (SIRT3), an important mitochondrial redox modulator. EGCG rapidly induced mitochondria-localized reactive oxygen species in human oral squamous carcinoma cells (SCC-25, SCC-9) and premalignant leukoplakia cells (MSK-Leuk1), but not in normal human gingival fibroblast cells (HGF-1). EGCG suppressed SIRT3 mRNA and protein expression, as well as, SIRT3 activity in SCC-25 cells, whereas it increased SIRT3 activity in HGF-1 cells. EGCG selectively decreased the nuclear localization of the estrogen-related receptor α (ERRα), the transcription factor regulating SIRT3 expression, in SCC-25 cells. This indicates that EGCG may regulate SIRT3 transcription in oral cancer cells via ERRα. EGCG also differentially modulated the mRNA expressions of SIRT3-associated downstream targets including glutathione peroxidase 1 and superoxide dismutase 2 in normal and oral cancer cells. SIRT3 represents a novel potential target through which EGCG exerts differential prooxidant effects in cancer and normal cells. Our results provide new biomarkers to be further explored in animal studies. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determining the Effect of Catechins on SOD1 Conformation and Aggregation by Ion Mobility Mass Spectrometry Combined with Optical Spectroscopy

NASA Astrophysics Data System (ADS)

Zhao, Bing; Zhuang, Xiaoyu; Pi, Zifeng; Liu, Shu; Liu, Zhiqiang; Song, Fengrui

2018-02-01

The aggregation of Cu,Zn-superoxide dismutase (SOD1) plays an important role in the etiology of amyotrophic lateral sclerosis (ALS). For the disruption of ALS progression, discovering new drugs or compounds that can prevent SOD1 aggregation is important. In this study, ESI-MS was used to investigate the interaction of catechins and SOD1. The noncovalent complex of catechins that interact with SOD1 was found and retained in the gas phase under native ESI-MS condition. The conformation changes of SOD1 after binding with catechins were also explored via traveling wave ion mobility (IM) spectrometry. Epigallocatechin gallate (EGCG) can stabilize SOD1 conformation against unfolding in three catechins. To further evaluate the efficacy of EGCG, we monitored the fluorescence changes of dimer E2,E2,-SOD1(apo-SOD1, E:empty) with and without ligands under denaturation conditions, and found that EGCG can inhibit apo-SOD1 aggregation. In addition, the circular dichroism spectra of the samples showed that EGCG can decrease the β-sheet content of SOD1, which can produce aggregates. These results indicated that orthogonal separation dimension in the gas-phase IM coupled with ESI-MS (ESI-IM-MS) can potentially provide insight into the interaction between SOD1 and small molecules. The advantage is that it dramatically decreases the analysis time. Meantime, optical spectroscopy techniques can be used to confirm ESI-IM-MS results. [Figure not available: see fulltext.

Separation of catechins and methylxanthines in tea samples by capillary electrochromatography.

PubMed

Uysal, Ulku Dilek; Aturki, Zeineb; Raggi, Maria Augusta; Fanali, Salvatore

2009-04-01

In this paper, the simultaneous separation of several polyphenols such as (+)-catechin, (-)-epicatechin, (-)-epigallocatechin, theophylline, caffeine in green and black teas by capillary electrochromatography (CEC) was developed. Several experimental parameters such as stationary phase type, mobile phase composition, buffer and pH, inner diameter of the columns, sample injection, were evaluated to obtain the complete separation of the analysed compounds. Baseline resolution of the studied polyphenols was achieved within 30 min by using a capillary column (id 100 microm) packed with bidentate C(18) particles for 24.5 cm and a mobile phase composed of 5 mM ammonium acetate buffer pH 4 with H(2)O/ACN (80:20, v/v). The applied voltage and the temperature were set at 30 kV and 20 degrees C. Precision, detection and quantification limits, linearity, and accuracy were investigated. A good linearity (R(2) > 0.9992) was achieved over a concentration working range of 2-100 microg/mL for all the analytes. LOD and LOQ were 1 and 2 microg/mL, respectively, for all studied compounds. The CEC method was applied to the analysis of those polyphenols in green and black tea samples after an extraction procedure. Good recovery data from accuracy studies ranged between 90% and 112% for all analytes.

Tea polyphenols dominate the short-term tea (Camellia sinensis) leaf litter decomposition*

PubMed Central

Fan, Dong-mei; Fan, Kai; Yu, Cui-ping; Lu, Ya-ting; Wang, Xiao-chang

2017-01-01

Polyphenols are one of the most important secondary metabolites, and affect the decomposition of litter and soil organic matter. This study aims to monitor the mass loss rate of tea leaf litter and nutrient release pattern, and investigate the role of tea polyphenols played in this process. High-performance liquid chromatography (HPLC) and classical litter bag method were used to simulate the decomposition process of tea leaf litter and track the changes occurring in major polyphenols over eight months. The release patterns of nitrogen, potassium, calcium, and magnesium were also determined. The decomposition pattern of tea leaf litter could be described by a two-phase decomposition model, and the polyphenol/N ratio effectively regulated the degradation process. Most of the catechins decreased dramatically within two months; gallic acid (GA), catechin gallate (CG), and gallocatechin (GC) were faintly detected, while others were outside the detection limits by the end of the experiment. These results demonstrated that tea polyphenols transformed quickly and catechins had an effect on the individual conversion rate. The nutrient release pattern was different from other plants which might be due to the existence of tea polyphenols. PMID:28124839

Tea polyphenols dominate the short-term tea (Camellia sinensis) leaf litter decomposition.

PubMed

Fan, Dong-Mei; Fan, Kai; Yu, Cui-Ping; Lu, Ya-Ting; Wang, Xiao-Chang

Polyphenols are one of the most important secondary metabolites, and affect the decomposition of litter and soil organic matter. This study aims to monitor the mass loss rate of tea leaf litter and nutrient release pattern, and investigate the role of tea polyphenols played in this process. High-performance liquid chromatography (HPLC) and classical litter bag method were used to simulate the decomposition process of tea leaf litter and track the changes occurring in major polyphenols over eight months. The release patterns of nitrogen, potassium, calcium, and magnesium were also determined. The decomposition pattern of tea leaf litter could be described by a two-phase decomposition model, and the polyphenol/N ratio effectively regulated the degradation process. Most of the catechins decreased dramatically within two months; gallic acid (GA), catechin gallate (CG), and gallocatechin (GC) were faintly detected, while others were outside the detection limits by the end of the experiment. These results demonstrated that tea polyphenols transformed quickly and catechins had an effect on the individual conversion rate. The nutrient release pattern was different from other plants which might be due to the existence of tea polyphenols.

Zinc ion enhances GABA tea-mediated oxidative DNA damage.

PubMed

Chuang, Show-Mei; Wang, Hsueh-Fang; Hsiao, Ching-Chuan; Cherng, Shur-Hueih

2012-02-15

GABA tea is a tea product that contains a high level of γ-aminobutyric acid (GABA). Previous study has demonstrated a synergistic effect of GABA tea and copper ions on DNA breakage. This study further explored whether zinc (Zn), a nonredox metal, modulated DNA cleavage induced by GABA tea extract. In a cell-free system, Zn(2+) significantly enhanced GABA tea extract and (-)-epigallocatechin-3-gallate (EGCG)- or H(2)O(2)-induced DNA damage at 24 h of incubation. Additionally, low dosages of GABA tea extract (1-10 μg/mL) possessed pro-oxidant activity to increase H(2)O(2)/Zn(2+)-induced DNA cleavage in a dose-dependent profile. By use of various reactive oxygen scavengers, it was observed that glutathione, catalase, and potassium iodide effectively inhibited DNA degradation caused by the GABA tea extract/H(2)O(2)/Zn(2+) system. Moreover, the data showed that the GABA tea extract itself (0.5-5 mg/mL) could induce DNA cleavage in a long-term exposure (48 h). EGCG, but not the GABA tea extract, enhanced H(2)O(2)-induced DNA cleavage. In contrast, GABA decreased H(2)O(2)- and EGCG-induced DNA cleavage, suggesting that GABA might contribute the major effect on the antioxidant activity of GABA tea extract. Furthermore, a comet assay revealed that GABA tea extract (0.25 mg/mL) and GABA had antioxidant activity on H(2)O(2)-induced DNA breakage in human peripheral lymphocytes. Taken together, these findings indicate that GABA tea has the potential of both pro-oxidant and antioxidant. It is proposed that a balance between EGCG-induced pro-oxidation and GABA-mediated antioxidation may occur in a complex mixture of GABA tea extract.

Role of catechins on ET-1 induced stimulation of PLD and NADPH oxidase activities in pulmonary smooth muscle cells: Determination of the probable mechanism by molecular docking studies.

PubMed

Chakraborti, Sajal; Sarkar, Jaganmay; Bhuyan, Rajabrata; Chakraborti, Tapati

2017-12-05

Treatment of human pulmonary artery smooth muscle cells with ET-1 stimulated PLD and NADPH oxidase activities, which were inhibited upon pretreatment with bosentan (ET-1 receptor antagonist), FIPI (PLD inhibitor), apocynin (NADPH oxidase inhibitor) and EGCG & ECG (catechins having galloyl group), but not EGC & EC (catechins devoid of galloyl group). Herein, we determined the probable mechanism by which the galloyl group containing catechins inhibit ET-1 induced stimulation of PLD activity by molecular docking analyses based on our biochemical studies. ET-1 induced stimulation of PLD activity was inhibited by SecinH3 (inhibitor of cytohesin). Arf-6 and cytohesin-1 were associated in the cell membrane, which was not inhibited by the catechins during ET-1 treatment to the cells. However, EGCG and ECG inhibited binding of GTPγS with Arf-6 even in presence of cytohesin-1. The molecular docking analyses revealed that the galloyl group containing catechins (EGCG/ECG) with cytohesin1-Arf6GDP, but not the non-galloyl-containing catechins (EGC and EC), prevents GDP/GTP exchange in Arf-6 which seems to be an important mechanism for inhibition of ET-1 induced activation of PLD and subsequently increase in NADPH oxidase activities.

Fish Oil Supplementation and Fatty Acid Synthase Expression in the Prostate: A Randomized Controlled Trial

DTIC Science & Technology

2008-03-01

green tea catechin, epigallocatechin -3- gallate ( EGCG ), is the fatty acid synthase (FAS) pathway. FAS, a lipogenic multienzyme that catalyzes the final...severity. Both EGCG and ω-3 FA have been shown in vitro and in vivo to inhibit this overexpression of FAS. Plan: The primary objective or our...proposal is to elucidate in men at high risk for prostate cancer, a potential biologic mechanism whereby EGCG , alone or in combination with ω-3 FA

Immunomodulating effect of epigallocatechin-3-gallate from green tea: mechanisms and applications

USDA-ARS?s Scientific Manuscript database

Consuming green tea or its active ingredient, epigallocatechin 3-gallate (EGCG), has been shown consistently to benefit the healthy functioning of several body systems. In the immune system specifically, accumulating evidence has revealed an immunomodulating effect of green tea/EGCG. Several types ...

Tea component, epigallocatechin gallate, potentiates anticataleptic and locomotor-sensitizing effects of caffeine in mice.

PubMed

Kasture, Sanjay B; Gaikar, Mayur; Kasture, Veena; Arote, Sanjay; Salve, Balu; Rosas, Michela; Cotti, Elisabetta; Acquas, Elio

2015-02-01

Tea is the most popular beverage worldwide. Caffeine, the psychoactive principle of tea, pharmacologically interacts with several drugs and bioactive molecules. Epigallocatechin gallate (EGCG) is a major component of tea and its known interactions with caffeine make it worthwhile to further study them by investigating the influence of EGCG on the anticataleptic and locomotor-sensitizing effects of caffeine. In the present investigation, we observed that (a) administration of caffeine or EGCG alone inhibited haloperidol-induced catalepsy, a widely used animal model to study parkinsonism, and (b) a combination of caffeine and EGCG produced greater inhibition of haloperidol-induced catalepsy. Furthermore, after repeated administration of caffeine and EGCG, either alone or in combination, we observed that (c) caffeine and EGCG contrasted the sensitization of catalepsy observed after repeated haloperidol administration by significantly reducing the duration of catalepsy. Furthermore, as haloperidol-induced catalepsy was also associated with increased lipid peroxidation, we observed that (d) EGCG administration reduced striatal lipid peroxide levels in a dose-dependent manner and that (e) the combination of caffeine with EGCG was most effective in reducing haloperidol-increased striatal lipid peroxide. Finally, we observed that (f) chronic caffeine and EGCG significantly elicited locomotor sensitization and that (g) their combination resulted in significantly greater effects. In conclusion, EGCG potentiated the effects of caffeine on haloperidol-induced catalepsy and of caffeine-elicited locomotor sensitization. Overall, these observations indicate critical interactions between caffeine and EGCG in an animal model of parkinsonism and locomotor activity and suggest that tea consumption might reduce antipsychotic-induced side effects.

Evaluation of the inhibitory effects of quercetin-related flavonoids and tea catechins on the monoamine oxidase-A reaction in mouse brain mitochondria.

PubMed

Bandaruk, Yauhen; Mukai, Rie; Kawamura, Tomoyuki; Nemoto, Hisao; Terao, Junji

2012-10-17

Quercetin, a typical dietary flavonoid, is thought to exert antidepressant effects by inhibiting the monoamine oxidase-A (MAO-A) reaction, which is responsible for regulation of the metabolism of the neurotransmitter 5-hydroxytryptamine (5-HT) in the brain. This study compared the MAO-A inhibitory activity of quercetin with those of O-methylated quercetin (isorhamnetin, tamarixetin), luteolin, and green tea catechins ((-)-epicatechin, (-)-epicatechin gallate, (-)-epigallocatechin, and (-)-epigallocatechin gallate) by measuring the formation of the oxidative deamination product of 5-HT, 5-hydroxyindole aldehyde (5-HIAL), in mouse brain mitochondria. Quercetin was inferior to luteolin in the inhibition of MAO-A activity, whereas isorhamnetin, tamarixetin, and tea catechins scarcely exerted inhibitory activity. Quercetin did not affect MAO-A activity in mouse intestinal mitochondria, indicating that it does not evoke side effects on the metabolism of dietary monoamines in the gut. These data suggest that quercetin is a weak (but safe) MAO-A inhibitor in the modulation of 5-HT levels in the brain.

Evaluation of unsaturated alkanoic acid amides as maskers of epigallocatechin gallate astringency.

PubMed

Obst, Katja; Paetz, Susanne; Backes, Michael; Reichelt, Katharina V; Ley, Jakob P; Engel, Karl-Heinz

2013-05-08

Some foods, beverages, and food ingredients show characteristic long-lasting aftertastes. The sweet, lingering taste of high intensity sweeteners or the astringency of tea catechins are typical examples. Epigallocatechin-3-gallate (EGCG), the most abundant catechin in green tea, causes a long-lasting astringency and bitterness. These sensations are mostly perceived as aversive and are only accepted in a few foods (e.g., tea and red wine). For the evaluation of the aftertaste of such constituents over a certain period of time, Intensity Variation Descriptive Methodology (IVDM) was used. The approach allows the measurement of different descriptors in parallel in one panel session. IVDM was evaluated concerning the inter- and intraindividual differences of panelists for bitterness and astringency of EGCG. Subsequently, the test method was used as a screening tool for the identification of potential modality-selective masking compounds. In particular, the intensity of the astringency of EGCG (750 mg kg(-1)) could be significantly lowered by 18-33% during the time course by adding the trigeminal-active compound trans-pellitorine (2E,4E-decadienoic acid N-isobutyl amide 1, 5 mg kg(-1)) without significantly affecting bitterness perception. Further, structurally related compounds were evaluated on EGCG to gain evidence for possible structure-activity relationships. A more polar derivative of 1, (2S)-2-[[(2E,4E)-deca-2,4-dienoyl]amino]propanoic acid 9, was also able to reduce the astringency of EGCG similar to trans-pellitorine but without showing the strong tingling effect.

The green tea polyphenol (-)-epigallocatechin gallate precipitates salivary proteins including alpha-amylase: biochemical implications for oral health.

PubMed

Hara, Kumiko; Ohara, Masaru; Hayashi, Ikue; Hino, Takamune; Nishimura, Rumi; Iwasaki, Yoriko; Ogawa, Tetsuji; Ohyama, Yoshihiko; Sugiyama, Masaru; Amano, Hideaki

2012-04-01

Green tea is a popular drink throughout the world, and it contains various components, including the green tea polyphenol (-)-epigallocatechin gallate (EGCG). Tea interacts with saliva upon entering the mouth, so the interaction between saliva and EGCG interested us, especially with respect to EGCG-protein binding. SDS-PAGE revealed that several salivary proteins were precipitated after adding EGCG to saliva. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) peptide mass fingerprinting indicated that the major proteins precipitated by EGCG were alpha-amylase, S100, and cystatins. Surface plasmon resonance revealed that EGCG bound to alpha-amylase at dissociation constant (K(d)) = 2.74 × 10(-6) M, suggesting that EGCG interacts with salivary proteins with a relatively strong affinity. In addition, EGCG inhibited the activity of alpha-amylase by non-competitive inhibition, indicating that EGCG is effective at inhibiting the formation of fermentable carbohydrates involved in caries formation. Interestingly, alpha-amylase reduced the antimicrobial activity of EGCG against the periodontal bacterium Aggregatibacter actinomycetemcomitans. Therefore, we considered that EGCG-salivary protein interactions might have both protective and detrimental effects with respect to oral health. © 2012 Eur J Oral Sci.

Green tea: Health benefits as cancer preventive for humans.

PubMed

Fujiki, Hirota

2005-01-01

Green tea is an acknowledged cancer preventive in Japan. The aim of this review article is to develop the concept of cancer prevention with green tea beverage for humans, which has largely been our exclusive research territory. This paper briefly reviews several topics, beginning with the introduction of our initial work on penta-O-galloyl-beta-D-glucose and (-)-epigallocatechin gallate (EGCG), the main constituent of green tea extract. The mechanisms of EGCG action, particularly the reduction of TNF-alpha are discussed, and we show how use of 3H-EGCG revealed a wide range of target organs for cancer prevention. The results of an epidemiological study in Saitama Prefecture allowed us to determine the cancer preventive amount of green tea-10 Japanese-size cups per day, about 2.5 g green tea extract-which made it possible for us to introduce the two-stage strategy of cancer prevention with green tea. The first stage is the delay of cancer onset for the general population. The second stage is the prevention of recurrence of cancer for patients following cancer treatment. Combination cancer prevention with green tea and cancer preventive drugs is proving especially beneficial for Japanese, who drink green tea every day. And finally, the stimulating comments of Prof. Jim Watson have encouraged green tea scientists. Copyright (c) 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.

(-)-Epigallocatechin gallate (EGCG)-nanoethosomes as a transdermal delivery system for docetaxel to treat implanted human melanoma cell tumors in mice.

PubMed

Liao, Bingwu; Ying, Hao; Yu, Chenhuan; Fan, Zhaoyang; Zhang, Weihua; Shi, John; Ying, Huazhong; Ravichandran, Nagaiya; Xu, Yongquan; Yin, Junfeng; Jiang, Yongwen; Du, Qizhen

2016-10-15

(-)-Epigallocatechin-3-O-gallate (EGCG), a versatile natural product in fresh tea leaves and green tea, has been investigated as a preventative treatment for cancers and cardiovascular disease. The objective of this study was to develop EGCG-nanoethosomes for transdermal delivery and to evaluate them for treating subcutaneously implanted human melanoma cell tumors. EGCG-nanoethosomes, composed of 0.2% EGCG, 2% soybean phosphatidylcholine, 30% ethanol, 1% Tween-80 and 0.1% sugar esters, were prepared and characterized using laser transmission electron microscopy. These nanoethosomes were smoother and more compact than basic-nanoethosomes with the same components except for EGCG. The effectiveness of transdermal delivery by EGCG-nanoethosomes was demonstrated in an in vitro permeability assay system using mouse skin. The inhibitory effect of docetaxel (DT) loaded in EGCG-nanoethosomes (DT-EGCG-nanoethosomes) was analyzed by monitoring growth of a subcutaneously implanted tumor from A-375 human melanoma cells in mice. Mice treated with DT-EGCG-nanoethosomes exhibited a significant therapeutic effect, with tumors shrinking, on average, by 31.5% of initial volumes after 14 d treatment. This indicated a potential for treating skin cancer. In a pharmacokinetic study, transdermal delivery by DT-EGCG-nanoethosomes enabled sufficient DT exposure to the tumor. Together, these findings indicated that EGCG-nanoethosomes have great potential as drug carriers for transdermal delivery. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of tea products on the in vitro enzymatic digestibility of starch.

PubMed

Zhang, Haihua; Jiang, Yulan; Pan, Junxian; Lv, Yangjun; Liu, Jun; Zhang, Shikang; Zhu, Yuejin

2018-03-15

The importance of postprandial hyperglycemia in the treatment of diabetes has been recognized recently. Tea products, such as tea polyphenols (TP), epigallocatechin gallate (EGCG), matcha, and instant tea, were chosen as constituents of tea-flour food, aimed at regulating the release of glucose from starchy foods in the postprandial period. Six starches were chosen for internal composition analysis and hydrolysis studies in vitro. Corn starch, wheat starch, and lily root flour appeared to have higher resistant starch content, slower digestion profiles, and lower kinetic constants, implying sustained release of glucose in the gastrointestinal tract. The effect of tea products on starch digestion was determined in order to get a desired formulation of dietary product for patients with hyperglycemia. Compared with macha and instant tea, TP and EGCG exerted greater inhibition of amylase and amyloglucosidase, especially for corn starch with 0.5% TP or 0.5% EGCG. Copyright © 2017 Elsevier Ltd. All rights reserved.

