Therapeutic effects of epigallocatechin and epigallocatechin gallate on the allergic reaction ofα_(s1)-casein sensitized mice

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.

Effect of epigallocatechin gallate in green tea on preventing lens opacity and αB-crystallin aggregation in rat model of diabetes

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.

Structural shift of gut microbiota during chemopreventive effects of epigallocatechin gallate on colorectal carcinogenesis in mice

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.

Does combined therapy of curcumin and epigallocatechin gallate have a synergistic neuroprotective effect against spinal cord injury？

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.

Comparison of the impact of epigallocatechin gallate and ellagic acid in an experimental cataract model induced by sodium selenite

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.

Epigallocatechin gallate inhibits dimethylhydrazine-induced colorectal cancer in rats

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.

Neuroprotective effect of epigallocatechin-3-gallate on hemisection-induced spinal cord injury in rats

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.

Inhibition of Invasion and Up-regulation of E-cadherin Expression in Human Malignant Melanoma Cell Line A375 by(-)-Epigallocatechin-3-gallate

The inhibitory effects of （-）-epigallocatechin-3-gallate （EGCG） on the invasion of human malignant melanoma cell line A375 and the possible molecular mechanisms of this effect were investiaged. A375 cells were pretreated with 20 μg/mL EGCG for 24, 48 and 72 h respectively and the E-cadherin expression was detected by Western blot analysis. A375 cells were also pretreated with different concentrations of EGCG （1, 5, 10 and 20 μg/mL） for 72 h and the expression of E-cadherin was measured by RT-PCR. The adhesion and invasion of A375 cells were tested by cell-matrigel adhesion assay and matrigel invasion assay respectively. The results showed that EGCG could significantly up-regulate the expression of E-cadherin time-and concentration-dependently （both P〈0.05）. Statistical analysis showed that A375 cells invasion was inhibited by EGCG and correlated with the up-regulation of E-cadherin expression. It was suggested that EGCG strongly inhibited invasion of A375 cells, and the inhibition mechanism was possibly associated with the up-regulation of E-cadherin expression.

Protective Effects of Epigallocatechin-3-gallate on Intestinal Ischemia Reperfusion Injury through Enhanced Activation of PI3K/Akt Pathway in Rats

Inflammation plays a critical role in intestinal ischemia reperfusion injury（IRI）. Epigallocatechin-3-gallate（EGCG） has been demonstrated to possess anti-inflammatory effect. This study examined the effect of EGCG on intestinal IRI and explored the possible mechanisms. Male Wistar rats were randomly divided into three groups： sham-operated group（Sham）, IRI control group（IRI） and IRI-EGCG group（EGCG）. Rats in IRI-EGCG group were administered dissolved EGCG in drinking water（0.4 mg/m L） for 14 days prior to IRI induction. A rat model of intestinal IRI was established by ligating the superior mesenteric artery（SMA） for 30 min, followed by reperfusion for 1 h. Intestinal histology, pro-inflammatory cytokines and mediators were examined and the effect of EGCG on PI3K/Akt signalling was assessed. EGCG significantly alleviated the pathological changes of the intestine and suppressed the IRI-induced up-regulation of TNF-α, IL-1 and IL-6 m RNA and protein expression in the serum and intestine. The mechanism might be that EGCG enhanced the activation of PI3K/Akt signalling pathway. In conclusion, the administration of EGCG can significantly mitigate the acute intestinal IRI in rats by enhancing the activation of PI3K/Akt signalling pathway to suppress inflammatory response and might be a promising alternative for the prevention or treatment of intestinal IRI in the clinical practice.

Green tea, epigallocatechin gallate and the prevention of Alzheimer’s disease: clinical evidence

Given its increasing global prevalence,Alzheimer’s disease(AD)has become a major public health challenge worldwide.The symptomatic treatments available for AD have shown no significant efficacy,and no disease-modifying interventions are capable of slowing the progression of the disorder.The potential of lifestyle-related factors,including diet,is increasingly recognized as an important consideration in the primary prevention of AD.Numerous mechanisms potentially underlying neuroprotective effects of bioactive components contained in tea,such as(-)-epigallocatechin-3-gallate,as well as their preventive efficacy against AD,have been elucidated in preclinical studies.However,in contrast to the abundance of mechanistic findings in animals,clinical results demonstrating efficacy in humans are scarce.While epidemiological studies have provided some evidence indicating that green tea consumption is associated with a reduced risk of age-related cognitive decline and AD,a causal relationship cannot be established on the basis of these observations.The clinical evidence regarding preventive or therapeutic effects of green tea and its bioactive components is unsatisfactory.A role of green tea in the prevention of AD cannot be recommended until well-designed,randomized,placebo-controlled clinical trials using standardized formulations confirm the purported beneficial effects of green tea.

