Compound In Green Tea Research Articles

Epigallocatechin-3-Gallate Pretreatment Improves Autologous Adipose-derived Stem Cells Against Rheumatoid Arthritis-induced Neuroinflammation in the Brain of Collagen-induced Rats.

Adipose tissue-derived mesenchymal stem cells (ADSC) exert neuroprotective and anti-inflammatory effects. ADSCs are considered potential therapeutics for rheumatoid arthritis (RA), an inflammatory, multisystemic autoimmune disease. Epigallocatechin-3-gallate (EGCG), the major polyphenolic compound in green tea, has strong anti-inflammatory and antioxidant properties. This study aimed to investigate whether EGCG has a synergistic effect on the neuroprotective effects of ADSCs to protect the RA-damaged brain. Wistar rats were classified into four groups: sham, RA, RA + ADSCs (1 × 106 cells per rat), and RA + EGCG (10µM)-pretreated ADSCs. After 2months of treatment, the brain tissues from the rats were collected and investigated. The brains of RA rats had higher inflammation and apoptosis. ADSC treatment ameliorated these negative effects significantly; however, the neuroprotective abilities of EGCG-pretreated ADSCs were significantly higher than ADSCs. Furthermore, the RA-induced repression of the PI3K/Akt survival pathway was reactivated by EGCG-pretreated ADSCs. Collectively, this study provides evidence that EGCG synergistically enhances the neuroprotective ability of ADSCs to repress the negative effects of RA on the brain. These findings could help develop new therapeutic strategies against RA or other neurodegenerative diseases after clinical validation in the future.

Changes in the metabolite composition and enzyme activity of fermented tea during processing

As the dominant microbial strain in Fuzhuan brick tea, Eurotium cristatum (E. cristatum) can biotransform the fermentation substrate during growth and reproduction, and in so doing enhance the tea’s health benefits. Green tea contains a large number of bioactive compounds with antihypertensive potential. However, as a nonfermented tea, inactivation of various enzymes (such as polyphenol oxidase) during processing results in a single secondary metabolite with limited health effects. The novel fermented tea we studied was processed by solid-state fermentation (SSF) with E. cristatum, and the substrate was a mixture of green tea and Radix Puerariae (RP). This study was aimed at evaluating the multiple effects by E. cristatum during fermentation. Compared to the unfermented control groups, the sample groups secreted enzymes (such as polyphenol oxidase and α-amylase), and the bioactive compounds content of sample groups changed, as well as significantly higher inhibition of Angiotensin-converting enzyme (ACE) in vitro (which also implies greater antihypertensive potential). These results will help further investigations of the antihypertensive bioactive compounds of green tea and the fermentation potential of E. cristatum.

Effect of Fixation Methods on Biochemical Characteristics of Green Teas and Their Lipid-Lowering Effects in a Zebrafish Larvae Model.

Fixation is a key process contributing to different flavors of green tea and pan-fire and steam were the common fixation methods applied conventionally. In this study, pan-fired green tea (PGT) and steamed green tea (SGT) produced by different fixation methods were compared in characteristic biochemicals including volatile compounds, amino acids, catechins and alkaloids, together with evaluating their tastes and lipid-lowering effects. PGT and SGT could be distinguished clearly by orthogonal partial least squares discriminant analysis (OPLS-DA) and heatmap. SGT had higher contents of volatile alcohols (44.75%) with green and floral attributes, while PGT had higher contents of volatile esters (22.63%) with fruity and sweet attributes. Results of electronic tongue analysis showed that PGT and SGT had similar taste of strong umami and sweetness, but little astringency and bitterness. In addition, amino acids were more abundant in PGT (41.47 mg/g in PGT, 33.79 mg/g in SGT), and catechins were more abundant in SGT (111.36 mg/g in PGT, 139.68 mg/mg in SGT). Zebrafish larvae high-fat model was applied to study the lipid-lowering effects of PGT and SGT. Results showed that both SGT and PGT had lipid-lowering effects, and the lipid level was decreased to 61.11 and 54.47% at concentration of 300 mg/L compared to high-fat group, respectively. Generally, different fixation methods of pan-fire and steam showed significant effects on aroma and contents of characteristic chemical compounds (amino acids and catechins) of green tea, but no effects on the taste and lipid-lowering activity.