Green tea: A boon for periodontal and general health

PubMed Central

Chatterjee, Anirban; Saluja, Mini; Agarwal, Gunjan; Alam, Mahtab

2012-01-01

Green tea is particularly rich in health-promoting flavonoids (which account for 30% of the dry weight of a leaf), including catechins and their derivatives. The most abundant catechin in green tea is epigallocatechin-3-gallate, which is thought to play a pivotal role in the green tea's anticancer and antioxidant effects. Catechins should be considered right alongside of the better-known antioxidants like vitamins E and C as potent free radical scavengers and health-supportive for this reason. It has been suggested that green tea also promotes periodontal health by reducing inflammation, preventing bone resorption and limiting the growth of certain bacteria associated with periodontal diseases. PMID:23055579

Exploring the Chemical Sensitivity of a Carbon Nanotube/Green Tea Composite

PubMed Central

Chen, Yanan; Lee, Yang Doo; Vedala, Harindra; Allen, Brett L.; Star, Alexander

2010-01-01

Single-walled carbon nanotubes (SWNTs) possess unique electronic and physical properties, which make them very attractive for a wide range of applications. In particular, SWNTs and their composites have shown a great potential for chemical and biological sensing. Green tea, or more specifically its main antioxidant component, epigallocatechin gallate (EGCG), has been found to disperse SWNTs in water. However, the chemical sensitivity of this SWNT/green tea (SWNT/EGCG) composite remained unexplored. With EGCG present, this SWNT composite should have strong antioxidant properties and thus respond to reactive oxygen species (ROS). Here we report on fabrication and characterization of SWNT/EGCG thin films and the measurement of their relative conductance as a function of H2O2 concentrations. We further investigated the sensing mechanism by Fourier-transform infrared (FTIR) spectroscopy and field-effect transistor measurements (FET). We propose here that the response to H2O2 arises from the oxidation of EGCG in the composite. These findings suggest that SWNT/green tea composite has a great potential for developing simple resistivity-based sensors. PMID:21043457

Reduction of Hexavalent Chromium by Green Tea Polyphenols and Green Tea Nano Zero-Valent Iron (GT-nZVI).

PubMed

Chrysochoou, M; Reeves, K

2017-03-01

This study reports on the direct reduction of hexavalent chromium [Cr(VI)] by green tea polyphenols, including a green tea solution and pure epigallocatechin gallate (EGCG) solution. A linear trend was observed between the amount of reduced Cr(VI) and the amount of added polyphenols. The green tea solution showed a continued decrease in the observed stoichiometry with increasing pH, from a maximum of 1.4 mol per gallic acid equivalent (GAE) of green tea at pH 2.5, to 0.2 mol/GAE at pH 8.8. The EGCG solution exhibited different behavior, with a maximum stoichiometry of 2 at pH 7 and minimum of 1.6 at pH 4.4 and 8.9. When green tea was used to first react with Fe 3+ and form GT-nZVI, the amount of Cr(VI) reduced by a certain volume of GT-nZVI was double compared to green tea, and 6 times as high considering that GT-nZVI only contains 33 % green tea.

A novel convenient process to obtain a raw decaffeinated tea polyphenol fraction using a lignocellulose column.

PubMed

Sakanaka, Senji

2003-05-07

Lignocellulose prepared from sawdust was investigated for its potential application in obtaining a raw decaffeinated tea polyphenol fraction from tea extract. Tea polyphenols having gallate residues, namely, (-)epigallocatechin gallate (EGCg) and (-)epicatechin gallate (ECg), were adsorbed on the lignocellulose column, while caffeine was passed through it. Adsorbed polyphenols were eluted with 60% ethanol, and the elute was found to consist mainly of EGCg and ECg. The caffeine/EGCg ratio was 0.696 before lignocellulose column treatment, but it became 0.004 after the column treatment. These results suggest that the lignocellulose column provides a useful and convenient process of purification of tea polyphenol fraction accompanied by decaffeination.

Molecular binding of catechins to biomembranes:Relationship to biolgical activity

USDA-ARS?s Scientific Manuscript database

Molecular dynamics simulations were used to study the interactions of four catechins commonly found in tea with lipid bilayers of cell membranes. Experimental studies in the literature have shown that catechins are linked to beneficial health effects, specifically as they are related to interaction...

Development and validation of a high throughput assay for the quantification of multiple green tea-derived catechins in human plasma.

PubMed

Mawson, Deborah H; Jeffrey, Keon L; Teale, Philip; Grace, Philip B

2018-06-19

A rapid, accurate and robust method for the determination of catechin (C), epicatechin (EC), gallocatechin (GC), epigallocatechin (EGC), catechin gallate (Cg), epicatechin gallate (ECg), gallocatechin gallate (GCg) and epigallocatechin gallate (EGCg) concentrations in human plasma has been developed. The method utilises protein precipitation following enzyme hydrolysis, with chromatographic separation and detection using reversed-phase liquid chromatography - tandem mass spectrometry (LC-MS/MS). Traditional issues such as lengthy chromatographic run times, sample and extract stability, and lack of suitable internal standards have been addressed. The method has been evaluated using a comprehensive validation procedure, confirming linearity over appropriate concentration ranges, and inter/intra batch precision and accuracies within suitable thresholds (precisions within 13.8% and accuracies within 12.4%). Recoveries of analytes were found to be consistent between different matrix samples, compensated for using suitable internal markers and within the performance of the instrumentation used. Similarly, chromatographic interferences have been corrected using the internal markers selected. Stability of all analytes in matrix is demonstrated over 32 days and throughout extraction conditions. This method is suitable for high throughput sample analysis studies. This article is protected by copyright. All rights reserved.

Reduction in promotor methylation utilizing EGCG (epigallocatechin-3-gallate) restores RXRα expression in human colon cancer cells.

PubMed

Morris, Jay; Moseley, Vondina R; Cabang, April B; Coleman, Katie; Wei, Wei; Garrett-Mayer, Elizabeth; Wargovich, Michael J

2016-06-07

Silencing of regulatory genes through hypermethylation of CpG islands is an important mechanism in tumorigenesis. In colon cancer, RXRα, an important dimerization partner with other nuclear transcription factors, is silenced through this mechanism. We previously found that colon tumors in ApcMin/+ mice had diminished levels of RXRα protein and expression levels of this gene were restored by treatment with a green tea intervention, due to reduced promoter methylation of RXRα. We hypothesized that CIMP+ cell lines, which epigenetically silence key regulatory genes would also evidence silencing of RXRα and EGCG treatment would restore its expression. We indeed found EGCG to restore RXRα activity levels in the human cell lines, in a dose dependent manner and reduced RXRα promoter methylation. EGCG induced methylation changes in several other colon cancer related genes but did not cause a decrease in global methylation. Numerous epidemiological reports have shown the benefits of green tea consumption in reducing colon cancer risk but to date no studies have shown that the risk reduction may be related to the epigenetic restoration by tea polyphenols. Our results show that EGCG modulates the reversal of gene silencing involved in colon carcinogenesis providing a possible avenue for colon cancer prevention and treatment.

Determination of catechins and catechin gallates in tissues by liquid chromatography with coulometric array detection and selective solid phase extraction.

PubMed

Chu, Kai On; Wang, Chi Chiu; Chu, Ching Yan; Rogers, Michael Scott; Choy, Kwong Wai; Pang, Chi Pui

2004-10-25

Catechins levels in organ tissues, particularly liver, determined by published methods are unexpectedly low, probably due to the release of oxidative enzymes, metal ions and reactive metabolites from tissue cells during homogenization and to the pro-oxidant effects of ascorbic acid during sample processing in the presence of metal ions. We describe a new method for simultaneous analysis of eight catechins in tissue: (+)-catechin (C), (-)-epicatechin (EC), (-)-gallocatechin (GC), (-)-epigallocatechin (EGC), (-)-catechin gallate (CG), (-)-epicatechin gallate (ECG), (-)-gallocatechin gallate (GCG) and (-)-epigallocatechin gallate (EGCG) (Fig. 1). The new extraction procedure utilized a methanol/ethylacetate/dithionite (2:1:3) mixture during homogenization for simultaneous enzyme precipitation and antioxidant protection. Selective solid phase extraction was used to remove most interfering bio-matrices. Reversed phase HPLC with CoulArray detection was used to determine the eight catechins simultaneously within 25 min. Good linearity (>0.9922) was obtained in the range 20-4000 ng/g. The coefficients of variance (CV) were less than 5%. Absolute recovery ranged from 62 to 96%, accuracy 92.5 +/- 4.5 to 104.9 +/- 6%. The detection limit was 5 ng/g. This method is capable for determining catechins in rat tissues of liver, brain, spleen, and kidney. The method is robust, reproducible, with high recovery, and has been validated for both in vitro and in vivo sample analysis.

Insight into Catechins Metabolic Pathways of Camellia sinensis Based on Genome and Transcriptome Analysis.

PubMed

Wang, Wenzhao; Zhou, Yihui; Wu, Yingling; Dai, Xinlong; Liu, Yajun; Qian, Yumei; Li, Mingzhuo; Jiang, Xiaolan; Wang, Yunsheng; Gao, Liping; Xia, Tao

2018-04-25

Tea is an important economic crop with a 3.02 Gb genome. It accumulates various bioactive compounds, especially catechins, which are closely associated with tea flavor and quality. Catechins are biosynthesized through the phenylpropanoid and flavonoid pathways, with 12 structural genes being involved in their synthesis. However, we found that in Camellia sinensis the understanding of the basic profile of catechins biosynthesis is still unclear. The gene structure, locus, transcript number, transcriptional variation, and function of multigene families have not yet been clarified. Our previous studies demonstrated that the accumulation of flavonoids in tea is species, tissue, and induction specific, which indicates that gene coexpression patterns may be involved in tea catechins and flavonoids biosynthesis. In this paper, we screened candidate genes of multigene families involved in the phenylpropanoid and flavonoid pathways based on an analysis of genome and transcriptome sequence data. The authenticity of candidate genes was verified by PCR cloning, and their function was validated by reverse genetic methods. In the present study, 36 genes from 12 gene families were identified and were accessed in the NCBI database. During this process, some intron retention events of the CsCHI and CsDFR genes were found. Furthermore, the transcriptome sequencing of various tea tissues and subcellular location assays revealed coexpression and colocalization patterns. The correlation analysis showed that CsCHIc, CsF3'H, and CsANRb expression levels are associated significantly with the concentration of soluble PA as well as the expression levels of CsPALc and CsPALf with the concentration of insoluble PA. This work provides insights into catechins metabolism in tea and provides a foundation for future studies.

Comparison of the nutrient and chemical contents of traditional Korean Chungtaejeon and green teas.

PubMed

Park, Yong-Seo; Lee, Mi-Kyung; Heo, Buk-Gu; Ham, Kyung-Sik; Kang, Seong-Gook; Cho, Ja-Yong; Gorinstein, Shela

2010-06-01

This study was conducted in order to compare the nutrient and chemical contents of two Korean teas: traditional Chungtaejeon tea (CTJ) with that of green tea (GT). Main bioactive compounds and the antioxidant activities using four radical scavenging assays (ABTS, CUPRAC, FRAP and DPPH) in methanol and acetone extracts of both teas were determined. It was found that the contents of vitamin C, amino acids and total nitrogen in CTJ were lower than that of GT (p < 0.05). Caffeine, reducing sugar and chlorophyll contents in CTJ were similar to GT. Catechin (C), epicatechin (EC), and epigallocatechin (EGC) contents were lower in CTJ than in green tea (p < 0.05), but gallocatechin (GC), epicatechin gallate (ECG), epigallocatechin gallate (EGCG) and catechin gallate (CG) showed no significant differences between CTJ and GT (p >/= 0.05). The contents of polyphenols, flavonoids, flavanols and tannins in CTJ methanol were 229.30 +/- 11.3 mg GAE/g dry weight (DW), 15.24 +/- 0.8 mg CE/g DW, 109.10 +/- 5.1 mg CE/g DW and 25.68 +/- 1.2 mg CE/g DW, respectively, and significantly higher than in acetone extracts (p < 0.05). Flavonoids (quercetin and kaempferol) were higher in GT than in CTJ and myricetin was higher in CTJ (p < 0.05). Threonine and aspartic acid was lower, and glutamic acid was higher in CTJ compared with GT (p < 0.05). Free amino acid content in CTJ and GT showed no significant difference. Potassium and magnesium in CTJ were lower compared to GT, but no significant difference was found for iron, manganese and calcium. Also, the level of the antioxidant activity by all four used assays was significantly higher in CTJ and in methanol was higher than in acetone extracts (p < 0.05). In conclusion, traditional fermented Korean tea Chungtaejeon contains high quantities of bioactive compounds and possesses high antioxidant activity. The contents of the bioactive compounds and the levels of antioxidant activities are significantly higher in methanol than in acetone

Catechin concentrates of garden tea leaves (Camellia sinensis L.): extraction/isolation and evaluation of chemical composition.

PubMed

Gadkari, Pravin Vasantrao; Kadimi, Udaya Sankar; Balaraman, Manohar

2014-11-01

Solid-liquid (SLE) and liquid-liquid (LLE) extraction techniques were applied to extract catechins and caffeine from quick mechanically expelled tea leaf juice (QMETLJ) and freeze-dried (FD)-QMETLJ of Camellia sinensis L. The concentrates obtained were analyzed for total polyphenol content and antioxidant activity (DPPH(•) inhibition, FRAP and phosphomolybdenum assay). Catechins were identified and quantified using HPLC. Overall, 95% (v/v) ethanol was the best solvent system for extracting total polyphenols (355.26 ± 23.68 to 457.89 ± 28.94 g GAE kg(-1) extractable solid yield (ESY)) and antioxidants (DPPH(•) inhibition, 16.97 ± 0.52 to 20.83 ± 3.11%; FRAP, 4.15 ± 0.32 to 6.38 ± 0.57 mmol TE g(-1) ESY; Mo(V) reduction, 2.47 ± 0.19 to 3.84 ± 0.39 mmol AAE g(-1) ESY) from FD-QMETLJ. Similarly, in LLE, ethyl acetate showed the best results for recovering polyphenols (960.52 ± 7.89 g GAE kg(-1) ESY) and antioxidants (DPPH(•) inhibition, 42.39 ± 0.91%; FRAP, 11.39 ± 0.83 mmol TE g(-1) ESY; Mo(V) reduction, 6.71 ± 1.14 mmol AAE g(-1) ESY) from QMETLJ. It was found that 95% ethanol can be used to increase the total polyphenols and antioxidants in extracts from FD-QMETLJ, while ethyl acetate can be effectively employed for concentrating catechins from QMETLJ. © 2014 Society of Chemical Industry.

Phytochemical profiles and antioxidant activities of Chinese dark teas obtained by different processing technologies.

PubMed

Lv, Hai-Peng; Zhang, Yue; Shi, Jiang; Lin, Zhi

2017-10-01

Dark teas are rich in secondary metabolites, such as phenolics and flavonoids, which have been suggested to be associated with their health benefits. In this study, the concentrations of tea polyphenols, tea pigments, catechins, flavonoids, alkaloid, and volatile components in 44 dark tea samples, including Pu-erh, Fuzhuan and Liubao teas, were systematically examined. Among the samples tested, Pu-erh tea contained the highest total flavonoid content (5.24±0.05%), followed by Liubao (4.45±0.61%) and Fuzhuan teas (3.33±0.23%). The tea polyphenols levels in the dark teas were approximately 10%, and no statistically significant differences (p>0.05) were found among the different types. Hexadecanoic acid was the most abundant aroma component in the dark teas, accounting for 15-20% of the total volatile oils. Moreover, the antioxidant activities of these dark teas were analyzed using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) assay, ferric reducing antioxidant power (FRAP) assay, and cellular antioxidant activity (CAA) assay (HepG2 cells). The fat metabolism modulation activities (FMMA) of the dark teas were tested using a high-throughput screening method (SMMC-7221 cells). The results indicated that the different dark teas had diverse antioxidant activities, and the variation in the activities was significant. Correlation analysis showed that there was a significant positive correlation between the levels of EGCG and antioxidant activities measured using the ABTS (r=0.916) and FRAP (r=0.853) assays, and the levels of total flavonoids and theabrownins correlated well with the values determined using the CAA (r=0.845 and 0.865, respectively) assay. Copyright © 2016 Elsevier Ltd. All rights reserved.

Green Tea in Prevention and Therapy of Prostate Cancer

DTIC Science & Technology

2002-09-01

that polyphenols present in green tea especially its major constituent (-) epigallocatechin - 3- gallate ( EGCG ) possesses both cancer preventive and...androgen-sensitive 22Rv1 and androgen-insensitive PC-3 CaP cells. We found that intraperitoneal administration of EGCG resulted in significant inhibition...in tumor growth and serum PSA levels. Importantly, mice treated with EGCG exhibited a marked decrease in tumor proliferation along with significant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, R.-W.; Orthopaedic Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan; Chen, C.-H.

People who regularly drink tea have been found to have a higher bone mineral density (BMD) and to be at less risk of hip fractures than those who do not drink it. Green tea catechins such as (-)-epigallocatechin gallate (EGCG) have been reported to increase osteogenic functioning in mesenchymal stem cells. However, its effect on osteoclastogenesis remains unclear. In this study, we investigated the effect of EGCG on RANKL-activation osteoclastogenesis and NF-{kappa}B in RAW 264.7, a murine preosteoclast cell line. EGCG (10-100 {mu}M) significantly suppressed the RANKL-induced differentiation of osteoclasts and the formation of pits in murine RAW 264.7 cellsmore » and bone marrow macrophages (BMMs). EGCG appeared to target osteoclastic differentiation at an early stage but had no cytotoxic effect on osteoclast precursors. In addition, it significantly inhibited RANKL-induced NF-{kappa}B transcriptional activity and nuclear translocation. We conclude that EGCG inhibits osteoclastogenesis through its activation of NF-{kappa}B.« less

Metabolic Flux Redirection and Transcriptomic Reprogramming in the Albino Tea Cultivar ‘Yu-Jin-Xiang’ with an Emphasis on Catechin Production

PubMed Central

Liu, Guo-Feng; Han, Zhuo-Xiao; Feng, Lin; Gao, Li-Ping; Gao, Ming-Jun; Gruber, Margaret Y.; Zhang, Zhao-Liang; Xia, Tao; Wan, Xiao-Chun; Wei, Shu

2017-01-01

In this study, shade-induced conversion from a young pale/yellow leaf phenotype to a green leaf phenotype was studied using metabolic and transcriptomic profiling and the albino cultivar ‘Yu-Jin-Xiang’ (‘YJX’) of Camellia sinensis for a better understanding of mechanisms underlying the phenotype shift and the altered catechin and theanine production. Shaded leaf greening resulted from an increase in leaf chlorophyll and carotenoid abundance and chloroplast development. A total of 1,196 differentially expressed genes (DEGs) were identified between the ‘YJX’ pale and shaded green leaves, and these DEGs affected ‘chloroplast organization’ and ‘response to high light’ besides many other biological processes and pathways. Metabolic flux redirection and transcriptomic reprogramming were found in flavonoid and carotenoid pathways of the ‘YJX’ pale leaves and shaded green leaves to different extents compared to the green cultivar ‘Shu-Cha-Zao’. Enhanced production of the antioxidant quercetin rather than catechin biosynthesis was correlated positively with the enhanced transcription of FLAVONOL SYNTHASE and FLAVANONE/FLAVONOL HYDROXYLASES leading to quercetin accumulation and negatively correlated to suppressed LEUCOANTHOCYANIDIN REDUCTASE, ANTHOCYANIDIN REDUCTASE and SYNTHASE leading to catechin biosynthesis. The altered levels of quercetin and catechins in ‘YJX’ will impact on its tea flavor and health benefits. PMID:28332598

A population-based, case–control study of green tea consumption and leukemia risk in southwestern Taiwan

PubMed Central

Yu, Chu-Ling; Liu, Chen-Yu; Wang, Su-Fen; Pan, Pi-Chen; Wu, Ming-Tsang; Ho, Chi-Kung; Lo, Yu-Shing; Li, Yi; Christiani, David C.

2011-01-01

Objective This study investigated the association between green tea consumption and leukemia. Methods A total of 252 cases (90.3% response) and 637 controls (53.4% response) were enrolled. Controls were matched for cases on age and gender. Information was collected on participants’ living habits, including tea consumption. Green tea was used as a standard to estimate the total amount of individual catechin consumption. We stratified individual consumption of catechins into four levels. Conditional logistic regression models were fit to subjects aged 0–15 and 16–29 years to evaluate separate associations between leukemia and catechin consumption. Results A significant inverse association between green tea consumption and leukemia risk was found in individuals aged 16–29 years, whereas no significant association was found in the younger age groups. For the older group with higher amounts of tea consumption (>550 units of catechins), the adjusted odds ratio (OR) compared with the group without tea consumption was 0.47 [95% confidence interval (CI) = 0.23–0.97]. After we adjusted for smoking status and medical irradiation exposure, the overall OR for all participants was 0.49 (95% CI = 0.27–0.91), indicating an inverse relation between large amounts of catechins and leukemia. Conclusion Drinking sufficient amounts of tea, especially green tea, which contains more catechins than oolong tea and black tea, may reduce the risk of leukemia. PMID:18752033

Epigallocatechin-3-gallate (EGCG) inhibits imiquimod-induced psoriasis-like inflammation of BALB/c mice.

PubMed

Zhang, Shuangshuang; Liu, Xiangdong; Mei, Lihong; Wang, Hongfeng; Fang, Fang

2016-08-31

Psoriasis is a chronic inflammatory immune disease with undefined pathogenesis. It is associated with T cells, and the IL-23/IL17 axis is believed to be crucial in the pathogenesis. The present treatments have side effects that influence the compliance of patients. Tea polyphenol is extracted from tea polyphenols, and its main active ingredient is Epigallocatechin-3-gallate (EGCG), which has been shown to have antioxidant, anti-tumor, and anti-ultraviolet radiation effects. Here, we aim to report that EGCG can inhibit imiquimod (IMQ)-induced psoriasis-like inflammation. We used BALB/c mice, which were topically treated with IMQ for 6 consecutive days, as a psoriasis mouse model. Topical application of EGCG and treatment with EGCG were conducted in the experiments. Then observed the effects of the two methods on psoriasis-like mice dermatitis. Statistics are presented as the means ± standard error of mean (SEM) and compared using unpaired two-tailed Student's t tests or one-way ANOVA. Topical application of EGCG alleviated psoriasiform dermatitis, improved the skin pathological structure by reduce the expression of epidermal PCNA, promoted the expression of caspase-14. Treatment with EGCG attenuated skin inflammation, accompanied by reduced infiltrations of T cells; reduced percentages of CD11c(+) DC in the composition of immunocytes of spleens; reduced levels of interleukin (IL)-17A, IL-17F, IL-22, IL-23 and malondialdehyde (MDA) in plasma; increased percentages of CD4(+) T cells in the composition of immunocytes of spleens; and increased bioactivities of superoxide dismutase (SOD) and catalase (CAT) in plasma. All the results demonstrated that EGCG had anti-inflammatory, immune regulatory and antioxidant effects. It is a promising intervention in psoriasis in the future.

