Concentrations Of Epigallocatechin-3-gallate Research Articles

The Effect of Green Tea Extract Supplementation and Different Catechol-O-Methyltransferase Genotypes on Plasma Catechins Concentrations in Women Who Are Post-menopause

ObjectivesTo determine if oral intake of green tea extract (GTE) capsules increases plasma concentrations of green tea catechins, and if genotypes impact changes in plasma concentrations of catechins. MethodsThis study was a secondary analysis of the Minnesota Green Tea Trial (MGTT), a randomized, double-blind, placebo-controlled trial. Participants were healthy postmenopausal women receiving GTE capsules with 843.0 mg epigallocatechin gallate (EGCG) or placebo daily for 12 months. In a subset of the participants (n = 178) plasma concentrations of green tea catechins were analyzed at baseline and month 12. Absolute changes in concentrations of plasma catechins including EGCG, epigallocatechin (EGC), epicatechin gallate (ECG), and epicatechin (EC) were compared between treatment groups, and between COMT genotypes among those in the GTE group. Findings were stratified by potential confounding factors. ResultsParticipants were mainly white non-Hispanic with a mean ± SD age of 60.13 ± 5.14 years and BMI of 24.97 ± 3.76 kg/m2. Absolute changes from baseline in plasma concentrations of EGCG (46.32 vs. 0.00 nM), ECG (18.39 vs. 0.00 nM), and EC (15.56 vs 0.06 nM) were significantly higher in the GTE than the placebo group, respectively (all Ps < 0.001). After adjusting for age and dietary intakes of fiber and vitamin C, absolute changes from baseline in plasma concentrations of EGCG were significantly greater in the high-activity COMT genotype (G/G) compared to those with the low-activity COMT genotypes (A/A or A/G) in the GTE group (P = 0.048). There was a statistically significant interaction between treatment and total vitamin C intake at baseline for absolute change from baseline of plasma EC (Pint = 0.008). Participants in the GTE group with vitamin C intake above median values at baseline experienced significantly greater positive increases in plasma concentration of EC compared to those in the placebo group. ConclusionsConcentrations of plasma EGCG, ECG, and EC were significantly increased after GTE supplementation for 12 months. COMT genotype may modify circulating EGCG concentrations; the entailed mechanism remains to be investigated. Funding SourcesNIH (Grant R01 CA127236).

Ethosomal (-)-epigallocatechin-3-gallate as a novel approach to enhance antioxidant, anti-collagenase and anti-elastase effects.

Controlled release systems containing natural compounds have been successfully applied in cosmetics as antiaging products to enhance the penetration of active compounds through the skin. In this study, we aimed to develop novel ethosomal formulations containing a potent antioxidant, epigallocatechin-3-gallate (EGCG), and to evaluate their potential for use in cosmetics by determining their antioxidant and antiaging effects. Ethosomes (ETHs) were prepared via mechanical dispersion and characterized in vitro in terms of particle size (PS), zeta potential (ZP), polydispersity index (PDI), encapsulation efficiency percentage (EE%), and in vitro release. The best ETH formulation was used to prepare the ethosome-based gel (ETHG) by using Carbopol 980 as a gelling agent at a ratio of 1:1 (v/v). The gel formulation was evaluated regarding organoleptic properties, pH values, and viscosity. Stability studies were conducted for three months and changes in characterization parameters and residual EGCG content of ETHs were examined. Besides, for ETHG, organoleptic properties, pH values (every two weeks), and viscosity (first and twelfth week) were determined for three months. The 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to test the cytotoxicity of the formulations and different EGCG solutions on the L929 cell line. The cell permeation properties and inhibitory effects of ETHs and ETHGs on collagenase and elastase enzymes were investigated compared to those of the solution form. Within the scope of antioxidant activity studies, 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+•) radical scavenging and β-carotene/linoleic acid co-oxidation inhibitory effects were carried out. The optimized EGCG-loaded ETHs (F3) were within the nanoscale range (238 ± 1.10 nm). The highest encapsulation efficiency and in vitro release values were 51.7 ± 1.15% and 50.8 ± 1.70%, respectively. The ETHG was successfully formulated with F3-coded ETHs and the cytotoxicity test revealed that the formulations and the EGCG solution at different concentrations were nontoxic. In terms of cell permeability, enzyme inhibition, and antioxidant activity, the ethosomal formulations yielded better results compared to the EGCG solution. It was observed that the formulations had a long-term effect due to the stability of EGCG. The findings of the study underline the potential of antioxidant and antiaging effects of the developed ethosomal formulations for use in the cosmetic field.