The Potential of Epigallocatechin Gallate (EGCG) in Targeting Autophagy for Cancer Treatment: A Narrative Review.

Autophagy is an evolutionarily conserved process for the degradation of redundant or damaged cellular material by means of a lysosome-dependent mechanism, contributing to cell homeostasis and survival. Autophagy plays a multifaceted and context-dependent role in cancer initiation, maintenance, and progression; it has a tumor suppressive role in the absence of disease and is upregulated in cancer cells to meet their elevated metabolic demands. Autophagy represents a promising but challenging target in cancer treatment. Green tea is a widely used beverage with healthy effects on several diseases, including cancer. The bioactive compounds of green tea are mainly catechins, and epigallocatechin-gallate (EGCG) is the most abundant and biologically active among them. In this review, evidence of autophagy modulation and anti-cancer effects induced by EGCG treatment in experimental cancer models is presented. Reviewed articles reveal that EGCG promotes cytotoxic autophagy often through the inactivation of PI3K/Akt/mTOR pathway, resulting in apoptosis induction. EGCG pro-oxidant activity has been postulated to be responsible for its anti-cancer effects. In combination therapy with a chemotherapy drug, EGCG inhibits cell growth and the drug-induced pro-survival autophagy. The selected studies rightly claim EGCG as a valuable agent in cancer chemoprevention.

Anti-SARS-CoV-2 activity of various PET-bottled Japanese green teas and tea compounds in vitro.

The outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a serious threat to global public health. The emergence of SARS-CoV-2 variants is a significant concern regarding the continued effectiveness of vaccines and antiviral therapeutics. Thus, natural products such as foods, drinks, and other compounds should be investigated for their potential to treat COVID-19. Here, we examined the in vitro antiviral activity against SARS-CoV-2 of various polyethylene terephthalate (PET)-bottled green Japanese teas and tea compounds. Six types of PET-bottled green tea were shown to inhibit SARS-CoV-2 at half-maximal inhibitory concentrations (IC50) of 121- to 323-fold dilution. Our study revealed for the first time that a variety of PET-bottled Japanese green tea drinks inhibit SARS-CoV-2 infection in a dilution-dependent manner. The tea compounds epigallocatechin gallate (EGCG) and epicatechin gallate showed virucidal activity against SARS-CoV-2, with IC50 values of 6.5 and 12.5 µM, respectively. The investigated teas and tea compounds inactivated SARS-CoV-2 in a dose-dependent manner, as demonstrated by the viral RNA levels and infectious titers. Furthermore, the green teas and EGCG showed significant inhibition at the entry and post-entry stages of the viral life cycle and inhibited the activity of the SARS-CoV-2 3CL-protease. These findings indicate that green tea drinks and tea compounds are potentially useful in prophylaxis and COVID-19 treatment.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00705-022-05483-x.

The effects of Epigallocatechin-3-gallate and Dabrafenib combination on apoptosis and the genes involved in epigenetic events in anaplastic thyroid cancer cells

Anaplastic thyroid cancer cases with poor prognosis are associated with epigenetic modifications such as abnormal DNA methylation. Epigallocathesin-3-gallate (EGCG) is a polyphenol compound of green tea that is still under investigation on its role in cancer prevention. EGCG is known as an epigenetic diet in DNA methyltransferase inhibitor. The cytotoxic effects of Dabrafenib, EGCG, and dabrafenib in combination with EGCG were assessed by using WST-8 assay; and also, Flow cytometry was utilized to identify cells undergoing apoptosis after treatments of the SW-1736 cells. We investigated the mRNA expression of genes involved in epigenetic events in SW-1736 cells by real-time qRT-PCR following the treatments. We demonstrated for the first time that the Dabrafenib-EGCG combination reduced cell viability significantly depending on concentration and induced apoptosis by 8.49-fold through investigating the additive effect together on SW-1736 cells. The IC50 doses of Dabrafenib and EGCG for 48h were determined as 6.7μM and 22.5μM, respectively. The results of qRT-PCR demonstrated that the Dabrafenib-EGCG combination significantly caused the down-regulation of genes involved in epigenetic regulation. We suggest that the combination of Dabrafenib and EGCG following in vivo phase studies will contribute as an alternative treatment option for the treatment of ATC.