Green Tea Extracts Epigallocatechin-3-gallate for Different Treatments

PubMed Central

Chu, Chenyu; Deng, Jia

2017-01-01

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. PMID:28884125

Epigallocatechin-3-gallate (EGCG) attenuates concanavalin A-induced hepatic injury in mice.

PubMed

Liu, Dongmei; Zhang, Xiaoli; Jiang, Li; Guo, Yun; Zheng, Changqing

2014-05-01

(-)-Epigallocatechin-3-gallate (EGCG) is the most abundant polyphenolic compound present in green tea and has been shown to possess anti-inflammatory and anti-oxidative properties. In this study, we investigated the protective effects of EGCG against concanavalin A (ConA)-induced liver injury and the underlying mechanisms. EGCG (5 mg/kg) was administered orally by gavage to mice twice daily for 10 days before an intravenous injection of ConA. We found that EGCG effectively rescued lethality, improved hepatic pathological damage, and decreased serum levels of alanine aminotransaminase (ALT) in ConA-challenged mice. Furthermore, EGCG also significantly prevented the release of tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-4, and IL-6 in serum, reduced malondialdehyde (MDA) levels, and restored glutathione (GSH) content and superoxide dismutase (SOD) activity in liver tissues from ConA-challenged mice. Finally, nuclear factor (NF)-κB activation and expression levels of Toll-like receptor (TLR) 2, TLR4 and TLR9 protein in liver tissues were significantly inhibited by EGCG pretreatment. Taken together, our data suggest that EGCG possesses hepatoprotective properties against ConA-induced liver injury through its anti-inflammatory and anti-oxidant actions. Copyright © 2013 Elsevier GmbH. All rights reserved.

In vitro antioxidant activity of phenolic-enriched extracts from Zhangping Narcissus tea cake and their inhibition on growth and metastatic capacity of 4T1 murine breast cancer cells* #

PubMed Central

Ying, Le; Kong, De-dong; Gao, Yuan-yuan; Yan, Feng; Wang, Yue-fei; Xu, Ping

2018-01-01

Phenolics, as the main bioactive compounds in tea, have been suggested to have potential in the prevention of various human diseases. However, little is known about phenolics and their bioactivity in Zhangping Narcissue tea cake which is considered the most special kind of oolong tea. To unveil its bioactivity, three phenolic-enriched extracts were obtained from Zhangping Narcissue tea cake using ethyl acetate, n-butanol, and water. Their main chemical compositions and in vitro bioactivity were analyzed by high-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). The ethyl acetate fraction (ZEF) consisted of higher content of phenolics, flavonoids, procyanidins, and catechin monomers (including epigallocatechin gallate (EGCG), epicatechin gallate (ECG), and gallocatechin gallate (GCG)) than n-butanol fraction (ZBF) and water fraction (ZWF). ZEF exhibited the strongest antioxidant capacity in vitro due to its abundant bioactive compounds. This was validated by Pearson correlation and hierarchical clustering analyses. ZEF also showed a remarkable inhibition on the growth, migration, and invasion of 4T1 murine breast cancer cells. PMID:29504313

[Effectiveness of green tea catechines for the correction of the alimentary obesity in the experiment].

PubMed

Chanadiri, T; Sanikidze, T; Esaishvili, M; Chkhikvishvili, I; Datunashvili, I

2005-09-01

Obesity is one of the most important problems of the modern medicine. The immobile life-style and consumption of high-calorie food are the most remarkable risk-factors of the obesity, which in presence of genetic predisposition contribute to the increasing of the body weight. In the modern literature there are numerous data about the important role of free radical oxidation in the pathogenesis of the obesity. In this relation application of natural antioxidants for the purpose of the correction of excess weight has gained an active research interest. Numerous researches showed natural antioxidants to be effective in correction of elevated blood cholesterol, triglycerides and LDL levels. In this relation the purpose of our research was to investigate effectiveness of green tea catechizes on lipid metabolism disorder, antioxidant status and excess body weight during experimental alimentary obesity. Experiment was conducted on rats kept on high-calorie diet for 7 weeks. Simultaneously one group of animals had been administered catechines in addition to the high-calorie diet during last 4 weeks. The experiment established corrective effect of catechines on the parameters of lipid metabolism (blood cholesterol, triglyceride and LDL levels), epididymal fat mass and antioxidant enzymes activity. Obtained results may be important for the development of weight losing diets.

Protective effects of epigallocatechin gallate (EGCG) on streptozotocin-induced diabetic nephropathy in mice.

PubMed

Yoon, Sang Pil; Maeng, Young Hee; Hong, Ran; Lee, Byung Rai; Kim, Chong Gue; Kim, Hyun Lee; Chung, Jong Hoon; Shin, Byung Chul

2014-10-01

There is increasing evidence suggesting that antioxidants in green tea extracts may protect kidneys on the progression of end-stage renal disease. We investigated the protective impacts of (-)-epigallocatechin 3-O-gallate (EGCG) against streptozotocin (STZ)-induced diabetic nephropathy in mice. The mice were divided into 5 groups (n=10 per group): control (saline, i.p.), STZ (200mg/kg, i.p.), EGCG50 (50mg/kg, S.Q.), EGCG100 (100mg/kg, S.Q.), and EGCG200 (200mg/kg, S.Q.). Animals were sacrificed at scheduled times after EGCG administration and then quantitative and qualitative analysis were performed. Compared with the control group, the STZ group showed an increase in levels of blood glucose, blood urea nitrogen, creatinine and urine protein amounts with a decrease in body weight. All the above parameters were significantly reversed with EGCG treatment, especially in the EGCG100 group. After STZ injection, there was a mesangial proliferation with increased renal osteopontin accumulation and its protein expression in the glomeruli and the proximal tubules. Mice kidneys after EGCG-treatment showed a reduced expression of above parameters and relatively improved histopathological findings. These results indicated that EGCG 100mg/kg might provide an effective protection against STZ-induced diabetic nephropathy in mice by osteopontin suppression. Copyright © 2014 Elsevier GmbH. All rights reserved.

(-)-Epigallocatechin-3-gallate (EGCG) attenuates arsenic-induced cardiotoxicity in rats.

PubMed

Sun, Tao-Li; Liu, Zhi; Qi, Zheng-Jun; Huang, Yong-Pan; Gao, Xiao-Qin; Zhang, Yan-Yan

2016-07-01

Chronic arsenic exposure in drinking water is associated with the abnormalities of cardiac tissue. Excessive generation of ROS induced by arsenic has a central role in arsenic-induced cardiotoxicity. (-)-Epigallocatechin-3-gallate (EGCG), the most abundant polyphenol in green tea, possesses a potent antioxidant capacity and exhibits extensive pharmacological activities. This study was aim to evaluate the effect of EGCG on arsenic-induced cardiotoxicity in vivo and in vitro. Treatment with NaAsO2 seriously affected the morphology and ultrastructure of myocardium, and induced cardiac injuries, oxidative stress, intracellular calcium accumulation and apoptosis in rats. In consistent with in vivo study, the injuries, oxidative stress and apoptosis were also observed in NaAsO2-treated H9c2 cells. All of these effects induced by NaAsO2 were attenuated by EGCG. These results suggest EGCG could attenuate NaAsO2-induced cardiotoxicity, and the mechanism may involve its potent antioxidant capacity. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Chemical studies on plant polyphenols and formation of black tea polyphenols].

PubMed

Tanaka, Takashi

2008-08-01

Recent biological and pharmacological studies strongly suggested that plant polyphenols in foods, beverages and crude drugs have various health benefits. However, still there are chemically uncharacterized polyphenols, especially those with large molecular weights. The typical example is black tea polyphenols. Four tea catechins of fresh tea leaves are enzymatically oxidized in tea fermentation process of black tea manufacture to give a complex mixture of the oxidation products. Despite many efforts since 1950's, major part of the black tea polyphenols has not been clarified yet. We have investigated the oxidation mechanism of each catechin by employing a newly developed in vitro model fermentation system. The oxidation was initiated by enzymatic dehydrogenation of catechins, and subsequent intermolecular quinone-phenol coupling reactions followed by cascade-type degradation of the unstable products resulted in the formation of complex black tea polyphenols. Besides black tea polyphenols, this review introduces the chemistry of insolubilization of persimmon proanthocyanidins, wood polyphenols in connection with whisky polyphenols, and co-polymerization of cinnamaldehyde and proanthocyanidins in cinnamon bark.

Anti-cancer effect of (-)-epigallocatechin-3-gallate (EGCG) in head and neck cancer through repression of transactivation and enhanced degradation of β-catenin.

PubMed

Shin, Yoo Seob; Kang, Sung Un; Park, Ju Kyeong; Kim, Yang Eun; Kim, Yeon Soo; Baek, Seung Joon; Lee, Seong-Ho; Kim, Chul-Ho

2016-11-15

Aberrant expression of β-catenin is highly associated with progression of various cancers including head and neck cancer (HNC). Green tea is most commonly used beverage in the world and one of the more bioactive compounds is the antioxidant epigallocatechin gallate (EGCG). This study was performed to investigate the mechanism by which EGCG inhibits the growth of HNC, focusing on the modulation of the expression and activity of β-catenin. In vitro effects of EGCG on the transcription, translation, or degradation of β-catenin were investigated. Antitumor effects of EGCG in vivo were evaluated in a syngeneic mouse model and β-catenin expression was checked in HNC patients' samples. β-catenin expression was elevated in tumor samples of HNC patients. EGCG induced apoptosis in KB and FaDu cells through the suppression of β-catenin signaling. Knockdown of β-catenin using siRNA enhanced the proapoptotic activities of EGCG. EGCG decreased mRNA and transcriptional activity of β-catenin in p53 wild-type KB cells. EGCG also enhanced the ubiquitination and proteasomal degradation of β-catenin. The suppression of β-catenin and consequent apoptosis were observed in response to EGCG treatment in a syngeneic mouse model. In conclusion, we report that EGCG inhibits β-catenin expression through multiple mechanisms including decreased transcription and increased ubiquitin-mediated 26S proteasomal degradation. This study proposes a novel molecular rationale for antitumor activities of green tea in HNCs. Copyright © 2016 Elsevier GmbH. All rights reserved.

Effect of Green Tea Phytochemicals on Mood and Cognition.

PubMed

Dietz, Christina; Dekker, Matthijs

2017-01-01

Green tea is traditionally known to induce mental clarity, cognitive function, physical activation and relaxation. Recently, a special green tea, matcha tea, is rapidly gaining popularity throughout the world and is frequently referred to as a mood- and brain food. Matcha tea consumption leads to much higher intake of green tea phytochemicals compared to regular green tea. Previous research on tea constituents caffeine, L-theanine, and epigallocatechin gallate (EGCG) repeatedly demonstrated benefits on mood and cognitive performance. These effects were observed when these phytochemicals were consumed separately and in combination. A review was conducted on 49 human intervention studies to summarize the research on acute psychoactive effects of caffeine, L-theanine, and EGCG on different dimensions of mood and cognitive performance. Caffeine was found to mainly improve performance on demanding long-duration cognitive tasks and self-reported alertness, arousal, and vigor. Significant effects already occurred at low doses of 40 mg. L-theanine alone improved self-reported relaxation, tension, and calmness starting at 200 mg. L-theanine and caffeine combined were found to particularly improve performance in attention-switching tasks and alertness, but to a lesser extent than caffeine alone. No conclusive evidence relating to effects induced by EGCG could be given since the amount of intervention studies was limited. These studies provided reliable evidence showing that L-theanine and caffeine have clear beneficial effects on sustained attention, memory, and suppression of distraction. Moreover, L-theanine was found to lead to relaxation by reducing caffeine induced arousal. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Enhanced oxidation of flavan-3-ols and proanthocyanidin accumulation in water-stressed tea plants.

PubMed

Hernández, Iker; Alegre, Leonor; Munné-Bosch, Sergi

2006-06-01

(-)-Epicatechin (EC) and (-)-epigallocatechin gallate (EGCG), two major tea flavan-3-ols, have received attention in food science and biomedicine because of their potent antioxidant properties. In plants, flavan-3-ols serve as proanthocyanidin (PA) building blocks, and although both monomeric flavan-3-ols and PAs show antioxidant activity in vitro, their antioxidant function in vivo remains unclear. In the present study, EC quinone (ECQ) and EGCG quinone (EGCGQ), the oxidation products of EC and EGCG, increased up to 100- and 30-fold, respectively, in tea plants exposed to 19 days of water deficit. Oxidation of EC and EGCG preceded PAs accumulation in leaves, which increased from 35 to 53 mg gDW(-1) after 26 days of water deficit. Aside from the role monomeric flavan-3-ols may play in PAs biosynthesis, formation of ECQ and EGCGQ strongly negatively correlated with the extent of lipid peroxidation in leaves, thus supporting a protective role for these compounds in drought-stressed plants. Besides demonstrating flavonoid accumulation in drought-stressed tea plants, we show for the first time that EC and EGCG are oxidized to their respective quinones in plants in vivo.

Difference of EGCg adhesion on cell surface between Staphylococcus aureus and Escherichia coli visualized by electron microscopy after novel indirect staining with cerium chloride.

PubMed

Nakayama, Motokazu; Shigemune, Naofumi; Tsugukuni, Takashi; Tokuda, Hajime; Miyamoto, Takahisa

2011-07-01

We developed a novel method using indirect staining with cerium chloride for visualization of the catechin derivative epigallocatechin gallate (EGCg) on the surface of particles, i.e., polystyrene beads and bacterial cells, by electron microscopy. The staining method is based on the fact that in an alkaline environment, EGCg produces hydrogen peroxide, and then hydrogen peroxide reacts with cerium, resulting in a cerium hydroperoxide precipitate. This precipitate subsequently reacts with EGCg to produce larger deposits. The amount of precipitate is proportional to the amount of EGCg. Highly EGCg-sensitive Staphylococcus aureus and EGCg-resistant Escherichia coli were treated with EGCg under various pH conditions. Transmission electron microscopy observation showed that the amount of deposits on S. aureus increased with an increase in EGCg concentration. After treating bacterial cells with 0.5mg/mL EGCg (pH 6.0), attachment of EGCg was significantly lower to E. coli than to S. aureus. This is the first report that shows differences in affinity of EGCg to the cell surfaces of Gram-positive and -negative bacteria by electron microscopy. Copyright © 2011 Elsevier B.V. All rights reserved.

Orthogonal analytical methods for botanical standardization: Determination of green tea catechins by qNMR and LC-MS/MS

PubMed Central

Napolitano, José G.; Gödecke, Tanja; Lankin, David C.; Jaki, Birgit U.; McAlpine, James B.; Chen, Shao-Nong; Pauli, Guido F.

2013-01-01

The development of analytical methods for parallel characterization of multiple phytoconstituents is essential to advance the quality control of herbal products. While chemical standardization is commonly carried out by targeted analysis using gas or liquid chromatography-based methods, more universal approaches based on quantitative 1H NMR (qHNMR) measurements are being used increasingly in the multi-targeted assessment of these complex mixtures. The present study describes the development of a 1D qHNMR-based method for simultaneous identification and quantification of green tea constituents. This approach utilizes computer-assisted 1H iterative Full Spin Analysis (HiFSA) and enables rapid profiling of seven catechins in commercial green tea extracts. The qHNMR results were cross-validated against quantitative profiles obtained with an orthogonal LC-MS/MS method. The relative strengths and weaknesses of both approaches are discussed, with special emphasis on the role of identical reference standards in qualitative and quantitative analyses. PMID:23870106

Human cancer stem cells are a target for cancer prevention using (-)-epigallocatechin gallate.

PubMed

Fujiki, Hirota; Sueoka, Eisaburo; Rawangkan, Anchalee; Suganuma, Masami

2017-12-01

Our previous experiments show that the main constituent of green-tea catechins, (-)-epigallocatechin gallate (EGCG), completely prevents tumor promotion on mouse skin initiated with 7,12-dimethylbenz(a)anthracene followed by okadaic acid and that EGCG and green tea extract prevent cancer development in a wide range of target organs in rodents. Therefore, we focused our attention on human cancer stem cells (CSCs) as targets of cancer prevention and treatment with EGCG. The numerous reports concerning anticancer activity of EGCG against human CSCs enriched from cancer cell lines were gathered from a search of PubMed, and we hope our review of the literatures will provide a broad selection for the effects of EGCG on various human CSCs. Based on our theoretical study, we discuss the findings as follows: (1) Compared with the parental cells, human CSCs express increased levels of the stemness markers Nanog, Oct4, Sox2, CD44, CD133, as well as the EMT markers, Twist, Snail, vimentin, and also aldehyde dehydrogenase. They showed decreased levels of E-cadherin and cyclin D1. (2) EGCG inhibits the transcription and translation of genes encoding stemness markers, indicating that EGCG generally inhibits the self-renewal of CSCs. (3) EGCG inhibits the expression of the epithelial-mesenchymal transition phenotypes of human CSCs. (4) The inhibition of EGCG of the stemness of CSCs was weaker compared with parental cells. (5) The weak inhibitory activity of EGCG increased synergistically in combination with anticancer drugs. Green tea prevents human cancer, and the combination of EGCG and anticancer drugs confers cancer treatment with tissue-agnostic efficacy.

Quercetin and fisetin enhanced the small intestine cellular uptake and plasma levels of epi-catechins in in vitro and in vivo models.

PubMed

Chung, Jin-Oh; Lee, Seon-Bong; Jeong, Kang-Hyun; Song, Ji-Hoon; Kim, Su-Kyung; Joo, Kyung-Mi; Jeong, Hyun-Woo; Choi, Jin-Kyu; Kim, Jeong-Kee; Kim, Wan-Gi; Shin, Song-Seok; Shim, Soon-Mi

2018-01-24

Quercetin and fisetin, known as catechol-containing flavonoids, could positively affect the absorption of catechins due to their strong affinity for catechol-O-methyl transferase (COMT), which can methylate and cause the excretion of catechins. The current study examined the effect of quercetin and fisetin on the absorption of epi-catechins (ECs) by using a Caco-2 cell line and an in vivo model. The intestinal transport of total catechins by Caco-2 cells was enhanced from 1.3- to 1.6-fold and 1.4- to 1.7-fold by adding quercetin and fisetin, respectively, compared to the control. It was even higher in the treatment with a mixture of quercetin and fisetin. While EC had the highest value of intestinal transport (169% of the control) in 10% quercetin treatment, EGC (235%), EGCG (244%), and ECG (242%) were significantly transported in the treatment with a 5% mixture of quercetin and fisetin (p < 0.05). In an in vivo pharmacokinetic study, the values of the area under the plasma concentration-time curve (AUC, ng h mL -1 ) were also higher in rats orally administered EGCG with 10% quercetin (365.5 ± 25.5) or 10% fisetin (825.3 ± 46.7) than in those administered EGCG only (111.3 ± 13.1). Methylated quercetin and methylated fisetin were determined to be m/z 317.24 and m/z 301.25 [M + H] + with their own product ions, respectively. The results indicate that quercetin or fisetin is superior to ECs for methylation by COMT.

Photodegradation of (-)-epigallocatechin-3-gallate in topical cream formulations and its photostabilization.

PubMed

Bianchi, Anna; Marchetti, Nicola; Scalia, Santo

2011-12-05

The aim of the study was to examine the photostability of the major catechin of green tea, (-)-epigallocatechin-3-gallate (EGCG), which possesses important antioxidant and skin photoprotective properties. In order to simulate realistic conditions of use of topical preparations, the photolysis studies were performed in model creams (oil-in-water emulsions) containing 1% (w/w) EGCG and exposed to a solar simulator at an irradiance corresponding to natural sunlight. The extent of photodegradation was measured by HPLC-UV and HPLC-ESI-MS. EGCG was found to decompose by 68.9±2.3%, after 1h irradiation. Addition of the coantioxidants, vitamin E or butylated hydroxytoluene to the emulsion formulation, significantly enhanced the photolability of the catechin, the EGCG loss reached 85.7±1.3% and 80.5±1.4%, respectively. On the other hand, inclusion of the UVB (290-320nm) filter, ethylhexyl methoxycinnamate in the cream produced a small but significant reduction of EGCG photodegradation to 61.0±2.9%, while the UVA (320-400nm) filter, butyl methoxydibenzoylmethane was ineffective (EGCG degradation, 67.8±1.5%). A more marked decrease in the light-induced decomposition of EGCG to 51.6±2.7% was achieved, under the same conditions, using the water-soluble UVB filter, benzophenone-4 (BP-4). This effect was concentration dependent, maximal EGCG photostabilization (catechin loss, 29.4±2.2%) was attained in the presence of 2.1% (w/w) BP-4. Therefore, BP-4 represents a useful additive to improve the light stability of EGCG in topical formulations for skin photoprotection. Copyright © 2011 Elsevier B.V. All rights reserved.

Computational and Biochemical Discovery of RSK2 as a Novel Target for Epigallocatechin Gallate (EGCG).

