Extract Epigallocatechin-3-gallate Research Articles

Effects of green tea extract epigallocatechin-3-gallate (EGCG) on orthodontic tooth movement and root resorption in rats

ObjectiveTo study the effect of EGCG on tooth movement and root resorption during orthodontic treatment in rats. MethodsA total of thirty six male Wistar rats were randomly and equally divided into three groups: control, 50 mg/kg EGCG, and 100 mg/kg EGCG. During the experiment, the subjects were submitted to an orthodontic tooth movement (OTM) model, rats in the experimental groups were given the corresponding dose of EGCG, while rats in the control group were administrated with an equal volume of normal saline solution by gavage. After 14 days of OTM, the rats were sacrificed by transcardial perfusion. Micro-CT of rat maxillaes was taken to analyze OTM distance and root resorption. The maxillary samples were prepared as histological sections for H&E staining, tartrate-resistant acid phosphatase (TRAP) staining and immunohistochemical (IHC) staining to be observed and analyzed. ResultsThe OTM distance and root resorption of rats in the dosed group decreased, and the number of TRAP positive cells in their periodontium decreased significantly. The expression level of RANKL was decreased in the EGCG group compared to the control group, while that of OPG, OCN and Runx2 was increased. Effects were more pronounced in 100 mg/kg group than in 50 mg/kg group. ConclusionEGCG reduces OTM and orthodontic induced root resorption (OIRR) in rats, and is able to attenuate osteoclastogenesis on the pressure side and promote osteogenesis on the tension side.

Epigallocatechin-3-gallate inhibits the growth of three-dimensional in vitro models of neuroblastoma cell SH-SY5Y

The aim of the study is to investigate the potential of using three-dimensional (3D) in vitro neuroblastoma models to mimic the neuroblastoma microenvironment by testing a potential therapeutic compound—the natural extract epigallocatechin-3-gallate (EGCG), and to further elucidate the roles of DYRK1A in the growth and differentiation of neuroblastoma tissue. In vitro models based on a classic neuroblastoma cell line SH-SY5Y were employed, including 3D models with extracellular matrix and co-cultured with vascular endothelial cells. Cell viability was tested using AlamarBlue and Resazurin assay. The growth and differentiation of in vitro models of SH-SY5Y were analysed based on microscopy images obtained from immunofluorescence or real-time imaging. Protein expression level was investigated using immunoblotting analysis. The two-dimensional (2D) in vitro model implies the cytotoxicity and DYRK1A inhibition effect of EGCG and shows the induction of neuronal differentiation marker TuJ1. 3D in vitro models suggest that EGCG treatment compromised the growth of SH-SY5Y multicellular 3D spheroids and the viability of SH-SY5Y cultured in 3D Matrigel matrix. In addition, co-culture of SH-SY5Y with human vascular umbilical vein endothelial cells implied the inhibitory effects by EGCG in a vascularised microenvironment. In this study, novel 3D in vitro models of neuroblastoma were established in the application of testing a potential anti-cancer candidate compound EGCG. In pursuit of the goals of the 3Rs (replacement, reduction and refinement), the usage of these 3D in vitro models has the potential to reduce and eventually replace current animal models used in neuroblastoma research. The DYRK1A inhibiting nature of EGCG, together with the facts that EGCG inhibits the growth and induces the differentiation of neuroblastoma in vitro models, suggests an oncogene role of DRYK1A.

Green tea extract EGCG plays a dual role in Aβ42 protofibril disruption and membrane protection: A molecular dynamic study