Research on microwave‐assisted extraction with blanching pretreatment effect on bioactive compounds of green tea leaves ( Camellia sinensis ) powder

Fresh green tea leaves have been considered by-products. They contain beneficial ingredients of polyphenols, approximately 30%. This study was aimed to investigate the blanching process combined with microwave-assisted extraction of green tea leaves. The best quality extract was obtained by blanching at 85°C for 45 s, then microwave-assisted extracting for 3 min with power of 16 W/g and frequency of 2450 MHz. The extract was added with whey protein isolate of 15%–15.3% and then spray-dried to form green tea powder. The highest antioxidant capacity was observed at 360.20 mg Trolox equivalent antioxidant capacity/g of tea powder. The bioactive compounds were determined as total polyphenol content of 336.65 mg GAE/g, epigallocatechin-gallate of 104.14 mg/g, epigallo-catechin of 62.15 mg/g, epicatechin-gallate of 22.09 mg/g, epicatechin of 19.27 mg/g, and caffeine of 3.13 mg/g. The tea powder was rich in chlorophyll content of 3.52 mg/g with nice green color and nutrition by abundant amino acids. Practical applications In Vietnam, fresh tea leaves, which are not in tea buds, have been often considered as by-products or even wastes. Our project investigated the extraction procedure for creating high-quality extract then used this extract for forming green tea powder by spray drying technology. The product obtained high content of total polyphenol, chlorophyll, and rich content of amino acids, which has better economic efficiency to use for the food or beverage industry in Vietnam.

A Robust Fermentation Process for Natural Chocolate-like Flavor Production with Mycetinis scorodonius.

Submerged fermentation of green tea with the basidiomycete Mycetinis scorodonius resulted in a pleasant chocolate-like and malty aroma, which could be a promising chocolate flavor alternative to current synthetic aroma mixtures in demand of consumer preferences towards healthy natural and ‘clean label’ ingredients. To understand the sensorial molecular base on the chocolate-like aroma formation, key aroma compounds of the fermented green tea were elucidated using a direct immersion stir bar sorptive extraction combined with gas chromatography–mass spectrometry–olfactometry (DI-SBSE-GC-MS-O) followed by semi-quantification with internal standard. Fifteen key aroma compounds were determined, the most important of which were dihydroactinidiolide (odor activity value OAV 345), isovaleraldehyde (OAV 79), and coumarin (OAV 24), which were also confirmed by a recombination study. Furthermore, effects of the fermentation parameters (medium volume, light protection, agitation rate, pH, temperature, and aeration) on the aroma profile were investigated in a lab-scale bioreactor at batch fermentation. Variation of the fermentation parameters resulted in similar sensory perception of the broth, where up-scaling in volume evoked longer growth cycles and aeration significantly boosted the concentrations yet added a green note to the overall flavor impression. All findings prove the robustness of the established fermentation process with M. scorodonius for natural chocolate-like flavor production.

Fabrication and characterization of biodegradable active films with modified morphology based on polycaprolactone-polylactic acid-green tea extract.

This research focused on developing an eco-friendly packaging for food products through blending polycaprolactone (PCL) and polylactic acid (PLA) as two biodegradable polymers, and green tea extract (GTE) as a natural antioxidant pushing the films toward active packaging; thereby, the morphological, mechanical, thermal, barrier, antioxidant, and biodegradation features of the composite films were analyzed. The films containing 30% PLA exhibited a reduction of 14.96%, 38.89%, 8.75%, and 35.55% in the hydrophilicity, water-solubility, water vapor permeability (WVP), and oxygen transition rate (OTR), respectively. Furthermore, GTE incorporation led to antioxidant behavior as well as better barrier properties (up to 6.25% decrease in WVP and 55.78% in OTR), mechanical properties (an increase of 14.96%, 38.89%, and 8.75% in elastic modulus, tensile strength, and elongation at break, respectively) and biodegradable rate (124.13%). Indeed, the presence of polyphenol compounds in green tea improved molecular interaction between the polymers and launched a co-continuous structure and an unparalleled level of compatibility, which was also approved by the changes in FTIR spectra of the PCL/PLA films. These results demonstrate the benefits of blending PLA with PCL and GTE integration in terms of operational enhancement and film activating, respectively, to provide reliable food packaging.