PubMed

Chen, Hanyong; Yao, Ke; Chang, Xiaoyu; Shim, Jung-Hyun; Kim, Hong-Gyum; Malakhova, Margarita; Kim, Dong-Joon; Bode, Ann M; Dong, Zigang

2015-01-01

The most active anticancer component in green tea is epigallocatechin-3-gallate (EGCG). Protein interaction with EGCG is a critical step for mediating the effects of EGCG on the regulation of various key molecules involved in signal transduction. By using computational docking screening methods for protein identification, we identified a serine/threonine kinase, 90-kDa ribosomal S6 kinase (RSK2), as a novel molecular target of EGCG. RSK2 includes two kinase catalytic domains in the N-terminal (NTD) and the C-terminal (CTD) and RSK2 full activation requires phosphorylation of both terminals. The computer prediction was confirmed by an in vitro kinase assay in which EGCG inhibited RSK2 activity in a dose-dependent manner. Pull-down assay results showed that EGCG could bind with RSK2 at both kinase catalytic domains in vitro and ex vivo. Furthermore, results of an ATP competition assay and a computer-docking model showed that EGCG binds with RSK2 in an ATP-dependent manner. In RSK2+/+ and RSK2-/- murine embryonic fibroblasts, EGCG decreased viability only in the presence of RSK2. EGCG also suppressed epidermal growth factor-induced neoplastic cell transformation by inhibiting phosphorylation of histone H3 at Ser10. Overall, these results indicate that RSK2 is a novel molecular target of EGCG.

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

PubMed

Eng, Qian Yi; Thanikachalam, Punniyakoti Veeraveedu; Ramamurthy, Srinivasan

2018-01-10

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. 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. 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. 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). 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. Copyright © 2017 Elsevier B.V. All rights reserved.

Spontaneously Assembled Nano-aggregates in Clear Green Tea Infusions from Camellia ptilophylla and Camellia sinensis.

PubMed

Lin, Xiaorong; Gao, Xiong; Chen, Zhongzheng; Zhang, Yuanyuan; Luo, Wei; Li, Xiaofei; Li, Bin

2017-05-10

Tea nano-aggregates spontaneously assembled in clear tea infusions are considered as the precursors of tea cream, although their molecular basis remains obscure. Here, we characterized nano-aggregates in green tea infusions from Camellia ptilophylla, a peculiar tea variety with 6.0% of theobromine, and Camellia sinensis as the control for comparative purpose. Numerous negatively charged spherical colloidal particles of 50-100 nm in diameter were primarily found in both green tea infusions. Catechins, proteins, and carbohydrates were confirmed as the dominant components in green tea nano-aggregates. In addition, iron, copper, nickel, proteins, and gallated catechins exhibited higher aggregating affinity than other components, whereas methylxanthines and calcium contributed to the transformation of nano-aggregates into tea cream. Green tea nano-aggregates were partly destroyed by simulated gastrointestinal digestion, and removing theses peculiar particles dramatically attenuated the bioaccessibility of methylxanthines, theanine, and some catechin monomers in green tea infusions. This study enhanced our knowledge of molecular interactions in the formation of green tea cream and provided insight into physicochemical profiles, phytochemical nature, and functional effects of green tea nano-aggregates.

Production of monodisperse epigallocatechin gallate (EGCG) microparticles by spray drying for high antioxidant activity retention.

PubMed

Fu, Nan; Zhou, Zihao; Jones, Tyson Byrne; Tan, Timothy T Y; Wu, Winston Duo; Lin, Sean Xuqi; Chen, Xiao Dong; Chan, Peggy P Y

2011-07-15

Epigallocatechin gallate (EGCG) originated from green tea is well-known for its pharmaceutical potential and antiproliferating effect on carcinoma cells. For drug delivery, EGCG in a micro-/nanoparticle form is desirable for their optimized chemopreventive effect. In this study, first time reports that EGCG microparticles produced by low temperature spray drying can maintain high antioxidant activity. A monodisperse droplet generation system was used to realize the production of EGCG microparticles. EGCG microparticles were obtained with narrow size distribution and diameter of 30.24 ± 1.88 μM and 43.39 ± 0.69 μM for pure EGCG and lactose-added EGCG, respectively. The EC50 value (the amount of EGCG necessary to scavenge 50% of free radical in the medium) of spray dried pure EGCG particles obtained from different temperature is in the range of 3.029-3.075 μM compared to untreated EGCG with EC50 value of 3.028 μM. Varying the drying temperatures from 70°C and 130°C showed little detrimental effect on EGCG antioxidant activity. NMR spectrum demonstrated the EGCG did not undergo chemical structural change after spray drying. The major protective mechanism was considered to be: (1) the use of low temperature and (2) the heat loss from water evaporation that kept the particle temperature at low level. With further drier optimization, this monodisperse spray drying technique can be used as an efficient and economic approach to produce EGCG micro-/nanoparticles. Published by Elsevier B.V.

Functional Properties of Novel Epigallocatechin Gallate Glucosides Synthesized by Using Dextransucrase from Leuconostoc mesenteroides B-1299CB4.

PubMed

Kim, Jiyoun; Nguyen, Thi Thanh Hanh; Kim, Nahyun M; Moon, Young-Hwan; Ha, Jung-Min; Park, Namhyeon; Lee, Dong-Gu; Hwang, Kyeong-Hwan; Park, Jun-Seong; Kim, Doman

2016-12-07

Epigallocatechin gallate (EGCG) is the most abundant catechin found in the leaves of green tea, Camellia sinensis. In this study, novel epigallocatechin gallate-glucocides (EGCG-Gs) were synthesized by using dextransucrase from Leuconostoc mesenteroides B-1299CB4. Response surface methodology was adopted to optimize the conversion of EGCG to EGCG-Gs, resulting in a 91.43% conversion rate of EGCG. Each EGCG-G was purified using a C 18 column. Of nine EGCG-Gs identified by nuclear magnetic resonance analysis, five EGCG-Gs (2 and 4-7) were novel compounds with yields of 2.2-22.6%. The water solubility of the five novel compounds ranged from 229.7 to 1878.5 mM. The 5'-OH group of EGCG-Gs expressed higher antioxidant activities than the 4'-OH group of EGCG-Gs. Furthermore, glucosylation at 7-OH group of EGCG-Gs was found to be responsible for maintaining tyrosinase inhibitory activity and increasing browning-resistant activities.

Phenolic promiscuity in the cell nucleus--epigallocatechingallate (EGCG) and theaflavin-3,3'-digallate from green and black tea bind to model cell nuclear structures including histone proteins, double stranded DNA and telomeric quadruplex DNA.

PubMed

Mikutis, Gediminas; Karaköse, Hande; Jaiswal, Rakesh; LeGresley, Adam; Islam, Tuhidul; Fernandez-Lahore, Marcelo; Kuhnert, Nikolai

2013-02-01

Flavanols from tea have been reported to accumulate in the cell nucleus in considerable concentrations. The nature of this phenomenon, which could provide novel approaches in understanding the well-known beneficial health effects of tea phenols, is investigated in this contribution. The interaction between epigallocatechin gallate (EGCG) from green tea and a selection of theaflavins from black tea with selected cell nuclear structures such as model histone proteins, double stranded DNA and quadruplex DNA was investigated using mass spectrometry, Circular Dichroism spectroscopy and fluorescent assays. The selected polyphenols were shown to display affinity to all of the selected cell nuclear structures, thereby demonstrating a degree of unexpected molecular promiscuity. Most interestingly theaflavin-digallate was shown to display the highest affinity to quadruplex DNA reported for any naturally occurring molecule reported so far. This finding has immediate implications in rationalising the chemopreventive effect of the tea beverage against cancer and possibly the role of tea phenolics as "life span essentials".

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

PubMed

Xia, En-Hua; Zhang, Hai-Bin; Sheng, Jun; Li, Kui; Zhang, Qun-Jie; Kim, Changhoon; Zhang, Yun; Liu, Yuan; Zhu, Ting; Li, Wei; Huang, Hui; Tong, Yan; Nan, Hong; Shi, Cong; Shi, Chao; Jiang, Jian-Jun; Mao, Shu-Yan; Jiao, Jun-Ying; Zhang, Dan; Zhao, Yuan; Zhao, You-Jie; Zhang, Li-Ping; Liu, Yun-Long; Liu, Ben-Ying; Yu, Yue; Shao, Sheng-Fu; Ni, De-Jiang; Eichler, Evan E; Gao, Li-Zhi

2017-06-05

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. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Tea, coffee, and cocoa as ultraviolet radiation protectants for the beet armyworm nucleopolyhedrovirus.

PubMed

El-Salamouny, S; Ranwala, D; Shapiro, M; Shepard, B M; Farrar, Robert R

2009-10-01

The addition of 1% (wt:vol) aqueous extracts of cocoa (Theobroma cacao L.) (Malvales: Malvaceae), coffee (Coffea arabica L.) (Gentianales: Rubiaceae), and green and black tea (Camellia sinensis L.) (Ericales: Theaceae) provided excellent UV radiation protection for the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), nucleopolyhedrovirus under laboratory conditions. Aqueous extracts of coffee, green tea, and black tea at 0.5% provided 85-100% UV protection, whereas cocoa provided 50% UV protection. Epigallocatechin gallate (EGCG), a component of green tea, and caffeine, a component of tea and coffee, also were tested as UV protectants. Both compounds were ineffective when tested alone. When EGCG and caffeine were combined, UV protection increased in a synergistic manner, but <35% of the original virus activity was maintained. This study demonstrated that coffee was comparable to green tea and black tea as a UV protectant. Further studies should be conducted to optimize their use in biopesticide formulations.

Epigallocatechin-3-Gallate (EGCG) Reduces Rotenone Effect on Stallion Sperm-Zona Pellucida Heterologous Binding.

PubMed

Plaza Dávila, M; Bucci, D; Galeati, G; Peña, F J; Mari, G; Giaretta, E; Tamanini, C; Spinaci, M

2015-12-01

Stallion spermatozoa are highly dependent on oxidative phosphorylation for ATP production to achieve normal sperm function and to fuel the motility. The aim of this study was to evaluate the response of equine sperm under capacitating conditions to the inhibition of mitochondrial complex I by rotenone and to test whether epigallocatechin-3-gallate (EGCG), a natural polyphenol component of green tea, could counteract this effect. After 2-h incubation of stallion spermatozoa in modified Tyrode's medium, rotenone (100 nm, 500 nm and 5 μm) and EGCG (10, 20 and 60 μm), alone or in combination, did not induce any significant difference on the percentage of viable cells, live sperm with active mitochondria and spermatozoa with intact acrosome. The inhibition of complex I of mitochondrial respiratory chain of stallion sperm with rotenone exerted a negative effect on heterologous ZP binding ability. EGCG at the concentrations of 10 and 20 μm (but not of 60 μm) induced a significant increase in the number of sperm bound to the ZP compared with that for control. Moreover, when stallion sperm were treated with rotenone 100 nm, the presence of EGCG at all the concentrations tested (10, 20 and 60 μm) significantly increased the number of sperm bound to the ZP up to control levels, suggesting that this green tea polyphenol is able to reduce the toxicity of rotenone. © 2015 Blackwell Verlag GmbH.

Epigallocatechin gallate (EGCG) stimulates autophagy in vascular endothelial cells: a potential role for reducing lipid accumulation.

PubMed

Kim, Hae-Suk; Montana, Vedrana; Jang, Hyun-Ju; Parpura, Vladimir; Kim, Jeong-a

2013-08-02

Epigallocatechin gallate (EGCG) is a major polyphenol in green tea that has beneficial effects in the prevention of cardiovascular disease. Autophagy is a cellular process that protects cells from stressful conditions. To determine whether the beneficial effect of EGCG is mediated by a mechanism involving autophagy, the roles of the EGCG-stimulated autophagy in the context of ectopic lipid accumulation were investigated. Treatment with EGCG increased formation of LC3-II and autophagosomes in primary bovine aortic endothelial cells (BAEC). Activation of calmodulin-dependent protein kinase kinase β was required for EGCG-induced LC3-II formation, as evidenced by the fact that EGCG-induced LC3-II formation was significantly impaired by knockdown of calmodulin-dependent protein kinase kinase β. This effect is most likely due to cytosolic Ca(2+) load. To determine whether EGCG affects palmitate-induced lipid accumulation, the effects of EGCG on autophagic flux and co-localization of lipid droplets and autophagolysosomes were examined. EGCG normalized the palmitate-induced impairment of autophagic flux. Accumulation of lipid droplets by palmitate was markedly reduced by EGCG. Blocking autophagosomal degradation opposed the effect of EGCG in ectopic lipid accumulation, suggesting the action of EGCG is through autophagosomal degradation. The mechanism for this could be due to the increased co-localization of lipid droplets and autophagolysosomes. Co-localization of lipid droplets with LC3 and lysosome was dramatically increased when the cells were treated with EGCG and palmitate compared with the cells treated with palmitate alone. Collectively, these findings suggest that EGCG regulates ectopic lipid accumulation through a facilitated autophagic flux and further imply that EGCG may be a potential therapeutic reagent to prevent cardiovascular complications.

EGCG Inhibits Proliferation, Invasiveness and Tumor Growth by Up-Regulation of Adhesion Molecules, Suppression of Gelatinases Activity, and Induction of Apoptosis in Nasopharyngeal Carcinoma Cells

PubMed Central

Fang, Chih-Yeu; Wu, Chung-Chun; Hsu, Hui-Yu; Chuang, Hsin-Ying; Huang, Sheng-Yen; Tsai, Ching-Hwa; Chang, Yao; Tsao, George Sai-Wah; Chen, Chi-Long; Chen, Jen-Yang

2015-01-01

(−)-Epigallocatechin-3-gallate (EGCG), a major green tea polyphenol, has been shown to inhibit the proliferation of a variety of tumor cells. Epidemiological studies have shown that drinking green tea can reduce the incidence of nasopharyngeal carcinoma (NPC), yet the underlying mechanism is not well understood. In this study, the inhibitory effect of EGCG was tested on a set of Epstein Barr virus-negative and -positive NPC cell lines. Treatment with EGCG inhibited the proliferation of NPC cells but did not affect the growth of a non-malignant nasopharyngeal cell line, NP460hTert. Moreover, EGCG treated cells had reduced migration and invasive properties. The expression of the cell adhesion molecules E-cadherin and β-catenin was found to be up-regulated by EGCG treatment, while the down-regulation of matrix metalloproteinases (MMP)-2 and MMP-9 were found to be mediated by suppression of extracellular signal-regulated kinase (ERK) phosphorylation and AP-1 and Sp1 transactivation. Spheroid formation by NPC cells in suspension was significantly inhibited by EGCG. Oral administration of EGCG was capable of suppressing tumor growth in xenografted mice bearing NPC tumors. Treatment with EGCG was found to elevate the expression of p53 and p21, and eventually led to apoptosis of NPC cells via caspase 3 activation. The nuclear translocation of NF-κB and β-catenin was also suppressed by EGCG treatment. These results indicate that EGCG can inhibit the proliferation and invasiveness, and induce apoptosis, of NPC cells, making it a promising agent for chemoprevention or adjuvant therapy of NPC. PMID:25625511

Nε-(carboxymethyl)lysine and Nε-(carboxyethyl)lysine in tea and the factors affecting their formation.

PubMed

Jiao, Ye; He, Jialiang; Li, Fengli; Tao, Guanjun; Zhang, Shuang; Zhang, Shikang; Qin, Fang; Zeng, Maomao; Chen, Jie

2017-10-01

The levels of N ε -(carboxymethyl)lysine (CML) and N ε -(carboxyethyl)lysine (CEL) in 99 tea samples from 14 geographic regions, including 44 green, 7 oolong, 41 black, and 7 dark teas were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The CML and CEL contents varied from 11.0 to 1701μg/g tea and 4.6 to 133μg/g tea, respectively. Dark tea presented the highest levels of CML and CEL, whereas green and oolong teas presented the lowest levels. Five kinds of catechins in the tea were also analyzed, and spearman's correlation coefficients showed that all the catechins negatively correlated with CML and CEL. The results suggested that withering, fermentation and pile fermentation may facilitate the formation of CML and CEL. Catechins might inhibit the formation of CML and CEL, but their inhibitory effects may be affected by tea processing. The results of this study are useful for the production of healthier tea. Copyright © 2017. Published by Elsevier Ltd.

Evaluation of thrombin inhibitory activity of catechins by online capillary electrophoresis-based immobilized enzyme microreactor and molecular docking.

PubMed

Li, Qiao-Qiao; Yang, Feng-Qing; Wang, Yin-Zhen; Wu, Zhao-Yu; Xia, Zhi-Ning; Chen, Hua

2018-08-01

An online capillary electrophoresis (CE)-based thrombin (THR) immobilized enzyme microreactor (IMER) method was established to screen THR inhibitors in this study. S-2366 was used as chromogenic substrate for determination of THR activity and other kinetic constants. After continuously run for 50 times, the prepared IMER could still remain 89% of the initial immobilized enzyme activity. The Michaelis-Menten constant (K m ) of immobilized THR was measured as 0.514 mmol/L and the half-maximal inhibitory concentration (IC 50 ) and inhibition constant (K i ) of argatroban on THR were determined as 78.07 and 26.53 nmol/L, respectively, which indicated that CE-based THR IMER was successfully established and could be applied to screen THR inhibitors. Then the prepared IMER was used to investigate the inhibitory potency on THR of four main catechins in green tea including epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG). The results showed that ECG and EGCG had good THR inhibition activity and their inhibition rates at concentration of 200 μmol/L were 53.2 ± 3.8% and 55.8 ± 2.6%, respectively, which was in consistent with the results of microplate reader assay. Additionally, molecular docking results showed that the benzopyran groups of ECG and EGCG were inserted into the THR active pocket and interacted with residues LYS60F, TRP60D, TRY60A, IEU99, GLY216, HIS57 and SER195, but EC and EGC did not. Therefore, the developed CE-based THR IMER is reliable method for measuring THR inhibitory activity of natural inhibitors. Copyright © 2018 Elsevier B.V. All rights reserved.

Extraction of Epigallocatechin Gallate and Epicatechin Gallate from Tea Leaves Using β-Cyclodextrin.

PubMed

Cui, Lu; Liu, Yuxuan; Liu, Ting; Yuan, Yahong; Yue, Tianli; Cai, Rui; Wang, Zhouli

2017-02-01

Use of organic solvents to extract phenolic compounds from plants may result in environmental pollution and cause health problems in persons. Replacing organic extraction solvents by green extracting agents without affecting the extraction yield is one of the most pressing problems to be solved. The aim of this study is to evaluate the capacity of β-cyclodextrin (β-CD) to recover phenolic compounds from tea leaves. The extract obtained using the ethanol/water mixture presented the highest total phenolic content, followed by those obtained using β-CD solution and water. HPLC analysis of the extracts showed that the addition of β-CD to the extracting agent had a selective effect on the extraction of epigallocatechin gallate (EGCG) and epicatechin gallate (ECG). The extraction yield of EGCG and ECG using 15 g/L β-CD were higher than that obtained using water and 50% ethanol. Molecular docking results indicated that the molecules of EGCG and ECG were more inclined to interact with β-CD than epigallocatechin, epicatechin, and gallocatechin. The impact of β-CD concentration, temperature, and time on EGCG and ECG extraction from tea leaves was investigated and the maximum amount of EGCG (118.7 mg/g) and ECG (54.6 mg/g) were achieved when extracted with 25 g/L aqueous β-CD solution at 60 °C for 60 min. The present study indicates that aqueous β-CD can be used as an alternative to organic solvents to recover EGCG and ECG from tea leaves. © 2017 Institute of Food Technologists®.

Synthesis and Structure activity relationships of EGCG Analogues, A Recently Identified Hsp90 Inhibitor

PubMed Central

Khandelwal, Anuj; Hall, Jessica

2014-01-01

Epigallocatechin-3-gallate (EGCG), the principal polyphenol isolated from green tea, was recently shown to inhibit Hsp90, however structure-activity relationships for this natural product have not yet been produced. Herein, we report the synthesis and biological evaluation of EGCG analogues to establish structure-activity relationships between EGCG and Hsp90. All four rings as well as the linker connecting the C- and the D-rings were systematically investigated, which led to the discovery of compounds that inhibit Hs90 and display improvement in efficacy over EGCG. Anti-proliferative activity of all the analogues was determined against MCF-7 and SKBr3 cell lines and Hsp90 inhibitory activity of four most potent analogues was further evaluated by western blot analyses and degradation of Hsp90-dependent client proteins. Prenyl substituted aryl ester of 3,5-dihydroxychroman-3-ol ring system was identified as novel scaffold that exhibit Hsp90 inhibitory activity. PMID:23834230

Wnt/β-catenin pathway mediates (-)-Epigallocatechin-3-gallate (EGCG) inhibition of lung cancer stem cells.

PubMed

Zhu, Jianyun; Jiang, Ye; Yang, Xue; Wang, Shijia; Xie, Chunfeng; Li, Xiaoting; Li, Yuan; Chen, Yue; Wang, Xiaoqian; Meng, Yu; Zhu, Mingming; Wu, Rui; Huang, Cong; Ma, Xiao; Geng, Shanshan; Wu, Jieshu; Zhong, Caiyun

2017-01-01

Cancer stem cells (CSCs) play essential role in the progression of many tumors. Wnt/β-catenin pathway is crucial in maintaining the stemness of CSCs. (-)-Epigallocatechin-3-gallate (EGCG), the major bioactive component in green tea, has been shown to possess anti-cancer activity. To date, the interventional effect of EGCG on lung CSCs has not been elucidated yet. In the present study, tumorsphere formation assay was used to enrich lung CSCs from A549 and H1299 cells. We revealed that Wnt/β-catenin pathway was activated in lung CSCs, and downregulation of β-catenin, abolished lung CSCs traits. Our study further illustrated that EGCG effectively diminished lung CSCs activity by inhibiting tumorsphere formation, decreasing lung CSCs markers, suppressing proliferation and inducing apoptosis. Moreover, We showed that EGCG downregulated Wnt/β-catenin activation, while upregulation of Wnt/β-catenin dampened the inhibitory effects of EGCG on lung CSCs. Taken together, these results demonstrated the role of Wnt/β-catenin pathway in regulating lung CSCs traits and EGCG intervention of lung CSCs. Findings from this study could provide new insights into the molecular mechanisms of lung CSCs intervention. Copyright © 2016 Elsevier Inc. All rights reserved.

