Concentrations Of Epigallocatechin-3-gallate Research Articles

Fabrication of oil-in-water high internal phase emulsions with enhanced antioxidative properties by modified starch/polyphenol mixtures: Effect of EGCG concentration, NaCl concentration, and temperature.

In this study, oil-in-water (O/W) high internal phase emulsions (HIPEs) with enhanced antioxidative properties stabilized by octenyl succinic anhydride modified starch (OSAS)/(-)-Epigallocatechin-3-gallate (EGCG) mixtures were prepared. The influence of EGCG concentration (0-0.2 %, w/v), NaCl concentration (0-400 mmol/L), and temperature (25-90 °C) on the stability of the HIPEs was evaluated. The formation of O/W HIPEs, and OSAS/EGCG mixtures formed a thicker barrier on the surface of the oil droplets was confirmed using confocal laser scanning microscopy (CLSM) and cryo-scanning electron microscopy (Cro-SEM), respectively. The results indicated the HIPEs stabilized by OSAS/EGCG mixtures exhibited good environmental stability. All HIPEs displayed excellent antioxidant properties. As the concentration of EGCG in the OSAS/EGCG mixtures was increased from 0 to 0.2 % (w/v), the lipid hydroperoxide (LH) content was reduced from 534.89 mmol/kg oil to 453.77 mmol/kg oil, and malondialdehyde (MDA) content was reduced from 10.08 mmol/kg oil to 6.07 mmol/kg oil. Combined with the effect of NaCl, the oxidative stability was improved further. This study provided a new formulation of food-grade O/W HIPEs with strong antioxidant properties could be a potential solid fat substitute for future foods.

Characterizing Curing Efficiency of EGCG-Encapsulated Halloysite Nanotube Modified Adhesives for Durable Dentin-Resin Interfaces.

Matrix metalloproteinase (MMP)-induced collagen degradation at the resin-dentin interface remains a significant challenge for maintaining the longevity of dental restorations. This study investigated the effects of epigallocatechin-3-gallate (EGCG), a potent MMP inhibitor, on dental adhesive curing efficiency when encapsulated in halloysite nanotubes (HNTs). EGCG-loaded HNTs were incorporated into a commercial dental adhesive (Adper Scotchbond Multi-Purpose) at 7.5% and 15% w/v concentrations. To isolate the effects of each component, the study included three control groups: unmodified adhesive (negative control), adhesive containing only HNTs, and adhesive containing only EGCG (0.16% and 0.32%, equivalent to the EGCG content in EGCG-HNT groups). Degree of conversion (DC), polymerization conversion (PC), and Vickers micro-hardness (VHN) were assessed to evaluate curing efficiency. The addition of 7.5% EGCG-encapsulated HNTs maintained curing properties similar to the control, showing no significant differences in DC (80.97% vs. 81.15%), PC (86.59% vs. 85.81%), and VHN (23.55 vs. 24.12) (p > 0.05). In contrast, direct incorporation of EGCG at 0.32% significantly decreased DC (73.59%), PC (80.63%), and VHN (20.56) values compared to both control and EGCG-HNT groups (p < 0.05). Notably, HNT encapsulation mitigated these negative effects on polymerization, even at higher EGCG concentrations. These findings demonstrate that EGCG encapsulation in HNTs can maintain the curing efficiency of dental adhesives while potentially preserving the MMP-inhibitory benefits of EGCG.

Restoring Multidrug-Resistant Escherichia coli Sensitivity to Ampicillin in Combination with (-)-Epigallocatechin Gallate.