Determination of the chemical compounds of Shuchazao tea flowers at different developmental stages and in young shoots using 1H NMR-based metabolomics

The chemical compounds in tea leaves have been extensively explored in recent decades. However, the compounds in tea flowers have not been fully investigated. In present study, the main chemical compounds in tea flowers were identified at four developmental stages using non-targeted metabonomics based on proton nuclear magnetic resonance (1H NMR) and an automatic amino acid analyzer, and compared with those in young tea shoots. The results showed significant differences in catechins, sugars, organic acids and amino acids between tea flowers and young shoots. The concentrations of epigallocatechin gallate, epigallocatechin, epicatechin, and caffeine were significantly lower (p < 0.01) and sugar content significantly higher (p < 0.01) in flowers than in young shoots. Caffeine and β-glucose gradually decreased and sucrose constantly increased during flower development; α-glucose and fructose were most concentrated in the white bud and then decreased with flower development. Tea flowers contained more succinic acid, citric acid, and chlorogenic acid but less quinic acid and malic acid than young shoots. Both tea flowers and young tea shoots contained 20 common amino acids, including 7 essential ones. The concentration of amino acids was highest in the white bud (27.66 mg/g); young tea shoots contained significantly more L-theanine than tea flowers (p < 0.01). Our data indicate that the different stages of tea flowers have a set of characteristic chemical compounds and are potentially useful for functional foods.Graphical abstract

Induction of mesenchymal-epithelial transition (MET) by epigallocatechin-3-gallate to reverse epithelial-mesenchymal transition (EMT) in SNAI1-overexpressed renal cells: A potential anti-fibrotic strategy

Dynamic transdifferentiation of epithelial cells from epithelial-mesenchymal transition (EMT) to its reverse process, mesenchymal-epithelial transition (MET), has gained wide attention for management of cancers and tissue fibrosis. In this study, we addressed beneficial effects of epigallocatechin-3-gallate (EGCG) on EMT-MET reversion using an in vitro EMT model by overexpressing SNAI1 gene encoding Snail1, an EMT-inducing transcription factor, into renal tubular epithelial cells (pcDNA6.2-SNAI1 cells). The cells transfected with empty vector (pcDNA6.2 cells) served as the control. Titrating EGCG concentrations revealed its optimal dose at 25 µM for 24-h, which was used throughout. pcDNA6.2-SNAI1 cells had increased spindle index and typical morphology of EMT, whereas EGCG could restore the normal index and morphology. Increased nuclear Snail1 and β-catenin; increased cytoplasmic Snail1, p-GSK-3β, vimentin, fibronectin and F-actin; and decreased occludin, ZO-1, transepithelial resistance (TER), E-cadherin and cell cluster size were observed in the pcDNA6.2-SNAI1 cells. These pcDNA6.2-SNAI1 cells also had increased migrating activity associated with increased forward but decreased non-forward α-tubulin filaments, G0/G1 cell cycle escape, and increased matrix metalloproteinase-2 (MMP-2) and MMP-9. All of these EMT features were successfully abolished by EGCG (partially, completely, or overly). Collectively, our data have demonstrated that EGCG can reverse EMT to MET processes in renal cells. Therefore, EGCG may have the therapeutic potential as one of the promising anti-fibrotic agents to reverse the fibrotic kidney.

Comparison of the Fungal Community, Chemical Composition, Antioxidant Activity, and Taste Characteristics of Fu Brick Tea in Different Regions of China.

In this study, the fungal community structure, metabolites, antioxidant ability, and taste characteristics of five Fu brick tea (FBT) from different regions of China were determined and compared. A total of 69 operational taxonomic units (OTUs) were identified and assigned into 5 phyla and 27 genera, with Eurotium as the predominant genus in all samples. Hunan (HN) sample had the strongest fungal diversity and richness, followed by Guangxi (GX) sample, and Zhejiang (ZJ) sample had the lowest. GX sample had higher amounts of gallic acid (GA), total catechins, gallocatechin (GC), and epicatechin gallate (ECG) as well as antioxidant activity than the other samples. The levels of total phenolics, total flavonoids, epigallocatechin (EGC), catechin, epicatechin (EC), thearubigins (TRs), and theaflavins (TFs) were the highest in the ZJ sample. Guizhou (GZ) and Shaanxi (SX) samples contained the highest contents of epigallocatechin gallate (EGCG) and gallocatechin gallate (GCG), respectively. Total phenolics, GA, EC, CG, and TFs were positively associated with most of fungal genera. Total phenolic content (TPC), total flavonoid content (TFC), and most of catechins contributed to the antioxidant activities of FBT. HN sample had the strongest sourness and sweetness, ZJ sample had the strongest saltiness, SX sample had the strongest umami, and GZ sample had the strongest astringency, which was ascribed to the varied metabolites. This work reveals that FBT in different regions vary greatly in fungal community, metabolites, antioxidant activity, and taste characteristics, and provides new insight into the quality characteristics formation of FBT in different regions.

