Epigallocatechin gallate and gallocatechin gallate in green tea catechins inhibit extracellular release of Vero toxin from enterohemorrhagic Escherichia coli O157:H7

1999 ◽  
Vol 1472 (1-2) ◽  
pp. 42-50 ◽  
Author(s):  
Yoshiko Sugita-Konishi ◽  
Yukiko Hara-Kudo ◽  
Fumio Amano ◽  
Tsutomu Okubo ◽  
Nobuyuki Aoi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Green Tea ◽  
Epigallocatechin Gallate ◽  
Enterohemorrhagic Escherichia Coli ◽  
Escherichia Coli O157 ◽  
Tea Catechins ◽  
Green Tea Catechins ◽  
Extracellular Release ◽  
Gallocatechin Gallate

Antipathogenic Properties of Green Tea Polyphenol Epigallocatechin Gallate at Concentrations below the MIC against Enterohemorrhagic Escherichia coli O157:H7

2009 ◽  
Vol 72 (2) ◽  
pp. 325-331 ◽  
Author(s):  
KANG-MU LEE ◽  
WAN-SEOK KIM ◽  
JEESUN LIM ◽  
SUNYOUNG NAM ◽  
MIN YOUN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Green Tea ◽  
Epigallocatechin Gallate ◽  
Enterohemorrhagic Escherichia Coli ◽  
Transcriptional Level ◽  
Escherichia Coli O157 ◽  
Tea Polyphenol ◽  
Autoinducer 2 ◽  
Green Tea Polyphenol

The inhibitory effects of green tea polyphenol epigallocatechin gallate (EGCG) on virulence phenotypes and gene expression regulated by quorum sensing (QS) in Escherichia coli O157:H7 were demonstrated at concentrations of 1 to 100 μg/ml, which are lower than the MIC (539 ± 22 μg/ml). At 25 μg/ml, the growth rate was not affected, but autoinducer 2 concentration, biofilm formation, and swarm motility decreased to 13.2, 11.8, and 50%, respectively. Survival at 5 days of nematodes (Caenorhabditis elegans) that were fed the pathogen without and with EGCG were 47.1 and 76%, respectively. Real-time PCR data indicated decreased transcriptional level in many quorum sensing–regulated virulence genes at 25 μg/ml. Our results suggest that EGCG at concentrations below its MIC has significant antipathogenic effects against E. coli O157:H7.

scholarly journals Green tea (−)-epigallocatechin gallate inhibits the growth of human villous trophoblasts via the ERK, p38, AMP-activated protein kinase, and protein kinase B pathways

2016 ◽  
Vol 311 (2) ◽  
pp. C308-C321 ◽  
Author(s):  
Li-Jane Shih ◽  
Tz-Fang Chen ◽  
Cheng-Kuo Lin ◽  
Hang-Shen Liu ◽  
Yung-Hsi Kao
Keyword(s):  
Protein Kinase ◽  
P38 Mapk ◽  
Green Tea ◽  
Protein Kinase B ◽  
Epigallocatechin Gallate ◽  
Cell Number ◽  
Brdu Incorporation ◽  
Tea Catechins ◽  
Green Tea Catechins ◽  
Amp Activated Protein Kinase

Green tea catechins, especially (−)-epigallocatechin gallate (EGCG), have been reported to circulate in the placenta of animals and blood of humans after consumption. Whether EGCG regulates activity of human villous trophoblasts (HVT) is unknown. This study investigated the pathways involved in EGCG modulation of trophoblast mitogenesis. EGCG inhibited trophoblast proliferation in a dose-dependent and time-dependent manner, as indicated by the number of cells and incorporation of bromodeoxyuridine (BrdU). EGCG was more effective than other green tea catechins in inhibiting cell growth. EGCG also increased the phosphorylation of the MAPK pathway proteins, ERK1/2, and p38, but not JNK. Furthermore, EGCG had no effects on the total amounts of ERK1/2, p38 MAPK, and JNK proteins. This suggests that EGCG selectively affects particular MAPK subfamilies. Pretreatment with specific inhibitors of ERK1/2, p38 MAPK, and AMP-activated protein kinase (AMPK) antagonized EGCG-induced decreases in both cell number and BrdU incorporation. These inhibitors also blocked EGCG-induced increases in the levels of phospho-ERK1/2, phospho-p38, and phospho-AMPK proteins, respectively. Moreover, EGCG was similar to the phosphatidylinositol 3-kinase inhibitors wortmannin and LY-294002 to decrease protein kinase B (AKT) phosphorylation, cell number, and BrdU incorporation. These data imply that EGCG inhibits the growth of HVT through the ERK, p38, AMPK, and AKT pathways.

scholarly journals Green Tea Catechins Induce Inhibition of PTP1B Phosphatase in Breast Cancer Cells with Potent Anti-Cancer Properties: In Vitro Assay, Molecular Docking, and Dynamics Studies

Antioxidants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1208
Author(s):  
Alicja Kuban-Jankowska ◽  
Tomasz Kostrzewa ◽  
Claudia Musial ◽  
Giampaolo Barone ◽  
Giosuè Lo-Bosco ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Enzymatic Activity ◽  
Cancer Cells ◽  
Green Tea ◽  
Breast Cancer Cells ◽  
Computational Analysis ◽  
Epigallocatechin Gallate ◽  
Tea Catechins ◽  
Green Tea Catechins ◽  
Mcf 7

The catechins derived from green tea possess antioxidant activity and may have a potentially anticancer effect. PTP1B is tyrosine phosphatase that is oxidative stress regulated and is involved with prooncogenic pathways leading to the formation of a.o. breast cancer. Here, we present the effect of selected green tea catechins on enzymatic activity of PTP1B phosphatase and viability of MCF-7 breast cancer cells. We showed also the computational analysis of the most effective catechin binding with a PTP1B molecule. We observed that epigallocatechin, epigallocatechin gallate, epicatechin, and epicatechin gallate may decrease enzymatic activity of PTP1B phosphatase and viability of MCF-7 cells. Conclusions: From the tested compounds, epigallocatechin and epigallocatechin gallate were the most effective inhibitors of the MCF-7 cell viability. Moreover, epigallocatechin was also the strongest inhibitor of PTP1B activity. Computational analysis allows us also to conclude that epigallocatechin is able to interact and bind to PTP1B. Our results suggest also the most predicted binding site to epigallocatechin binding to PTP1B.

