To investigate the anti-α_(s1)-casein allergy mechanism of two tea-derived polyphenols,epigallocatechin(EGC)and epigallocatechin gallate(EGCG),BALB/c mice were sensitized and challenged withα_(s1)-casein and nutriti...To investigate the anti-α_(s1)-casein allergy mechanism of two tea-derived polyphenols,epigallocatechin(EGC)and epigallocatechin gallate(EGCG),BALB/c mice were sensitized and challenged withα_(s1)-casein and nutritional intervention was given by EGC and EGCG during the sensitization provocation phase.The main evaluation indexes used were levels of mast cell proteases,histamine,and specific antibody immunoglobulin E(IgE),as well as cytokine secretion and pathological observation.The results showed that both EGC and EGCG significantly reduced levels of mast cell protease,histamine,specific IgE antibodies,and Th2 cytokines in allergic mice.The histopathology results showed that both EGC and EGCG markedly reduced the degree of lesions in the intestine,thymus,spleen,and lung.The conclusions from this study can provide a theoretical basis for the mechanism by which tea polyphenols regulate food allergens.展开更多
AIM:To evaluate the effect of epigallocatechin gallate(EGCG) in preventing lens opacity and the aggregation of lens αB-crystallin in model rats of diabetes mellitus(DM).METHODS:This experimental study included Wistar...AIM:To evaluate the effect of epigallocatechin gallate(EGCG) in preventing lens opacity and the aggregation of lens αB-crystallin in model rats of diabetes mellitus(DM).METHODS:This experimental study included Wistar rats for DM as in vivo models and divided into 5 groups.The treatment groups were administered EGCG by orally for 20d and were then assessed for their degree of lens opacity with binocular microscope and lens αB-crystallin expression from Western blot analyze.RESULTS:Pearson correlation test and regression analysis on EGCG exposure and final random blood sugar(RBS) obtained a significance level of P<0.05.EGCG exposure can significantly lower RBS with an R~2 of 0.5634(56.34%).The same analysis on EGCG exposure and the degree of lens opacity obtained a significance level of P<0.05 and increased exposure to EGCG can significantly lower the degree of lens opacity with an R~2 of 0.8577(85.77%).Correlation analysis between EGCG and the expression of lens αB-crystallin can be concluded that the higher the EGCG exposure administered,the higher the native lens αB-crystallin expression and the lower the aggregate lens αB-crystallin expression.There was also significant effect in which every 1 mg/kg body weight dose of EGCG can increase the native lens αB-crystallin expression by 0.0063 and decrease the aggregate lens αB-crystallin expression by 0.0076.CONCLUSION:The administration of EGCG at a dose of 300,600,and 1200 mg shows a significant effect on preventing lens opacity and aggregation of αB-crystallin in diabetic rat models and this research could be a biomolecular prevention of cataract.展开更多
AIM To investigate the effect of epigallocatechin gallate(EGCG) on structural changes of gut microbiota in colorectal carcinogenesis.METHODS An azoxymethane(AOM)/dextran sodium sulfate(DSS)-induced colitis mouse model...AIM To investigate the effect of epigallocatechin gallate(EGCG) on structural changes of gut microbiota in colorectal carcinogenesis.METHODS An azoxymethane(AOM)/dextran sodium sulfate(DSS)-induced colitis mouse model was established. Fortytwo female FVB/N mice were randomly divided into the following three groups: group 1(10 mice, negative control) was treated with vehicle, group 2(16 mice, positive control) was treated with AOM plus vehicle, and group 3(16 mice, EG) was treated with AOM plus EGCG. For aberrant crypt foci(ACF) evaluation, the colons were rapidly took out after sacrifice, rinsed with saline, opened longitudinally, laid flat on a polystyrene board, and fixed with 10% buffered formaldehyde solution before being stained with 0.2% methylene blue in saline. For tumor evaluation, the colon was macroscopically inspected and photographed, then the total number of tumors was enumerated and tumor size measured. For histological examination, the fixed tissues were paraffin-embedded and sectioned at 5 mm thickness. Microbial genomic DNA was extracted from fecal and intestinal content samples using a commercial kit. The V4 hypervariable regions of 16 S r RNA were PCR-amplified with the barcoded fusion primers. Using the best hit classification option, the sequences from each sample were aligned to the RDP 16 S r RNA training set to classify the taxonomic abundance in QIIME. Statistical analyses were then performed.RESULTS Treatment of mice with 1% EGCG caused a significant decrease in the mean number of ACF per mouse, when compared with the model mice treated with AOM/DSS(5.38 ± 4.24 vs 13.13 ± 3.02, P < 0.01). Compared with the positive control group, 1% EGCG treatment dependently decreased tumor load per mouse by 85%(33.96 ± 6.10 vs 2.96 ± 2.86, respectively, P < 0.01). All revealed that EGCG could inhibit colon carcinogenesis by decreasing the number of precancerous lesions as well as solid tumors, with reduced tumor load and delayed histological progression of CRC. During the cancerization, the diversity of gut microbiota increased, potential carcinogenic bacteria such as Bacteroides were enriched, and the abundance of butyrate-producing bacteria(Clostridiaceae, Ruminococcus, etc.) decreased continuously. In contrast, the structure of gut microbiota was relatively stable during the intervention of EGCG on colon carcinogenesis. Enrichment of probiotics(Bifidobacterium, Lactobacillu, etc.) might be a potential mechanism for EGCG's effects on tumor suppression. Via bioinformatics analysis, principal coordinate analysis and cluster analysis of the tumor formation process, we found that the diversity of gut microbiota increased in the tumor model group while that in the EGCG interfered group(EG) remained relatively stable.CONCLUSION Gut microbiota imbalance might be a potential mechanism for the prevention of malignant transformation by EGCG, which is significant for diagnosis, treatment, prognosis evaluation, and prevention of colorectal cancer.展开更多
The fresh leaves of China green tea, Camellia sinensis, were collected from Fuyang, Zhejiang Province, China, in April. The tea polyphenols was extracted by four different methods (homogenized with distilled water at ...The fresh leaves of China green tea, Camellia sinensis, were collected from Fuyang, Zhejiang Province, China, in April. The tea polyphenols was extracted by four different methods (homogenized with distilled water at room temperature, homogenized with 0.3% citric acid (w/v) at room temperature, 5- min boiling and homogenized with distilled water at room temperature, homogenized with 85°C distilled water), and after preserving at room temperature, the change of the Epigallocatechin gallate (EGCG) contents of the extracts was investigated. Results indicated that the EGCG content of homogenate extracted with 85°C distilled water was the highest before the extract was preserved, followed by that of the extract homogenized with 0.3% citric acid at room temperature. During preservation, EGCG content changed obviously. The EGCG contents of homogenates extracted with distilled water at room temperature and 85°C distilled water declined quickly and separately reduced to 21.52% and 54.6% of their initial contents after preservation for 12 h. The EGCG contents extracted by 0.3% citric acid (w/v) solvent at room temperature and 5- min boiling/homogenized with distilled water at room temperature declined relatively slowly ,and separately reduced to 76.9% and 85.16% of their initial contents after preservation for 12 h. It was also found that the citric acid can prevent the degradation of EGCG and the extract solution color is light展开更多