Multidrug-resistant (MDR) bacteria, especially Escherichia coli, are a major contributor to healthcare-associated infections globally, posing significant treatment challenges. This study explores the efficacy of (-)-epigallocatechin gallate (EGCG), a natural constituent of green tea, in combination with ampicillin (AMP) to restore the effectiveness of AMP against 40 isolated MDR E. coli strains. Antimicrobial activity assays were conducted to determine the minimum inhibitory concentrations (MIC) of EGCG using the standard microdilution technique. Checkerboard assays were employed to assess the potential synergistic effects of EGCG combined with AMP. The pharmacodynamic effects of the combination were evaluated through time-kill assays. Outer membrane disruption was analyzed by measuring DNA and protein leakage and with assessments using N-phenyl-1-naphthylamine (NPN) and rhodamine 123 (Rh123) fluorescence dyes. Biofilm eradication studies involved biofilm formation assays and preformed biofilm biomass and viability assays. Scanning electron microscopy (SEM) was used to examine changes in cellular morphology. The results indicated that EGCG demonstrated activity against all isolates, with MICs ranging from 0.5 to 2 mg/mL, while AMP exhibited MIC values between 1.25 and 50 mg/mL. Importantly, the EGCG-AMP combination showed enhanced efficacy compared to either treatment alone, as indicated by a fractional inhibitory concentration index between 0.009 and 0.018. The most pronounced synergy was observed in 13 drug-resistant strains, where the MIC for EGCG dropped to 8 µg/mL (from 1 mg/mL alone) and that for AMP to 50 µg/mL (from 50 mg/mL alone), achieving a 125-fold and 1000-fold reduction, respectively. Time-kill assays revealed that the bactericidal effect of the EGCG-AMP combination occurred within 2 h. The mechanism of EGCG action includes the disruption of membrane permeability and biofilm eradication in a dose-dependent manner. SEM confirmed that the combination treatment consistently outperformed the individual treatments. This study underscores the potential of restoring AMP efficacy in combination with EGCG as a promising strategy for treating MDR E. coli infections.

Epigallocatechin gallate boosted Fe(II) activated peracetic acid process for coumarin degradation: Performance and mechanisms investigation

The Fe(II)/peracetic acid (PAA) process shows significant potential for the removal of organic pollutants due to the rapid reaction between Fe(II) and PAA. However, the slow reduction from Fe(III) to Fe(II) leads to the continuous or excess dosing of Fe(II) during practical application. In this study, epigallocatechin gallate (EGCG), a typical reagent extracted from green tea, was used to enhance the degradation of coumarin (COU) by Fe(II)/PAA for the first time. A complete elimination of COU (25 μM) was achieved in the presence of 50 μM Fe(II), 300 μM PAA, and 25 μM EGCG, exhibiting a kobs value of 0.108 min−1, which was 27 times higher than that observed with Fe(II)/PAA (0.004 min−1). Further, Fe(II)/EGCG/PAA demonstrated remarkable pH tolerance, with a COU removal efficiency exceeding 80 % across a pH range of 3–9. Mechanisms investigations revealed that •OH played a dominant role in COU degradation by Fe(II)/EGCG/PAA (accounting for 98.2 %). The increase in EGCG concentration from 10 to 100 μM resulted in a decreased formation of •OH yield and an enhanced generation of RO•. These findings highlight the capability of EGCG to improve the oxidation capacity of Fe(II)/PAA and modulate reactive species formation. The outstanding oxidation capacity and environmental friendliness of Fe(II)/EGCG/PAA process render it a potential strategy to eliminate organic pollutants in actual water treatment.

CsWRKY12 interacts with CsVQ4L to promote the accumulation of galloylated catechins in tender leaves of tea plants.