Wnt/β-catenin pathway mediates (−)-Epigallocatechin-3-gallate (EGCG) inhibition of lung cancer stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Jianyun; Jiang, Ye; Yang, Xue

Cancer stem cells (CSCs) play essential role in the progression of many tumors. Wnt/β-catenin pathway is crucial in maintaining the stemness of CSCs. (−)-Epigallocatechin-3-gallate (EGCG), the major bioactive component in green tea, has been shown to possess anti-cancer activity. To date, the interventional effect of EGCG on lung CSCs has not been elucidated yet. In the present study, tumorsphere formation assay was used to enrich lung CSCs from A549 and H1299 cells. We revealed that Wnt/β-catenin pathway was activated in lung CSCs, and downregulation of β-catenin, abolished lung CSCs traits. Our study further illustrated that EGCG effectively diminished lung CSCs activitymore » by inhibiting tumorsphere formation, decreasing lung CSCs markers, suppressing proliferation and inducing apoptosis. Moreover, We showed that EGCG downregulated Wnt/β-catenin activation, while upregulation of Wnt/β-catenin dampened the inhibitory effects of EGCG on lung CSCs. Taken together, these results demonstrated the role of Wnt/β-catenin pathway in regulating lung CSCs traits and EGCG intervention of lung CSCs. Findings from this study could provide new insights into the molecular mechanisms of lung CSCs intervention. - Highlights: • EGCG inhibited lung CSCs activity. • EGCG inhibited lung CSCs activity via Wnt/β-catenin pathway suppression. • EGCG may prove to be a potential therapeutic agent for lung cancer.« less

Interactions of tea tannins and condensed tannins with proteins.

PubMed

Frazier, Richard A; Deaville, Eddie R; Green, Rebecca J; Stringano, Elisabetta; Willoughby, Ian; Plant, John; Mueller-Harvey, Irene

2010-01-20

Binding parameters for the interactions of four types of tannins: tea catechins, grape seed proanthocyanidins, mimosa 5-deoxy proanthocyanidins, and sorghum procyanidins (mDP=17), with gelatin and bovine serum albumin (BSA) have been determined from isothermal titration calorimetry data. Equilibrium binding constants determined for the interaction with gelatin were in the range 10(4) to 10(6) M(-1) and in the order: sorghum procyanidins > grape seed proanthocyanidins > mimosa 5-deoxy proanthocyanidins > tea catechins. Interaction with BSA was generally weaker, with equilibrium binding constants of < or =10(3)M(-1) for grape seed proanthocyanidins, mimosa 5-deoxy proanthocyanidins and tea catechins, and 10(4)M(-1) for the sorghum procyanidins. In all cases the interactions with proteins were exothermic and involved multiple binding sites on the protein. The data are discussed in relation to the structures and the known nutritional effects of the condensed tannins.

Improving the sweet aftertaste of green tea infusion with tannase.

PubMed

Zhang, Ying-Na; Yin, Jun-Feng; Chen, Jian-Xin; Wang, Fang; Du, Qi-Zhen; Jiang, Yong-Wen; Xu, Yong-Quan

2016-02-01

The present study aims to improve the sweet aftertaste and overall acceptability of green tea infusion by hydrolyzing (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG) with tannase. The results showed that the intensity of the sweet aftertaste and the score of overall acceptability of the green tea infusion significantly increased with the extension of the hydrolyzing treatment. (-)-Epigallocatechin (EGC) and (-)-epicatechin (EC) were found to be the main contributors for the sweet aftertaste, based on a trial compatibility with EGCG, ECG, EGC, and EC monomers, and a synergistic action between EGC and EC to sweet aftertaste was observed. A 2.5:1 (EGC/EC) ratio with a total concentration of 3.5 mmol/L gave the most satisfying sweet aftertaste, and the astringency significantly inhibited the development of the sweet aftertaste. These results can help us to produce a tea beverage with excellent sweet aftertaste by hydrolyzing the green tea infusion with tannase. Copyright © 2015 Elsevier Ltd. All rights reserved.

White and green teas (Camellia sinensis var. sinensis): variation in phenolic, methylxanthine, and antioxidant profiles.

PubMed

Unachukwu, Uchenna J; Ahmed, Selena; Kavalier, Adam; Lyles, James T; Kennelly, Edward J

2010-08-01

Recent investigations have associated white teas with anti-carcinogenic, immune-boosting, and antioxidative properties that may impact human health in a manner comparable to green teas. An in-depth chemical analysis of white tea types was conducted to quantify polyphenols and antioxidant potential of 8 commercially available white teas, and compare them to green tea. Extraction and HPLC protocols were optimized and validated for the quantification of 9 phenolic and 3 methylxanthine compounds to examine inter- and intra-variation in white and green tea types and subtypes. A sampling strategy was devised to assess various subtypes procured from different commercial sources. Variation in antioxidant activity and total phenolic content (TPC) of both tea types was further assessed by the 1-1-diphenyl-2-picrylhydrazyl (DPPH) and Folin-Ciocalteau (F-C) assays, respectively. Total catechin content (TCC) for white teas ranged widely from 14.40 to 369.60 mg/g of dry plant material for water extracts and 47.16 to 163.94 mg/g for methanol extracts. TCC for green teas also ranged more than 10-fold, from 21.38 to 228.20 mg/g of dry plant material for water extracts and 32.23 to 141.24 mg/g for methanol extracts. These findings indicate that statements suggesting a hierarchical order of catechin content among tea types are inconclusive and should be made with attention to a sampling strategy that specifies the tea subtype and its source. Certain white teas have comparable quantities of total catechins to some green teas, but lesser antioxidant capacity, suggesting that white teas have fewer non-catechin antioxidants present. Practical Application: In this investigation white and green teas were extracted in ways that mimic common tea preparation practices, and their chemical profiles were determined using validated analytical chemistry methods. The results suggest certain green and white tea types have comparable levels of catechins with potential health promoting qualities

Stability of catechins in green tea nutraceutical products: application of solid phase extraction-thin layer chromatography densitometry.

PubMed

Abd-Elsalam, Heba-Alla H; Al-Ghobashy, Medhat A; Zaazaa, Hala E; Ibrahim, Mohamed A

2014-08-01

Epigallocatechin gallate (EGCG) is a powerful antioxidant and commonly used nutraceutical. Accelerated stability of EGCG in tablet formulations was investigated. LLE and SPE were employed for sample clean-up and enrichment of EGCG over caffeine. Samples were analysed after spiking with fixed concentration of gallic acid (GA), in order to verify reproducibility of analysis. A TLC-densitometric assay was developed and validated for determination of % loss EGCG. EGCG, GA and caffeine were resolved with Rf values 0.54, 0.69 and 0.80, respectively. LC-MS/MS was used to verify identity and purity of the EGCG band. Determination was carried out over a concentration range of 0.50-5.00μg/band and 0.20-2.40μg/band for GA and caffeine, respectively. Results showed significant reduction in EGCG content after one, three and six months: 24.00%, 28.00% and 52.00% respectively. Results continue to demonstrate that stability of nutraceutical products should be investigated in-depth using industry-oriented protocols before granting marketing authorisation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Repeated dose studies with pure Epigallocatechin-3-gallate demonstrated dose and route dependant hepatotoxicity with associated dyslipidemia.

PubMed

Ramachandran, Balaji; Jayavelu, Subramani; Murhekar, Kanchan; Rajkumar, Thangarajan

2016-01-01

EGCG (Epigallocatechin-3-gallate) is the major active principle catechin found in green tea. Skepticism regarding the safety of consuming EGCG is gaining attention, despite the fact that it is widely being touted for its potential health benefits, including anti-cancer properties. The lack of scientific data on safe dose levels of pure EGCG is of concern, while EGCG has been commonly studied as a component of GTE (Green tea extract) and not as a single active constituent. This study has been carried out to estimate the maximum tolerated non-toxic dose of pure EGCG and to identify the treatment related risk factors. In a fourteen day consecutive treatment, two different administration modalities were compared, offering an improved [i.p (intraperitoneal)] and limited [p.o (oral)] bioavailability. A trend of dose and route dependant hepatotoxicity was observed particularly with i.p treatment and EGCG increased serum lipid profile in parallel to hepatotoxicity. Fourteen day tolerable dose of EGCG was established as 21.1 mg/kg for i.p and 67.8 mg/kg for p.o. We also observed that, EGCG induced effects by both treatment routes are reversible, subsequent to an observation period for further fourteen days after cessation of treatment. It was demonstrated that the severity of EGCG induced toxicity appears to be a function of dose, route of administration and period of treatment.

Novel epigallocatechin gallate analogs as potential anticancer agents: a patent review (2009 – present)

PubMed Central

Landis-Piwowar, Kristin; Chen, Di; Foldes, Robert; Chan, Tak-Hang; Dou, Qing Ping

2013-01-01

Introduction Over the past three years numerous patents and patent applications have been published relating to scientific advances in the use of the green tea polyphenol epigallocatechin gallate (EGCG) (the most abundant, and bioactive compound in green tea) and its analogs as anticancer agents. EGCG affects multiple molecular targets involved in cancer cell proliferation and survival; however, polyphenolic catechins, such as EGCG, generally exhibit poor oral bioavailability. Since the anticancer activity of polyphenols largely depends on their susceptibility to biotransformation reactions, numerous EGCG derivatives, analogs and prodrugs have been designed to improve the stability, bioavailability and anticancer potency of the native compound. Areas covered This review focuses on the applications of EGCG and its analogs, derivatives and prodrugs in the prevention and treatment of human cancers. A comprehensive description of patents related to EGCG and its derivatives, analogs and prodrugs and their uses as anticancer agents is included. Expert opinion EGCG targets multiple essential survival proteins and pathways in human cancer cells. Because it is unstable physiologically, numerous alterations to the EGCG molecule have been patented, either to improve the integrity of the native compound or to generate a more stable yet similarly efficacious molecule. EGCG and its derivatives, analogs and prodrugs could be developed into future drugs for chemoprevention, chemosensitization, radiosensitization and/or cancer interception. PMID:23230990

[Preparation and component analysis of tea pigments].

PubMed

Li, Daxiang; Wan, Xiaochun; Xia, Tao

2004-11-01

To prepare tea pigments. Tea pigments are prepared by solvent extraction from Sri lanka black tea. Tea pigments contains the components as follows: caffeine 1.77%, epigallocatechin 1.37%, catechin 1.20%, epicatechin 9.55%, epigallocatechin gallate 10.52%, epicatechin gallate 9.94%, theaflavin 10.34%, theaflavin monogallate 9.57%, theaflavin digallate 4.81%, thearubigin about 40.93%. The best proportions of the compound that are obtained with HPLC analysis.

Bioassay-guided purification and identification of antimicrobial components in Chinese green tea extract.

PubMed

Si, Weiduo; Gong, Joshua; Tsao, Rong; Kalab, Milosh; Yang, Raymond; Yin, Yulong

2006-09-01

The Chinese green tea extract was found to strongly inhibit the growth of major food-borne pathogens, Escherichia coli O157:H7, Salmonella Typhimurium DT104, Listeria monocytogenes, Staphylococcus aureus, and a diarrhoea food-poisoning pathogen Bacillus cereus, by 44-100% with the highest activity found against S. aureus and lowest against E. coli O157:H7. A bioassay-guided fractionation technique was used for identifying the principal active component. A simple and efficient reversed-phase high-speed counter-current chromatography (HSCCC) method was developed for the separation and purification of four bioactive polyphenol compounds, epicatechin gallate (ECG), epigallocatechin gallate (EGCG), epicatechin (EC), and caffeine (CN). The structures of these polyphenols were confirmed with mass spectrometry. Among the four compounds, ECG and EGCG were the most active, particularly EGCG against S. aureus. EGCG had the lowest MIC90 values against S. aureus (MSSA) (58 mg/L) and its methicilin-resistant S. aureus (MRSA) (37 mg/L). Scanning electron microscopy (SEM) studies showed that these two compounds altered bacterial cell morphology, which might have resulted from disturbed cell division. This study demonstrated a direct link between the antimicrobial activity of tea and its specific polyphenolic compositions. The activity of tea polyphenols, particularly EGCG on antibiotics-resistant strains of S. aureus, suggests that these compounds are potential natural alternatives for the control of bovine mastitis and food poisoning caused by S. aureus.

Optimization on condition of epigallocatechin-3-gallate (EGCG) nanoliposomes by response surface methodology and cellular uptake studies in Caco-2 cells

NASA Astrophysics Data System (ADS)

Luo, Xiaobo; Guan, Rongfa; Chen, Xiaoqiang; Tao, Miao; Ma, Jieqing; Zhao, Jin

2014-06-01

The major component in green tea polyphenols, epigallocatechin-3-gallate (EGCG), has been demonstrated to prevent carcinogenesis. To improve the effectiveness of EGCG, liposomes were used as a carrier in this study. Reverse-phase evaporation method besides response surface methodology is a simple, rapid, and beneficial approach for liposome preparation and optimization. The optimal preparation conditions were as follows: phosphatidylcholine-to-cholesterol ratio of 4.00, EGCG concentration of 4.88 mg/mL, Tween 80 concentration of 1.08 mg/mL, and rotary evaporation temperature of 34.51°C. Under these conditions, the experimental encapsulation efficiency and size of EGCG nanoliposomes were 85.79% ± 1.65% and 180 nm ± 4 nm, which were close with the predicted value. The malondialdehyde value and the release test in vitro indicated that the prepared EGCG nanoliposomes were stable and suitable for more widespread application. Furthermore, compared with free EGCG, encapsulation of EGCG enhanced its inhibitory effect on tumor cell viability at higher concentrations.

PPARα activation sensitizes cancer cells to epigallocatechin-3-gallate (EGCG) treatment via suppressing heme oxygenase-1.

PubMed

Zhang, Shuyu; Yang, Xiaodong; Luo, Judong; Ge, Xin; Sun, Wanping; Zhu, Hong; Zhang, Weiping; Cao, Jianping; Hou, Yinglong

2014-01-01

Epigallocatechin-3-gallate (EGCG), the major polyphenolic constituent of green tea, is a potent antioxidant that may have potential therapeutic applications for the treatment of many disorders, including cancer. Peroxisome proliferator-activated receptor-α (PPARα) has been shown to play a key role in diverse metabolic and cellular functions. PPARα modulates target gene expression by binding to specific regions on the DNA of target genes. The effects and mechanisms of PPARα activation on EGCG efficacy have not yet been analyzed in cancer cells. We found that when cancer cells were exposed to EGCG, the expression of PPARα was increased at the protein level in a dose-dependent manner. The PPARα agonist clofibrate blocked cytoprotective heme oxygenase-1 (HO-1) induction and sensitized multiple types of cancer cells to EGCG-induced cell death. Conversely, the PPARα inhibitor G6471 and PPARα siRNA increased HO-1 expression. Electro-mobility shift assays (EMSA) and in vivo chromatin immunoprecipitation (ChIP) confirmed that PPARα interacts with the peroxisome proliferator-responsive element of the HO-1 promoter. Moreover, cell death induced by EGCG plus clofibrate was partially reversed by HO-1 overexpression in PANC1 cells. These results indicate that PPARα is a direct and negative regulator of HO-1 induced by EGCG and confers cell susceptibility to EGCG.

Polyphenolic chemistry of tea and coffee: a century of progress.

PubMed

Wang, Yu; Ho, Chi-Tang

2009-09-23

Tea and coffee, the most popular beverages in the world, have been consumed for thousands of years for their alluring flavors and health benefits. Polyphenols, particularly flavonoids and phenolic acids, are of great abundance in tea and coffee and contribute a lot to their flavor and health properties. This paper reviews the polyphenol chemistry of tea and coffee, specifically their stability, and scavenging ability of reactive oxygen species (ROS) and reactive carbonyl species (RCS). During the manufacturing and brewing process, green tea and black tea polyphenols undergo epimerization and oxidation, respectively. Meanwhile, the lactonization and the polymerization of chlorogenic acid are the major causes for the degradation of polyphenols in coffee. Tea catechins, besides having antioxidant properties, have the novel characteristic of trapping reactive carbonyl species. The A ring of the catechins is the binding site for RCS trapping, whereas the B ring is the preferred site for antioxidation.

Safety and anti-hyperglycemic efficacy of various tea types in mice

PubMed Central

Han, Manman; Zhao, Guangshan; Wang, Yijun; Wang, Dongxu; Sun, Feng; Ning, Jingming; Wan, Xiachun; Zhang, Jinsong

2016-01-01

Tea, a beverage consumed worldwide, has proven anti-hyperglycemic effects in animal models. Better efficacies of tea beverages are frequently associated with high-dose levels, whose safety attracts considerable attention. Based on the inherent nature of tea catechin oxidation, fresh tea leaves are manufactured into diverse tea types by modulating the oxidation degree of catechins. The present study aimed to assess various tea types for their safety properties and anti-hyperglycemic effects. Mice were allowed free access to tea infusion (1:30, w/v) for one week, and the rare smoked tea caused salient adverse reactions, including hepatic and gastrointestinal toxicities; meanwhile, the widely-consumed green and black teas, unlike the rare yellow tea, suppressed growth in fast-growing healthy mice. When mice were fed a high-fat diet and allowed free access to tea infusion (1:30, w/v) for 25 days, only yellow tea significantly reduced blood glucose. Therefore, various teas showed different safety profiles as well as anti-hyperglycemic efficacy strengths. To achieve an effective and safe anti-hyperglycemic outcome, yellow tea, which effectively suppressed high-fat diet-induced early elevation of hepatic thioredoxin-interacting protein, is an optimal choice. PMID:27531374

A 3-day EGCG-supplementation reduces interstitial lactate concentration in skeletal muscle of overweight subjects

PubMed Central

Most, Jasper; van Can, Judith G P; van Dijk, Jan-Willem; Goossens, Gijs H.; Jocken, Johan; Hospers, Jeannette J.; Bendik, Igor; Blaak, Ellen E.

2015-01-01

Green tea, particularly epigallocatechin-3-gallate (EGCG), may affect body weight and composition, possibly by enhancing fat oxidation. The aim of this double-blind, randomized placebo-controlled cross-over study was to investigate whether 3-day supplementation with EGCG (282mg/day) stimulates fat oxidation and lipolysis in 24 overweight subjects (age = 30 ± 2yrs, BMI = 27.7 ± 0.3 kg/m2). Energy expenditure, substrate metabolism and circulating metabolites were determined during fasting and postprandial conditions. After 6 h, a fat biopsy was collected to examine gene expression. In 12 subjects, skeletal muscle glycerol, glucose and lactate concentrations were determined using microdialysis. EGCG-supplementation did not alter energy expenditure and substrate oxidation compared to placebo. Although EGCG reduced postprandial circulating glycerol concentrations (P = 0.015), no difference in skeletal muscle lipolysis was observed. Fasting (P = 0.001) and postprandial (P = 0.003) skeletal muscle lactate concentrations were reduced after EGCG-supplementation compared to placebo, despite similar tissue blood flow. Adipose tissue leptin (P = 0.05) and FAT/CD36 expression (P = 0.08) were increased after EGCG compared to placebo. In conclusion, 3-day EGCG-supplementation decreased postprandial plasma glycerol concentrations, but had no significant effects on skeletal muscle lipolysis and whole-body fat oxidation in overweight individuals. Furthermore, EGCG decreased skeletal muscle lactate concentrations, which suggest a shift towards a more oxidative muscle phenotype. PMID:26647963

Sustained Release Oral Nanoformulated Green Tea for Prostate Cancer

DTIC Science & Technology

2011-05-01

of EGCG : 457/168.9; • m/z transitions of ethyl gallate (internal standard): 168.9/124.9 Page 8 (A...with green tea polyphenol epigallocatechin -3- gallate . Cancer Res 2009; 69:1712-6. PMID: 19223530 3. Perez C, Sanchez A, Putnam D, Ting D, Langer R...We developed an HPLC method to determine the amount of EGCG encapsulated in the nanoparticles. HPLC analysis showed that chitosan nanoparticles can

Reorganisation of the Salivary Mucin Network by Dietary Components: Insights from Green Tea Polyphenols

PubMed Central

Davies, Heather S.; Pudney, Paul D. A.; Georgiades, Pantelis; Waigh, Thomas A.; Hodson, Nigel W.; Ridley, Caroline E.; Blanch, Ewan W.; Thornton, David J.

2014-01-01

The salivary mucins that include MUC5B (gel-forming) and MUC7 (non-gel-forming) are major contributors to the protective mucus barrier in the oral cavity, and it is possible that dietary components may influence barrier properties. We show how one dietary compound, the green tea polyphenol epigallocatechin gallate (EGCG), can substantially alter the properties of both the polymeric MUC5B network and monomeric MUC7. Using rate-zonal centrifugation, MUC5B in human whole saliva and MUC5B purified from saliva sedimented faster in the presence of EGCG. The faster sedimentation by EGCG was shown to be greater with increasing MUC5B concentration. Particle tracking microrheology was employed to determine the viscosity of purified MUC5B solutions and showed that for MUC5B solutions of 200–1600 µg/mL, EGCG caused a significant increase in mucin viscosity, which was greater at higher MUC5B concentrations. Visualisation of the changes to the MUC5B network by EGCG was performed using atomic force microscopy, which demonstrated increased aggregation of MUC5B in a heterogeneous manner by EGCG. Using trypsin-resistant, high-molecular weight oligosaccharide-rich regions of MUC5B and recombinant N-terminal and C-terminal MUC5B proteins, we showed that EGCG causes aggregation at the protein domains of MUC5B, but not at the oligosaccharide-rich regions of the mucin. We also demonstrated that EGCG caused the majority of MUC7 in human whole saliva to aggregate. Furthermore, purified MUC7 also underwent a large increase in sedimentation rate in the presence of EGCG. In contrast, the green tea polyphenol epicatechin caused no change in the sedimentation rate of either MUC5B or MUC7 in human whole saliva. These findings have demonstrated how the properties of the mucin barrier can be influenced by dietary components. In the case of EGCG, these interactions may alter the function of MUC5B as a lubricant, contributing to the astringency (dry puckering sensation) of green tea. PMID

Effect of the type of brewing water on the chemical composition, sensory quality and antioxidant capacity of Chinese teas.