Amyloid plaques accumulated by the amyloid-β (Aβ) fibrillar aggregates are the major pathological hallmark of the Alzheimer’s disease (AD). Inhibiting aggregation and disassembling preformed fibrils of Aβ by natural small molecules have developed into a promising therapeutic strategy for AD. Previous experiments reported that the green tea extract epigallocatechin-3-gallate (EGCG) can disrupt Aβ fibril and reduce Aβ cytotoxicity. The inhibitory ability of EGCG can also be affected by cellular membranes. Thus, it is essential to consider the membrane influences in the investigation of protofibril-disruptive capability of EGCG. Here, we performed multiple all-atom molecular dynamic simulations to investigate the effect of EGCG on the Aβ42 protofibril in the presence of a mixed POPC/POPG (7:3) lipid bilayer and the underlying molecular mechanisms of action. Our simulations show that in the presence of membrane bilayers, EGCG has a preference to bind to the membrane, and this binding alters the binding modes between Aβ42 protofibril and the lipid bilayer, leading to a reduced membrane thinning, indicative of a protective effect of EGCG on the membrane. And EGCG still displays a disruptive effect on Aβ42 protofibril, albeit with a lesser extent of disruption than that in the membrane-free environment. EGCG destabilizes the two hydrophobic core regions (L17-F19-I31 and F4-L34-V36), and disrupts the intrachain K28-A42 salt bridges. Our results reveal that in the presence of lipid bilayers, EGCG plays a dual role in Aβ42 protofibril disruption and membrane protection, suggesting that EGCG could be a potential effective drug candidate for the treatment of AD.

Codelivery of epigallocatechin-3-gallate and diallyl trisulfide by near-infrared light-responsive mesoporous polydopamine nanoparticles for enhanced antitumor efficacy.

Green tea extract epigallocatechin-3-gallate (EGCG), as a kind of natural active compounds, has become a research hotspot in cancer treatment. However, poor stability, low bioavailability and antitumor efficacy limit the application of EGCG. In this study, mesoporous dopamine (MPDA) with high drug loading and good biocompatibility loaded EGCG, garlic extract diallyl trisulfide (DATS) and photosensitizer (indocyanine green, ICG) by π-π stacking and hydrophobic-hydrophobic interaction, and the nano-system involved filling the mesoporous of the MPDA with phase change material (1-tetradecanol, 1-TD) molecules, which acted as a thermosensitive gatekeeper. The results indicated that MPDA-ICG@TD has an excellent photothermal effect and good stability. Due to the solid-liquid phase transition characteristics of the phase change material, MPDA-ICG@TD could control the release of drugs under near-infrared laser irradiation. Besides, cytotoxicity and apoptosis experiments showed that MPDA-ICG/EGCG/DATS@TD could be efficiently inhibited 4T1 cell proliferation and accelerate cell apoptosis than use diallyl trisulfide or EGCG alone, which means that the combination of natural active compounds EGCG and diallyl trisulfide has excellent synergy and can effectively improve the antitumor effect of EGCG. Moreover, this nano-system exhibited non-toxicity and good blood compatibility. This study provides a promising and effective strategy for improving the antitumor efficacy of natural active compound EGCG.

Efficacy of green tea and its extract, epigallocatechin-3-gallate, in the reduction of cariogenic microbiota in children: a randomized clinical trial

ObjectiveThis study was conducted to evaluate and compare the antimicrobial efficacy of green tea and its extract epigallocatechin-3-gallate (EGCG) as a mouthwash in children. DesignThe study group included 47 children aged 5-12 years at high caries risk and prevalence. Children selected were asked to rinse with one of the substances (EGCG, green tea, chlorhexidine and distilled water) for one min. A non-stimulated salivary sample (2 mL) was collected at baseline and after rinsing. The concentration of cariogenic microorganisms (mutans streptococci and lactobacilli) was determined before and after rinsing based on the count of colony-forming units (CFU). CFU were counted with the aid of a stereomicroscope through the perfunctory identification of the morphological characteristics of CFU. The microbial reduction percentage was then calculated. ResultsThe analysis of the effectiveness of the treatments showed that there was a significant reduction in relation to the values obtained before and after the mouthwash, both for mutans streptococci (pCHX = 0.001; pEGCG = 0.001; pGreen Tea = 0.005; pDistilled Water = 0.018) and lactobacilli (pCHX = 0.001; pEGCG = 0.002; pGreen Tea = 0.008; pDistilled Water = 0.033). The percentage of microbial reduction of both cariogenic microorganisms caused by the EGCG solution was higher than green tea and distilled water, but less than CHX. The percentage of microbial reduction by the EGCG solution for mutans streptococci was 79.9%, green tea 68.3%, distilled water 50.6% and CHX 95.5%. For lactobacilli, the percentage reduction of all solutions was relatively lower when compared to mutans streptococci. For the EGCG solution it was 72.09%, followed by green tea 59.17% and distilled water 41.96%, but less than CHX 86.02%. ConclusionRinsing with EGCG solution reduced the levels of mutans streptococci and lactobacilli in the oral cavity of children. Although EGCG had better antimicrobial activity than green tea, this study supports the effectiveness of both as an antibacterial mouthwash option. Both EGCG and green tea could be used as alternatives to chlorhexidine-based mouthwashes.