Galloylated catechins in tea leaves, primarily epigallocatechin-3-gallate (EGCG) and epicatechin gallate (ECG), possess prominent biological activities. It is well established that EGCG and ECG are abundantly present in tender leaves but are less prevalent in mature leaves. However, the fundamental regulatory mechanisms underlying this distribution remain unknown. In this study, we integrated transcriptome data and catechin component levels in tea leaves from six leaf positions using weighted gene co-expression network analysis. This analysis revealed a positive correlation between variations in CsWRKY12 expression and EGCG and ECG levels. Further investigation using yeast one-hybrid and dual-luciferase assays, as well as electrophoretic mobility shift assay, demonstrated that CsWRKY12 activated the transcription of CsSCPL4 and CsSCPL5, which encode enzymes responsible for galloylated catechins biosynthesis, by directly binding to W-box elements in their promoters. Overexpression of CsWRKY12 in tea leaves promoted the expression of CsSCPL4 and CsSCPL5, leading to an increase in EGCG and ECG content. Moreover, we found that a VQ motif-containing protein, CsVQ4L, interacted with CsWRKY12 and facilitated its transcriptional function by regulating the expression of CsSCPL4 and CsSCPL5. Collectively, our findings suggest that the interaction between CsWRKY12 and CsVQ4L contributes to the accumulation of galloylated catechins in tender leaves of tea plants.

Biophysical Analysis of EGCG’s Protective Effects on Camptothecin-Induced Oxidative Stress in Bone-like Cancer Cells Using Electric Cell-Substrate Impedance Sensing (ECIS)

Various medical treatments aim to counteract the impact of oxidants on mammalian cells. One such antioxidant is Epigallocatechin-3-gallate (EGCG), an active ingredient in green tea, which has demonstrated protective effects against cellular oxidants like camptothecin (CAMPT). This study examines how EGCG mitigates CAMPT’s effects on UMR cells, focusing on cell proliferation and biophysical parameters. UMR cells were treated with different CAMPT concentrations and incubated for 72 h. Subsequently, cell proliferation and viability were assessed. In a separate experiment, UMR cells were co-treated with CAMPT and varying EGCG concentrations to evaluate EGCG’s ability to mitigate CAMPT’s oxidative effect. Electric Cell–Substrate Impedance Sensing (ECIS) technology was also used to assess the biophysical parameters of CAMPT-treated UMR cells, including cell monolayer resistance, cell spreading, and cell attachment. The results showed a concentration-dependent decrease in cell proliferation for CAMPT-treated UMR cells. However, co-treatment with EGCG reversed CAMPT’s oxidative effects in a concentration-dependent manner. ECIS technology revealed a decrease in biophysical parameters when UMR cells were treated with CAMPT alone. Statistical analysis indicated significant differences with p-values &lt; 0.05. This study suggests that EGCG effectively protects UMR cells from oxidative stress and highlights its potential role in mitigating oxidative stress in mammalian cells. Additionally, the use of ECIS technology validates its application in corroborating the biological effects of CAMPT and EGCG on UMR cells.

Inhibitory effects of polyphenols on the Maillard reaction in low-lactose milk and the underlying mechanism

In this study, low lactose milk (LLM) was heat-treated under different conditions and stored at 4, 25 and 37°C for 15 d, after which the changes in the Maillard reaction (MR) of LLM were investigated. The contents of α-dicarbonyl compounds and 5-hydroxymethylfurfural(5-HMF) in LLM after the addition of polyphenols were determined via HPLC, and the inhibitory effects of 3 different concentrations of epigallocatechin gallate (EGCG), dihydromyricetin (DMY), and procyanidin (PC) on the MR of LLM were studied. The fluorescence intensity of LLM was measured at 290, 300 and 310 K, the fluorescence quenching types and binding constants of PC on casein were investigated, and thermodynamic analysis was carried out. These results suggest that the optimal heat treatment conditions were 80°C for 15 s and that the optimal storage conditions were 4°C. In the α-dicarbonyl compound capture and 5-HMF inhibition tests, PC had the greatest inhibitory effect at a concentration of 0.2 mg/mL, with an inhibition rate of 48.19%. Therefore, PC is more stable than the other 2 polyphenols. The mechanism of inhibition involves the formation of matrix complexes between PC and casein in LLM, resulting in static quenching of the LLM and thus a reduction of the inhibitory effect. The thermodynamic analysis revealed that the binding of PC to casein was an exothermic reaction, and the combination of the 2 was driven mainly by hydrogen bonding and van der Waals forces. This study lays a theoretical foundation for the development of LLM.