Systematic inflammatory response after spinal cord injury (SCI) is one of the factors leading to lesion development and a profound degree of functional loss. Anti-inflammatory compounds, such as curcumin and epigall...Systematic inflammatory response after spinal cord injury (SCI) is one of the factors leading to lesion development and a profound degree of functional loss. Anti-inflammatory compounds, such as curcumin and epigallocatechin gallate (EGCG) are known for their neuroprotective effects. In this study, we investigated the effect of combined therapy of curcumin and EGCG in a rat model of acute SCI induced by balloon compression. Immediately after SCI, rats received curcumin, EGCG, curcumin + EGCG or saline [daily intraperitoneal doses (curcumin, 6 mg/kg; EGCG 17 mg/kg)] and weekly intramuscular doses (curcumin,60 mg/kg; EGCG 17 mg/kg)] for 28 days. Rats were evaluated using behavioral tests (the Basso, Beattie, and Bresnahan (BBB) open-field locomotor test, flat beam test). Spinal cord tissue was analyzed using histological methods (Luxol Blue-cresyl violet staining) and mmunohistochemistry (anti-glial fibrillary acidic protein, anti-growth associated protein 43). Cytokine levels (interleukin-1β, interleukin-4, interleukin-2,interleukin-6, macrophage inflammatory protein 1-alpha, and RANTES) were measured using Luminex assay. Quantitative polymerase chain reaction was performed to determine the relative expression of genes (Sort1, Fgf2, Irf5, Mrc1, Olig2, Casp3, Gap43, Gfap, Vegf, NfκB, Cntf) related to regenerative processes in injured spinal cord. We found that all treatments displayed significant behavioral recovery, with no obvious synergistic effect after combined therapy of curcumin and ECGC. Curcumin and EGCG alone or in combination increased axonal sprouting, decreased glial scar formation, and altered the levels of macrophage inflammatory protein 1-alpha, interleukin-1β, interleukin-4 and interleukin-6 cytokines. These results imply that although the expected synergistic response of this combined therapy was less obvious, aspects of tissue regeneration and immune responses in severe SCI were evident.展开更多
AIM:To compare the potential protective effects of epigallocatechin gallate(EGCG) and ellagic acid(EA) in an experimental cataract model.●METHODS:Twenty-eight Spraque-Dawley rat pups were assigned into four gro...AIM:To compare the potential protective effects of epigallocatechin gallate(EGCG) and ellagic acid(EA) in an experimental cataract model.●METHODS:Twenty-eight Spraque-Dawley rat pups were assigned into four groups.All the rats,except for those in the control group,were injected subcutaneously sodium selenite to induce experimental cataract on the postpartum ninth day,and between 10 th and 14 th days.Rats in the sham,EGCG,and EA groups were intraperitoneally administered 50 mg/(kg·d) saline solution,50 mg/(kg·d) EGCG and 200 mg/(kg·d) EA,respectively.The reduced glutathione(GSH) and malondialdehyde(MDA) levels,total antioxidant status(TAS) and total oxidant status(TOS) in lens supernatants were measured.RESULTS:The mean cataract gradings in EGCG and EA groups were found to be significantly lower than that in sham group(P〈0.001).The mean GSH levels and TASs in EGCG and EA groups were significantly higher than that in sham group while mean MDA levels and TOSs in EGCG and EA groups were significantly lower than that in the sham group(P〈0.001).CONCLUSION:EGCG and EA have protective effects on cataract development via the inhibition of oxidative stress.展开更多
AIM: To investigate whether Epigallocatechin-3-gallate (EGCG) can induce apoptosis of the gastric cancer cell line MKN45 and its apoptotic pathway. METHODS: To determine this, apoptotic rates of MKN45 cells after EGCG...AIM: To investigate whether Epigallocatechin-3-gallate (EGCG) can induce apoptosis of the gastric cancer cell line MKN45 and its apoptotic pathway. METHODS: To determine this, apoptotic rates of MKN45 cells after EGCG treatment with or without caspase-3 inhibitor were evaluated by Annexin V-FITC + PI staining The influence of EGCG on the activity of caspase-3 in the MKN45 cells was determined by ELISA. By Rhodamine123 staining, the membrane potential change of the mitochondrion was also investigated, and mRNAs and protein expression of the bcl-2 family were analyzed by RT-PCR and Western blot. RESULTS: EGCG can induce apoptosis of MKN45 cells in time-and dose-dependent manner. Eight hours after EGCG treatment, the activity of caspase-3 in the MKN45 increased, especially 12 h after treatment. The mitochondrial membrane potential was significantly weakened 4 h after EGCG insult. The mRNA and protein expression levels of pro-apoptotic members, such as Bax, Bid and Bad, were upregulated gradually as treated time increased. Moreover, the mRNA and protein expression levels of anti-apoptotic members, such as Bcl-xL and Bcl-2, were inhibited. CONCLUSION: These data support that EGCG can induce apoptosis of the human gastric cancer cell line MKN45, and the effect is in a time-and dose-dependent manner. The apoptotic pathway triggered by EGCG in MKN45 is mitochondrial-dependent.展开更多
AIM:To determine the effects of curcumin,(-)-epigallocatechin-3-gallate (EGCG),lovastatin,and their combinations on inhibition of esophageal cancer.METHODS:Esophageal cancer TE-8 and SKGT-4 cell lines were subjected t...AIM:To determine the effects of curcumin,(-)-epigallocatechin-3-gallate (EGCG),lovastatin,and their combinations on inhibition of esophageal cancer.METHODS:Esophageal cancer TE-8 and SKGT-4 cell lines were subjected to cell viability methyl thiazolyl tetrazolium and tumor cell invasion assays in vitro and tumor formation and growth in nude mouse xenografts with or without curcumin,EGCG and lovastatin treatment.Gene expression was detected using immunohistochemistry and Western blotting in tumor cell lines,tumor xenografts and human esophageal cancer tissues,respectively.RESULTS:These drugs individually or in combinations significantly reduced the viability and invasion capacity of esophageal cancer cells in vitro.Molecularly,these three agents reduced the expression of phosphorylated extracellular-signal-regulated kinases (Erk1/2),c-Jun and cyclooxygenase-2 (COX-2),but activated caspase 3 in esophageal cancer cells.The nude mouse xenograft assay showed that EGCG and the combinations of curcumin,EGCG and lovastatin suppressed esophageal cancer cell growth and reduced the expression of Ki67,phosphorylated Erk1/2 and COX-2.The expression of phosphorylated Erk1/2 and COX-2 in esophageal cancer tissue specimens was also analyzed using immunohistochemistry.The data demonstrated that 77 of 156 (49.4%) tumors expressed phosphorylated Erk1/2 and that 121 of 156 (77.6%) esophageal cancers expressed COX-2 protein.In particular,phosphorylated Erk1/2 was expressed in 23 of 50 (46%) cases of esophageal squamous cell carcinoma (SCC) and in 54 of 106 (50.9%) cases of adenocarcinoma,while COX-2 was expressed in 39 of 50 (78%) esophageal SCC and in 82 of 106 (77.4%) esophageal adenocarcinoma.CONCLUSION:The combinations of curcumin,EGCG and lovastatin were able to suppress esophageal cancer cell growth in vitro and in nude mouse xenografts,these drugs also inhibited phosphorylated Erk1/2,c-Jun and COX-2 expression.展开更多