Insights into acylation mechanisms: co-expression of serine carboxypeptidase-like acyltransferases and their non-catalytic companion paralogs.

SUMMARYSerine carboxypeptidase‐like acyltransferases (SCPL‐ATs) play a vital role in the diversification of plant metabolites. Galloylated flavan‐3‐ols highly accumulate in tea (Camellia sinensis), grape (Vitis vinifera), and persimmon (Diospyros kaki). To date, the biosynthetic mechanism of these compounds remains unknown. Herein, we report that two SCPL‐AT paralogs are involved in galloylation of flavan‐3‐ols: CsSCPL4, which contains the conserved catalytic triad S‐D‐H, and CsSCPL5, which has the alternative triad T‐D‐Y. Integrated data from transgenic plants, recombinant enzymes, and gene mutations showed that CsSCPL4 is a catalytic acyltransferase, while CsSCPL5 is a non‐catalytic companion paralog (NCCP). Co‐expression of CsSCPL4 and CsSCPL5 is likely responsible for the galloylation. Furthermore, pull‐down and co‐immunoprecipitation assays showed that CsSCPL4 and CsSCPL5 interact, increasing protein stability and promoting post‐translational processing. Moreover, phylogenetic analyses revealed that their homologs co‐exist in galloylated flavan‐3‐ol‐ or hydrolyzable tannin‐rich plant species. Enzymatic assays further revealed the necessity of co‐expression of those homologs for acyltransferase activity. Evolution analysis revealed that the mutations of the CsSCPL5 catalytic residues may have taken place about 10 million years ago. These findings show that the co‐expression of SCPL‐ATs and their NCCPs contributes to the acylation of flavan‐3‐ols in the plant kingdom.

Epigallocatechin Gallate (EGCG) Mitigates The Effect of Camptothecin‐Induced Oxidative Stress on Bone Cancer‐like cells (UMR 106‐01 BSP) by Inhibiting Apoptosis

Many medical treatments have been proposed and utilized to mitigate the effects of oxidants on mammalian cells. Some studies have demonstrated the antioxidative effects of EGCG (an active ingredient in green tea) against cellular oxidants such as camptothecin (CAMPT). However, not many studies have shown how EGCG mitigates the effects of CAMPT on UMR cells. We hypothesized that EGCG mitigates the effects of CAMPT on cell proliferation and biophysical parameters in UMR cells by inhibiting CAMPT‐induced apoptosis. Briefly, UMR cells were routinely passaged, counted, plated at 4.8 x 105 cells/mL in six‐well culture plates, then treated with varying concentrations of CAMPT. The cultures were incubated for 72 hours at 37°C + 5% CO₂ infusion. Cells were subsequently counted to establish the proliferation and viability of the induced cells as compared to controls. In another experiment, designated UMR cells were co‐treated with CAMPT and different concentrations of EGCG then processed, as mentioned above, to evaluate whether or not the EGCG treatment was able to mitigate the oxidative effect of CAMPT through proliferation / viability studies. Apoptosis markers were assessed for each experiment by using a Caspase‐3/CPP32 Colorimetric Assay Kit. Lastly, designated cells were treated with CAMPT alone, or CAMPT +EGCG then assessed using electric cell‐substrate impedance sensing (ECIS) technology to explore the effects of the chemicals used on key biophysical parameters of UMR cells (i.e. cell membrane resistance, rate of cell spreading and cell attachment). Briefly, CAMPT‐treated and CAMPT+EGCG‐treated UMR cells were plated at 2.5 x 105 cells/mL in eight‐well ECIS array plates. The plates were placed into the ECIS array holder and incubated at 37°C with 5% CO₂. The biophysical parameters (cell membrane resistance/impedance, cell spreading, cell attachment) were monitored and measured in real‐time for 48 hours, using the ECIS instrument. F test ANOVA was used to compare variances between all trials and all values in the results were expressed as means ±SD. The results of the proliferation study showed a decrease in CAMPT‐treated UMR cell proliferation in a concentration‐dependent manner (Figure 1). Cells co‐treated with CAMPT + EGCG revealed that EGCG was able to reverse the oxidative effects of CAMPT on the UMR cells in a concentration‐dependent manner *Figure 2). The Caspase‐3/CPP32 Colorimetric Assay showed an increase in apoptotic marker activity from the CAMPT‐induced samples in contrast with the uninduced controls. The ECIS technology documented decreases in biophysical parameters in the UMR cells when CAMPT alone was used. Co‐treatment of the cells with CAMPT+EGCG showed a reverse effect on the biophysical parameters. F‐Test ANOVA yielded statistically significant values with p values &lt;0.05. The results of this research suggest that EGCG is effective in protecting UMR cells from oxidative stress by inhibiting apoptosis. Moreover, results from the ECIS instrument validates this technology as a corroborator of the biological effects of CAMPT and EGCG on UMR cells. This study suggests that EGCG has a protective role in mitigating oxidative stress in mammalian cells.