Cold plasma-induced covalent binding with epigallo-catechin 3-gallate: A strategy for antigenicity reduction and antioxidant improvement of β-lactoglobulin

The application of cold plasma (CP) treatment was investigated for its effectiveness in promoting the covalent grafting of β-lactoglobulin (β-LG) and epigallo-catechin 3 -gallate (EGCG), as well as improving the antioxidant capacity of β-LG and eliminating its antigenicity. The results indicated that CP treatment significantly enhanced the covalent grafting of β-LG and EGCG. The maximum EGCG content in β-LG-EGCG complexes reached 47.08 ± 0.58 mg/g (with 45 s treatment), as confirmed by SDS-PAGE analysis and FTIR spectroscopy. Additionally, LC-MS/MS identifies two binding sites (T76 and K77) of EGCG in the β-LG-EGCG conjugates. After 60 s treatments, there was a significant reduction in the IgG binding capacity of β-LG-EGCG conjugates (29.97 ± 0.05%). Further analysis suggested that the change in the conformational epitopes of β-LG, due to the conjugating with EGCG, was likely the main factor responsible for the reduced binding Immunoglobulin G (IgG) capacity. The maximum antioxidant activities of β-LG-EGCG conjugates were found to be 974.14 ± 1.94 μmol TE g−1 for ABTS and 748.48 ± 9.66 μmol TE g−1 for DPPH). These values represent an eightfold increase in DPPH activity and a twofold increase in ABTS compared to the control sample. This study demonstrated that the CP treatment is highly effective technology for facilitating the covalent grafting of polyphenols to proteins, thereby enhancing their antioxidant properties and eliminate their antigenicity.

EGCG inhibits migration, invasion and epithelial-mesenchymal transition of renal cell carcinoma by activating TFEB-mediated autophagy

BackgroundThe incidence of renal cell carcinoma (RCC) is already in the top ten of all types of cancers, with more than 4 %. Epigallocatechin gallate (EGCG), a polyphenolic compound extracted from green tea, has been shown to be effective in the treatment of various tumors. However, limited studies have demonstrated the effect of EGCG on RCC and its underlying molecular mechanisms. MethodsAfter exposure to gradient concentration (0,5,10,20,40,60,80,100 μM) of EGCG, the cell viability of RCC cells was determined by MTT assay. The migration and invasion abilities of RCC cells were investigated by wound healing and transwell assays. The expression levels of proteins involved in the epithelial-mesenchymal transition (EMT) and autophagy were explored by Western blotting assays. The formation of autophagosome was detected by electron microscope and LC3 puncta assays. Nude mouse xenograft model was used as the model system in vivo. ResultsIn the present study, EGCG significantly inhibited the migration, invasion and EMT of RCC cells in a concentrated manner. Further exploration of its mechanism indicated that autophagy is involved in EGCG-mediated metastasis inhibition and EMT inhibition of RCC cells. In addition, EGCG could significantly up-regulate the transcription factor EB (TFEB) and promotes its nuclear localization. The incorporation of TFEB into the nucleus enhanced the transcriptional levels of molecules associated with autophagy. TFEB knockdown inhibited EGCG-mediated autophagy activation, metastasis and EMT inhibition in RCC cells. ConclusionsIn conclusion, these findings demonstrate for the first time that EGCG inhibits migration, invasion, and EMT of RCC by activating TFEB-mediated autophagy. Therefore, the combination of EGCG and TFFB activators or EMT inhibitors is expected to be a promising therapeutic strategy for RCC.