Epigallocatechin-3-gallate (EGCG) has shown remarkably anti-cancer activity, with its bioactivity being related to reactive conditions, such as pH and metal ions. The present study investigated the degradation of EGCG...Epigallocatechin-3-gallate (EGCG) has shown remarkably anti-cancer activity, with its bioactivity being related to reactive conditions, such as pH and metal ions. The present study investigated the degradation of EGCG and its effect on prostate cancer cell in the presence of Cu2+. EGCG was incubated with prostate cancer cells, LNCaP, pretreated with or without Cu2+.EGCG in F-12 medium was quantified using HPLC and the viability of cells was assessed by gel electrophoresis, flow cytometry,and electron microscope. The results of HPLC showed that EGCG degraded completely within 12 h in F-12 medium with or without Cu2+. Gel electrophoresis and flow cytometry did not detect apoptosis of LNCaP cells when they were incubated with EGCG. Electron microscopy examination revealed that EGCG-Cu2+ complex led to damage of cytoplasm membrane in LNCaP cells. It was speculated that not EGCG, but its oxide and complex with Cu2+, are the bioactive components responsible for its cytotoxicity to LNCaP prostate cancer cells.展开更多
AIM: To demonstrate that (-)-Epigallocatechin-3-gallate (EGCG) inhibits vascular endothelial growth factor (VEGF) expression and angiogenesis induced by interleukin-6 (IL-6) via suppressing signal transducer and activ...AIM: To demonstrate that (-)-Epigallocatechin-3-gallate (EGCG) inhibits vascular endothelial growth factor (VEGF) expression and angiogenesis induced by interleukin-6 (IL-6) via suppressing signal transducer and activator of transcription 3 (Stat3) activity in gastric cancer. METHODS: Human gastric cancer (AGS) cells were treated with IL-6 (50 ng/mL) and EGCG at different concentrations. VEGF, total Stat3 and activated Stat3 protein levels in the cell lyses were examined by Western blotting, VEGF protein level in the conditionedmedium was measured by enzyme-linked immunosorbent assay, and the level of VEGF mRNA was evaluated by reverse transcription polymerase chain reaction (RTPCR). Stat3 nuclear translocation was determined by Western blotting with nuclear extract, and Stat3-DNA binding activity was examined with Chromatin immunoprecipitation (ChIP) assay. IL-6 induced endothelial cell proliferation was measured with 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazoliumbromide assay, in vitro angiogenesis was determined with endothelial cell tube formation assay in Matrigel, and IL-6-induced angiogenesis in vitro was measured with Matrigel plug assay. RESULTS: There was a basal expression and secretion of VEGF in AGS cells. After stimulation with IL-6, VEGF expression was apparently up-regulated and a 2.4-fold increase was observed. VEGF secretion in the conditioned medium was also increased by 2.8 folds. When treated with EGCG, VEGF expression and secretion were dose-dependently decreased. IL-6 also increased VEGF mRNA expression by 3.1 folds. EGCG treatment suppressed VEGF mRNA expression in a dose-dependent manner. EGCG dose-dependently inhibited Stat3 activation induced by IL-6, but did not change the total Stat3 expression. When treated with EGCG or AG490, VEGF expressions were reduced to the level or an even lower level in the tumor cells not stimulated with IL-6. However, PD98059 and LY294002 did not change VEGF expression induced by IL-6. EGCG inhibited Stat3 nucleus translocation, and Stat3-DNA binding activity was also markedly decreased by EGCG. Furthermore, EGCG inhibited IL-6 induced vascular endothelial cell proliferation and tube formation in vitro and angiogenesis in vitro . CONCLUSION: EGCG inhibits IL-6-induced VEGF expression and angiogenesis via suppressing Stat3 activity in gastric cancer, which has provided a novel mechanistic insight into the anti-angiogenic activity of EGCG.展开更多
AIM: To investigate the effect of (-)-epigallocatechin- 3-gallate (EGCG) on growth of gastric cancer and its possible mechanism. METHODS: Heterotopic tumors were induced by subcutaneously injection of SGC-7901 cells i...AIM: To investigate the effect of (-)-epigallocatechin- 3-gallate (EGCG) on growth of gastric cancer and its possible mechanism. METHODS: Heterotopic tumors were induced by subcutaneously injection of SGC-7901 cells in nude mice. Tumor growth was measured by calipers in two dimensions. Tumor angiogenesis was determined with tumor microvessel density (MVD) by immunohistology. Vascular endothelial growth factor (VEGF) protein level and activation of signal transducer and activator of transcription 3 (Stat3) were examined by Western blotting. VEGF mRNA expression was determined by RT-PCR and VEGF release in tumor culture medium by ELISA. VEGF-induced cell proliferation was studied by MTT assay, cell migration by gelatin modified Boyden chamber (Transwell) and in vitro angiogenesis by endothelial tube formation in Matrigel. RESULTS: Intraperitoneal injection of EGCG inhibited the growth of gastric cancer by 60.4%. MVD in tumor tissues treated with EGCG was markedly reduced. EGCG treatment reduced VEGF protein level in vitro and in vivo. Secretion and mRNA expression of VEGF in tumor cells were also suppressed by EGCG in a dose-dependent manner. This inhibitory effect was associated with reduced activation of Stat3, but EGCG treatment did not change the total Stat3 expression. EGCG also inhibited VEGF-induced endothelial cell proliferation, migration and tube formation. CONCLUSION: EGCG inhibits the growth of gastriccancer by reducing VEGF production and angiogenesis, and is a promising candidate for anti-angiogenic treatment of gastric cancer.展开更多
BACKGROUND Epigallocatechin gallate(EGCG)is a polyhydroxy phenolic compound extracted from tea and its antitumor effect has received widespread attention.We explored the inhibitory effect of EGCG on dimethylhydrazine(...BACKGROUND Epigallocatechin gallate(EGCG)is a polyhydroxy phenolic compound extracted from tea and its antitumor effect has received widespread attention.We explored the inhibitory effect of EGCG on dimethylhydrazine(DMH)-induced colorectal cancer(CRC)using a rat model,predicted the interaction between EGCG and CRC target genes using a database,and explained the EGCG associated target pathways and mechanisms in CRC.AIM To understand the inhibitory mechanisms of EGCG on CRC cell proliferation and identify its pharmacological targets by network pharmacology analysis.METHODS DMH(40 mg/kg,s.c.,twice weekly for eight weeks)was used to induce CRC in rats.After model establishment,the rats were administered with EGCG(50,100,or 200 mg/kg,p.o.,once daily for eight weeks)and killed 12 and 20 wk after the start of the experiment.Formation of aberrant crypt foci and tumor was studied by histological analysis.Using network pharmacology analysis,candidate and collective targets of EGCG and CRC were identified,and Gene ontology(GO)and Kyoto Encyclopedia of Genes and Genomes analyses were used to predict the pathways altered by EGCG.RESULTS At week 12,high-dose EGCG treatment significantly reduced the tumor formation rate,total number of tumors,cancerous and non-cancerous tumors,tumor volume,ascites formation,and aberrant crypt foci count.At week 20,all three doses of EGCG were effective.Seventy-eight collective targets of EGCG and CRC were identified,of which 28 genes were dysregulated in CRC.Kyoto Encyclopedia of Genes and Genomes and GO analyses showed that the dysregulated genes were enriched in hsa05210(CRC),hsa04115(p53 signaling pathway),and hsa04151(PI3K-Akt signaling pathway),GO:0043124(negative regulation of I-kappaB kinase/NF-kappaB signaling pathway),GO:0043409(negative regulation of mitogen-activated protein kinase cascade),and GO:2001244(positive regulation of intrinsic apoptotic signaling pathway)respectively.CONCLUSION EGCG inhibits the formation of DMH-induced CRC by regulating key pathways involved in tumorigenesis.展开更多