PubMed

Xu, Yong-Quan; Zou, Chun; Gao, Ying; Chen, Jian-Xin; Wang, Fang; Chen, Gen-Sheng; Yin, Jun-Feng

2017-12-01

The physicochemical characteristics, sensory quality, and antioxidant activity of tea infusions prepared with purified water (PW), mineral water (MW), mountain spring water (MSW), and tap water (TW) from Hangzhou were investigated. The results showed that the taste quality, catechin concentration, and antioxidant capacity of green, oolong, and black tea infusions prepared using MW and TW were significantly lower than those prepared using PW. Extraction of catechins and caffeine was reduced with high-conductivity water, while high pH influenced the stability of catechins. PW and MSW were more suitable for brewing green and oolong teas, while MSW, with low pH and moderate ion concentration, was the most suitable water for brewing black tea. Lowering the pH of mineral water partially improved the taste quality and increased the concentration of catechins in the infusions. These results aid selection of the most appropriate water for brewing Chinese teas. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cytoprotective Effect of Epigallocatechin Gallate (EGCG)-5'-O-α-Glucopyranoside, a Novel EGCG Derivative.

PubMed

Han, Sang Yun; Kim, Eunji; Hwang, Kyeonghwan; Ratan, Zubair Ahmed; Hwang, Hyunsik; Kim, Eun-Mi; Kim, Doman; Park, Junseong; Cho, Jae Youl

2018-05-15

Epigallocatechin gallate (EGCG) is a well-studied polyphenol with antioxidant effects. Since EGCG has low solubility and stability, many researchers have modified EGCG residues to ameliorate these problems. A novel EGCG derivative, EGCG-5'- O -α-glucopyranoside (EGCG-5'Glu), was synthesized, and its characteristics were investigated. EGCG-5'Glu showed antioxidant effects in cell and cell-free systems. Under SNP-derived radical exposure, EGCG-5'Glu decreased nitric oxide (NO) production, and recovered ROS-mediated cell viability. Moreover, EGCG-5'Glu regulated apoptotic pathways (caspases) and cell survival molecules (phosphoinositide 3-kinase (PI3K) and phosphoinositide-dependent kinase 1 (PDK1)). In another radical-induced condition, ultraviolet B (UVB) irradiation, EGCG-5'Glu protected cells from UVB and regulated the PI3K/PDK1/AKT pathway. Next, the proliferative effect of EGCG-5'Glu was examined. EGCG-5'Glu increased cell proliferation by modulating nuclear factor (NF)-κB activity. EGCG-5'Glu protects and repairs cells from external damage via its antioxidant effects. These results suggest that EGCG-5'Glu could be used as a cosmetics ingredient or dietary supplement.

Alkaloid and polyphenol analysis by HPLC in green and black tea powders and their potential use as additives in ruminant diets

NASA Astrophysics Data System (ADS)

Ramdani, Diky; Chaudhry, Abdul S.; Seal, Chris J.

2018-02-01

We used HPLC to examine the bioactive compounds such as alkaloids and polyphenols in green and black tea powders and their use as potential additives in ruminant diets. Caffeine was the highest alkaloid in both green and black teas. Green tea had significantly higher concentrations of alkaloids and catechins but lower theaflavins than black tea. Epigallocatechin gallate, epicatechin gallate and epigallocatechin were the major catechins in green tea while theaflavin-3, 3'-digallate and theaflavin-3-gallate were the major theaflavins in black tea. Tea powders in ruminant diets decreased in vitro rumen ammonia and methane production without affecting volatile fatty acid profiles and the degradability of the diets. The tea powders containing variable amounts of alkaloids, catechins and theaflavins can potentially be used to decrease rumen ammonia and methane productions without any detrimental effect on rumen functions in vitro and perhaps ruminant productive efficiency.

Effects of O-methylated (-)-epigallocatechin gallate (EGCG) on LPS-induced osteoclastogenesis, bone resorption, and alveolar bone loss in mice.

PubMed

Tominari, Tsukasa; Ichimaru, Ryota; Yoshinouchi, Shosei; Matsumoto, Chiho; Watanabe, Kenta; Hirata, Michiko; Grundler, Florian M W; Inada, Masaki; Miyaura, Chisato

2017-12-01

(-)-Epigallocatechin-3- O -gallate (EGCG), present in green tea, exhibits antioxidant and antiallergy effects. EGCG3″Me, a 3- O -methylated derivative of EGCG, has been reported to show similar biological functions; the inhibitory activity of EGCG3″Me in a mouse allergy model was more potent than that of EGCG, probably due to the efficiency of absorption from the intestine. However, the functional potency of these EGCGs is controversial in each disease model. We previously observed that EGCG suppressed inflammatory bone resorption and prevented alveolar bone loss in a mouse model of periodontosis. In this study, we examined the role of EGCG3″Me in bone resorption using a mouse model of periodontitis. Lipopolysaccharide (LPS)-induced osteoclast formation was suppressed by adding EGCG3″Me to cocultures of osteoblasts and bone marrow cells, and LPS-induced bone resorption was also inhibited by EGCG3″Me in calvarial organ cultures. EGCG3″Me acted on osteoblasts and suppressed prostaglandin E (PGE) production, which is critical for inflammatory bone resorption, by inhibiting the expression of COX-2 and mPGES-1, key enzymes for PGE synthesis. In osteoclast precursor macrophages, EGCG3″Me suppressed RANKL-dependent differentiation into mature osteoclasts. In a mouse model of periodontitis, LPS-induced bone resorption was suppressed by EGCG3″Me in organ culture of mouse alveolar bone, and the alveolar bone loss was further attenuated by the treatment of EGCG3″Me in the lower gingiva in vivo . EGCG3″Me may be a potential natural compound for the protection of inflammatory bone loss in periodontitis.

The spectral properties of (-)-epigallocatechin 3-O-gallate (EGCG) fluorescence in different solvents: dependence on solvent polarity.

PubMed

Snitsarev, Vladislav; Young, Michael N; Miller, Ross M S; Rotella, David P

2013-01-01

(-)-Epigallocatechin 3-O-gallate (EGCG) a molecule found in green tea and known for a plethora of bioactive properties is an inhibitor of heat shock protein 90 (HSP90), a protein of interest as a target for cancer and neuroprotection. Determination of the spectral properties of EGCG fluorescence in environments similar to those of binding sites found in proteins provides an important tool to directly study protein-EGCG interactions. The goal of this study is to examine the spectral properties of EGCG fluorescence in an aqueous buffer (AB) at pH=7.0, acetonitrile (AN) (a polar aprotic solvent), dimethylsulfoxide (DMSO) (a polar aprotic solvent), and ethanol (EtOH) (a polar protic solvent). We demonstrate that EGCG is a highly fluorescent molecule when excited at approximately 275 nm with emission maxima between 350 and 400 nm depending on solvent. Another smaller excitation peak was found when EGCG is excited at approximately 235 nm with maximum emission between 340 and 400 nm. We found that the fluorescence intensity (FI) of EGCG in AB at pH=7.0 is significantly quenched, and that it is about 85 times higher in an aprotic solvent DMSO. The Stokes shifts of EGCG fluorescence were determined by solvent polarity. In addition, while the emission maxima of EGCG fluorescence in AB, DMSO, and EtOH follow the Lippert-Mataga equation, its fluorescence in AN points to non-specific solvent effects on EGCG fluorescence. We conclude that significant solvent-dependent changes in both fluorescence intensity and fluorescence emission shifts can be effectively used to distinguish EGCG in aqueous solutions from EGCG in environments of different polarity, and, thus, can be used to study specific EGCG binding to protein binding sites where the environment is often different from aqueous in terms of polarity.

Epigallocatechin-3-gallate (EGCG) protects skin cells from ionizing radiation via heme oxygenase-1 (HO-1) overexpression.

PubMed

Zhu, Wei; Xu, Jing; Ge, Yangyang; Cao, Han; Ge, Xin; Luo, Judong; Xue, Jiao; Yang, Hongying; Zhang, Shuyu; Cao, Jianping

2014-11-01

Epigallocatechin-3-gallate (EGCG), the major polyphenolic constituent of green tea, is a potent antioxidant and free radical scavenger that may have therapeutic applications for the treatment of many disorders. Radiation therapy is widely used for the treatment of various types of cancers; however, radiation-induced skin injury remains a serious concern. EGCG has not yet been reported as protecting skin cells against ionizing radiation. In the present study, we investigated whether EGCG confers cytoprotection against ionizing radiation. We found that, compared with the control, pretreatment with EGCG significantly enhanced the viability of human skin cells that were irradiated with X-rays, and decreased apoptosis induced by X-ray irradiation. Mito-Tracker assay showed that EGCG suppressed the damage to mitochondria induced by ionizing radiation via upregulation of SOD2. Reactive oxygen species (ROS) in HaCaT cells were significantly reduced when pretreated with EGCG before irradiation. Radiation-induced γH2AX foci, which are representative of DNA double-strand breaks, were decreased by pretreatment with EGCG. Furthermore, EGCG induced the expression of the cytoprotective molecule heme oxygenase-1 (HO-1) in a dose-dependent manner via transcriptional activation. HO-1 knockdown or treatment with the HO-1 inhibitor tin protoporphyrin (SnPPIX) reversed the protective role of EGCG, indicating an important role for HO-1. These results suggest that EGCG offers a new strategy for protecting skin against ionizing radiation. © The Author 2014. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

Epigallocatechin gallate (EGCG) attenuates infrasound-induced neuronal impairment by inhibiting microglia-mediated inflammation.

PubMed

Cai, Jing; Jing, Da; Shi, Ming; Liu, Yang; Lin, Tian; Xie, Zhen; Zhu, Yi; Zhao, Haibo; Shi, Xiaodan; Du, Fang; Zhao, Gang

2014-07-01

Infrasound, a kind of common environmental noise and a major contributor of vibroacoustic disease, can induce the central nervous system (CNS) damage. However, no relevant anti-infrasound drugs have been reported yet. Our recent studies have shown that infrasound resulted in excessive microglial activation rapidly and sequential inflammation, revealing a potential role of microglia in infrasound-induced CNS damage. Epigallocatechin gallate (EGCG), a major bioactive component in green tea, has the capacity of protecting against various neurodegenerative diseases via an anti-inflammatory mechanism. However, it is still unknown to date whether EGCG acts on infrasound-induced microglial activation and neuronal damage. We showed that, after 1-, 2- or 5-day exposure of rats to 16 Hz, 130 dB infrasound (2 h/day), EGCG significantly inhibited infrasound-induced microglial activation in rat hippocampal region, evidenced by reduced expressions of Iba-1 (a marker for microglia) and proinflammatory cytokines (IL-1β, IL-6, IL-18 and TNF-α). Moreover, infrasound-induced neuronal apoptosis in rat hippocampi was significantly suppressed by EGCG. EGCG also inhibited infrasound-induced activation of primary microglia in vitro and decreased the levels of proinflammatory cytokines in the supernatants of microglial culture, which were toxic to cultured neurons. Furthermore, EGCG attenuated infrasound-induced increases in nuclear NF-κB p65 and phosphorylated IκBα, and ameliorated infrasound-induced decrease in IκB in microglia. Therefore, our study provides the first evidence that EGCG acts against infrasound-induced neuronal impairment by inhibiting microglia-mediated inflammation through a potential NF-κB pathway-related mechanism, suggesting that EGCG can be used as a promising drug for the treatment of infrasound-induced CNS damage. Copyright © 2014 Elsevier Inc. All rights reserved.

Effect of epigallocatechin-3-gallate, major ingredient of green tea, on the pharmacokinetics of rosuvastatin in healthy volunteers

PubMed Central

Kim, Tae-Eun; Ha, Na; Kim, Yunjeong; Kim, Hyunsook; Lee, Jae Wook; Jeon, Ji-Young; Kim, Min-Gul

2017-01-01

Previous in vitro studies have demonstrated the inhibitory effect of green tea on drug transporters. Because rosuvastatin, a lipid-lowering drug widely used for the prevention of cardiovascular events, is a substrate for many drug transporters, there is a possibility that there is interaction between green tea and rosuvastatin. The aim of this study was to investigate the effect of green tea on the pharmacokinetics of rosuvastatin in healthy volunteers. An open-label, three-treatment, fixed-sequence study was conducted. On Day 1, 20 mg of rosuvastatin was given to all subjects. After a 3-day washout period, the subjects received 20 mg of rosuvastatin plus 300 mg of epigallocatechin-3-gallate (EGCG), a major ingredient of green tea (Day 4). After a 10-day pretreatment of EGCG up to Day 14, they received rosuvastatin (20 mg) plus EGCG (300 mg) once again (Day 15). Blood samples for the pharmacokinetic assessments were collected up to 8 hours after each dose of rosuvastatin. A total of 13 healthy volunteers were enrolled. Compared with the administration of rosuvastatin alone, the concomitant use at Day 4 significantly reduced the area under the concentration–time curve from time 0 to the last measurable time (AUClast) by 19% (geometric mean ratio 0.81, 90% confidence interval [CI] 0.67–0.97) and the peak plasma concentration (Cmax) by 15% (geometric mean ratio 0.85, 90% CI 0.70–1.04). AUClast or Cmax of rosuvastatin on Day 15 was not significantly different from that on Day 1. This study demonstrated that co-administration of EGCG reduces the systemic exposure of rosuvastatin by 19%, and pretreatment of EGCG can eliminate that effect of co-administration of EGCG. PMID:28533679

A randomized controlled trial of green tea catechins in protection against ultraviolet radiation-induced cutaneous inflammation.

PubMed

Farrar, Mark D; Nicolaou, Anna; Clarke, Kayleigh A; Mason, Sarah; Massey, Karen A; Dew, Tristan P; Watson, Rachel E B; Williamson, Gary; Rhodes, Lesley E

2015-09-01

Safe systemic protection from the health hazards of ultraviolet radiation (UVR) in sunlight is desirable. Green tea is consumed globally and is reported to have anti-inflammatory properties, which may be mediated through the impact on cyclooxygenase and lipoxygenase pathways. Recent data suggest that green tea catechins (GTCs) reduce acute UVR effects, but human trials examining their photoprotective potential are scarce. We performed a double-blind, randomized, placebo-controlled trial to examine whether GTCs protect against clinical, histologic, and biochemical indicators of UVR-induced inflammation. Healthy adults (aged 18-65 y, phototypes I-II) were randomly allocated to 1350 mg encapsulated green tea extract (540 mg GTC) with 50 mg vitamin C or placebo twice daily for 3 mo. Impact on skin erythema, dermal leukocytic infiltration, and concentrations of proinflammatory eicosanoids was assessed after solar-simulated UVR challenge, and subject compliance was determined through assay of urinary GTC metabolite epigallocatechin glucuronide. Volunteers were assigned to the active (n = 25) or the placebo (n = 25) group. After supplementation, median (IQR) sunburn threshold (minimal erythema dose) was 28 (20-28) and 20 (20-28) mJ/cm(2) in the active and placebo groups, respectively (nonsignificant), with no difference in AUC analysis for measured erythema index after a geometric series of 10 UVR doses. Skin immunohistochemistry showed increased neutrophil and CD3(+) T-lymphocyte numbers post-UVR in both groups (P < 0.01) with no statistically significant differences between groups after supplementation. Cyclooxygenase and lipoxygenase metabolites prostaglandin E2 (vasodilator) and 12-hydroxyeicosatetraenoicacid (chemoattractant), respectively, increased after UVR (P < 0.05), with no differences between supplementation groups. Oral GTC (1080 mg/d) with vitamin C over 3 mo did not significantly reduce skin erythema, leukocyte infiltration, or eicosanoid response to UVR

Determination of catechins and caffeine in camillia sinensis raw materials, extracts, and dietary supplements by HPLC-uv: single-laboratory validation.

PubMed

Roman, Mark C

2013-01-01

A rapid method has been developed to quantify seven catechins and caffeine in green tea (Camillia sinensis) raw material and powdered extract, and dietary supplements containing green tea extract. The method utilizes RP HPLC with a phenyl-based stationary phase and gradient elution. Detection is by UV absorbance. The total run time, including column re-equilibration, is 13 min. Single-laboratory validation (SLV) has been performed on the method to determine the repeatability, accuracy, selectivity, LOD, LOQ, ruggedness, and linearity for (+)-catechin, (-)-epicatechin, (-)-epicatechin gallate, (-)-epigallocatechin, (-)-gallocatechin gallate, (-)-epigallocatechin gallate, and (+)-gallocatechin, as well as caffeine. Repeatability precision and recovery results met AOAC guidelines for SLV studies for all catechins and caffeine down to a level of approximately 20 mg/g. Finished products containing high concentrations of minerals require the use of EDTA to prevent decomposition of the catechins.

Antioxidant and Cytoprotective Effects of Tibetan Tea and Its Phenolic Components.

PubMed

Xie, Hong; Li, Xican; Ren, Zhenxing; Qiu, Weimin; Chen, Jianlan; Jiang, Qian; Chen, Ban; Chen, Dongfeng

2018-01-24

Tibetan tea (Kangzhuan) is an essential beverage of the Tibetan people. In this study, a lyophilized aqueous extract of Tibetan tea ( LATT ) was prepared and analyzed by HPLC. The results suggested that there were at least five phenolic components, including gallic acid, and four catechins (i.e., (+)-catechin, (-)-catechin gallate ( CG ), (-)-epicatechin gallate ( ECG ), and (-)-epigallocatechin gallate). Gallic acid, the four catechins, and LATT were then comparatively investigated by four antioxidant assays: ferric reducing antioxidant power, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO•) scavenging, 1,1-diphenyl-2-picryl-hydrazl radical scavenging, and 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) radical scavenging assays. In these assays, LATT, along with the five phenolic components, increased their antioxidant effects in a concentration-dependent manner; however, the half maximal scavenging concentrations of ECG were always lower than those of CG . Gallic acid and the four catechins were also suggested to chelate Fe 2+ based on UV-visible spectral analysis. Ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) analysis suggested that, when mixed with PTIO•, the five phenolic components could yield two types of radical adduct formation (RAF) products (i.e., tea phenolic dimers and tea phenolic-PTIO• adducts). In a flow cytometry assay, (+)-catechin and LATT was observed to have a cytoprotective effect towards oxidative-stressed bone marrow-derived mesenchymal stem cells. Based on this evidence, we concluded that LATT possesses antioxidative or cytoprotective properties. These effects may mainly be attributed to the presence of phenolic components, including gallic acid and the four catechins. These phenolic components may undergo electron transfer, H⁺-transfer, and Fe 2+ -chelating pathways to exhibit antioxidative or

Green tea flavour determinants and their changes over manufacturing processes.

PubMed

Han, Zhuo-Xiao; Rana, Mohammad M; Liu, Guo-Feng; Gao, Ming-Jun; Li, Da-Xiang; Wu, Fu-Guang; Li, Xin-Bao; Wan, Xiao-Chun; Wei, Shu

2016-12-01

Flavour determinants in tea infusions and their changes during manufacturing processes were studied using Camellia sinensis cultivars 'Bai-Sang Cha' ('BAS') possessing significant floral scents and 'Fuding-Dabai Cha' ('FUD') with common green tea odour. Metabolite profiling based on odour activity threshold revealed that 'BAS' contained higher levels of the active odorants β-ionone, linalool and its two oxides, geraniol, epoxylinalool, decanal and taste determinant catechins than 'FUD' (p<0.05). Enhanced transcription of some terpenoid and catechin biosynthetic genes in 'BAS' suggested genetically enhanced production of those flavour compounds. Due to manufacturing processes, the levels of linalool and geraniol decreased whereas those of β-ionone, linalool oxides, indole and cis-jasmone increased. Compared with pan-fire treatment, steam treatment reduced the levels of catechins and proportion of geraniol, linalool and its derivatives, consequently, reducing catechin-related astringency and monoterpenol-related floral scent. Our study suggests that flavour determinant targeted modulation could be made through genotype and manufacturing improvements. Copyright © 2016 Elsevier Ltd. All rights reserved.

Free radicals generated during oxidation of green tea polyphenols: electron paramagnetic resonance spectroscopy combined with density functional theory calculations.

PubMed

Severino, Joyce Ferreira; Goodman, Bernard A; Kay, Christopher W M; Stolze, Klaus; Tunega, Daniel; Reichenauer, Thomas G; Pirker, Katharina F

2009-04-15

Electron paramagnetic resonance spectroscopy and density functional theory calculations have been used to investigate the redox properties of the green tea polyphenols (GTPs) (-)-epigallocatechin gallate (EGCG), (-)-epigallocatechin (EGC), and (-)-epicatechin gallate (ECG). Aqueous extracts of green tea and these individual phenols were autoxidized at alkaline pH and oxidized by superoxide anion (O(2)(-)) radicals in dimethyl sulfoxide. Several new aspects of the free radical chemistry of GTPs were revealed. EGCG can be oxidized on both the B and the D ring. The B ring was the main oxidation site during autoxidation, but the D ring was the preferred site for O(2)(-) oxidation. Oxidation of the D ring was followed by structural degradation, leading to generation of a radical identical to that of oxidized gallic acid. Alkaline autoxidation of green tea extracts produced four radicals that were related to products of the oxidation of EGCG, EGC, ECG, and gallic acid, whereas the spectra from O(2)(-) oxidation could be explained solely by radicals generated from EGCG. Assignments of hyperfine coupling constants were made by DFT calculations, allowing the identities of the radicals observed to be confirmed.

Highly selective defluoridation of brick tea infusion by tea waste supported aluminum oxides.