Epigallocatechin-3-gallate attenuates lipopolysaccharideinduced inflammation in human retinal endothelial cells

AIM:To investigate the mechanism underlying the anti-inflammatory effects of epigallocatechin-3-gallate(EGCG)in lipopolysaccharide(LPS)-stimulated human retinal endothelial cells(HRECs).METHODS:HRECspre-treatedwithEGCG(0-100μmol/L)were stimulated with LPS(250 ng/mL).Levels of tumor necrosis factor alpha(TNF-α),vascular endothelial growth factor(VEGF),monocyte chemotactic protein-1(MCP-1)and nitric oxide(NO)in the supernatants were determined by enzyme-linked immunosorbent assay(ELISA)and Griess assay.The protein expression of phosphorylated extracellular signal-regulated kinase(ERK)1/2 and p38 mitogen-activated protein kinases(p38)were determined by Western blot analysis.RESULTS:EGCG pre-treatment significantly inhibited the secretion of TNF-α,VEGF,MCP-1 and NO in LPSstimulated HRECs.Moreover,EGCG effectively attenuated LPS-induced activation and phosphorylation of ERK1/2 and p38 in HRECs in a dose-dependent manner.CONCLUSION:EGCG exhibited inhibitory effects on LPS-induced pro-inflammatory cytokines production by modulating ERK1/2 and p38 pathways in HRECs,suggesting EGCG as a potential candidate for antiinflammatory intervention.

Green tea extract and epigallocatechin 3-gallate reduced labile iron pool and protected oxidative stress in iron-loaded cultured hepatocytes

Cellular and mitochondrial damage can be caused by labile iron pool (LIP) and mediated by reactive oxygen species (ROS). Livers of the thalassemias have highly increased levels of LIP and ROS. Green tea extract (GTE) and epigallocatechin 3-gallatte (EGCG) can potentially protect liver inflammation, fibrosis and cancer due to their anti-oxidative and iron-chelating activities. We studied the effects of GTE and EGCG on intracellular LIP and ROS, and mitochondrial membrane potential (ΔΨm) in mouse hepatocyte and HepG2 cell cultures using specific fluorescent techniques. Treatment with GTE (12.5 - 25 mg/dl) and EGCG (25 - 50 μM) significantly lowered levels of ΔΨm in the mouse hepatocytes;however, combined treatment of 25 μM DFP with GTE and EGCG did not enhance the decrease of hepatic ΔΨm. The results showed that GTE and EGCG effectively removed the intracellular LIP and ROS, and relieved the mitochondria membrane collapse of the liver cells, suggesting a hepatoprotective effect of green tea extract and EGCG in the hepatocytes with iron overload. Their actions might be related to iron-chelating and free radical-scavenging capacities. Whether the effects can improve iron overload and oxidative stress in thalassemia patients remains to be seen upon further examination.

(-)-Epigallocatechin-3-gallate enhances poly I:C-induced interferon-λ1 production and inhibits hepatitis C virus replication in hepatocytes

AIM To investigate the effect of(-)-epigallocatechin-3-gallate(EGCG) on polyinosinic-polycytidylic acid(poly I:C)-triggered intracellular innate immunity against hepatitis C virus(HCV) in hepatocytes. METHODS A cell culture model of HCV infection was generated by infecting a hepatoma cell line, Huh7, with HCV JFH-1 strain(JFH-1-Huh7). Poly I:C with a high molecular weight and EGCG were used to stimulate the JFH-1-Huh7 cells. Real-time reverse transcription-polymerase chain reaction was used to detect the expression levels of intracellular m RNAs and of intracellular and extracellular HCV RNA. Enzyme-linked immunosorbent assay was used to evaluate the interferon(IFN)-λ1 protein level in the cell culture supernatant. Immunostaining was used to examine HCV core protein expression in Huh7 cells.RESULTS Our recent study showed that HCV replication could impair poly I:C-triggered intracellular innate immune responses in hepatocytes. In the current study, we showed that EGCG treatment significantly increased the poly I:C-induced expression of Toll-like receptor 3(TLR3), retinoic acid-inducible gene I, and IFN-λ1 in JFH-1-Huh7 cells. In addition, supplementation with EGCG increased the poly I:C-mediated antiviral activity in JFH-1-Huh7 cells at the intracellular and extracellular HCV RNA and protein levels. Further investigation of the mechanisms showed that EGCG treatment significantly enhanced the poly I:C-induced expression of IFN-regulatory factor 9 and several antiviral IFNstimulated genes, including ISG15, ISG56, myxovirus resistance A, and 2'-5'-oligoadenylate synthetase 1, which encode the key antiviral elements in the IFN signaling pathway. CONCLUSION Our observations provide experimental evidence that EGCG has the ability to enhance poly I:C-induced intracellular antiviral innate immunity against HCV replication in hepatocytes.