Epigallocatechin-3-gallate (EGCG), a naturally occurring compound in green tea, has been widely used as an antioxidant agent. In the present study, model rats with acute spinal cord injury were intraperitoneally inj...Epigallocatechin-3-gallate (EGCG), a naturally occurring compound in green tea, has been widely used as an antioxidant agent. In the present study, model rats with acute spinal cord injury were intraperitoneally injected with 25, 50, and 100 mg/kg EGCG, and spinal cord ultrastructure, oxidative stress reaction, inflammatory factors, and apoptosis-associated gene expression were observed. Results showed that EGCG attenuated neuronal and axonal injury 24 hours post injury. It also decreased serum intedeukin-113, tumor necrosis factor-a, and intercellular adhesion molecule-1 release, and decreased apoptosis-associated gene expression. Furthermore, it increased the level of the superoxide anion (O2-), superoxide dismutase, and B-cell lymphoma/leukemia-2, and reduced malondialdehyde levels. Furthermore, it reduced the expression of the pro-apoptotic protein Bax. Noticeably, EGCG at the 100 mg/kg dosage exhibited similar effects as methylprednisolone sodium succinate, which has been frequently used for clinical acute spinal cord injury. The results demonstrated that EGCG can significantly inhibit inflammation, suppress oxidation, and reduce apoptosis in acute spinal cord injury.展开更多
AIM: To clarify the effects of epigallocatechin-3-gallate (EGCG) on the platelet-derived growth factor (PDGF)-BBinduced proliferation and migration of pancreatic stellate cells (PSCs).METHODS: PSCs were isolated from ...AIM: To clarify the effects of epigallocatechin-3-gallate (EGCG) on the platelet-derived growth factor (PDGF)-BBinduced proliferation and migration of pancreatic stellate cells (PSCs).METHODS: PSCs were isolated from rat pancreas tissue and used in their culture-activated, myofibroblast-like phenotype. Cell proliferation was assessed by measuring the incorporation of 5-bromo-2'-deoxyuridine. Cell migration was assessed using modified Boyden chambers. CyclinD1, p21waf1, and p27kip1 expression and phosphorylation of PDGF β-receptor, extracellular signal-regulated kinase, and Akt were examined by Western blotting. Activation of phosphatidylinositol 3-kinase was examined by kinase assay using phosphatidylinositol as a substrate. Cell cycle was assessed by flow cytometry after staining with propidium iodide. RESULTS: EGCG at non-cytotoxic concentrations inhibited PDGF-induced proliferation and migration. This effect was associated with the inhibition of cell cycle progression beyondthe G1 phase, decreased cyclin D1 and increased p27Kip1 expression. EGCG inhibited tyrosine phosphorylation of PDGF β-receptor and downstream activation of extracellular signal-regulated kinase and phosphatidylinositol 3-kinase/ Akt pathways.CONCLUSION: EGCG inhibited PDGF-BB-induced proliferation and migration of PSCs through the inhibrdon of PDGF-mediated signaling pathways.展开更多
Lipophilic tea polyphenols (LTP) were prepared by catalytic esterifieation of green tea polyphenols (GRIP) with hexadeeanoyl chloride. A novel long-chain aeyl-derivative of epigalloeateehin-3-o-gallate(EGCG) was first...Lipophilic tea polyphenols (LTP) were prepared by catalytic esterifieation of green tea polyphenols (GRIP) with hexadeeanoyl chloride. A novel long-chain aeyl-derivative of epigalloeateehin-3-o-gallate(EGCG) was first isolated from purification of LTP by high-speed eountereurrent ehromatography (HSCCC)using a solvent system composed of n-hexane-ethyl acetate-methanol-water ( 1 : 1 : 1 : 1, v/v) . The moleeularstructure of the acyl-derivative, Epigallocatechin-3-O-gallate-4'-O-hexadeeanate , was elucidated by meansof elemental analysis, IR, 1H-NMR and MS spectra.展开更多
AIM:To analyze the antiviral mechanism of Epigallocatechin gallate(EGCG)against hepatitis B virus(HBV) replication.METHODS:In this research,the HBV-replicating cell line HepG2.117 was used to investigate the antiviral...AIM:To analyze the antiviral mechanism of Epigallocatechin gallate(EGCG)against hepatitis B virus(HBV) replication.METHODS:In this research,the HBV-replicating cell line HepG2.117 was used to investigate the antiviral mechanism of EGCG.Cytotoxicity of EGCG was analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.Hepatitis B virus e antigen(HBeAg)and hepatitis B virus surface antigen(HBsAg)in the supernatant were detected by enzyme-linked immunosorbent assay.Precore mRNA and pregenomic RNA(pgRNA) levels were determined by semi-quantitative reverse transcription polymerase chain reaction(PCR)assay.The effect of EGCG on HBV core promoter activity was measured by dual luciferase reporter assay.HBV covalently closed circular DNA and replicative intermediates of DNA were quantified by real-time PCR assay.RESULTS:When HepG2.117 cells were grown in the presence of EGCG,the expression of HBeAg was suppressed,however,the expression of HBsAg was not affected.HBV precore mRNA level was also downregulated by EGCG,while the transcription of precore mRNA was not impaired.The synthesis of both HBV covalently closed circular DNA and replicative intermediates of DNA were reduced by EGCG treatment to a similar extent,however,HBV pgRNA transcripted from chromosome-integrated HBV genome was not affected by EGCG treatment,indicating that EGCG targets only replicative intermediates of DNA synthesis.CONCLUSION:In HepG2.117 cells,EGCG inhibits HBV replication by impairing HBV replicative intermediates of DNA synthesis and such inhibition results in reduced production of HBV covalently closed circular DNA.展开更多
基金supported by the National Key Research and Development Program of China(2019YFC1605002)the National Natural Science Foundation of China(31872886)。
文摘To investigate the anti-α_(s1)-casein allergy mechanism of two tea-derived polyphenols,epigallocatechin(EGC)and epigallocatechin gallate(EGCG),BALB/c mice were sensitized and challenged withα_(s1)-casein and nutritional intervention was given by EGC and EGCG during the sensitization provocation phase.The main evaluation indexes used were levels of mast cell proteases,histamine,and specific antibody immunoglobulin E(IgE),as well as cytokine secretion and pathological observation.The results showed that both EGC and EGCG significantly reduced levels of mast cell protease,histamine,specific IgE antibodies,and Th2 cytokines in allergic mice.The histopathology results showed that both EGC and EGCG markedly reduced the degree of lesions in the intestine,thymus,spleen,and lung.The conclusions from this study can provide a theoretical basis for the mechanism by which tea polyphenols regulate food allergens.