Induction of foxo3a protects turtle neurons against oxidative stress

The detrimental effects of oxidative stress caused by the accumulation of Reactive Oxygen Species (ROS) factor into aging, senescence and several neurodegenerative diseases. Mammalian models are extremely susceptible to the stresses that follow the restoration of oxygen after anoxia; however some organisms including the freshwater turtle Trachemys scripta can withstand extended anoxia and reoxygenation without apparent pathology. The ability of the turtle to withstand these conditions is thought to be linked to the upregulation of protective mechanisms such as heat shock proteins (HSP) as well as the suppression of ROS formation and the upregulation of antioxidant defenses. One such antioxidant mechanism is the transcription factor Forkhead box O3a (FOXO3a), that has been shown to be activated in several animal models during oxidative stress. In this study, we utilized both the transfection of a plasmid carrying foxo3a and the pharmacological manipulation of foxo3a using the green tea extract Epigallocatechin-3-gallate (EGCG) to investigate the protective role of FOXO3a in the turtle brain. Our studies found that transcript levels of foxo3a were upregulated significantly during reoxygenation with greater increases during chemical oxidative stress. Induction of foxo3a by direct transfection significantly decreased cell death during chemical oxidative stress. Cells treated with EGCG also showed increased foxo3a expression and decreased cell death in the presence of H2O2. These results agree with results seen in other animal models and suggest that EGCG (through the upregulation of foxo3a) may be a therapeutic target against oxidative stress damage that warrants further investigation.

Phase II trial of daily, oral green tea extract in patients with asymptomatic, Rai stage 0-II chronic lymphocytic leukemia (CLL).

6522 Background: Green tea has long been touted as a health promoting substance. In vitro testing and a phase I trial suggest the green tea extract epigallocatechin 3 gallate(EGCG) may have clinical efficacy for chronic lymphocytic leukemia (CLL) patients. To follow-up on these results, we performed a phase II trial of daily EGCG in patients with CLL. Methods: Previously untreated patients with asymptomatic, Rai stage 0-II CLL and a minimum absolute lymphocyte count (ALC) ≥10 x109/L were eligible for participation. Polyphenon E with a standardized dose of EGCG (2,000 mg/dose) was administered twice daily for 6 months. Response was classified using the NCI Working Group (WG) Criteria. Results: Forty-two eligible patients received EGCG 2000 mg twice daily for up to 6 months. Patients received a median of 6 cycles of treatment (range: 1-6). Accrual to the trial is complete. Thirty-one patients have completed study therapy while 11 patients have not yet completed treatment. The most common side effects included transaminitis (31% grade 1, 12% grade 2), abdominal pain (21% grade 1, 7% grade 2, 2% grade 3), and nausea (55% grade 1, 2% grade 2). Only 2/48 (4.8%) patients experienced grade 3 toxicity. One patient experienced an NCI WG partial remission. Other signs of clinical activity were observed with 13 (31%) patients experiencing a sustained ≥ 20% reduction in ALC and 19 of 29 (66%) patients with palpable adenopathy experiencing at least a 50% reduction in the sum of the products of all nodal areas during treatment. Overall 28 (67%) patients fulfilled the criteria for a biologic response (JCO 27:3808) based on attaining either a sustained ≥ 20% decline in ALC and/or a ≥ 50% reduction in the sum of the products of all nodal areas at some point during the 6 months of active treatment. Conclusions: Daily oral EGCG in the Polyphenon E preparation was well tolerated by CLL patients in this phase II trial. Declines in ALC and/or lymphadenopathy were observed in the majority of patients. EGCG containing green tea extracts may have potential as disease stabilizing agents in patients with early-stage CLL. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Genentech, Genzyme, Novartis, Polyphenon E International FDA

The Green Tea Extract EGCG Demonstrates Synergist Activity against CLL B-Cells When Combined with Fludarabine and Chlorambucil.