Epigallocatechin 3‐Gallate Inhibitory Effects on Inflammatory Mediators in BV‐2 Microglial Cells

Chronic neuroinflammation has been associated with many neurodegenerative diseases such as Alzheimer's and Parkinson's Disease. The chronic activation of microglia can cause neuronal damage by releasing proinflammatory cytokines and reactive oxygen mediators. Epigallocatechin‐3‐Gallate (EGCG) is a bioactive polyphenol that exhibits significant anti‐inflammatory and neuroprotective properties in green tea extract. The current study aims to examine how EGCG can prevent chronic inflammation by inhibiting proinflammatory responses and oxidative stress induction. If proven to be the case, EGCG may serve as a nutraceutical for preventing neurodegenerative disorders. In this study, we evaluated the anti‐inflammatory activity of EGCG in lipopolysaccharide (LPS) stimulated BV‐2 microglia cells. BV‐2 microglial cells were first stimulated with 1µg/mL LPS for 1hr; then incubated for 24 hrs using different concentrations of EGCG. Cell viability was assessed using resazurin (Alamar™ Blue) indicator dye. In addition, inflammatory cytokines were profiled using QIAGEN mouse inflammatory cytokines multi‐analyte ELISA array, and nitric oxide (NO) release was evaluated using the Griess Reagent Assay. Our results showed that EGCG caused a concentration‐dependent decrease in cell viability of LPS stimulated BV‐2 microglia cells for EGCG concentrations higher than 150 µM. EGCG also significantly inhibited the release of the proinflammatory cytokine IL‐6 and the inflammatory mediator NO production at 150 µM, and 175µM in LPS stimulated BV‐2 microglial cells. In conclusion, EGCG has decreased IL‐6 and NO production, but further research will be performed to elucidate the anti‐inflammatory and antioxidative attributes of EGCG on inflammation‐induced neurodegenerative diseases.

Synthesis of A Tetrahydrocannabinol (THC) Analog For Analyzing Cellular Proliferation in Concert With Epigallocatechin Gallate (EGCG) on A Bone‐like Cancer Cell Line (UMR 106‐01 BSP)

Cannabinoids have been extensively studied in the field of cancer research. Tetrahydrocannabinol (THC) has shown promising results in influencing cellular proliferation when in association with other cannabinoids. This traditional entourage effect solely focuses on the study of THC with other cannabinoids. However, not many studies have been done to explore the synergistic effect of THC analogs when used with non‐cannabinoid compounds. THC in its isolate form for experimentation is very strictly regulated. Therefore, this study was conducted in the pursuit of synthesizing and experimenting with analogs of THC to observe a potential entourage effect with epigallocatechin gallate (EGCG), a compound known for its efficacy to reduce proliferation at higher concentrations in UMR cells. It was hypothesized that active analogs of THC can be synthesized and used in concert with EGCG to potentiate decreased proliferation in the bone‐like cancer cell line UMR 106‐01 BSP (UMR cells). Briefly, a Knoevenagel condensation and a Diels‐Alder reaction using 1,3‐cyclohexanediol dissolved in methanol (MeOH) and citronellal with ethylenediamine diacetic acid (EDDA) at a temperature of 60℃ was used to synthesize a novel THC analog, 3,10,10‐Trimethyl‐1,2,3,4,4a,6,7,8,10,10a‐decahydro‐9‐oxa‐5‐phenanthrenone (TDP). UMR cells were routinely passaged, counted, plated in six‐well culture plates at 480,00 cells/mL, then treated with 10‐fold dilutions of TDP. The plates were incubated for 72 hours in a humidified incubator at 37 degrees Celsius with 5% carbon dioxide infusion. At the end of the experiment, the cells were routinely washed with HANKS buffered saline solution (HBSS), then routinely counted using the Luna Automated Cell Counter. In another experiment, designated cells were co‐treated with TDP+EGCG, following the protocol above. F test ANOVA was used to compare variances and all values in the results were expressed as means ± SD. The results from the attempted cannabinoid analog synthesis yielded a novel active THC analog, TDP. Serial dilutions treatment of the UMR cells with TDP alone showed its ability to decrease cell count in a concentration dependent manner. However, when coupled with higher concentrations of EGCG, the co‐treatment increased cell count rather than potentiating the effect of decreasing cellular proliferation. The F Test ANOVA showed robust statistical significance (p values &lt;0.05) with regard to TDP’s effect of decreasing cell proliferation in UMR cells in a concentration‐dependent manner. Overall, the outcomes of this study suggest that active forms of THC analogs can be synthesized and tested in concert with other non‐cannabinoid compounds like EGCG. This study opens the door to explore the entourage effect of TDP with other non‐cannabinoid compounds that may provide another tool in the therapeutic treatment of bone cancer cells.