文摘AIM:To evaluate the effect of epigallocatechin gallate(EGCG) in preventing lens opacity and the aggregation of lens αB-crystallin in model rats of diabetes mellitus(DM).METHODS:This experimental study included Wistar rats for DM as in vivo models and divided into 5 groups.The treatment groups were administered EGCG by orally for 20d and were then assessed for their degree of lens opacity with binocular microscope and lens αB-crystallin expression from Western blot analyze.RESULTS:Pearson correlation test and regression analysis on EGCG exposure and final random blood sugar(RBS) obtained a significance level of P<0.05.EGCG exposure can significantly lower RBS with an R~2 of 0.5634(56.34%).The same analysis on EGCG exposure and the degree of lens opacity obtained a significance level of P<0.05 and increased exposure to EGCG can significantly lower the degree of lens opacity with an R~2 of 0.8577(85.77%).Correlation analysis between EGCG and the expression of lens αB-crystallin can be concluded that the higher the EGCG exposure administered,the higher the native lens αB-crystallin expression and the lower the aggregate lens αB-crystallin expression.There was also significant effect in which every 1 mg/kg body weight dose of EGCG can increase the native lens αB-crystallin expression by 0.0063 and decrease the aggregate lens αB-crystallin expression by 0.0076.CONCLUSION:The administration of EGCG at a dose of 300,600,and 1200 mg shows a significant effect on preventing lens opacity and aggregation of αB-crystallin in diabetic rat models and this research could be a biomolecular prevention of cataract.
基金Supported by Natural Science Foundation of Minhang District of Shanghai,No.2012MHZ001
文摘AIM To investigate the effect of epigallocatechin gallate(EGCG) on structural changes of gut microbiota in colorectal carcinogenesis.METHODS An azoxymethane(AOM)/dextran sodium sulfate(DSS)-induced colitis mouse model was established. Fortytwo female FVB/N mice were randomly divided into the following three groups: group 1(10 mice, negative control) was treated with vehicle, group 2(16 mice, positive control) was treated with AOM plus vehicle, and group 3(16 mice, EG) was treated with AOM plus EGCG. For aberrant crypt foci(ACF) evaluation, the colons were rapidly took out after sacrifice, rinsed with saline, opened longitudinally, laid flat on a polystyrene board, and fixed with 10% buffered formaldehyde solution before being stained with 0.2% methylene blue in saline. For tumor evaluation, the colon was macroscopically inspected and photographed, then the total number of tumors was enumerated and tumor size measured. For histological examination, the fixed tissues were paraffin-embedded and sectioned at 5 mm thickness. Microbial genomic DNA was extracted from fecal and intestinal content samples using a commercial kit. The V4 hypervariable regions of 16 S r RNA were PCR-amplified with the barcoded fusion primers. Using the best hit classification option, the sequences from each sample were aligned to the RDP 16 S r RNA training set to classify the taxonomic abundance in QIIME. Statistical analyses were then performed.RESULTS Treatment of mice with 1% EGCG caused a significant decrease in the mean number of ACF per mouse, when compared with the model mice treated with AOM/DSS(5.38 ± 4.24 vs 13.13 ± 3.02, P < 0.01). Compared with the positive control group, 1% EGCG treatment dependently decreased tumor load per mouse by 85%(33.96 ± 6.10 vs 2.96 ± 2.86, respectively, P < 0.01). All revealed that EGCG could inhibit colon carcinogenesis by decreasing the number of precancerous lesions as well as solid tumors, with reduced tumor load and delayed histological progression of CRC. During the cancerization, the diversity of gut microbiota increased, potential carcinogenic bacteria such as Bacteroides were enriched, and the abundance of butyrate-producing bacteria(Clostridiaceae, Ruminococcus, etc.) decreased continuously. In contrast, the structure of gut microbiota was relatively stable during the intervention of EGCG on colon carcinogenesis. Enrichment of probiotics(Bifidobacterium, Lactobacillu, etc.) might be a potential mechanism for EGCG's effects on tumor suppression. Via bioinformatics analysis, principal coordinate analysis and cluster analysis of the tumor formation process, we found that the diversity of gut microbiota increased in the tumor model group while that in the EGCG interfered group(EG) remained relatively stable.CONCLUSION Gut microbiota imbalance might be a potential mechanism for the prevention of malignant transformation by EGCG, which is significant for diagnosis, treatment, prognosis evaluation, and prevention of colorectal cancer.