PubMed

Peng, Chuanyi; Xi, Junjun; Chen, Guijie; Feng, Zhihui; Ke, Fei; Ning, Jingming; Li, Daxiang; Ho, Chi-Tang; Cai, Huimei; Wan, Xiaochun

2017-03-01

Brick tea usually contains very high fluoride, which may affect human health. Biosorbents have received much attention for selective removal of fluoride because of low cost, environmental friendliness, and relative safeness. In the present study, a highly selective fluoride tea waste based biosorbent, namely, aluminum (Al) oxide decorated tea waste (Tea-Al), was successfully prepared. The Tea-Al biosorbent was characterized by energy-dispersive spectrometry, Fourier transform infrared spectroscopy, powder X-ray diffraction and X-ray photoelectron spectroscopic analysis. The Tea-Al sample exhibited remarkably selective adsorption for fluoride (52.90%), but a weaker adsorption for other major constituents of brick tea infusion, such as catechins, polyphenols and caffeine, under the same conditions. Fluoride adsorption by Tea-Al for different times obeyed the surface reaction and adsorption isotherms fit the Freundlich model. In addition, the fluoride adsorption mechanism appeared to be an ion exchange between hydroxyl and fluoride ions. Results from this study demonstrated that Tea-Al is a promising biosorbent useful for the removal of fluoride in brick tea infusion. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Epigallocatechin-3-gallate attenuates lipopolysaccharide-induced mastitis in rats via suppressing MAPK mediated inflammatory responses and oxidative stress.

PubMed

Chen, Jinglou; Xu, Jun; Li, Jingjing; Du, Lifen; Chen, Tao; Liu, Ping; Peng, Sisi; Wang, Mingwei; Song, Hongping

2015-05-01

Green tea (Camellia sinensis) is an extremely popular beverage worldwide. Epigallocatechin-3-gallate (EGCG) is one of the major catechins isolated from green tea and contributes to its beneficial therapeutic functions including antioxidant, anti-inflammatory and anti-cancer effects. However, the effect of EGCG on mastitis is not yet known. This study was to investigate the protective potential of EGCG against mastitis in rats. The rat mastitis model was induced by injecting lipopolysaccharide (LPS) into the duct of mammary gland. The mammary gland was collected after the experimental period. The levels of mammary oxidative stress and inflammatory responses were assessed by measuring the local activities of antioxidant enzymes and the levels of inflammatory cytokines. The mammary expressions of mitogen-activated protein kinases (MAPKs), nuclear factor κB-p65 (NFκB-p65) and hypoxia-inducible factor-1α (HIF-1α) were evaluated by western blot analysis. It was found that EGCG obviously normalized LPS-induced low activities of antioxidant enzymes as well as decreased the high levels of inflammatory cytokines. Additionally, EGCG inhibited the mammary over-expression of MAPKs, NFκB-p65 and HIF-1α. These results indicated that EGCG was able to attenuate LPS-induced mastitis in rats by suppressing MAPK related oxidative stress and inflammatory responses. Copyright © 2015 Elsevier B.V. All rights reserved.

A randomized controlled trial of green tea catechins in protection against ultraviolet radiation–induced cutaneous inflammation12

PubMed Central

Farrar, Mark D; Nicolaou, Anna; Clarke, Kayleigh A; Mason, Sarah; Massey, Karen A; Dew, Tristan P; Watson, Rachel EB; Williamson, Gary; Rhodes, Lesley E

2015-01-01

Background: Safe systemic protection from the health hazards of ultraviolet radiation (UVR) in sunlight is desirable. Green tea is consumed globally and is reported to have anti-inflammatory properties, which may be mediated through the impact on cyclooxygenase and lipoxygenase pathways. Recent data suggest that green tea catechins (GTCs) reduce acute UVR effects, but human trials examining their photoprotective potential are scarce. Objective: We performed a double-blind, randomized, placebo-controlled trial to examine whether GTCs protect against clinical, histologic, and biochemical indicators of UVR-induced inflammation. Design: Healthy adults (aged 18–65 y, phototypes I–II) were randomly allocated to 1350 mg encapsulated green tea extract (540 mg GTC) with 50 mg vitamin C or placebo twice daily for 3 mo. Impact on skin erythema, dermal leukocytic infiltration, and concentrations of proinflammatory eicosanoids was assessed after solar-simulated UVR challenge, and subject compliance was determined through assay of urinary GTC metabolite epigallocatechin glucuronide. Results: Volunteers were assigned to the active (n = 25) or the placebo (n = 25) group. After supplementation, median (IQR) sunburn threshold (minimal erythema dose) was 28 (20–28) and 20 (20–28) mJ/cm2 in the active and placebo groups, respectively (nonsignificant), with no difference in AUC analysis for measured erythema index after a geometric series of 10 UVR doses. Skin immunohistochemistry showed increased neutrophil and CD3+ T-lymphocyte numbers post-UVR in both groups (P < 0.01) with no statistically significant differences between groups after supplementation. Cyclooxygenase and lipoxygenase metabolites prostaglandin E2 (vasodilator) and 12-hydroxyeicosatetraenoicacid (chemoattractant), respectively, increased after UVR (P < 0.05), with no differences between supplementation groups. Conclusion: Oral GTC (1080 mg/d) with vitamin C over 3 mo did not significantly reduce skin erythema

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

PubMed

Lee, Yun Ha; Jang, Yo Han; Kim, Young-Seok; Kim, Jinku; Seong, Baik Lin

2018-01-01

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. 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 10 6 PFU of the virus (6 log 10 reduction), and 0.01% and 0.05% GTE resulted in 2 log 10 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. 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 log 10 reduction of viral titers even after storage for up to two months at a wide range of

Epigallocatechin-3-gallate (EGCG) Suppresses the Trafficking of Lymphocytes to Epidermal Melanocytes via Inhibition of JAK2: Its Implication for Vitiligo Treatment.

PubMed

Ning, Weixuan; Wang, Suiquan; Dong, Xiaowu; Liu, Dongyin; Fu, Lifang; Jin, Rong; Xu, Aie

2015-01-01

Vitiligo is an inflammatory skin disorder in which activated T cells play an important role in its onset and progression. Epigallocatechin-3-gallate (EGCG), the major chemical constituent of green tea, exhibits remarkable anti-oxidative and anti-inflammatory properties. EGCG administration has been confirmed to decrease the risk of vitiligo; however, the underlying mechanism is undetermined. In this study, we proved that EGCG directly inhibited the kinase activity of Janus kinase 2 (JAK2). In primary cultured human melanocytes, EGCG pre-treatment attenuated interferon (IFN)-γ-induced phosphorylation of JAK2 and its downstream signal transducer and activator of transcription (STAT)1 and STAT3 in a dose-dependent manner. We further examined the chemoattractant expression in melanocytes and demonstrated that EGCG significantly inhibited IFN-γ-induced expression of intracellular adhesion molecule (ICAM)-1, CXCL10, and monocyte chemotactic protein (MCP)-1 in human melanocytes. In addition, EGCG reduced the protein levels of the corresponding receptors including CD11a, CXCR3, and CCR2 in human T lymphocytes. As a consequence, adhesion of human T cells to melanocytes induced by IFN-γ was effectively suppressed by EGCG. Taken together, our results provided new evidence for the effectiveness of EGCG in vitiligo treatment and supported JAK2 as a molecular target for vitiligo medicine development.

Ambient Profiling of Phenolic Content in Tea Infusions by Matrix-Assisted Ionization in Vacuum

NASA Astrophysics Data System (ADS)

Cody, Robert B.

2018-05-01

Matrix-assisted ionization in vacuum (MAIV) was used to analyze the polyphenol content of ten different tea infusions. Nine different Camellia sinensis infusions were analyzed including three green teas, two black teas, two oolong teas, jasmine tea, and white tea. An infusion of rooibos (Aspalathus linearis) tea was also analyzed. Each freshly brewed tea was diluted 1:1 with methanol, and 100 ppm of phenolphthalein was added as an internal standard. An excess of 3-nitrobenzonitrile (NBN) was added to each vial, and the solution containing NBN crystals was analyzed by aspiration directly into the mass spectrometer sampling orifice. A working curve constructed for dilutions of catechin with phenolphthalein internal standard showed good linearity for five replicates of each concentration. The measured relative abundances of flavonoid polyphenols in each tea were in good agreement with previously reported values. Polyphenol content in tea infusions varied from 19.2 to 108.6 mg 100 mL-1. In addition to the expected catechin flavonoids, abundant quinic acid and gallic acid was detected in the C. sinensis infusions. Characteristic A. linearis flavonoids were detected in the rooibos tea.

Functional characterization of proanthocyanidin pathway enzymes from tea and their application for metabolic engineering.

PubMed

Pang, Yongzhen; Abeysinghe, I Sarath B; He, Ji; He, Xianzhi; Huhman, David; Mewan, K Mudith; Sumner, Lloyd W; Yun, Jianfei; Dixon, Richard A

2013-03-01

Tea (Camellia sinensis) is rich in specialized metabolites, especially polyphenolic proanthocyanidins (PAs) and their precursors. To better understand the PA pathway in tea, we generated a complementary DNA library from leaf tissue of the blister blight-resistant tea cultivar TRI2043 and functionally characterized key enzymes responsible for the biosynthesis of PA precursors. Structural genes encoding enzymes involved in the general phenylpropanoid/flavonoid pathway and the PA-specific branch pathway were well represented in the library. Recombinant tea leucoanthocyanidin reductase (CsLAR) expressed in Escherichia coli was active with leucocyanidin as substrate to produce the 2R,3S-trans-flavan-ol (+)-catechin in vitro. Two genes encoding anthocyanidin reductase, CsANR1 and CsANR2, were also expressed in E. coli, and the recombinant proteins exhibited similar kinetic properties. Both converted cyanidin to a mixture of (+)-epicatechin and (-)-catechin, although in different proportions, indicating that both enzymes possess epimerase activity. These epimers were unexpected based on the belief that tea PAs are made from (-)-epicatechin and (+)-catechin. Ectopic expression of CsANR2 or CsLAR led to the accumulation of low levels of PA precursors and their conjugates in Medicago truncatula hairy roots and anthocyanin-overproducing tobacco (Nicotiana tabacum), but levels of oligomeric PAs were very low. Surprisingly, the expression of CsLAR in tobacco overproducing anthocyanin led to the accumulation of higher levels of epicatechin and its glucoside than of catechin, again highlighting the potential importance of epimerization in flavan-3-ol biosynthesis. These data provide a resource for understanding tea PA biosynthesis and tools for the bioengineering of flavanols.

Volatile and non-volatile compounds in green tea affected in harvesting time and their correlation to consumer preference.

PubMed

Kim, Youngmok; Lee, Kwang-Geun; Kim, Mina K

2016-10-01

Current study was designed to find out how tea harvesting time affects the volatile and non-volatile compounds profiles of green tea. In addition, correlation of instrumental volatile and non-volatile compounds analyses to consumer perception were analyzed. Overall, earlier harvested green tea had stronger antioxidant capacity (~61.0%) due to the polyphenolic compounds from catechin (23,164 mg/L), in comparison to later harvested green teas (11,961 mg/L). However, high catechin content in green tea influenced negatively the consumer likings of green tea, due to high bitterness (27.6%) and astringency (13.4%). Volatile compounds drive consumer liking of green tea products were also identified, that included linalool, 2,3-methyl butanal, 2-heptanone, (E,E)-3,5-Octadien-2-one. Finding from current study are useful for green tea industry as it provide the difference in physiochemical properties of green tea harvested at different intervals.

Draft genome sequence of Camellia sinensis var. sinensis provides insights into the evolution of the tea genome and tea quality

PubMed Central

Wei, Chaoling; Yang, Hua; Wang, Songbo; Zhao, Jian; Liu, Chun; Gao, Liping; Xia, Enhua; Lu, Ying; Tai, Yuling; She, Guangbiao; Sun, Jun; Cao, Haisheng; Tong, Wei; Gao, Qiang; Li, Yeyun; Deng, Weiwei; Jiang, Xiaolan; Wang, Wenzhao; Chen, Qi; Zhang, Shihua; Li, Haijing; Wu, Junlan; Wang, Ping; Li, Penghui; Shi, Chengying; Zheng, Fengya; Jian, Jianbo; Huang, Bei; Shan, Dai; Shi, Mingming; Fang, Congbing; Yue, Yi; Li, Fangdong; Li, Daxiang; Wei, Shu; Han, Bin; Jiang, Changjun; Yin, Ye; Xia, Tao; Zhang, Zhengzhu; Bennetzen, Jeffrey L.; Zhao, Shancen; Wan, Xiaochun

2018-01-01

Tea, one of the world’s most important beverage crops, provides numerous secondary metabolites that account for its rich taste and health benefits. Here we present a high-quality sequence of the genome of tea, Camellia sinensis var. sinensis (CSS), using both Illumina and PacBio sequencing technologies. At least 64% of the 3.1-Gb genome assembly consists of repetitive sequences, and the rest yields 33,932 high-confidence predictions of encoded proteins. Divergence between two major lineages, CSS and Camellia sinensis var. assamica (CSA), is calculated to ∼0.38 to 1.54 million years ago (Mya). Analysis of genic collinearity reveals that the tea genome is the product of two rounds of whole-genome duplications (WGDs) that occurred ∼30 to 40 and ∼90 to 100 Mya. We provide evidence that these WGD events, and subsequent paralogous duplications, had major impacts on the copy numbers of secondary metabolite genes, particularly genes critical to producing three key quality compounds: catechins, theanine, and caffeine. Analyses of transcriptome and phytochemistry data show that amplification and transcriptional divergence of genes encoding a large acyltransferase family and leucoanthocyanidin reductases are associated with the characteristic young leaf accumulation of monomeric galloylated catechins in tea, while functional divergence of a single member of the glutamine synthetase gene family yielded theanine synthetase. This genome sequence will facilitate understanding of tea genome evolution and tea metabolite pathways, and will promote germplasm utilization for breeding improved tea varieties. PMID:29678829

Separation of polyphenols and caffeine from the acetone extract of fermented tea leaves (Camellia sinensis) using high-performance countercurrent chromatography.

PubMed

Choi, Soo Jung; Hong, Yong Deog; Lee, Bumjin; Park, Jun Seong; Jeong, Hyun Woo; Kim, Wan Gi; Shin, Song Seok; Yoon, Kee Dong

2015-07-21

Leaves from Camellia sienensis are a popular natural source of various beverage worldwide, and contain caffeine and polyphenols derived from catechin analogues. In the current study, caffeine (CAF, 1) and three tea polyphenols including (-)-epigallocatechin 3-O-gallate (EGCg, 2), (-)-gallocatechin 3-O-gallate (GCg, 3), and (-)-epicatechin 3-O-gallate (ECg, 4) were isolated and purified by flow-rate gradient high-performance countercurrent chromatography (HPCCC) using a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:9:1:9, v/v). Two hundred milligrams of acetone-soluble extract from fermented C. sinensis leaves was separated by HPCCC to give 1 (25.4 mg), 2 (16.3 mg), 3 (11.1 mg) and 4 (4.4 mg) with purities over 98%. The structures of 1-4 were elucidated by QTOF-MS, as well as 1H- and 13C-NMR, and the obtained data were compared to the previously reported values.

Green tea extract (epigallocatechin-3-gallate) reduces efficacy of radiotherapy on prostate cancer cells.

PubMed

Thomas, Francis; Holly, Jeff M P; Persad, Rajendra; Bahl, Amit; Perks, Claire M

2011-08-01

To assess the influence of epigallocatechin-3-gallate (EGCG) on the efficacy of ionizing radiation on prostate cancer cells because of the increased use of dietary interventions, especially by patients with prostate cancer. Radiotherapy is used to treat localized prostate cancer. Some people consume green tea (EGCG) as a chemopreventive agent against prostate cancer. Green tea can act as an antioxidant and induce superoxide dismutase enzymes, which could scavenge the free oxygen radicals generated by radiotherapy. Prostate cancer cell line DU145 cells were treated with EGCG or radiotherapy, or both. Cell death was assessed using trypan blue cell counting, and apoptosis was confirmed by assessing poly (adenosine phosphate ribose) polymerase cleavage. The antioxidant potential was assessed using Western immunoblotting for manganese superoxide dismutase and copper zinc superoxide dismutase enzymes. Radiotherapy was delivered using a linear accelerator. Cell cycle analysis was performed using flow cytometry. Radiotherapy at 3.5 Gy induced a 5.9-fold increase in apoptosis of DU145 cells. Subapoptotic doses of EGCG (1.5-7.5 μM) significantly reduced ionizing radiation-induced apoptosis (P < .001), with the inhibitory effect of EGCG on ionizing radiation being most effective when added 30 minutes before radiotherapy (P < .001). In addition, when radiotherapy and EGCG were used together, an approximate 1.5-fold increase in manganese superoxide dismutase levels was seen compared with the control and a 2-fold increase compared with radiotherapy alone. Radiotherapy is effective in inducing apoptosis in DU145 cells, but its effect was significantly reduced in the presence of EGCG, and this was associated with an increase in the induction of manganese superoxide dismutase. Copyright © 2011 Elsevier Inc. All rights reserved.

Chemoprevention of dibenzo[a,l]pyrene transplacental carcinogenesis in mice born to mothers administered green tea: primary role of caffeine

PubMed Central

Castro, David J.; Yu, Zhen; Löhr, Christiane V.; Pereira, Clifford B.; Giovanini, Jack N.; Fischer, Kay A.; Orner, Gayle A.; Dashwood, Roderick H.; Williams, David E.

2008-01-01

Our laboratory recently developed a mouse model of transplacental induction of lymphoma, lung and liver cancer by the polycyclic aromatic hydrocarbon, dibenzo[a,l]pyrene (DBP). Pregnant B6129SF1 females, bred to 129S1/SvIm males, were treated on day 17 of gestation with an oral dose of 15 mg/kg DBP. Beginning on day 0 of gestation, dams were given (ad lib) buffered water, 0.5% green tea, 0.5% decaffeinated green tea, caffeine or epigallocatechin-3-gallate (EGCG) (both at equivalent concentrations found in tea). The concentration of the teas (and corresponding caffeine and EGCG) was increased to 1.0% upon entering the second trimester, 1.5% at onset of the third trimester and continued at 1.5% until pups were weaned at 21 days of age. Offspring were raised with normal drinking water and AIN93G diet. Beginning at 2 months of age, offspring experienced significant mortalities due to an aggressive T-cell lymphoma as seen in our previous studies. Ingestion of caffeinated, but not decaffeinated, green tea provided modest but significant protection (P = 0.03) against mortality. Caffeine provided a more robust (P = 0.006) protection, but EGCG was without effect. Offspring also developed DBP-dependent lung adenomas. All treatments significantly reduced lung tumor multiplicity relative to controls (P < 0.02). EGCG was most effective at decreasing tumor burden (P = 0.005) by on average over 40% compared with controls. Induction of Cytochrome P450 (Cyp)1b1 in maternal liver may reduce bioavailability of DBP to the fetus as a mechanism of chemoprevention. This is the first demonstration that maternal ingestion of green tea, during pregnancy and nursing, provides protection against transplacental carcinogenesis. PMID:18635525

Both phenolic and non-phenolic green tea fractions inhibit migration of cancer cells

USDA-ARS?s Scientific Manuscript database

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-p...

Epigallocatechin gallate (EGCG) prevents H2O2-induced oxidative stress in primary rat retinal pigment epithelial cells.

PubMed

Cia, David; Vergnaud-Gauduchon, Juliette; Jacquemot, Nathalie; Doly, Michel

2014-09-01

To determine whether the green tea polyphenol epigallocatechin gallate (EGCG) could prevent H(2)O(2)-induced oxidative stress in primary rat retinal pigment epithelial cells. Primary cultures of retinal pigment epithelium (RPE) cells were established from Long-Evans newborn rats. RPE cells were pretreated with various concentrations of EGCG for 24 h before being exposed to hydrogen peroxide (H(2)O(2)) for 2 h to induce oxidative stress. Cell metabolic activity was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell death was quantified by flow cytometry using propidium iodide (PI). Treatment of RPE cells with EGCG alone does not affect the cell viability up to 50 µM. Exposure of RPE cells to 600 µM H(2)O(2) caused a significant decrease in cell viability; whereas pretreatment with 10, 25, and 50 µM EGCG significantly reduced this decrease in a dose-dependent manner. The proportion of PI-positive cells increased significantly in cultures treated with H(2)O(2) alone; whereas pretreatment of RPE cells with 50 µM EGCG significantly reduced H(2)O(2)-induced RPE cell death. Our study shows that EGCG pretreatment can protect primary rat RPE cells from H(2)O(2)-induced death. This suggests potential effect of EGCG in the prevention of retinal diseases associated with H(2)O(2)-induced oxidative stress.

A combination of (+)-catechin and (-)-epicatechin underlies the in vitro adipogenic action of Labrador tea (Rhododendron groenlandicum), an antidiabetic medicinal plant of the Eastern James Bay Cree pharmacopeia.

PubMed

Eid, Hoda M; Ouchfoun, Meriem; Saleem, Ammar; Guerrero-Analco, Jose A; Walshe-Roussel, Brendan; Musallam, Lina; Rapinski, Michel; Cuerrier, Alain; Martineau, Louis C; Arnason, John T; Haddad, Pierre S

2016-02-03

Rhododendron groenlandicum (Oeder) Kron & Judd (Labrador tea) was identified as an antidiabetic plant through an ethnobotanical study carried out with the close collaboration of Cree nations of northern Quebec in Canada. In a previous study the plant showed glitazone-like activity in a 3T3-L1 adipogenesis bioassay. The current study sought to identify the active compounds responsible for this potential antidiabetic activity using bioassay guided fractionation based upon an in vitro assay that measures the increase of triglycerides content in 3T3-L1 adipocyte. Isolation and identification of the crude extract's active constituents was carried out. The 80% ethanol extract was fractionated using silica gel column chromatography. Preparative HPLC was then used to isolate the constituents. The identity of the isolated compounds was confirmed by UV and mass spectrometry. Nine chemically distinct fractions were obtained and the adipogenic activity was found in fraction 5 (RGE-5). Quercetins, (+)-catechin and (-)-epicatechin were detected and isolated from this fraction. While (+)-catechin and (-)-epicatechin stimulated adipogenesis (238±26% and 187±21% relative to vehicle control respectively) at concentrations equivalent to their concentrations in the active fraction RGE-5, none afforded biological activity similar to RGE-5 or the plant's crude extract when used alone. When cells were incubated with a mixture of the two compounds, the adipogenic activity was close to that of the crude extract (280.7±27.8 vs 311± 30%). Results demonstrate that the mixture of (+)-catechin and (-)-epicatechin is responsible for the adipogenic activity of Labrador tea. This brings further evidence for the antidiabetic potential of R. groenlandicum and provides new opportunities to profile active principles in biological fluids or in traditional preparations. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Evaluation of epigallocatechin-3-gallate (EGCG) cross-linked collagen membranes and concerns on osteoblasts.