Barnacle-inspired and polyphenol-assisted modification of bacterial cellulose-based wound dressings for promoting infectious wound healing

Bacterial cellulose (BC) is an ideal candidate for wound dressings due to its natural origin, exceptional water-holding capacity, pliability, biocompatibility, and high absorption capability. However, the lack of essential antimicrobial activity limits its biomedical applications. This study reported BC-based wound dressings containing silk fibroin protein (SF), offering the potential for biomimetic properties, and (−)-epigallocatechin-3-gallate (EGCG) for polyphenol-assisted surface modification to promote infectious wound healing. Glycerol was used as the carbon source to promote the formation of an adhesive layer by facilitating the β-sheet folding of SF, and different concentrations of EGCG were employed to interact with SF through strong hydrogen bonding facilitated by the polyphenolic groups. The functionalized membrane exhibited outstanding water-holding capacity, swelling ratio, and degradation properties, along with enhanced hydrophilicity, adhesiveness, and a remarkable free radical scavenging ability. Both in vitro and in vivo experiments confirmed its potent bacteriostatic activity. The composite membrane displayed excellent biocompatibility, including cellular and hemocompatibility. Importantly, it effectively promoted wound healing in murine back infections. These findings suggest the significant feasibility of the innovative modification approach, and that functionalized membranes have great potential as wound-dressing materials for infection management in future clinical applications.

In Vitro Effect of Epigallocatechin Gallate on Heme Synthesis Pathway and Protoporphyrin IX Production.

Photodynamic therapy (PDT) treats nonmelanoma skin cancer. PDT kills cells through reactive oxygen species (ROS), generated by interaction among cellular O2, photosensitizer and specific light. Protoporphyrin IX (PpIX) is a photosensitizer produced from methyl aminolevulinate (MAL) by heme group synthesis (HGS) pathway. In PDT-resistant cells, PDT efficacy has been improved by addition of epigallocatechin gallate (EGCG). Therefore, the aim of this work is to evaluate the effect of EGCG properties over MAL-TFD and PpIX production on A-431 cell line. EGCG's role over cell proliferation (flow cytometry and wound healing assay) and clonogenic capability (clonogenic assay) was evaluated in A-431 cell line, while the effect of EGCG over MAL-PDT was determined by cell viability assay (MTT), PpIX and ROS detection (flow cytometry), intracellular iron quantification and gene expression of HGS enzymes (RT-qPCR). Low concentrations of EGCG (<50 µM) did not have an antiproliferative effect over A-431 cells; however, EGCG inhibited clonogenic cell capability. Furthermore, EGCG (<50 µM) improved MAL-PDT cytotoxicity, increasing PpIX and ROS levels, exerting a positive influence on PpIX synthesis, decreasing intracellular iron concentration and modifying HGS enzyme gene expression such as PGB (upregulated) and FECH (downregulated). EGCG inhibits clonogenic capability and modulates PpIX synthesis, enhancing PDT efficacy in resistant cells.

Smartphone-assisted colorimetric biosensor for the rapid visual detection of natural antioxidants in food samples

Quantitative monitoring of the concentrations of epigallocatechin gallate (EGCG) and cysteine (Cys) is of great significance for promoting human health. In this study, iron/aluminum bimetallic MOF material MIL-53 (Fe, Al) was rapidly prepared under room temperature using a co-precipitation method, followed by investigating the peroxidase-like (POD-like) activity of MIL-53(Fe, Al) using 3,3',5,5'-tetramethylbenzidine (TMB) as a chromogenic substrate. The results showed that the Michaelis -Menten constants of TMB and H2O2 as substrates were 0.167 mM and 0.108 mM, respectively. A colorimetric sensing platform for detecting EGCG and Cys was developed and successfully applied for analysis and quantitative detection using a smartphone. The linear detection range for EGCG was 15∼80 μM (R2=0.994) and for Cys was 7∼95 μM (R2=0.998). The limits of detection (LOD) were 0.719 μM and 0.363 μM for EGCG and Cys, respectively. This work provides a new and cost-effective approach for the real-time analysis of catechins and amino acids.