Relationship between theanine, catechins and related genes reveals accumulation mechanism during spring and summer in tea plant (Camellia sinensis L.)

The tea plant (Camellia sinensis L.) is an important commercial crop. Theanine and catechins, abundant in the tea plant and represented as secondary metabolites of the tea plant, contribute to the refreshing and astringent taste of tea, respectively. In this study, three C. sinensis cultivars, ‘Baojing Huangjincha 1′ (HJC1), ‘Huangjincha 2′ (HJC2), and ‘Huangjincha 168′ (HJC168) harvested in spring and summer were used to investigate differences in theanine and catechin concentrations by high-performance liquid chromatography. The expression levels of genes associated with theanine and catechin biosynthesis were investigated using a real-time quantitative polymerase chain reaction. Results indicated that theanine, aspartic acid, serine, glutamate and alanine contents were higher in spring in three cultivars, while CsGDH1 showed higher expression in summer. As for catechins, HJC1 and HJC2 accumulated more epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) contents in summer. On the contrary, HJC168 showed higher EGCG and ECG contents in spring. CsF3H showed higher expression in spring than in summer in three cultivars. Correlation analysis indicated a positive correlation between the CsGABA-T expression and theanine contents in spring and summer (p<0.05), with the activity of GABA-T in theanine synthesis, implying that CsGABA-T might be a crucial positive regulator in theanine accumulation. Besides, most catechin compounds were positively correlated with related genes expression during summer. It was presumed that catechin synthesis contributes to catechin accumulation in summer. In summary, this study provides insights into the potential regulatory mechanisms of theanine and catechins in spring and summer.

Nanocarriers Based on Gold Nanoparticles for Epigallocatechin Gallate Delivery in Cancer Cells.

Gold nanoparticles (AuNPs) are inorganic and biocompatible nanovehicles capable of conjugating biomolecules to enhance their efficacy in cancer treatment. The high and reactive surface area provides good advantages for conjugating active compounds. Two approaches were developed in this work to improve the Epigallocatechin-3-gallate (EGCG) antioxidant efficacy. AuNPs were synthesized by reducing gold salt with chitosan. One other nanosystem was developed by functionalizing AuNPs with cysteamine using the Turkevitch method. The physico-chemical characterization of EGCG conjugated in the two nanosystems-based gold nanoparticles was achieved. The in vitro toxic effect induced by the nanoconjugates was evaluated in pancreatic cancer cells, showing that encapsulated EGCG keeps its antioxidant activity and decreasing the BxPC3 cell growth. A significant cell growth inhibition was observed in 50% with EGCG concentrations in the range of 2.2 and 3.7 μM in EGCG-ChAuNPs and EGCG-Cyst-AuNPs nanoconjugates, respectively. The EGCG alone had to be present at 23 μM to induce the same cytotoxicity response. Caspase-3 activity assay demonstrated that the conjugation of EGCG induces an enhancement of BxPC3 apoptosis compared with EGCG alone. In conclusion, AuNPs complexes can be used as delivery carriers to increase EGCG antioxidant activity in cancer tissues.

High Internal Phase Emulsions Stabilized with Polyphenol-Amyloid Fibril Supramolecules for Encapsulation and Protection of Lutein.