文摘The fresh leaves of China green tea, Camellia sinensis, were collected from Fuyang, Zhejiang Province, China, in April. The tea polyphenols was extracted by four different methods (homogenized with distilled water at room temperature, homogenized with 0.3% citric acid (w/v) at room temperature, 5- min boiling and homogenized with distilled water at room temperature, homogenized with 85°C distilled water), and after preserving at room temperature, the change of the Epigallocatechin gallate (EGCG) contents of the extracts was investigated. Results indicated that the EGCG content of homogenate extracted with 85°C distilled water was the highest before the extract was preserved, followed by that of the extract homogenized with 0.3% citric acid at room temperature. During preservation, EGCG content changed obviously. The EGCG contents of homogenates extracted with distilled water at room temperature and 85°C distilled water declined quickly and separately reduced to 21.52% and 54.6% of their initial contents after preservation for 12 h. The EGCG contents extracted by 0.3% citric acid (w/v) solvent at room temperature and 5- min boiling/homogenized with distilled water at room temperature declined relatively slowly ,and separately reduced to 76.9% and 85.16% of their initial contents after preservation for 12 h. It was also found that the citric acid can prevent the degradation of EGCG and the extract solution color is light
基金supported by the grant GACR(Grant Agency of the Czech Republic)P304/12/G069the Ministry of Education,Youth and Sports under the project“Centre of Reconstructive Neuroscience”,registration number CZ.02.1.01/0.0./0.0/15_003/0000419project Inter Action LTAUSA17120
文摘Systematic inflammatory response after spinal cord injury (SCI) is one of the factors leading to lesion development and a profound degree of functional loss. Anti-inflammatory compounds, such as curcumin and epigallocatechin gallate (EGCG) are known for their neuroprotective effects. In this study, we investigated the effect of combined therapy of curcumin and EGCG in a rat model of acute SCI induced by balloon compression. Immediately after SCI, rats received curcumin, EGCG, curcumin + EGCG or saline [daily intraperitoneal doses (curcumin, 6 mg/kg; EGCG 17 mg/kg)] and weekly intramuscular doses (curcumin,60 mg/kg; EGCG 17 mg/kg)] for 28 days. Rats were evaluated using behavioral tests (the Basso, Beattie, and Bresnahan (BBB) open-field locomotor test, flat beam test). Spinal cord tissue was analyzed using histological methods (Luxol Blue-cresyl violet staining) and mmunohistochemistry (anti-glial fibrillary acidic protein, anti-growth associated protein 43). Cytokine levels (interleukin-1β, interleukin-4, interleukin-2,interleukin-6, macrophage inflammatory protein 1-alpha, and RANTES) were measured using Luminex assay. Quantitative polymerase chain reaction was performed to determine the relative expression of genes (Sort1, Fgf2, Irf5, Mrc1, Olig2, Casp3, Gap43, Gfap, Vegf, NfκB, Cntf) related to regenerative processes in injured spinal cord. We found that all treatments displayed significant behavioral recovery, with no obvious synergistic effect after combined therapy of curcumin and ECGC. Curcumin and EGCG alone or in combination increased axonal sprouting, decreased glial scar formation, and altered the levels of macrophage inflammatory protein 1-alpha, interleukin-1β, interleukin-4 and interleukin-6 cytokines. These results imply that although the expected synergistic response of this combined therapy was less obvious, aspects of tissue regeneration and immune responses in severe SCI were evident.
基金Funded by an unrestricted grant from Firat University Scientific Research Unit
文摘AIM:To compare the potential protective effects of epigallocatechin gallate(EGCG) and ellagic acid(EA) in an experimental cataract model.●METHODS:Twenty-eight Spraque-Dawley rat pups were assigned into four groups.All the rats,except for those in the control group,were injected subcutaneously sodium selenite to induce experimental cataract on the postpartum ninth day,and between 10 th and 14 th days.Rats in the sham,EGCG,and EA groups were intraperitoneally administered 50 mg/(kg·d) saline solution,50 mg/(kg·d) EGCG and 200 mg/(kg·d) EA,respectively.The reduced glutathione(GSH) and malondialdehyde(MDA) levels,total antioxidant status(TAS) and total oxidant status(TOS) in lens supernatants were measured.RESULTS:The mean cataract gradings in EGCG and EA groups were found to be significantly lower than that in sham group(P〈0.001).The mean GSH levels and TASs in EGCG and EA groups were significantly higher than that in sham group while mean MDA levels and TOSs in EGCG and EA groups were significantly lower than that in the sham group(P〈0.001).CONCLUSION:EGCG and EA have protective effects on cataract development via the inhibition of oxidative stress.
基金Supported by a grant from Shanghai Leading Academic Discipline Project, No.Y0205
文摘AIM: To investigate whether Epigallocatechin-3-gallate (EGCG) can induce apoptosis of the gastric cancer cell line MKN45 and its apoptotic pathway. METHODS: To determine this, apoptotic rates of MKN45 cells after EGCG treatment with or without caspase-3 inhibitor were evaluated by Annexin V-FITC + PI staining The influence of EGCG on the activity of caspase-3 in the MKN45 cells was determined by ELISA. By Rhodamine123 staining, the membrane potential change of the mitochondrion was also investigated, and mRNAs and protein expression of the bcl-2 family were analyzed by RT-PCR and Western blot. RESULTS: EGCG can induce apoptosis of MKN45 cells in time-and dose-dependent manner. Eight hours after EGCG treatment, the activity of caspase-3 in the MKN45 increased, especially 12 h after treatment. The mitochondrial membrane potential was significantly weakened 4 h after EGCG insult. The mRNA and protein expression levels of pro-apoptotic members, such as Bax, Bid and Bad, were upregulated gradually as treated time increased. Moreover, the mRNA and protein expression levels of anti-apoptotic members, such as Bcl-xL and Bcl-2, were inhibited. CONCLUSION: These data support that EGCG can induce apoptosis of the human gastric cancer cell line MKN45, and the effect is in a time-and dose-dependent manner. The apoptotic pathway triggered by EGCG in MKN45 is mitochondrial-dependent.
基金Supported by A United States National Cancer Institute Grant,No.R01CA117895a grant from the Duncan Family Institute for Cancer Prevention and Risk Assessment,UT MDAnderson Cancer Center
文摘AIM:To determine the effects of curcumin,(-)-epigallocatechin-3-gallate (EGCG),lovastatin,and their combinations on inhibition of esophageal cancer.METHODS:Esophageal cancer TE-8 and SKGT-4 cell lines were subjected to cell viability methyl thiazolyl tetrazolium and tumor cell invasion assays in vitro and tumor formation and growth in nude mouse xenografts with or without curcumin,EGCG and lovastatin treatment.Gene expression was detected using immunohistochemistry and Western blotting in tumor cell lines,tumor xenografts and human esophageal cancer tissues,respectively.RESULTS:These drugs individually or in combinations significantly reduced the viability and invasion capacity of esophageal cancer cells in vitro.Molecularly,these three agents reduced the expression of phosphorylated extracellular-signal-regulated kinases (Erk1/2),c-Jun and cyclooxygenase-2 (COX-2),but activated caspase 3 in esophageal cancer cells.The nude mouse xenograft assay showed that EGCG and the combinations of curcumin,EGCG and lovastatin suppressed esophageal cancer cell growth and reduced the expression of Ki67,phosphorylated Erk1/2 and COX-2.The expression of phosphorylated Erk1/2 and COX-2 in esophageal cancer tissue specimens was also analyzed using immunohistochemistry.The data demonstrated that 77 of 156 (49.4%) tumors expressed phosphorylated Erk1/2 and that 121 of 156 (77.6%) esophageal cancers expressed COX-2 protein.In particular,phosphorylated Erk1/2 was expressed in 23 of 50 (46%) cases of esophageal squamous cell carcinoma (SCC) and in 54 of 106 (50.9%) cases of adenocarcinoma,while COX-2 was expressed in 39 of 50 (78%) esophageal SCC and in 82 of 106 (77.4%) esophageal adenocarcinoma.CONCLUSION:The combinations of curcumin,EGCG and lovastatin were able to suppress esophageal cancer cell growth in vitro and in nude mouse xenografts,these drugs also inhibited phosphorylated Erk1/2,c-Jun and COX-2 expression.