Influence of EGCG (Epigallocatechin Gallate) on Physicochemical-Rheological Properties of Surimi Gel and Mechanism Based on Molecular Docking.

The influence of epigallocatechin gallate (EGCG) on the physicochemical-rheological properties of silver carp surimi gel was investigated. The gel strength, texture, water-holding capacity (WHC), dynamic distribution of water, and rheological properties of surimi gels added with different levels (0, 0.02, 0.04, 0.06, 0.08, and 0.1%) of EGCG were measured. The results showed that with the increase of EGCG content, the gel strength, hardness, WHC, and immobilized water contents of surimi gels showed a trend of first increasing and then decreasing, and EGCG 0.02% and EGCG 0.04% showed better gel performance as compared with the control. EGCG 0.02% had the highest gel strength (406.62 g·cm), hardness (356.67 g), WHC (64.37%), and immobilized water contents (98.958%). The gel performance decreased significantly when the amounts of EGCG were higher than 0.06%. The viscosity, G', and G″ of the rheological properties also showed the same trends. The chemical interaction of surimi gels, secondary structure of myofibrillar protein (MP), and molecular docking results of EGCG and silver carp myosin showed that EGCG mainly affected the structure and aggregation behavior of silver carp myosin through non-covalent interactions such as those of hydrogen bonds, hydrophobic interactions, and electrostatic interactions. The microstructures of EGCG 0.02% and EGCG 0.04% were compact and homogeneous, and had better gel formation ability. The lower concentrations of EGCG formed a large number of chemical interactions such as those of disulfide bonds and hydrophobic interactions inside the surimi gels by proper cross-linking with MP, and also increased the ordered β-sheet structure of MP, which facilitated the formation of the compact three-dimensional network gel.

Reducing the Allergenicity of β-Lactoglobulin by Covalent Modification with Different Contents of Epigallocatechin Gallate (EGCG): In Vitro and In Vivo Studies.

β-Lactoglobulin (βLG) is a major allergen in bovine milk protein. This study was designed to investigate changes in βLG structure, digestibility, and allergenicity induced by covalent binding modification with different contents of (-)-epigallocatechin 3-gallate (EGCG). The reaction of EGCG conjugation with βLG reached saturation at a molar ratio of 1:60 βLG:EGCG. Conjugation with EGCG altered the βLG structure, decreased IgE-binding capacity, and increased digestibility in a dose-dependent manner. In vivo studies showed that covalent conjugation with EGCG can reduce βLG-induced allergic symptoms with reducing levels of IgE, histamine, and mast cell protease-1 (mMCP-1) and the percentage of sensitized mast cells. Allergenicity was reduced more effectively in saturated βLG-EGCG conjugates compared to semisaturated conjugates. Observed changes in IFN-γ, IL-4, IL-5, IL-10, and TGF-β levels suggested that βLG-EGCG conjugates were able to promote Th1/Th2 immune balance. These findings further our understanding of the relationship between the degree of polyphenol conjugation and the allergenicity of food allergens.

Formation mechanism of injured bacteria after disinfection with epigallocatechin gallate (EGCG) as a disinfectant

ABSTRACT This study explored the effects of epigallocatechin gallate (EGCG), the main antibacterial component of tea polyphenols, on Escherichia coli in terms of disinfection damage and the underlying mechanisms. The researchers assessed inactivation and injury rates, cell morphology, and antioxidant indicators of E. coli when subjected to different concentrations of EGCG. The results showed that varying EGCG concentrations produced damaged bacteria, with the extent of damage depending on EGCG dosage and treatment duration. The disinfection process involving EGCG resulted in oxidative damage in E. coli, evoking alterations in the antioxidant system of the affected bacteria. During disinfection-induced bacterial injury, E. coli showed the active regulation of metabolism and redox activities in response to EGCG-induced environmental stimuli. Transcriptomic analysis was conducted to investigate the damage mechanism at the gene level. The damaged E. coli countered oxidative stress by adjusting gene expression related to peroxidase and glutathione metabolism processes. In this way, E. coli adjusts its gene expression to alleviate the detrimental effects of EGCG-induced oxidative stress and maintain cellular homeostasis. These findings contribute to our understanding of tea polyphenols' disinfection effects and provide insights into EGCG's mechanisms of damaging bacteria such as E. coli.