Abstract 3452Poster Board III-340 PURPOSEChronic Lymphocytic Leukemia (CLL) is incurable with current chemotherapy treatments. Epigallocatechin 3 gallate (EGCG), the major catechin in green tea, has been shown to induced caspase-dependent death CLL B-cells and down regulate anti-apoptotic proteins (Mcl-1; XIAP) known to increase the resistance of CLL B-cells to apoptosis (Blood 104:788-94). In Phase I testing for patients with early stage CLL (Rai 0-II), EGCG treatment was well tolerated and induced a decline in absolute lymphocyte count (ALC) and/or lymphadenopathy in the majority of treated patients without myelosuppression (JCO 27:3808-14). Although peak plasma EGCG levels were not measured in this study, trough plasma EGCG levels as high as 4 μg/ML were achieved. To further our understanding of the potential clinical applications of EGCG for patients with CLL, we evaluated the effects of EGCG on the viability of CLL B-cells when combined with fludarabine (F), chlorambucil (C), or fludarabine and chlorambucil in combination (FC). METHODSPrimary CLL B-cells were treated with various doses of F (0.25-1 μM), C (10-30 μM), or FC either alone or in combination EGCG (50 to 100 μM). In other experiments, CLL B-cells were treated with various doses of F (0.25-1 μM), C (10-30 μM), or FC with or without a fixed dose of EGCG known to be physiologically achievable in vivo (4 μM). After 48 hours (experiments with C +/− EGCG) or 72 hours (experiments with F +/− EGCG or FC +/− EGCG), cells were harvested, stained with annexin/PI and viability analyzed by flow cytometry. After concentration-effect curves were generated for each agent, data were also analyzed using the CalcuSyn software program (Biosoft, Cambridge, UK) which uses the method of Chou and Talalay to determine whether combination treatment yielded greater effects than expected from summation alone. A combination index (CI) of 0.8 – 1.2 indicates an additive effect, a CI >1.2 indicates an antagonistic effect and a CI <0.8 indicates a synergistic effect. RESULTSPrimary leukemic B-cells from 56 CLL patients were cultured in vitro with various doses of EGCG alone or in combination with F, C, or FC. The median LD50 was approximately 100 μM. Although % apoptotic cells at the 100 μM EGCG dose did not vary based on Rai stage, ZAP-70 status, IGHV gene mutation status, or cytogenetic abnormalities by FISH, CD38 negative patients had greater cell death than CD38 positive patients (67% vs. 49%; p=0.05). In co-titration experiments, EGCG had an additive (CI 0.8 – 1.2) or synergistic (CI <0.8) effect on apoptosis when combined with C in the majority of patients (13/15; additive 11, synergism 2) with rare individuals demonstrating antagonism (CI >1.2; 2/15). The effects of EGCG when combined with F in co-titration experiments were more variable with a relatively even distribution between antagonism (8/18), additive effects (4/18), and synergy (6/18). However, co-titration experiments of FC with or without EGCG demonstrated additive or synergistic effect in most patients (8/10; additive 7, synergism 1). Next we evaluated the effect of F (0.25 - 1 μM), C (10 - 30 μM), or FC with or without a fixed dose of EGCG known to be physiologically achievable in vivo (4 μM). This dose of EGCG had an additive or synergistic effect in the majority of samples across the spectrum of dose levels under all 3 conditions (F, C, and FC). For example, at the 10 μM dose of C the addition of 4 μM EGCG had an additive or synergistic effect in 11/14 patients (synergistic 6; additive 5). With F at the 2.5 μM dose level the addition of 4 μM EGCG had an additive or synergistic effect in 13/16 patients (synergistic 7, additive 6). The addition of 4 μM EGCG appeared particularly beneficial when given in combination with FC (Fig.). For example, at F 2.5 μM in combination with C 5 μM the addition of 4 μM EGCG had an additive or synergistic effect in 10/10 patients (synergism 7; additive 3). CONCLUSIONSPhysiologically achievable doses of EGCG appear to enhance the efficacy of alkylating agents, purine nucleoside analogues, and alkylating agent/purine analogue combination therapy for the majority of CLL patients on in vitro testing. The favorable toxicity profile of EGCG and lack of myelosuppression with this agent in the phase I trial (JCO 27:3808-14) make it an attractive agent to test in combination with purine analogue and alkylator based chemo-immunotherapy for patients with CLL. [Display omitted] DisclosuresKay:Genentech, Celgene, Hospira, Polyphenon Pharma, Sanofi-Aventis: Research Funding; Biogenc-Idec, Celgene, Genentech, genmab: Membership on an entity's Board of Directors or advisory committees. Shanafelt:Genentech: Research Funding; Hospira: Membership on an entity's Board of Directors or advisory committees, Research Funding; Polyphenon Pharma : Patents & Royalties, Research Funding; Celgene: Research Funding; Cephalon: Research Funding; Bayer Health Care Pharmaceuticals: Research Funding.