文摘Epigallocatechin-3-gallate (EGCG) has shown remarkably anti-cancer activity, with its bioactivity being related to reactive conditions, such as pH and metal ions. The present study investigated the degradation of EGCG and its effect on prostate cancer cell in the presence of Cu2+. EGCG was incubated with prostate cancer cells, LNCaP, pretreated with or without Cu2+.EGCG in F-12 medium was quantified using HPLC and the viability of cells was assessed by gel electrophoresis, flow cytometry,and electron microscope. The results of HPLC showed that EGCG degraded completely within 12 h in F-12 medium with or without Cu2+. Gel electrophoresis and flow cytometry did not detect apoptosis of LNCaP cells when they were incubated with EGCG. Electron microscopy examination revealed that EGCG-Cu2+ complex led to damage of cytoplasm membrane in LNCaP cells. It was speculated that not EGCG, but its oxide and complex with Cu2+, are the bioactive components responsible for its cytotoxicity to LNCaP prostate cancer cells.
基金Supported by National Natural Science Foundation of China, Grant, No. 30571833Natural Science Foundation of Guangdong Province, 05001785China Postdoctoral Science Foundation 20100470963
文摘AIM: To demonstrate that (-)-Epigallocatechin-3-gallate (EGCG) inhibits vascular endothelial growth factor (VEGF) expression and angiogenesis induced by interleukin-6 (IL-6) via suppressing signal transducer and activator of transcription 3 (Stat3) activity in gastric cancer. METHODS: Human gastric cancer (AGS) cells were treated with IL-6 (50 ng/mL) and EGCG at different concentrations. VEGF, total Stat3 and activated Stat3 protein levels in the cell lyses were examined by Western blotting, VEGF protein level in the conditionedmedium was measured by enzyme-linked immunosorbent assay, and the level of VEGF mRNA was evaluated by reverse transcription polymerase chain reaction (RTPCR). Stat3 nuclear translocation was determined by Western blotting with nuclear extract, and Stat3-DNA binding activity was examined with Chromatin immunoprecipitation (ChIP) assay. IL-6 induced endothelial cell proliferation was measured with 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazoliumbromide assay, in vitro angiogenesis was determined with endothelial cell tube formation assay in Matrigel, and IL-6-induced angiogenesis in vitro was measured with Matrigel plug assay. RESULTS: There was a basal expression and secretion of VEGF in AGS cells. After stimulation with IL-6, VEGF expression was apparently up-regulated and a 2.4-fold increase was observed. VEGF secretion in the conditioned medium was also increased by 2.8 folds. When treated with EGCG, VEGF expression and secretion were dose-dependently decreased. IL-6 also increased VEGF mRNA expression by 3.1 folds. EGCG treatment suppressed VEGF mRNA expression in a dose-dependent manner. EGCG dose-dependently inhibited Stat3 activation induced by IL-6, but did not change the total Stat3 expression. When treated with EGCG or AG490, VEGF expressions were reduced to the level or an even lower level in the tumor cells not stimulated with IL-6. However, PD98059 and LY294002 did not change VEGF expression induced by IL-6. EGCG inhibited Stat3 nucleus translocation, and Stat3-DNA binding activity was also markedly decreased by EGCG. Furthermore, EGCG inhibited IL-6 induced vascular endothelial cell proliferation and tube formation in vitro and angiogenesis in vitro . CONCLUSION: EGCG inhibits IL-6-induced VEGF expression and angiogenesis via suppressing Stat3 activity in gastric cancer, which has provided a novel mechanistic insight into the anti-angiogenic activity of EGCG.
基金Supported by the grants from the National Natural Science Foundation of China, No. 30571833the Natural Science Foundation of Guangdong Province, China, No. 05001785
文摘AIM: To investigate the effect of (-)-epigallocatechin- 3-gallate (EGCG) on growth of gastric cancer and its possible mechanism. METHODS: Heterotopic tumors were induced by subcutaneously injection of SGC-7901 cells in nude mice. Tumor growth was measured by calipers in two dimensions. Tumor angiogenesis was determined with tumor microvessel density (MVD) by immunohistology. Vascular endothelial growth factor (VEGF) protein level and activation of signal transducer and activator of transcription 3 (Stat3) were examined by Western blotting. VEGF mRNA expression was determined by RT-PCR and VEGF release in tumor culture medium by ELISA. VEGF-induced cell proliferation was studied by MTT assay, cell migration by gelatin modified Boyden chamber (Transwell) and in vitro angiogenesis by endothelial tube formation in Matrigel. RESULTS: Intraperitoneal injection of EGCG inhibited the growth of gastric cancer by 60.4%. MVD in tumor tissues treated with EGCG was markedly reduced. EGCG treatment reduced VEGF protein level in vitro and in vivo. Secretion and mRNA expression of VEGF in tumor cells were also suppressed by EGCG in a dose-dependent manner. This inhibitory effect was associated with reduced activation of Stat3, but EGCG treatment did not change the total Stat3 expression. EGCG also inhibited VEGF-induced endothelial cell proliferation, migration and tube formation. CONCLUSION: EGCG inhibits the growth of gastriccancer by reducing VEGF production and angiogenesis, and is a promising candidate for anti-angiogenic treatment of gastric cancer.
基金Supported by Nursing Advantage Discipline Construction Project Foundation of Jiangsu Province University,No.2019YSHL107Nanjing Medical Science and Technique Development Foundation,No.NWQR-201705.