Unveiling the therapeutic potential of epigallocatechin gallate in liver cancer: insights from network pharmacology and in vitro assays

Epigallocatechin gallate (EGCG) is a prominent catechin found in green tea polyphenols and has shown promising anti-tumor properties. However, the exact regulatory mechanism of EGCG on liver cancer is not fully revealed. In this study, we conducted integrative analyses using the SwissTargetPrediction and GeneCards repositories, which identified 98 targets. These targets were used to construct a protein-protein interaction network using STRING and visualised with Cytoscape. Central to this network are hub proteins, notably TNF and PIK3CA, suggesting pivotal roles in the therapeutic landscape. Gene Ontology (GO) enrichment analysis unveiled 1,570 biological terms with a notable preponderance within oxidative stress response processes. Complementary pathway enrichment via the Kyoto Encyclopaedia of Genes and Genomes (KEGG) highlighted 134 pathways, with the PI3K-Akt pathway emerging as prominent. In silico molecular docking supported these findings, revealing binding energies of EGCG-target complexes below −7.0 kcal/mol, indicative of robust interactions. Moreover, cellular assays including CCK-8, wound-healing, and Transwell modalities, established EGCG’s inhibitory concentration-dependent effects on HepG2 cell proliferation, migration, and invasion. Apoptotic assays affirmed by FACS, evidenced enhanced apoptosis with escalating EGCG concentrations, underpinned by modulations in caspase activity and apoptotic protein levels. Notably, Western blot analysis demonstrated the attenuation of the PI3K/AKT signalling cascade by EGCG, paralleling the inhibitory profile of LY294002. These multifaceted inhibitory effects underscore EGCG's potential as an anti-tumor agent, deploying a strategic blockade of oncogenic pathways and augmenting apoptotic mechanisms, which provide a strong rationale for its application in liver cancer therapeutics.

Conjugation of Lysozyme and Epigallocatechin Gallate for Improving Antibacterial and Antioxidant Properties.

One of the main interests in the food industry is the preservation of food from spoilage by microorganisms or lipid oxidation. A novel alternative is the development of additives of natural origin with dual activity. In the present study, a chemically modified lysozyme (Lys) with epigallocatechin gallate (EGCG) was developed to obtain a conjugate (Lys-EGCG) with antibacterial/antioxidant activity to improve its properties and increase its application potential. The modification reaction was carried out using a free radical grafting method for the Lys modification reaction, using ascorbic acid and hydrogen peroxide as radical initiators in an aqueous medium. The synthesis of Lys-EGCG conjugate was confirmed by spectroscopic (FT-IR, 1H-RMN, and XPS) and calorimetry differential scanning (DSC) analyses. The EGCG binding to the Lys biomolecule was quantified by the Folin-Ciocalteu method; the antibacterial activity was evaluated by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MCB) against Staphylococcus aureus and Pseudomonas fluorescens; the antioxidant activity was evaluated by ABTS, DPPH, and FRAP. The spectroscopic results showed that the Lys-EGCG conjugate was successfully obtained, and the DSC analysis revealed a 20°C increase (P < 0.05) in the denaturation temperature of Lys due to EGCG modification. The EGCG concentration in Lys-EGCG was 97.97 ± 4.7µmol of EGCG/g of sample. The antibacterial and antioxidant activity of the Lys-EGCG conjugate was higher (P < 0.05) than pure EGCG and Lys. The chemical modification of Lys with EGCG allows for the bioconjugate with a dual function (antibacterial/antioxidant), broadening the range of Lys and EGCG applications to different areas such as food, cosmetic, and pharmaceutical industries.