Systematic Review of the Anti-Cancer Activity of Green Tea (Camellia sinensis) -Derived Compounds in Breast Cancer In Vitro

Breast cancer is the most common type of cancer occurring in women with increasing prevalence in these past few years. Although many targeted therapies have been developed to increase the specificity of the treatment, many patients still suffer from cancer resistance and relapse. Green tea, a common beverage derived from natural plants, has been shown to induce chemopreventive effects and exhibit anti-cancer activity through its catechins and polyphenols content. The main well-known compound that induces these effects is epigallocatechin-3-gallate (EGCG). Green tea also contains other naturally occurring compounds such as catechin (C), epicatechin (EC), epigallocatechin (EGC), epicatechin-3-gallate (ECG), and others. In this study, we assessed and compared the anti-cancer activity of these green tea-derived compounds towards different types of breast cancer cell lines. A total of 15 original research papers from PubMed, Google Scholar, and DOAJ databases were collected and evaluated for the data extraction. The results showed that EGCG was the most potent compound in green tea that was able to reduce cell viability, wound closure, and induce apoptosis even in highly aggressive MDA-MB-231 and lower grade MCF-7 cell lines with ranging concentration. The second potent compound was ECG, followed by EGC and EC that exhibited intermediate effects. Lastly, catechin was shown to have the lowest anti-cancer activity among all other compounds. Flavonols were also shown to exert cytotoxic effects toward breast cancer cells. Moreover, further study is needed to discover the exact mechanism of each compound and determine its relationship toward different types of breast cancer cell lines.

Natural Compounds Derived from Camellia sinensis as Therapeutic Agent to Treat Non-Small Cell Lung Carcinoma (NSCLC): A Molecular Docking Study

Cancer is one of the biggest health problems with lung cancer as the first rank in the number of new cases and deaths. Non-small cell lung carcinoma (NSCLC) is a type of lung cancer which accounts for about 85% cases. Previous research identified the role of epidermal growth factor receptor (EGFR) as the most suitable target to treat NSCLC. This study used a molecular docking technique to identify the potential compounds derived from Camellia sinensis (green tea) leaves as therapeutic agent to treat NSCLC. We tested 12 compounds in green tea leaves along with gefitinib as a comparative drug. Docking was carried out on EGFR as receptor target by Autodock Tools and Autodock Vina. Molecular interactions were visualized by Discovery Studio v16. All compounds met the criteria as drugs based on Lipinski’s solubility test and were safe to use based on toxicity test with AdmetSAR. Docking results showed that all compounds had affinity to EGFR receptor. Catechin and myricetin had the same energy bonds as gefitinib which were -7,9 kcal/mol, while theaflavin gallate, theaflavin digallate, epicatechin gallate, epigallocatechin-3-gallate, catechin gallate, thearubigin, quercetin, and kaempferol were proven to have the strongest binding energy compared to gefitinib which were -10.6, -9.8, -8.9, -8.9, -8.5, -8.3, -8.0, and -8.0 kcal/mol, respectively. All compounds have the potential for development into drugs for NSCLC treatment. Further in vitro and in vivo investigations are needed to bring these compounds to the clinical setting.

Catechin from green tea had the potential to decrease the chlorpyrifos induced oxidative stress in larval zebrafish (Danio rerio)

Catechin is a biological compound in green tea (Camellia sinesis), which has anti-oxidant, anti-cancer, anti-apoptotic, anti-inflammatory, and attenuated effects in different experimental models. Chlorpyrifos (CPF), a broad-spectrum organophosphate insecticide, has resulted in oxidative stress, mitochondrial dysfunction, and apoptosis in zebrafish. The goal of this study is to assess whether catechin can alleviate CPF-induced oxidative damage and apoptosis in the early developmental stage of zebrafish. According to the results, we observed that 200 μg/L CPF exposure could induce oxidative stress, ROS production and changing the antioxidant-related enzymes and genes in larval zebrafish. Interestingly, catechin had the potential to reduce the oxidative damage and cell apoptosis caused by CPF exposure in larval zebrafish at different endpoints. Especially, catechin could promote the contents of GSH and activity of GST in zebrafish larvae injured by CPF, suggesting that catechin could repair oxidative damage at a certain degree by regulating the activities and gene transcription of some key enzymes related to GSH pathway in zebrafish. In addition, at transcriptional levels, a high concentration of catechin exposure reduced the expression genes of Mn-SOD, Cat, gst, and GPX induced by CPF in larval zebrafish. These genes mainly reflected the degree of oxidative damage of zebrafish, which was basically consistent with the enzyme activity. Catechin also could reduce the transcription of p53 and bax, which are tightly related to the apoptosis induced by CPF in zebrafish larvae. The expression of genes was consistent with ROS production, which proved that catechin could alleviate the apoptosis induced by CPF. This study discovered that catechin had some antioxidant effects in aquatic animals to reduce the toxicity caused by pesticides and offered the scientific basis for the utilization and development of catechin.