Skin Penetration of Epigallocatechin-3-Gallate and Quercetin from Green Tea and Ginkgo biloba Extracts Vehiculated in Cosmetic Formulations

Green tea (Camellia sinensis) and Ginkgo biloba extracts in cosmetic formulations have been suggested to protect the skin against UV-induced damage and skin ageing. Thus, it is very important to assess the human skin penetration of their major flavonoids to verify if they penetrate and remain in the skin to exert their proposed effects. The aim of this study was to evaluate the human skin penetration of epigallocatechin-3-gallate (EGCG) and quercetin from green tea and G. biloba extracts vehiculated in cosmetic formulations. This study was conducted with fresh dermatomed human Caucasian skin from abdominal surgery mounted on static Franz diffusion cells. Skin samples were mounted between two diffusion half-cells and 10 mg/cm² of formulations supplemented with 6% of green tea or G. biloba extract were applied on the skin surface. The receptor fluid was removed after 6 and 24 h and analyzed by high-performance liquid chromatography for the quantification of the flavonoids. The stratum corneum was removed by tape stripping and immersed in methanol and the epidermis was mechanically separated from the dermis and triturated in methanol to extract EGCG and quercetin. The results showed that the flavonoids under study penetrated into the skin, without reaching the receptor fluid. The majority of EGCG was quantified in the stratum corneum (0.87 μg/cm²), which was statistically higher than the EGCG concentrations found in viable epidermis (0.54 μg/cm²) and in the dermis (0.38 μg/cm²). The majority of quercetin was quantified in the viable epidermis (0.23 μg/cm²), which was statistically higher than the EGCG concentration found in the stratum corneum layer (0.17 μg/cm²). Finally, it can be concluded that EGCG and quercetin from green tea and G. biloba extracts vehiculated in cosmetic formulations presented good skin penetration and retention, which can favor their skin effects.

Curcumin Inhibits Prosurvival Pathways in Chronic Lymphocytic Leukemia B Cells and May Overcome Their Stromal Protection in Combination with EGCG

Chronic lymphocytic leukemia (CLL) is incurable with current chemotherapy treatments. Curcumin (diferuloylmethane), an active ingredient in the spice turmeric, inhibits tumor metastasis, invasion, and angiogenesis in tumor cell lines. We evaluated the effects of curcumin on the viability of primary CLL B cells and its ability to overcome stromal mediated protection. The in vitro effect of curcumin on primary CLL B cells was evaluated using fluorescence activated cell sorter analysis and Western blotting. For some experiments, CLL B cells were cocultured with human stromal cells to evaluate the effects of curcumin on leukemia cells cultured in their microenvironment. Finally, the effect of curcumin in combination with the green tea extract epigallocatechin-3 gallate (EGCG) was evaluated. Curcumin induced apoptosis in CLL B cells in a dose-dependent (5-20 micromol/L) manner and inhibited constitutively active prosurvival pathways, including signal transducers and activators of transcription 3 (STAT3), AKT, and nuclear factor kappaB. Moreover, curcumin suppressed expression of the anti-apoptotic proteins Mcl-1 and X-linked inhibitor of apoptosis protein (XIAP), and up-regulated the pro-apoptotic protein BIM. Coculture of CLL B cells with stromal cells resulted in elevated levels of STAT3, increased expression of Mcl-1 and XIAP, and decreased sensitivity to curcumin. When curcumin was administered simultaneously with EGCG, antagonism was observed for most patient samples. In contrast, sequential administration of these agents led to substantial increases in CLL B-cell death and could overcome stromal protection. Curcumin treatment was able to overcome stromal protection of CLL B cells on in vitro testing and to synergize with EGCG when administered in a sequential fashion. Additional evaluation of curcumin as a potential therapeutic agent for treatment of CLL seems warranted.