Epigallocatechin-3-gallate suppresses transforming growth factor-beta signaling by interacting with the transforming growth factor-beta typeⅡreceptor

AIM: To investigate the(-)-epigallocatechin-3-gallate(EGCG) binding to transforming growth factor-β(TGF-β) type Ⅱ receptor(TGFRⅡ).METHODS: The expression of α-smooth muscle actin(α-SMA) was used as a marker for fibrotic change inhuman lung fibroblast MRC-5 cells. The α-SMA expression level was determined by western blotting and immunohistological analysis. We examined whether the anti-fibrotic effects of EGCG on MRC-5 cells was dependent on antioxidant mechanism by using edaravone and N-acetylcysteine(NAC). The suppression effects of EGCG on Smad2/3 activation were studied by confocal fluorescence microscopy. The binding of EGCG to recombinant TGFRⅡ protein was analyzed by immunoprecipitation and affinity chromatography.RESULTS: When MRC-5 cells were treated with TGF-β, EGCG decreased the expression of α-SMA in a dose dependent manner, whereas catechin did not influence the α-SMA expression in the cells. Except for EGCG, antioxidant compounds(e.g., edaravone and NAC) had no effects on the TGF-β-induced α-SMA expression. Nuclear localization of phosphorylated Smad2/3 was observed after TGF-β treatment; however, EGCG treatment attenuated the nuclear transportation of Smad2/3 in the presence or absence of TGF-β. After a TGFRⅡ expression vector was introduced into COS-7 cells, cell lysates were untreated or treated with EGCG or catechin. The immunoprecipitation experiments using the lysates showed that EGCG dose-dependently bound to TGFRⅡ and that catechin did not at all. Affinity chromatography study indicated that EGCG would bind to TGFRⅡ.CONCLUSION: Our results demonstrate that EGCG interacts with TGFRⅡ and inhibits the expression of α-SMA via the TGF-β-Smad2/3 pathway in human lung fibroblast MRC-5 cells.

Study on the Epigallocatechin Gallate and Konjac Glucomannan Mosaic Topological Structure

In order to effectively protect the activity of Epigallocatechin gallate（EGCG）, we explored the protection mechanism of Konjac glucomannan（KGM） for EGCG by experiments and theory analyses. We synthesized KGM/EGCG nanofibers by using electrostatic spinning method. The microstructure of nanofibers was characterized by SEM, FTIR, TGA, XRD and Raman spectroscopic. The formation mechanism and the protection effects of KGM/EGCG nanofibers were also discussed. The results showed that the EGCG activity was protected due to the hydrogen bonds between-OH of EGCG and KGM, and EGCG was embedded in KGM nanofiber with bead style. The reducing force and DPPH scavenging ability data indicated that KGM/EGCG nanofibers have stronger antioxidant activity than the EGCG solution under the same condition. Hence, the mosaic topological structure of KGM can effectively extend the EGCG activity.

Protective effects of (-)-epigallocatechin-3-gallate on D-galactose-induced neuronal apoptosis in mice

BACKGROUND： The neuroprotective effects of （-）-epigallocatechin-3-gallate （EGCG）, the main polyphenolic constituent of green tea, have been widely reported. However, the action mechanisms, in particular in D-galactose-induced aging mice, remain poorly understood. OBJECTIVE： The present study investigated the protective effects of EGCG on D-galactose-induced hippocampus neuronal apoptosis in aging mice, as well as the relationship with expression of p751CD, JNK2, and p53 proteins. DESIGN, TIME AND SETTING： A randomized, controlled, molecular biological, animal experiment was performed at the Laboratory of Pharmacology, Pharmaceutical College of China Medical University, China, from September 2006 to July 2008. MATERIALS： D-galactose and EGCG （Sigma, USA）, as well as terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling （TUNEL） In Situ Cell Apoptosis Detection Kit （Promega, USA）, were used in this study. METHODS： A total of 64 mice were equally and randomly divided into D-galactose model, low-dose EGCG, high-dose EGCG, and control groups. Mice in the D-galactose model, low-dose EGCG, and high-dose EGCG groups were subcutaneously injected with 3% D-galactose （150 mg/kg）, daily for 6 weeks, to establish a mouse model of aging. Mice in the control group were treated with saline （5 mL/kg）. At 3 weeks following injection, mice in the low-dose EGCG and high-dose EGCG groups were orally administered EGCG at a dose of 2 mg/kg and 6 mg/kg, respectively, once a day, for 4 consecutive days. Mice in the control and D-galactose model groups received distilled water （5 mL/kg）. MAIN OUTCOME MEASURES： Memory function was evaluated using a step-through passive avoidance test. Neuronal apoptosis in the mouse hippocampus was detected using TUNEL staining. Expression levels of the intracellular domain of the p75 neurotrophin receptor （p75NTR）-p751CD, JNK2, and p53 proteins in the hippocampus were determined using Western blot analysis. RESULTS： The aging mouse model was induced by subcutaneous injection of D-galactose, which resulted in obvious memory impairment, increased apoptotic index, and increased protein expression levels of p751CD, JNK2, and p53 in the hippocampus, compared with control mice （P 〈 0.01）. Oral EGCG administration （2 or 6 mg/kg） for 4 weeks significantly improved levels of memory deficit in the aging mice and reduced apoptotic indices and protein expression levels of p751CD, JNK2, and p53 in the mouse hippocampus （P 〈 0.01）. CONCLUSION： Results from this study demonstrated increased protein expression levels of p751CD, JNK2, and p53, as well as increased hippocampal neuronal apoptosis in a D-galactose-induced mouse model of aging. EGCG provided protective effects against D-galactose-induced neuronal apoptosis in the hippocampus by reducing protein expression levels of p751CD, JNK2, and p53 proteins in the hippocampus of aging mice.