EGCG induced the formation of protein nanofibrils hydrogels with enhanced anti-bacterial activity

The functional properties of the amyloid fibrils could be further improved after physical modification. Simply adding epigallocatechin gallate (EGCG) to ovalbumin amyloid fibrils (OAFs) could successfully drive the formation of hydrogels through the self-assembly of hybrid supermolecules, however the functional properties of amyloid fibrils as well as the underlying formation mechanisms have not been well revealed. In present study, the rheological properties, thermal stability, and morphology of the resulting OAFs hydrogels were investigated, and the secondary structural changes of the proteins in OAFs hydrogels was analyzed. The results showed that the addition of EGCG would affect the diameter of OAFs, mainly as the concentration of EGCG increased from 0.1% to 2%, the diameter of OAFs increased from 3 nm to 5.5 nm. In addition, when the EGCG concentration increased from 0.1% to 0.5%, the content of β-sheet structure increased from 24.3% to 43.7%. Moreover, the OAFs hydrogels exhibited good viscoelasticity and heat resistance, as well as displayed good antioxidant activity and strong anti-bacterial activity against both Gram-negative and Gram-positive bacteria. The present study might provide a theoretical basis for antimicrobial food packaging based on animal amyloid fibrils hydrogels.

Factors influencing the inactivation of Bacillus subtilis by epigallocatechin gallate (EGCG)

ABSTRACT Epigallocatechin gallate (EGCG) is an exceptional plant polyphenol for drinking water disinfection, due to its lasting antibacterial capabilities and broad spectrum of health benefits. Nevertheless, its effectiveness and the underlying mechanisms against chlorine-resistant bacteria, such as Bacillus subtilis, have not been thoroughly explored under various water conditions. The study at hand probed the inactivation rates of EGCG on B. subtilis was subjected to different concentrations, contact times, acidic or basic environments, and temperatures; biological mechanisms were examined by analyzing alkaline phosphatase, proteins, glucose, ATP, and redox biomolecules. Results indicated a positive correlation between EGCG concentration and the inactivation rate of B. subtilis, with the rate notably rising at EGCG levels below 800 mg/l and under acidic pH. The inactivation efficiency increased with temperature increments from 25 to 45 °C. Moreover, EGCG exerted a detrimental impact on the structural integrity, energy metabolism, and the antioxidant defense system of B. subtilis showed a dose-dependent antimicrobial activity against Escherichia coli. Consequently, this study provides a strong foundation for evaluating EGCG's efficacy against chlorine-resistant bacteria, promoting its theoretical application for drinking water treatment and guiding methodological advancements for broader applications.

Formation of pea protein amyloid-like nanofibrils-derived hydrogels mediated by epigallocatechin gallate

This study investigated the interaction between pea protein amyloid-like nanofibril and epigallocatechin gallate, constructed and characterized the novel pea protein nanofibrils-derived hydrogel mediated by epigallocatechin gallate, and researched the functionalities of the hydrogel. Epigallocatechin gallate remodeled the structure of pea protein nanofibrils, and a stable and strong hydrogel was formed at a relatively low protein concentration (4.5%). Additionally, the hydrogels exhibited various surface structures and hydrogel properties dependent on the mass ratio. Strongest gel strength (51 g) was attained at 0.25 epigallocatechin gallate/pea protein nanofibrils mass ratio. Whereas, the hydrogels exhibited the highest water holding capacity (87%) at 0.05 mass ratio. The primary driving forces in the formation and maintaining of the hydrogels were hydrophobic interactions and ionic bonds. Progressive rise of β-sheet content of pea protein nanofibrils occurred increasing epigallocatechin gallate concentration. This hydrogel holds great potential for applications in food processing, targeted delivery of nutraceuticals and biomedicine.