The Green Tea Extract Epigallocatechin Induces In Vitro Cell Death in Primary Human Lymphoma Cells through an ROS Dependent Mechanism.

BACKGROUND: We have demonstrated the green tea extract epigallocatechin-3-gallate (EGCG) has anticancer activity in primary CLL B-cells (Lee, Blood 2004). After dissemination of our in vitro findings by the lay press, many patients with CLL and other low grade non-Hodgkin lymphomas (NHL) began using over the counter green tea extracts as an alternative treatment strategy. We recently reported a case series of 3 patients with CLL and 1 patient with follicular lymphoma who appeared to derive objective clinical benefit from such treatment (Shanafelt, Leukemia Research 2006). Based on these findings EGCG has entered clinical testing for treatment of CLL at Mayo Clinic. Here we explore the in vitro antitumor activity of EGCG against other types of non-Hodgkin lymphoma.METHODS: Five established human B-cell lymphoma cell lines (HT, DOHH2, KARPAS, Ramos, RL) and primary lymphoma cells from 7 patients with various B-cell NHL sub-types [DLBC, FL, SMZ (2), MCL, SLL(2)] were used to evaluate the in vitro sensitivity of human lymphoma cells to EGCG. Freshly isolated primary lymphoma cells harvested in suspension from lymph nodes/spleen were obtained from patients with NHL who provided written informed consent. All patients were untreated at the time of biopsy. Lymphoma cell lines and primary lymphoma cells (n=7) were cultured with increasing doses of purified EGCG (3.12–50 ug/ml) for 24–72 hrs. Viability was assessed by using annexin/PI staining by FACS analysis.RESULTS: EGCG-induced dose dependent cell death in both established human B-cell lymphoma cell lines (average LD50 at 24 hrs between 25–50 ug/mL) and primary NHL cells (average LD50 at 24 hrs between 25–50ug/mL). In contrast, EGCG had minimal effect on purified normal B-cells (n=3) at the highest doses tested (50 ug/mL). By immunoblotting, EGCG-induced death in primary cells and cell lines was associated with PARP cleavage, suggesting the agent induced apoptotic cell death. Despite this finding, EGCG had no effect on levels of MCL-1, XIAP, or Bcl-1 by either immunoblot or FACS analysis. Based on reports that EGCG induces cell death in some cancer cell types through generation of oxidative stress (Furukawa, 2003; Nakazato, 2005), we explored this mechanism in lymphoma cells. To determine whether reactive oxygen species (ROS) generation was necessary for EGCG-induced cell death, lymphoma cell lines were cultured with or without catalase (which catalyzes the conversion of hydrogen peroxide to water and oxygen) for 30 min prior to subsequent 24 hr EGCG exposure (50 and 100 mg/ml). Pre-treatment with catalase (100 U) provided dramatic protection against cell death in both primary NHL cells and NHL cell lines suggesting that EGCG-induced cell death in lymphoma cells is dependent on ROS generation (Fig. 1 shows an example for a patient with mantle cell lymphoma and a patient with splenic marginal zone lymphoma).CONCLUSION: EGCG has in vitro anti-tumor activity against a variety of B-cell NHLs. Given its known favorable toxicity profile in vivo, EGCG is an attractive agent for clinical testing in patients with indolent NHL who otherwise are currently being managed with observation. [Display omitted]