文摘BACKGROUND Epigallocatechin gallate(EGCG)is a polyhydroxy phenolic compound extracted from tea and its antitumor effect has received widespread attention.We explored the inhibitory effect of EGCG on dimethylhydrazine(DMH)-induced colorectal cancer(CRC)using a rat model,predicted the interaction between EGCG and CRC target genes using a database,and explained the EGCG associated target pathways and mechanisms in CRC.AIM To understand the inhibitory mechanisms of EGCG on CRC cell proliferation and identify its pharmacological targets by network pharmacology analysis.METHODS DMH(40 mg/kg,s.c.,twice weekly for eight weeks)was used to induce CRC in rats.After model establishment,the rats were administered with EGCG(50,100,or 200 mg/kg,p.o.,once daily for eight weeks)and killed 12 and 20 wk after the start of the experiment.Formation of aberrant crypt foci and tumor was studied by histological analysis.Using network pharmacology analysis,candidate and collective targets of EGCG and CRC were identified,and Gene ontology(GO)and Kyoto Encyclopedia of Genes and Genomes analyses were used to predict the pathways altered by EGCG.RESULTS At week 12,high-dose EGCG treatment significantly reduced the tumor formation rate,total number of tumors,cancerous and non-cancerous tumors,tumor volume,ascites formation,and aberrant crypt foci count.At week 20,all three doses of EGCG were effective.Seventy-eight collective targets of EGCG and CRC were identified,of which 28 genes were dysregulated in CRC.Kyoto Encyclopedia of Genes and Genomes and GO analyses showed that the dysregulated genes were enriched in hsa05210(CRC),hsa04115(p53 signaling pathway),and hsa04151(PI3K-Akt signaling pathway),GO:0043124(negative regulation of I-kappaB kinase/NF-kappaB signaling pathway),GO:0043409(negative regulation of mitogen-activated protein kinase cascade),and GO:2001244(positive regulation of intrinsic apoptotic signaling pathway)respectively.CONCLUSION EGCG inhibits the formation of DMH-induced CRC by regulating key pathways involved in tumorigenesis.
文摘Epigallocatechin-3-gallate (EGCG), a naturally occurring compound in green tea, has been widely used as an antioxidant agent. In the present study, model rats with acute spinal cord injury were intraperitoneally injected with 25, 50, and 100 mg/kg EGCG, and spinal cord ultrastructure, oxidative stress reaction, inflammatory factors, and apoptosis-associated gene expression were observed. Results showed that EGCG attenuated neuronal and axonal injury 24 hours post injury. It also decreased serum intedeukin-113, tumor necrosis factor-a, and intercellular adhesion molecule-1 release, and decreased apoptosis-associated gene expression. Furthermore, it increased the level of the superoxide anion (O2-), superoxide dismutase, and B-cell lymphoma/leukemia-2, and reduced malondialdehyde levels. Furthermore, it reduced the expression of the pro-apoptotic protein Bax. Noticeably, EGCG at the 100 mg/kg dosage exhibited similar effects as methylprednisolone sodium succinate, which has been frequently used for clinical acute spinal cord injury. The results demonstrated that EGCG can significantly inhibit inflammation, suppress oxidation, and reduce apoptosis in acute spinal cord injury.
基金Supported by the Grant-in-Aid for Encouragement of Young Scientists from Japan Society for the Promotion of Science, No. 16590572 Pancreas Research Foundation of Japan, No. 01-01 the Kanae Foundation for Life and Socio-Medical Science
文摘AIM: To clarify the effects of epigallocatechin-3-gallate (EGCG) on the platelet-derived growth factor (PDGF)-BBinduced proliferation and migration of pancreatic stellate cells (PSCs).METHODS: PSCs were isolated from rat pancreas tissue and used in their culture-activated, myofibroblast-like phenotype. Cell proliferation was assessed by measuring the incorporation of 5-bromo-2'-deoxyuridine. Cell migration was assessed using modified Boyden chambers. CyclinD1, p21waf1, and p27kip1 expression and phosphorylation of PDGF β-receptor, extracellular signal-regulated kinase, and Akt were examined by Western blotting. Activation of phosphatidylinositol 3-kinase was examined by kinase assay using phosphatidylinositol as a substrate. Cell cycle was assessed by flow cytometry after staining with propidium iodide. RESULTS: EGCG at non-cytotoxic concentrations inhibited PDGF-induced proliferation and migration. This effect was associated with the inhibition of cell cycle progression beyondthe G1 phase, decreased cyclin D1 and increased p27Kip1 expression. EGCG inhibited tyrosine phosphorylation of PDGF β-receptor and downstream activation of extracellular signal-regulated kinase and phosphatidylinositol 3-kinase/ Akt pathways.CONCLUSION: EGCG inhibited PDGF-BB-induced proliferation and migration of PSCs through the inhibrdon of PDGF-mediated signaling pathways.
文摘Lipophilic tea polyphenols (LTP) were prepared by catalytic esterifieation of green tea polyphenols (GRIP) with hexadeeanoyl chloride. A novel long-chain aeyl-derivative of epigalloeateehin-3-o-gallate(EGCG) was first isolated from purification of LTP by high-speed eountereurrent ehromatography (HSCCC)using a solvent system composed of n-hexane-ethyl acetate-methanol-water ( 1 : 1 : 1 : 1, v/v) . The moleeularstructure of the acyl-derivative, Epigallocatechin-3-O-gallate-4'-O-hexadeeanate , was elucidated by meansof elemental analysis, IR, 1H-NMR and MS spectra.
基金Supported by National Technology and Science Key Project (2008ZX10002-010)the Important National Science and Technology Specific Projects(2009ZX09301-014)
文摘AIM:To analyze the antiviral mechanism of Epigallocatechin gallate(EGCG)against hepatitis B virus(HBV) replication.METHODS:In this research,the HBV-replicating cell line HepG2.117 was used to investigate the antiviral mechanism of EGCG.Cytotoxicity of EGCG was analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.Hepatitis B virus e antigen(HBeAg)and hepatitis B virus surface antigen(HBsAg)in the supernatant were detected by enzyme-linked immunosorbent assay.Precore mRNA and pregenomic RNA(pgRNA) levels were determined by semi-quantitative reverse transcription polymerase chain reaction(PCR)assay.The effect of EGCG on HBV core promoter activity was measured by dual luciferase reporter assay.HBV covalently closed circular DNA and replicative intermediates of DNA were quantified by real-time PCR assay.RESULTS:When HepG2.117 cells were grown in the presence of EGCG,the expression of HBeAg was suppressed,however,the expression of HBsAg was not affected.HBV precore mRNA level was also downregulated by EGCG,while the transcription of precore mRNA was not impaired.The synthesis of both HBV covalently closed circular DNA and replicative intermediates of DNA were reduced by EGCG treatment to a similar extent,however,HBV pgRNA transcripted from chromosome-integrated HBV genome was not affected by EGCG treatment,indicating that EGCG targets only replicative intermediates of DNA synthesis.CONCLUSION:In HepG2.117 cells,EGCG inhibits HBV replication by impairing HBV replicative intermediates of DNA synthesis and such inhibition results in reduced production of HBV covalently closed circular DNA.