Effects of the psychoactive compounds in green tea on risky decision-making.

Epigallocatechin-3-gallate (EGCG) and caffeine are the two primary compounds found in green tea. While EGCG has anxiolytic and anti-inflammatory effects, its acute effects on cognition are not well understood. Furthermore, despite widespread green tea consumption, little is known about how EGCG and caffeine co-administration impacts behavior. Here, we investigated the effects of multiple doses of either EGCG or caffeine on a rat model of risk-taking. This was assessed using the risky decision-making task (RDT), in which rats choose between a small, well-tolerated reward and a large reward with escalating risk of mild footshock. Rats were tested in RDT after acute systemic administration of EGCG, caffeine or joint EGCG and caffeine. EGCG caused a dose-dependent reduction in risk-taking without affecting reward discrimination or task engagement. Caffeine did not impact risk-taking, but elevated locomotor activity and reduced task engagement at high doses. Finally, exposure to both EGCG and caffeine had no effect on risk-taking, suggesting that low-dose caffeine is sufficient to mask the risk-aversion caused by EGCG. These data suggest EGCG as a potential therapeutic treatment for psychological disorders that induce compulsive risky decision-making.

Bioactive compounds in green tea may improve transplant tolerance: A computational systems biology analysis.

Green tea (Camellia sinensis) has bioactive compounds that have been shown to possess nutritive effects on various biomolecular processes such as immunomodulation. This research explores the immunomodulatory effects of green tea in reducing transplant rejection. The study employs computational systems biology: 1) to identify biomolecular mechanisms of immunomodulation in transplant rejection; 2) to identify the bioactive compounds of green tea and their specific effects on mechanisms of immunomodulation in transplant rejection; and, 3) to predict the quantitative effects of those bioactive compounds on immunomodulation in transplant rejection. Three bioactive compounds of green tea - epicatechin (EC), gallic acid (GA), and epigallocatechin gallate (EGCG), were identified for their potential effects on immunomodulation of transplant rejection. Of the three, EGCG was the only one determined to enhance anti-inflammatory activity by: 1) upregulating synthesis of HO-1 that is known to promote Treg and Th2 phenotypes associated with enabling transplant tolerance; and, 2) downregulating pro-inflammatory cytokines IL-2, IL-17, IFN-γ, TNF-α, NO, IL-6, and IL-1β that are known to promote Th1 and Th17 phenotypes associated with transplant rejection. To the best of our knowledge, this study provides the first molecular mechanistic understanding the clinical nutritive value of green tea, specifically the bioactive compound EGCG, in enabling transplant tolerance.

Physiological Effects of Green-Colored Food-Derived Bioactive Compounds on Cancer

Green-colored foods, such as broccoli, sprouts, soybean, and green leafy vegetables are considered one of the representative healthy foods for containing various functional ingredients that can combat chronic diseases, including diabetes, obesity, and cancer. Herein, we reviewed the anti-cancer activities and the underlying mechanisms of some important bioactive compounds, such as sulforaphane, catechins, chlorophyll, isoflavone, indole dervatives, and lutein, present in green-colored foods. In vivo and clinical studies suggest that sulforaphane, a sulfur-containing compound found in cruciferous vegetables, can ameliorate prostate and breast cancer symptoms by arresting cell-cycle progression and modulating Ki67 and HDAC expression. A green tea compound, known as epigallocatechin-3-gallate (EGCG), has shown remarkable anti-cancer effects against prostate cancer and lung adenocarcinoma in human trials through its antioxidative defense and immunomodulatory functions. Chlorophyll, a natural pigment found in all green plants, can regulate multiple cancer-related genes, including cyclin D1, CYP1A, CYP1B1, and p53. Epidemiological studies indicate that chlorophyll can substantially reduce aflatoxin level and can mitigate colon cancer in human subjects. Remarkably, the consumption of soy isoflavone has been found to be associated with the lower incidence and mortality of breast and prostate cancers in East Asia and in Canada. In vivo and in vitro data point out that isoflavone has modulatory effects on estrogen and androgen signaling pathways and the expression of MAPK, NfκB, Bcl-2, and PI3K/AKT in different cancer models. Other green food bioactive compounds, such as indole derivatives and lutein, also exhibited suppressing effects in rodent models of lung, liver, stomach, cervical, and prostate cancers. In addition, some micronutrients, such as folate, riboflavin, retinoic acid, and vitamin D3 present in green foods, also showed potential cancer suppressing effects. Taken together, these data suggest potential chemopreventive functions of the bioactive compounds from green-colored foods. This paper could be beneficial for further research on the anti-carcinogenic effects of green-colored food-derived compounds, in order to develop green chemotherapeutics for cancers.