High internal phase emulsions (HIPEs), also called highly concentrated emulsions with a minimal internal phase volume fraction of 74%, have been paid increasing attention in the development of functional foods due to their high potential in loading with large amounts of hydrophobic nutriceuticals. In the present study, HIPEs stabilized by polyphenol-amyloid supramolecular filaments were prepared for encapsulation of olive oil and loading with lutein. Binding and stacking of the green tea polyphenol epigallocatechin gallate (EGCG) on the surface of amyloid fibrils fabricated from hen egg lysozyme resulted in the hybrid supramolecules, which assembled to form hydrogels. The amyloid fibril clusters shrouded by EGCG were observed in the microstructure of the hydrogels characterized by atomic force microscopy (AFM). HIPEs stabilized by the EGCG-amyloid fibril supramolecules showed the typical microstructure of highly packed polyhedral geometric oil droplets. The gel strength of the HIPEs stabilized by the hybrid supramolecules was greater than that of HIPEs stabilized by pure amyloid fibrils. The droplet size of the HIPEs first decreased and then increased with the increase of EGCG contents in the hybrid supramolecules, which was consistent with the corresponding emulsion morphologies obtained from the images of confocal laser scanning microscopy (CLSM). Aggregation of the protein-based nanofibrils appeared in the continuous phase at higher EGCG contents. The droplet size of the HIPEs decreased with the increase of the amyloid fibril concentration, accompanied by more packed and homogenously dispersed lipid droplets, as shown in the CLSM images. A high loading content of lutein of up to 10 mg/mL in the prepared HIPEs was realized, and the stability of lutein against ultraviolet irradiation, heat, iron, and hydrogen peroxide was promoted significantly. In addition, encapsulation with the HIPEs prevented the oxidization of olive oil, and this effect was enhanced with the increase of the EGCG content in the hybrid supramolecules ranging from 0 to 0.25 wt %. The protection function of the HIPEs might be ascribed to the membrane of interfacial amyloid fibrils and the crowded oil droplet environment, both of which could shield the pro-oxidation factors.

Risk Assessment of Caffeine and Epigallocatechin Gallate in Coffee Leaf Tea.

Coffee leaf tea is prepared as an infusion of dried leaves of Coffea spp. in hot water. It is a traditional beverage in some coffee-producing countries and has been authorized in 2020 within the European Union (EU) according to its novel food regulation. This article reviews current knowledge on the safety of coffee leaf tea. From the various ingredients contained in coffee leaves, only two were highlighted as possibly hazardous to human health, namely, caffeine and epigallocatechin gallate (EGCG), with maximum limits implemented in EU legislation, which is why this article focuses on these two substances. While the caffeine content is comparable to that of roasted coffee beans and subject to strong fluctuations in relation to the age of the leaves, climate, coffee species, and variety, a maximum of 1–3 cups per day may be recommended. The EGCG content is typically absent or below the intake of 800 mg/day classified as hepatotoxic by the European Food Safety Authority (EFSA), so this compound is suggested as toxicologically uncritical. Depending on selection and processing (age of the leaves, drying, fermentation, roasting, etc.), coffee leaf tea may exhibit a wide variety of flavors, and its full potential is currently almost unexplored. As a coffee by-product, it is certainly interesting to increase the income of coffee farmers. Our review has shown that coffee leaf tea is not assumed to exhibit risks for the consumer, apart from the well-known risk of caffeine inherent to all coffee-related beverages. This conclusion is corroborated by the history of its safe use in several countries around the world.

Epigallocatechin gallate enhances human lens epithelial cell survival after UVB irradiation via the mitochondrial signaling pathway.

The aim of the present study was to explore the mechanism underlying the ultraviolet B (UVB) irradiation-induced apoptosis of human lens epithelial cells (HLECs), and to investigate the protective effect of epigallocatechin gallate (EGCG) against the UVB-induced apoptosis of HLECs. HLECs were exposed to different concentrations of EGCG plus UVB (30 mJ/cm2). Cell viability was determined using the MTT assay. Furthermore, mitochondrial membrane potential (Δψm) and apoptosis were assessed by flow cytometry with JC-1 and Annexin V/PI staining, respectively. Moreover, the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), as well as the levels of GSH, hydrogen peroxide (H2O2) and hydroxyl free radicals were determined using biochemical assay techniques. Reverse transcription-quantitative PCR and western blotting were used to detect the mRNA and protein expression levels of Bcl-2, Bax, cytochrome c, caspase-9 and caspase-3, respectively. The results revealed that UVB irradiation reduced the Δψm of HLECs and induced apoptosis. Notably, EGCG significantly attenuated the generation of H2O2 and hydroxyl free radicals caused by UVB irradiation in HLECs, and significantly increased CAT, SOD and GSH-Px activities, however, the GSH levels were not significantly increased. EGCG also reduced UVB-stimulated Bax, cytochrome c, caspase-9 and caspase-3 expression, and elevated Bcl-2 expression, suggesting that EGCG may possess free radical-scavenging properties, thus increasing cell viability. In conclusion, EGCG may be able to protect against UVB-induced HLECs apoptosis through the mitochondria-mediated apoptotic signaling pathway, indicating its potential application in clinical practice.