ANTIOXIDANT CHEMISTRY OF GREEN TEA CATECHINS: OXIDATION PRODUCTS OF (-)-EPIGALLOCATECHIN GALLATE AND (-)-EPIGALLOCATECHIN WITH PEROXIDASE

2007 ◽  
Vol 7 (4) ◽  
pp. 275-282 ◽  
Author(s):  
NANQUN ZHU ◽  
SHENGMIN SANG ◽  
TZOU-CHI HUANG ◽  
NAISHENG BAI ◽  
CHUNG S. YANG ◽  
...  
Keyword(s):  
Green Tea ◽  
Epigallocatechin Gallate ◽  
Oxidation Products ◽  
Tea Catechins ◽  
Green Tea Catechins

scholarly journals Efficacy of Topical Treatment with (−)-Epigallocatechin Gallate, A Green Tea Catechin, in Mice with Cutaneous Leishmaniasis

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1741
Author(s):  
Andrea M. Sosa ◽  
Agustín Moya Álvarez ◽  
Estefanía Bracamonte ◽  
Masataka Korenaga ◽  
Jorge D. Marco ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Green Tea ◽  
Topical Treatment ◽  
Epigallocatechin Gallate ◽  
Parasite Burden ◽  
Antileishmanial Activity ◽  
Control Group ◽  
Tea Catechins ◽  
Reference Drug ◽  
Green Tea Catechins

The treatment of leishmaniasis includes pentavalent antimony drugs but, because of the side effects, toxicity and cases of treatment failure or resistance, the search of new antileishmanial compounds are necessary. The aims of this study were to evaluate and compare the in vitro antileishmanial activity of four green tea catechins, and to assess the efficacy of topical (−)-epigallocatechin gallate in a cutaneous leishmaniasis model. The antileishmanial activity of green tea catechins was evaluated against intracellular amastigotes, and cytotoxicity was performed with human monocytic cell line. BALB/c mice were infected in the ear dermis with Leishmania (Leishmania) amazonensis and treated with topical 15% (−)-epigallocatechin gallate, intraperitoneal Glucantime, and control group. The efficacy of treatments was evaluated by quantifying the parasite burden and by measuring the lesions size. (−)-Epigallocatechin gallate and (−)-epigallocatechin were the most active compounds with IC50 values <59.6 µg/mL and with a selectivity index >1. Topical treatment with (−)-epigallocatechin gallate decreased significantly both lesion size and parasite burden (80.4% inhibition) compared to control group (p < 0.05), and moreover (−)-epigallocatechin gallate showed a similar efficacy to Glucantime (85.1% inhibition), the reference drug for leishmaniasis treatment.

scholarly journals Health effects of green tea catechins in overweight and obese men: a randomised controlled cross-over trial

2011 ◽  
Vol 106 (12) ◽  
pp. 1880-1889 ◽  
Author(s):  
A. L. Brown ◽  
J. Lane ◽  
C. Holyoak ◽  
B. Nicol ◽  
A. E. Mayes ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Health Effects ◽  
Green Tea ◽  
Metabolic Flux ◽  
Epigallocatechin Gallate ◽  
Metabolic Function ◽  
Tea Catechins ◽  
Green Tea Catechins ◽  
Modifying Effect

Regular consumption of green tea may be cardioprotective. In the present study we investigated the health effects of dietary supplementation with green tea catechins and the potential modifying effect of the catechol-O-methyltransferase (COMT) Val/Met genotype. Subjects (sedentary males, aged 40–69 years, with BMI ≥  28 and ≤  38 kg/m2) were randomly assigned to consume decaffeinated green tea extract (DGT; 530 mg containing about 400 mg total catechins/capsule, twice daily) and placebo in a complete cross-over design. Ambulatory blood pressure and biomarkers of metabolic function (cholesterol, TAG, glucose and insulin) were measured at weeks 0 and 6. Although a marked increase in the concentration of plasma epigallocatechin gallate (EGCG), urinary epigallocatechin (EGC) and urinary 4′-O-methyl EGC was found after DGT treatment, no effect on blood pressure or biomarkers of metabolic function was observed. However, a period × treatment interaction (P < 0·05) was detected for body-weight change. Despite a similar increase in estimated energy intake during intervention period 1, body weight decreased by 0·64 (sd 2·2) kg and increased by 0·53 (sd 1·9) kg in the DGT and placebo groups, respectively (P = 0·025), suggesting a protective effect of green tea catechins on weight gain. Additionally, the COMT Val/Met genotype influenced urinary accumulation of EGC and 4′-O-methyl EGC (P < 0·01). Mean concentrations were lower in individuals homozygous for the high-activity G-allele, possibly reflecting increased metabolic flux and a more rapid conversion to downstream metabolic species, compared with individuals carrying at least one copy of the low-activity A-allele. Additional studies are needed to confirm these findings and further explore the modifying effect of genotype.

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