Epicatechin gallate prevents the de novo synthesis of fatty acid and the migration of prostate cancer cells.

Lipid metabolism disorder caused by the upregulation of lipogenic genes is a typical feature of prostate cancer. The synthesis of fatty acids is enhanced to accelerate the development of prostate cancer and is considered as a potential therapeutic target. Epicatechin gallate, an active compound of green tea, has been reported to modulate lipid metabolism. In this research, the potential role of epicatechin gallate in prostate cancer cells was evaluated. The results indicated that epicatechin gallate downregulates the expression of acetyl-CoA carboxylase, ATP citrate lyase, and fatty acid synthase in prostate cancer cells and prostate xenograft tissues, suggesting that epicatechin gallate can inhibit de novo fatty acid synthesis. Moreover, epicatechin gallate significantly restrains the migration rather than the viability of prostate cancer cells. PI3K/AKT/mTOR signaling pathway, which exhibits regulatory effect on lipogenesis, is also inhibited under epicatechin gallate treatment, while pretreatment with AKT activator SC79 or mTOR activator MHY1485 blocks the inhibitory effect of epicatechin gallate on the expression of lipogenic genes and the migration of prostate cancer cells. In conclusion, this study revealed that epicatechin gallate impairs the synthesis of fatty acids via inhibition PI3K/AKT/mTOR signaling pathway and then attenuates the migration of prostate cancer cells.

Evaluation of Roasting Effect on Selected Green Tea Volatile Flavor Compound and Pyrazine Content by HS-SPME GC-MS

The present study aims at the development and validation of a quali-quantitative headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME GC-MS) method for the analysis of odorants in different Chinese and Japanese green teas. A 65 µm PDMS/DVB fiber was used, and GC-MS was performed on a ZB-5 (30 m × 0.25 mm ID, 0.25 μm film) column. The main odorants in green tea samples were identified and the method was fully validated. Linearity (r2 0.981–0.999), sensitivity (LOQ 0.005–0.04 µg/mL), reproducibility (CV% 3.12–10.37), accuracy (recovery% 79.08–99.17) and matrix effect (ME% −9.5 to +4.5) were determined. Quantitation of 2,4-heptadienal, β-damascenone, β-ionone, linalool, indole, 2-ethyl-6-methyl-pyrazine, 2-ethyl-5-methyl-pyrazine, 2-ethyl-3,6-dimethylpirazine, 2-ethyl-3,5-dimethyl-pyrazine and 2-acetyl-pyrazine was carried out in the presence of isotopically labeled compounds as the internal standards. The proposed method was applied to the comparison of the profile of the volatile flavor compounds (VFCs) of green tea subjected to roasting treatment at three different temperatures (160, 180 and 200 °C for 30 min). In particular, the roasting process was monitored by following the quantitative variations of the selected odorant content, considered as the most important contributory components to the Hojicha or black tea (roasted tea) flavor. A temperature of 160 °C was found to be the best roasting temperature.

On the Validity of Adipogenic Cell Lines as Model Systems for Browning Processes: In Authentic Brown, Brite/Beige, and White Preadipocytes, There is No Cell-Autonomous Thermogenic Recruitment by Green Tea Compounds.