Effect of brewing conditions on polyphenols in the dark tea (Camellia sinensis L.) infusions: content, composition and antioxidant activities

The study was the first to investigate the content and composition along with the antioxidant activities of polyphenols in the dark tea infusions. The effect of brewing conditions on total polyphenolic contents (TPC) in dark tea infusions was conducted by response surface methodology (RSM), and the composition of polyphenolic compounds was investigated using ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS), and DPPH and ABTS assay were used to evaluate the antioxidant activity of dark tea. Results showed that brewing at water/tea radio 50 : 1 mL/g, temperature 92 °C and time 27 min was the best condition to obtain the highest TPC (3.90 mg/mL). The composition of polyphenolic compounds in the infusions included 11 catechins and derivatives, 19 flavones and flavone glycosides, and 1 phenolic acid, and the concentrations of epigallocatechin gallate (91.32 mg/L) and epicatechin-3-O-gallate (23.10 mg/L) was the highest among the quantitative compounds. Moreover, the dark tea had good scavenging activities on DPPH (IC50 = 9.94 μg/mL) and ABTS (IC50 = 17.26 μg/mL) free radicals.

In situ mucoadhesive hydrogel capturing tripeptide KPV: the anti-inflammatory, antibacterial and repairing effect on chemotherapy-induced oral mucositis.

The self-healing of chemotherapy-induced oral mucositis is difficult in practice because of both local bacterial infection and severe inflammation. Herein, in situ mucoadhesive hydrogels (PPP_E) were successfully prepared by using temperature-sensitive PLGA-PEG-PLGA (PPP) as a matrix and epigallocatechin-3-gallate (EGCG) with inherent antibacterial activity as an adhesion enhancer. A series of PPP_E precursor solutions with various EGCG concentrations (1%, 2% and 5%) were prepared by fixing the PPP concentration at 25%. EGCG slightly decreased the sol-gel transition temperature and shortened the sol-gel transition time of the PPP hydrogel. Moreover, the incorporation of EGCG could significantly increase the tissue adhesion properties of the PPP hydrogel at 37 °C. PPP_2%E displayed a suitable gelation temperature (36.2 °C), gelation time (100 s) and storage modulus (48 Pa). Tripeptide KPV as a model drug was easily dissolved in cold PPP_2%E precursor solution to prepare KPV@PPP_2%E hydrogel. The anti-inflammatory activity and promotion of cell migration potential by KPV in PPP-2% E hydrogel were well maintained. Moreover, KPV@PPP_2%E exhibited strong antibacterial efficacy against S. aureus. PPP_2%E precursor solution rapidly transformed to a hydrogel and adhered to the wound surface for 7 hours when administrated to the gingival mucosa of rats. Treatment with KPV@PPP_2%E hydrogel greatly improved the food intake and body weight recovery of rats with chemotherapy-induced oral mucositis. Moreover, the tissue morphology of the ulcerated gingiva after application of KPV@PPP_E hydrogel was also well repaired by promoting CK10 and PCNA expression. In addition, the inflammatory cytokines including IL-1β and TNF-α were significantly inhibited by KPV@PPP_2%E hydrogel while IL-10 was up-regulated. KPV@PPP_2%E hydrogel also had an anti-bacterial effect on MRSA-infected gingival ulcer wounds, which resulted in the obvious inhibition of infiltration by inflammatory cells into submucosal tissues. Conclusively, KPV@PPP_E may be a promising practical application for cancer patients with chemotherapy-induced oral mucositis.

Epigallocatechin-3-gallate inhibits replication of white spot syndrome virus in the freshwater crayfish Procambarus clarkii.

The freshwater crayfish Procambarus clarkii is native to North America and Mexico, and it was introduced to China in 1929. The production and consumption of P.clarkii in China are the highest worldwide, reaching 208.96 million tons in 2020. The white spot syndrome virus (WSSV) is a major pathogen that affects shrimp, crayfish, crabs and lobsters, and it has caused widespread loss to the P.clarkii industry. Epigallocatechin-3-gallate (EGCG), a small-molecule compound, has a multitude of biological functions and the ability to bind to the 37kDa/67kDa laminin receptor (LamR). EGCG has potential antiviral effects against WSSV. In this study, we evaluated the potential anti-WSSV applications of EGCG in P.clarkii. We demonstrated that various concentrations (10μg/g·bw, 20μg/g·bw and 40μg/g·bw) of EGCG can suppress WSSV infection in P.clarkii. Histopathological examination revealed no characteristic pathological changes due to EGCG administration in P.clarkii tissues. Furthermore, pharmacokinetics studies of EGCG in P.clarkii revealed its rapid absorption (Tmax =2h), and the peak concentrations of EGCG were 73.78µg/g in the liver and 24.87µg/g in the muscle. Our results indicate the high potential applications of EGCG against WSSV in P.clarkii.