(–)-Epigallocatechingallate Interferes RANKL/RANK Signal Pathway and Induces Apoptosis during Osteoclastogenesis in RAW264 Cell

Green tea catechin, (–)-epigallocatechin-3-gallate [(–)-EGCG], was found to increase osteogenic functioning in mesenchymal stem cells. This study qualified EGCG, the strongest inhibitory efficiency for receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-activated osteoclastogenesis among other green tea catechins for RAW264, a murine preosteoclast cell line. Moreover, EGCG inhibited tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cell formation dose dependently in both single culture and co-culture systems, the expression of transcription factor, nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) and some osteoclastic genes. Especially, EGCG exhibited a strong inhibitory effect on the expression levels of RANK, the receptor of RANKL, and OSCAR, a key co-stimulator of the RANKL/RANK signal. Simultaneously, apoptotic genes expression and Hoechst staining revealed that EGCG induced apoptosis in RAW264. Taken together, these data suggest that the inhibitory effect of EGCG to osteoclastogenesis is associated with a down regulation of RANKL/RANK signal, and increased apoptosis of preosteoclasts.

Effects of (-)-Epigallocatechin gallate on some protein factors involved in the epidermal growth factor receptor signaling pathway

（-）-Epigallocatechin gallate （EGCG）, a major polyphenolic constituent of green tea, can inhibit activity of specific receptor tyrosine kinases （RTKs） and related downstream signal transduction pathways, resulting in the control of unwanted cell proliferation. The epidermal growth factor receptor （EGFR） signaling pathway is one of the most important pathways that regulates growth, survival,proliferation and differentiation in mammalian cells. This review addresses the effects of EGCG on some protein factors involved in the EGFR signaling pathway in a direct or indirect manner. Based on our understanding of the interaction between EGCG and these factors, and based on their structures, EGCG could be used as a lead compound for designing and synthesizing novel drugs with significant biological activity.

(-)-Epigallocatechin-3-gallate protects spiral ganglion neurons against amikacin-induced apoptosis

Morphology of spiral ganglion neurons （SGNs） in Sprague-Dawley rats before and after amikacin treatment was observed by transmission electron microscopy. Amikacin induced cochlear SGN apoptosis. Immunohistochemical staining and RT-PCR revealed a decrease in Bcl-2 protein ex-pression, and an increase in Bax protein, caspase-3 protein and caspase-6 mRNA expression fol-lowing amikacin treatment. （-）-Epigallocatechin-（3）-gallate （EGCG） inhibited SGN Bax protein, caspase-3 protein and caspase-6 mRNA expression, and enhanced Bcl-2 protein expression, thereby decreasing SGN apoptosis. Results demonstrated that EGCG can protect SGNs against amikacin-induced injury.

The <i>in Vivo</i>Antioxidant Effects of (&minus;)-Epigallocatechin-3-Gallate Consumption in Healthy Postmenopausal Women Measured by Urinary Excretion of Secondary Lipid Peroxidation Products

The present study was carried out to determine whether the consumption of epigallocatechin (EGCG), the major bioactive green tea catechin, exerts a positive effect on lowering in vivo lipid peroxidation, a measure of oxidative stress, in healthy postmenopausal women. Urinary excretion of secondary lipid peroxidation products, a measure of in vivo lipid peroxidation, was determined in 40 participants randomly assigned to consume a green tea catechin extract (843.0 ± 44.0 mg EGCG/d) or placebo capsules for 12 months. Urine samples were analyzed for individual polar and nonpolar lipophilic aldehydes and related carbonyl compounds by high-performance liquid chromatography (HPLC) at the beginning and at the end of the 12-month intervention period. Results show that two nonpolar aldehydes, nonanal and decatrienal, were both 48% lower (p in vivo antioxidant activity exists with long-term EGCG consumption, which could slightly limit oxidative damage associated with lipid peroxidation and the onset and progression of chronic diseases.