PubMed

Chu, Chenyu; Deng, Jia; Xiang, Lin; Wu, Yingying; Wei, Xiawei; Qu, Yili; Man, Yi

2016-10-01

Collagen membranes have ideal biological and mechanical properties for supporting infiltration and proliferation of osteoblasts and play a vital role in guided bone regeneration (GBR). However, pure collagen can lead to inflammation, resulting in progressive bone resorption. Therefore, a method for regulating the level of inflammatory cytokines at surgical sites is paramount for the healing process. Epigallocatechin-3-gallate (EGCG) is a component extracted from green tea with numerous biological activities including an anti-inflammatory effect. Herein, we present a novel cross-linked collagen membrane containing different concentrations of EGCG (0.0064%, 0.064%, and 0.64%) to regulate the level of inflammatory factors secreted by pre-osteoblast cells; improve cell proliferation; and increase the tensile strength, wettability, and thermal stability of collagen membranes. Scanning electron microscope images show that the surfaces of collagen membranes became smoother and the collagen fiber diameters became larger with EGCG treatment. Measurement of the water contact angle demonstrated that introducing EGCG improved membrane wettability. Fourier transform infrared spectroscopy analyses indicated that the backbone of collagen was intact, and the thermal stability was significant improved in differential scanning calorimetry. The mechanical properties of 0.064% and 0.64% EGCG-treated collagen membranes were 1.5-fold greater than those of the control. The extent of cross-linking was significantly increased, as determined by a 2,4,6-trinitrobenzenesulfonic acid solution assay. The Cell Counting Kit-8 (CCK-8) and live/dead assays revealed that collagen membrane cross-linked by 0.0064% EGCG induced greater cell proliferation than pure collagen membranes. Additionally, real-time polymerase chain reaction and enzyme-linked immunosorbent assay results showed that EGCG significantly affected the production of inflammatory factors secreted by MC3T3-E1 cells. Taken together, our

(-)Epigallocatechin-3-gallate prevents the reserpine-induced impairment of short-term social memory in rats.

PubMed

Tseng, Hsiang-Chien; Wang, Mao-Hsien; Soung, Hung-Sheng; Chang, Yi; Chang, Kuo-Chi

2015-12-01

Reserpine has been confirmed to induce cognitive dysfunction and increase brain neural oxidative stress. Green tea catechins, particularly (-)epigallocatechin-3-gallate (EGCG), have strong antioxidative properties and can protect against numerous oxidative damages. In this study, we examined the possible protective effects of EGCG on reserpine-induced impairment of short-term memory in rats. Reserpine (1 mg/kg, intraperitoneal)-induced memory impairment was assessed using the social recognition task method; locomotor activity and the olfactory discrimination ability were not altered as measured by an open-field test and an olfactory discrimination test, respectively. EGCG treatment (100 and 300 mg/kg, intraperitoneal, for 7 days, starting 6 days before the reserpine injection) could improve the worsened social memory of reserpine-treated rats. Also, EGCG treatment reduced reserpine-induced lipid peroxidation and enhanced the antioxidation power in the hippocampi of reserpine-treated rats. These results suggest a protective effect of EGCG in treating reserpine-induced impairment of memory, most probably through its powerful antioxidative activities. Accordingly, EGCG may hold a clinically relevant value in preventing reserpine-induced cognitive dysfunction.

Epigallocatechin-gallate (EGCG) regulates autophagy in human retinal pigment epithelial cells: A potential role for reducing UVB light-induced retinal damage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Chao-Peng; Yao, Jin; Tao, Zhi-Fu

Highlights: •UVB irradiation induces RPE autophagy. •EGCG treatment represses UVB-mediated autophagy. •EGCG regulates UVB-mediated autophagy through mTOR signaling pathway. •EGCG sensitizes RPE cells to UVB-induced damage in an autophagy-dependent manner. -- Abstract: Autophagy is an intracellular catabolic process involved in protein and organelle degradation via the lysosomal pathway that has been linked in the pathogenesis of age-related macular degeneration (AMD). UVB irradiation-mediated degeneration of the macular retinal pigment epithelial (RPE) cells is an important hallmark of AMD, which is along with the change in RPE autophagy. Thus, pharmacological manipulation of RPE autophagy may offer an alternative therapeutic target in AMD.more » Here, we found that epigallocatechin-3-gallate (EGCG), a polyphenolic compound from green tea, plays a regulatory role in UVB irradiation-induced autophagy in RPE cells. UVB irradiation results in a marked increase in the amount of LC3-II protein in a dose-dependent manner. EGCG administration leads to a significant reduction in the formation of LC3-II and autophagosomes. mTOR signaling activation is required for EGCG-induced LC3-II formation, as evidenced by the fact that EGCG-induced LC3-II formation is significantly impaired by rapamycin administration. Moreover, EGCG significantly alleviates the toxic effects of UVB irradiation on RPE cells in an autophagy-dependent manner. Collectively, our study reveals a novel role of EGCG in RPE autophagy. EGCG may be exploited as a potential therapeutic reagent for the treatment of pathological conditions associated with abnormal autophagy.« less

An efflux pump (MexAB-OprM) of Pseudomonas aeruginosa is associated with antibacterial activity of Epigallocatechin-3-gallate (EGCG).

PubMed

Kanagaratnam, Rashmi; Sheikh, Rida; Alharbi, Fahad; Kwon, Dong H

2017-12-01

Pseudomonas aeruginosa is a notorious multidrug resistant nosocomial pathogen. An efflux pump (MexAB-OprM) is the main contributor to the multidrug resistance in clinical isolates of P. aeruginosa. Epigallocatechin-3-gallate (EGCG), a polyphenolic compound extracted from green tea, exhibits antibacterial activity. It is unclear that molecular details of the antibacterial activity of EGCG, EGCG-effect on antibiotic susceptibility, and clinical relevance of EGCG in bacteria. This study aimed to determine the roles of the efflux pump and an efflux pump inhibitor (phenylalanine-arginine β-naphthylamide; PAβN) in the antibacterial activity of EGCG and the EGCG-effect on antibiotic susceptibility. Twenty-two multidrug resistant clinical isolates of P. aeruginosa and a wild type P. aeruginosa PAO1 were used to determine antibacterial activity of EGCG and EGCG-effect on antibiotic susceptibility. An efflux pump (MexAB-OPrM) mutant strain, its complemented strain carrying an intact mexAB-oprM, and their parental strain were used to determine roles of MexAB-OprM in the antibacterial activity of EGCG and EGCG-mediated antibiotic susceptibility. PAβN was also used to evaluate EGCG as a possible efflux pump inhibitor. EGCG inhibited cellular growth and killed 100% of cells at 64-512 µg/ml and at 256-1024 µg/ml, respectively, in all tested 22 clinical isolates including the wild type strain. A subinhibitory concentration of EGCG significantly enhanced susceptibility to antibiotics, unexceptionally to chloramphenicol and tetracyclines (≥4-fold) of the clinical isolates. Both the antibacterial activity of EGCG and the EGCG-mediated antibiotic susceptibility were enhanced more in the efflux pump mutant strain (mexB::Gm) than the parental strain, suggesting additionally accumulated-EGCG produced the more antibacterial activity in the mutant strain. EGCG was synergistically interacted with PAβN with enhancing susceptibility to all tested antibiotics (up to >500-fold) at

EGCG evokes Nrf2 nuclear translocation and dampens PTP1B expression to ameliorate metabolic misalignment under insulin resistance condition.

PubMed

Mi, Yashi; Zhang, Wentong; Tian, Haoyu; Li, Runnan; Huang, Shuxian; Li, Xingyu; Qi, Guoyuan; Liu, Xuebo

2018-03-01

As a major nutraceutical component of green tea (-)-epigallocatechin-3-gallate (EGCG) has attracted interest from scientists due to its well-documented antioxidant and antiobesity bioactivities. In the current study, we aimed to investigate the protective effect of EGCG on metabolic misalignment and in balancing the redox status in mice liver and HepG2 cells under insulin resistance condition. Our results indicated that EGCG accelerates the glucose uptake and evokes IRS-1/Akt/GLUT2 signaling pathway via dampening the expression of protein tyrosine phosphatase 1B (PTP1B). Consistently, ectopic expression of PTP1B by Ad-PTP1B substantially impaired EGCG-elicited IRS-1/Akt/GLUT2 signaling pathway. Moreover, EGCG co-treatment stimulated nuclear translocation of Nrf2 by provoking P13K/AKT signaling pathway and thus modulated the downstream expressions of antioxidant enzymes such as HO-1 and NQO-1 in HepG2 cells. Furthermore, knockdown Nrf2 by small interfering RNA (siRNA) notably enhanced the expression of PTP1B and blunt EGCG-stimulated glucose uptake. Consistent with these results, in vivo study revealed that EGCG supplement significantly ameliorated high-fat and high-fructose diet (HFFD)-triggered insulin resistance and oxidative stress by up-regulating the IRS-1/AKT and Keap1/Nrf2 transcriptional pathways. Administration of an appropriate chemopreventive agent, such as EGCG, could potentially serve as an additional therapeutic intervention in the arsenal against obesity.

Oxygen partial pressure modulates 67-kDa laminin receptor expression, leading to altered activity of the green tea polyphenol, EGCG.

PubMed

Tsukamoto, Shuntaro; Yamashita, Shuya; Kim, Yoon Hee; Kumazoe, Motofumi; Huang, Yuhui; Yamada, Koji; Tachibana, Hirofumi

2012-09-21

(-)-Epigallocatechin-3-O-gallate (EGCG) exhibits anti-tumor activity mediated via the 67-kDa laminin receptor (67LR). In this study, we found that 67LR protein levels are reduced by exposure to low O(2) levels (5%), without affecting the expression of HIF-1α. We also found that EGCG-induced anti-cancer activity is abrogated under low O(2) levels (5%) in various cancer cells. Notably, treatment with the proteasome inhibitor, prevented down-regulation of 67LR and restored sensitivity to EGCG under 5% O(2). In summary, 67LR expression is highly sensitive to O(2) partial pressure, and the activity of EGCG can be regulated in cancer cells by O(2) partial pressure. Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Biological and Mechanistic Characterization of Novel Prodrugs of Green Tea Polyphenol Epigallocatechin Gallate Analogs in Human Leiomyoma Cell Lines.

PubMed

Ahmed, Reda Saber Ibrahim; Liu, Gang; Renzetti, Andrea; Farshi, Pershang; Yang, Huanjie; Soave, Claire; Saed, Ghassan; El-Ghoneimy, Ashraf Ahmed; El-Banna, Hossny Awad; Foldes, Robert; Chan, Tak-Hang; Dou, Q Ping

2016-10-01

Uterine fibroids (leiomyomas) are very common benign tumors grown on the smooth muscle layer of the uterus, present in up to 75% of reproductive-age women and causing significant morbidity in a subset of this population. Although the etiology and biology of uterine fibroids are unclear, strong evidence supports that cell proliferation, angiogenesis and fibrosis are involved in their formation and growth. Currently the only cure for uterine fibroids is hysterectomy; the available alternative therapies have limitations. Thus, there is an urgent need for developing a novel strategy for treating this condition. The green tea polyphenol epigallocatechin gallate (EGCG) inhibits the growth of uterine leiomyoma cells in vitro and in vivo, and the use of a green tea extract (containing 45% EGCG) has demonstrated clinical activity without side effects in women with symptomatic uterine fibroids. However, EGCG has a number of shortcomings, including low stability, poor bioavailability, and high metabolic transformations under physiological conditions, presenting challenges for its development as a therapeutic agent. We developed a prodrug of EGCG (Pro-EGCG or 1) which shows increased stability, bioavailability and biological activity in vivo as compared to EGCG. We also synthesized prodrugs of EGCG analogs, compounds 2a and 4a, in order to potentially reduce their susceptibility to methylation/inhibition by catechol-O-methyltransferase. Here, we determined the effect of EGCG, Pro-EGCG, and 2a and 4a on cultured human uterine leiomyoma cells, and found that 2a and 4a have potent antiproliferative, antiangiogenic, and antifibrotic activities. J. Cell. Biochem. 117: 2357-2369, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Blood brain barrier permeability of (-)-epigallocatechin gallate, its proliferation-enhancing activity of human neuroblastoma SH-SY5Y cells, and its preventive effect on age-related cognitive dysfunction in mice.

PubMed

Pervin, Monira; Unno, Keiko; Nakagawa, Aimi; Takahashi, Yuu; Iguchi, Kazuaki; Yamamoto, Hiroyuki; Hoshino, Minoru; Hara, Aya; Takagaki, Akiko; Nanjo, Fumio; Minami, Akira; Imai, Shinjiro; Nakamura, Yoriyuki

2017-03-01

The consumption of green tea catechins (GTCs) suppresses age-related cognitive dysfunction in mice. GTCs are composed of several catechins, of which epigallocatechin gallate (EGCG) is the most abundant, followed by epigallocatechin (EGC). Orally ingested EGCG is hydrolyzed by intestinal biota to EGC and gallic acid (GA). To understand the mechanism of action of GTCs on the brain, their permeability of the blood brain barrier (BBB) as well as their effects on cognitive function in mice and on nerve cell proliferation in vitro were examined. The BBB permeability of EGCG, EGC and GA was examined using a BBB model kit. SAMP10, a mouse model of brain senescence, was used to test cognitive function in vivo . Human neuroblastoma SH-SY5Y cells were used to test nerve cell proliferation and differentiation. The in vitro BBB permeability (%, in 30 min) of EGCG, EGC and GA was 2.8±0.1, 3.4±0.3 and 6.5±0.6, respectively. The permeability of EGCG into the BBB indicates that EGCG reached the brain parenchyma even at a very low concentration. The learning ability of SAMP10 mice that ingested EGCG (20 mg/kg) was significantly higher than of mice that ingested EGC or GA. However, combined ingestion of EGC and GA showed a significant improvement comparable to EGCG. SH-SY5Y cell growth was significantly enhanced by 0.05 µM EGCG, but this effect was reduced at higher concentrations. The effect of EGC and GA was lower than that of EGCG at 0.05 µM. Co-administration of EGC and GA increased neurite length more than EGC or GA alone. Cognitive dysfunction in mice is suppressed after ingesting GTCs when a low concentration of EGCG is incorporated into the brain parenchyma via the BBB. Nerve cell proliferation/differentiation was enhanced by a low concentration of EGCG. Furthermore, the additive effect of EGC and GA suggests that EGCG sustains a preventive effect after the hydrolysis to EGC and GA.

Long-term supplementation of decaffeinated green tea extract does not modify body weight or abdominal obesity in a randomized trial of men at high risk for prostate cancer

PubMed Central

Kumar, Nagi B.; Patel, Roshni; Pow-Sang, Julio; Spiess, Philippe E.; Salup, Raoul; Williams, Christopher R.; Schell, Michael J.

2017-01-01

Background Evidence continues to demonstrate the role of obesity in prostate carcinogenesis and prognosis, underscoring the need to identify and continue to evaluate the effective interventions to reduce obesity in populations at high risk. The aim of the study was to determine the effect of daily consumption of decaffeinated green tea catechins (GTC) formulation (Polyphenon E® (PolyE)) for 1 year on biomarkers of obesity in men who are at high risk for prostate cancer. Materials and Methods A randomized, double-blinded trial was conducted targeting 97 men diagnosed with HGPIN or ASAP. Subjects were randomized to receive GTC (PolyE) (n = 49) or placebo (n = 48) for 1 year. Anthropometric data were collected at baseline, 6 and 12 months and data analyzed to observe change in weight, body mass index (indicator of obesity) and waist: hip ratio (indicator of abdominal obesity). Results Decaffeinated GTC containing 400 mgs of the bioactive catechin, EGCG administered for 1 year to men diagnosed with ASAP and HGPIN appears to be bioavailable, well tolerated but not effective in reducing biomarkers of obesity including body weight, body mass index and waist: hip ratio. Conclusions The results of our trial demonstrates that men who are obese and at high risk for prostate cancer should resort to effective weight management strategies to reduce obesity and not resort to ineffective measures such as taking supplements of green tea to reduce biomarkers of obesity. Changes in body mass index and abdominal obesity seen in other studies were potentially due to caffeine and not GTC. PMID:29228755

Draft genome sequence of Camellia sinensis var. sinensis provides insights into the evolution of the tea genome and tea quality.

PubMed

Wei, Chaoling; Yang, Hua; Wang, Songbo; Zhao, Jian; Liu, Chun; Gao, Liping; Xia, Enhua; Lu, Ying; Tai, Yuling; She, Guangbiao; Sun, Jun; Cao, Haisheng; Tong, Wei; Gao, Qiang; Li, Yeyun; Deng, Weiwei; Jiang, Xiaolan; Wang, Wenzhao; Chen, Qi; Zhang, Shihua; Li, Haijing; Wu, Junlan; Wang, Ping; Li, Penghui; Shi, Chengying; Zheng, Fengya; Jian, Jianbo; Huang, Bei; Shan, Dai; Shi, Mingming; Fang, Congbing; Yue, Yi; Li, Fangdong; Li, Daxiang; Wei, Shu; Han, Bin; Jiang, Changjun; Yin, Ye; Xia, Tao; Zhang, Zhengzhu; Bennetzen, Jeffrey L; Zhao, Shancen; Wan, Xiaochun

2018-05-01

Tea, one of the world's most important beverage crops, provides numerous secondary metabolites that account for its rich taste and health benefits. Here we present a high-quality sequence of the genome of tea, Camellia sinensis var. sinensis (CSS), using both Illumina and PacBio sequencing technologies. At least 64% of the 3.1-Gb genome assembly consists of repetitive sequences, and the rest yields 33,932 high-confidence predictions of encoded proteins. Divergence between two major lineages, CSS and Camellia sinensis var. assamica (CSA), is calculated to ∼0.38 to 1.54 million years ago (Mya). Analysis of genic collinearity reveals that the tea genome is the product of two rounds of whole-genome duplications (WGDs) that occurred ∼30 to 40 and ∼90 to 100 Mya. We provide evidence that these WGD events, and subsequent paralogous duplications, had major impacts on the copy numbers of secondary metabolite genes, particularly genes critical to producing three key quality compounds: catechins, theanine, and caffeine. Analyses of transcriptome and phytochemistry data show that amplification and transcriptional divergence of genes encoding a large acyltransferase family and leucoanthocyanidin reductases are associated with the characteristic young leaf accumulation of monomeric galloylated catechins in tea, while functional divergence of a single member of the glutamine synthetase gene family yielded theanine synthetase. This genome sequence will facilitate understanding of tea genome evolution and tea metabolite pathways, and will promote germplasm utilization for breeding improved tea varieties. Copyright © 2018 the Author(s). Published by PNAS.

Metformin Sensitizes Non-small Cell Lung Cancer Cells to an Epigallocatechin-3-Gallate (EGCG) Treatment by Suppressing the Nrf2/HO-1 Signaling Pathway.

PubMed

Yu, Chenxiao; Jiao, Yang; Xue, Jiao; Zhang, Qi; Yang, Hongying; Xing, Ligang; Chen, Guangxia; Wu, Jinchang; Zhang, Shuyu; Zhu, Wei; Cao, Jianping

2017-01-01

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. (-)-Epigallocatechin-3-gallate (EGCG), a major polyphenol in green tea, is widely studied as a cancer chemopreventive agent with potential anti-cancer effects. The NF-E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway is considered to mediate cellular resistance to EGCG. Metformin, a classical antidiabetic drug, has been shown to prevent cancer progression. Researchers have not reported whether metformin potentiates the anti-cancer efficacy of EGCG. In this study, metformin inhibited HO-1 expression and augmented the anti-tumor effect of EGCG. Metformin also enhanced ROS (reactive oxygen species) generation induced by EGCG (100 μM), subsequently resulting in apoptosis. Based on the results of the in vivo study, size of xenografts treated with the combination of metformin and EGCG was smaller than other groups. Mechanistically, metformin modulated the EGCG-activated Nrf2/HO-1 pathway through Sirtuin 1 (SIRT1)-dependent deacetylation of Nrf2. Moreover, metformin upregulated SIRT1 expression partially through the NF-kB pathway. Comparatively, the combination of EGCG and metformin showed little impact on normal lung epithelial BEAS-2B cells. Based on our findings, metformin sensitized NSCLC cells to the EGCG treatment by suppressing the Nrf2/HO-1 signaling pathway.

[Induction of NAD(P)H: quinone reductase by anticarcinogenic ingredients of tea].

PubMed

Qi, L; Han, C

1998-09-30

By assaying the activity of NAD(P)H: quinone reductase (QR) in Hep G2 cells exposed to inducing agents, a variety of ingredients in tea, we compared their abilities on inducing QR and preventing cancer. The results showed that tea polyphenols, tea pigments and mixed tea were all able to induce the activity of QR significantly. The single-component ingredients of tea polyphenols and tea pigments, including thearubigens, EGCG and ECG, also enhanced the activity of QR. But EGC, EC, theaflavins, tea polysaccharide and tea caffeine, showed no apparent induction of QR. We found that among those tea ingredients studied, the multi-component ingredients were more effective than the single-component ones. So we thought that the abilities of antioxidation and cancer prevention of tea depended on the combined effects of several kinds of active ingredients, which mainly include tea polyphenols and tea pigments.

Epigallocatechin-gallate (EGCG) regulates autophagy in human retinal pigment epithelial cells: a potential role for reducing UVB light-induced retinal damage.

PubMed