DEVELOPMENT OF THE TECHNOLOGY FOR THE SEPARATION OF THE COMPONENTS FROM GREEN TEA USING THE PREPARATIVE LIQUID CHROMATOGRAPHY BY DESIGN OF PERIODICAL PROCESS

Leaves of the green tea plant camellis sinensis contain up to 36 % polyphenols. Epigallocatechin gallate (EGCG) is the most interesting polyphenols because it exhibits a strong antioxidant effect. Furthermore, it has been demonstrated that EGCG has an antimutagenic and an anticancer effects, an antibacterial effect and a beneficial effect on cholesterol level in blood. Therefore, is needed to isolate EGCG in a pure form in high yield by simple and commercial process. This method for isolation of EGCG contents the following steps: a) selection of macroporous polar resin for the preparative liquid chromatography; b) selection of polar elution solvent; c) determination the temperature and pressure for adsorbtion and desorbtion of the polyphenols of the green tea. Therefore, it was searched the interconnection between yield of EGCG and the range of temperature and amount of eluent. Finally, the process for the separation of Epigallocatechin gallate from green tea extract was developed in the laboratory and EGCG was isolated with the concentration 92% by the yield 43%. Accordingly, the technology of EGCG production based on the preparative liquid chromatography was launched and introduced on the market.

Fructooligosaccharides Increase in Plasma Concentration of (-)-Epigallocatechin-3-Gallate in Rats.

(-)-Epigallocatechin-3-gallate (EGCG) undergoes auto-oxidation at physiological pH and therefore may be poorly absorbed in the intestine. Fructooligosaccharides (FOS), comprising a group of 1-kestose, nystose, and 1F-β fructofuranosyl-nystose, are fermentable by gut bacteria and converted mainly into lactate. This study was conducted to determine whether dietary FOS may help to increase the plasma concentration of EGCG in rats by preventing it from auto-oxidation. Rats consumed an assigned diet, either a 0.3% (w/w) EGCG diet or an EGCG diet with additional 1, 3, or 5% (w/w) FOS, for 2 weeks. The results showed that the plasma concentration of EGCG was 0.21 ± 0.05 μM for the EGCG alone group, and it was significantly higher at 0.65 ± 0.12 μM for the EGCG plus 5% FOS group. Treatments with FOS resulted in a dose-dependent increase in the cecal level of lactate and brought the cecal pH down, with an accompanying alteration in the abundance of Lactobacillus and Collinsella. Because EGCG concentrations in the cecal digesta of rats fed the FOS-containing diet maintained comparatively high levels, FOS likely contributed to the protection of EGCG from auto-oxidation. In conclusion, FOS reduced the pH of the lumen of the intestine, kept EGCG intact to a certain degree, and consequently allowed EGCG to be taken into the blood circulation from the intestine.

Cytotoxic Aβ Protofilaments Are Generated in the Process of Aβ Fibril Disaggregation

Significant research on Alzheimer’s disease (AD) has demonstrated that amyloid β (Aβ) oligomers are toxic molecules against neural cells. Thus, determining the generation mechanism of toxic Aβ oligomers is crucial for understanding AD pathogenesis. Aβ fibrils were reported to be disaggregated by treatment with small compounds, such as epigallocatechin gallate (EGCG) and dopamine (DA), and a loss of fibril shape and decrease in cytotoxicity were observed. However, the characteristics of intermediate products during the fibril disaggregation process are poorly understood. In this study, we found that cytotoxic Aβ aggregates are generated during a moderate disaggregation process of Aβ fibrils. A cytotoxicity assay revealed that Aβ fibrils incubated with a low concentration of EGCG and DA showed higher cytotoxicity than Aβ fibrils alone. Atomic force microscopy imaging and circular dichroism spectrometry showed that short and narrow protofilaments, which were highly stable in the β-sheet structure, were abundant in these moderately disaggregated samples. These results indicate that toxic Aβ protofilaments are generated during disaggregation from amyloid fibrils, suggesting that disaggregation of Aβ fibrils by small compounds may be one of the possible mechanisms for the generation of toxic Aβ aggregates in the brain.