The potential ability of nutritional compounds to induce or enhance the browning of adipocytes has attracted large interest as a workable means of combatting the obesity epidemic. Green tea compounds are discussed as such inducers of an enhanced thermogenic capacity and activity. However, the cell-autonomous effects of green tea compounds on adipocytes have until now only been demonstrated in adipogenic cell lines (3T3-L1 and 3T3-F442A), i.e., cells of undefined tissue lineage. In this study, we examine the ability of green tea compounds to cell-autonomously induce thermogenic recruitment in authentic brown and brite/beige adipocytes in vitro. In primary brown adipocytes, the green tea compounds suppressed basal UCP1 gene expression, and there was no positive interaction between the compounds and adrenergic stimulation. In white adipocytes, green tea compounds decreased both basal and norepinephrine-induced UCP1 mRNA levels, and this was associated with the suppression of cell differentiation, indicated by reduced lipogenic gene expression and lipid accumulation. A lack of interaction between rosiglitazone and green tea compounds suggests that the green tea compounds do not directly interact with the PPARγ pathway. We conclude that there is a negative effect of the green tea compounds on basal UCP1 gene expression, in both brown and white primary adipocytes, in contrast to the positive effects earlier reported from studies in adipogenic cell lines. We posit that the epigenetic status of the adipogenic cell lines is fundamentally different from that of genuine brown and white adipocytes, reflected, e.g., in several-thousand-fold differences in UCP1 gene expression levels. Thus, results obtained with adipogenic cell lines cannot unreservedly be extrapolated as being relevant for authentic effects in brown and white adipocytes. We suggest that this conclusion can be of general concern for studies attempting to establish physiologically relevant cell-autonomous effects.

Combined Curcumin and EGCG Target Key Markers in Hepatocellular and Colorectal Cancers

Objective: Incidence rates of colon and liver cancers differ dramatically between Northern vs. Southern India. It has been suggested that differences in regional diet may play a role, specifically in the disparity in consumption rates of curcumin, an active agent of turmeric, and epigallocatechin gallate (EGCG), a compound in green tea. Curcumin and EGCG have well-known multi-targeted and beneficial effects as chemopreventive agents. However, natural compounds typically require high concentrations to be effective, which can also negatively impact healthy cells. Alternatively, low-dose combination of these compounds, if proven effective, may be one way to avoid this problem. This study proposed to demonstrate the effects of individual and combined treatments of EGCG and curcumin on viability and cancer pathway signaling, in hepatocellular carcinoma (HCC) and colorectal cancer (CCR) cell lines. Methods: HCC and CCR cell lines (HepG2 and SW1417, respectively) were treated with curcumin and EGCG in a dose- and time-dependent manner. Regorafenib, a chemotherapeutic used to treat colon and liver cancers, was then combined with the effective low-dose EGCG/curcumin. Cell viability, proliferation, and expression of cancer target genes were assessed. Results: Low-dose combination of curcumin and EGCG influenced the expression of 28 cancer target genes in HepG2 and 14 genes in SW1417. Six of these targets were verified by quantitative polymerase chain reaction. Regorafenib treatment elicited an effect similar to curcumin + EGCG treatment in a number of these targets and enhanced their regulation when used in combination. Conclusions: Low-dose combinations of curcumin and EGCG have a beneficial effect on regulating important cancer targets in HepG2 and SW1417 cell lines. The data suggest a supportive role for phytochemicals as complementary treatments to chemotherapy.

Green Tea and Its Relation to Human Gut Microbiome.

Green tea can influence the gut microbiota by either stimulating the growth of specific species or by hindering the development of detrimental ones. At the same time, gut bacteria can metabolize green tea compounds and produce smaller bioactive molecules. Accordingly, green tea benefits could be due to beneficial bacteria or to microbial bioactive metabolites. Therefore, the gut microbiota is likely to act as middle man for, at least, some of the green tea benefits on health. Many health promoting effects of green tea seems to be related to the inter-relation between green tea and gut microbiota. Green tea has proven to be able to correct the microbial dysbiosis that appears during several conditions such as obesity or cancer. On the other hand, tea compounds influence the growth of bacterial species involved in inflammatory processes such as the release of LPS or the modulation of IL production; thus, influencing the development of different chronic diseases. There are many studies trying to link either green tea or green tea phenolic compounds to health benefits via gut microbiota. In this review, we tried to summarize the most recent research in the area.