Concentrations Of Epigallocatechin-3-gallate Research Articles

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.

Inhibited the walnut oil oxidation through the microcapsules that consisted of (−)-Epigallocatechin gallate and sodium caseinate

(−)-Epigallocatechin gallate (EGCG) possesses potent antioxidant properties and can enhance the encapsulation efficiency and stability of oil microcapsule with sodium caseinate (NaCas). Hence, the present study aimed to investigate the effects of different concentrations of EGCG on the physicochemical properties of walnut oil microcapsules. The impact of EGCG on the morphology, structure, physical attributes, and functional traits of walnut oil microcapsules was characterized through scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, molecular docking, thermogravimetric analysis, etc. Results demonstrated that EGCG interacted with NaCas via hydrogen bonding and hydrophobic interactions to form walnut oil microcapsules, significantly enhancing the encapsulation efficiency up to 86.42%. With increasing concentration of EGCG, the NaCas-EGCG complex displayed heightened DPPH free radical scavenging capacity (up to 68.27 μg Trolox/mL). Furthermore, in vitro digestion indicated that the microcapsules could effectively regulate the release rate of free fatty acids. In conclusion, the present study successfully prepared walnut oil microcapsules with elevated oxidative stability by employing EGCG and NaCas as the wall materials, providing new insight for preparing walnut oil microcapsules with improved stability and release properties.

Epigallocatechin gallate modulates ferroptosis through downregulation of tsRNA-13502 in non-small cell lung cancer

Ferroptosis, an iron-dependent regulated cell death mechanism, holds significant promise as a therapeutic strategy in oncology. In the current study, we explored the regulatory effects of epigallocatechin gallate (EGCG), a prominent polyphenol in green tea, on ferroptosis and its potential therapeutic implications for non-small cell lung cancer (NSCLC). Treatment of NSCLC cell lines with varying concentrations of EGCG resulted in a notable suppression of cell proliferation, as evidenced by a reduction in Ki67 immunofluorescence staining. Western blot analyses demonstrated that EGCG treatment led to a decrease in the expression of glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) while increasing the levels of acyl-CoA synthetase long-chain family member 4 (ACSL4). These molecular changes were accompanied by an increase in intracellular iron, malondialdehyde (MDA), and reactive oxygen species (ROS), alongside ultrastructural alterations characteristic of ferroptosis. Through small RNA sequencing and RT-qPCR, transfer RNA-derived small RNA 13502 (tsRNA-13502) was identified as a significant target of EGCG action, with its expression being upregulated in NSCLC tissues compared to adjacent non-tumorous tissues. EGCG was found to modulate the ferroptosis pathway by downregulating tsRNA-13502 and altering the expression of key ferroptosis regulators (GPX4/SLC7A11 and ACSL4), thereby promoting the accumulation of iron, MDA, and ROS, and ultimately inducing ferroptosis in NSCLC cells. This study elucidates EGCG’s multifaceted mechanisms of action, underscoring the modulation of ferroptosis as a viable therapeutic approach for enhancing NSCLC treatment outcomes.

Comparative study on dynamic in vitro digestion characteristics of lotus seed starch-EGCG complex prepared by different processing methods

To study the effect of starch-polyphenol interaction induced by different processing methods on digestion characteristics, a dynamic in vitro human gastrointestinal system was employed to investigate the digestive characteristics of lotus seed starch–epigallocatechin gallate (EGCG) complex (LS–EGCG) prepared by different processing methods. Digestion altered crystal structure, particle size, morphology, pH, starch hydrolysis, and EGCG content. Processing broke physical barriers, reducing particle size by enzyme erosion. Enzymatic hydrolysis gradually exposed EGCG, indicated by green fluorescence. Heat and high pressure treatments enhanced starch dissolution, increasing sugar accumulation and hydrolysis. However, ultrasonic-microwave and high pressure microfluidization treatments formed dense structures, decreasing hydrolysis rates. Overall, the complex formed by high pressure microfluidization showed better enzyme resistance. The results provide a scientific basis for the development of food with quality and functional properties.

Simultaneous Determination of Four Catechins in Black Tea via NIR Spectroscopy and Feature Wavelength Selection: A Novel Approach.

As a non-destructive, fast, and cost-effective technique, near-infrared (NIR) spectroscopy has been widely used to determine the content of bioactive components in tea. However, due to the similar chemical structures of various catechins in black tea, the NIR spectra of black tea severely overlap in certain bands, causing nonlinear relationships and reducing analytical accuracy. In addition, the number of NIR spectral wavelengths is much larger than that of the modeled samples, and the small-sample learning problem is rather typical. These issues make the use of NIRS to simultaneously determine black tea catechins challenging. To address the above problems, this study innovatively proposed a wavelength selection algorithm based on feature interval combination sensitivity segmentation (FIC-SS). This algorithm extracts wavelengths at both coarse-grained and fine-grained levels, achieving higher accuracy and stability in feature wavelength extraction. On this basis, the study built four simultaneous prediction models for catechins based on extreme learning machines (ELMs), utilizing their powerful nonlinear learning ability and simple model structure to achieve simultaneous and accurate prediction of catechins. The experimental results showed that for the full spectrum, the ELM model has better prediction performance than the partial least squares model for epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), and epigallocatechin gallate (EGCG). For the feature wavelengths, our proposed FIC-SS-ELM model enjoys higher prediction performance than ELM models based on other wavelength selection algorithms; it can simultaneously and accurately predict the content of EC (Rp2 = 0.91, RMSEP = 0.019), ECG (Rp2 = 0.96, RMSEP = 0.11), EGC (Rp2 = 0.97, RMSEP = 0.15), and EGCG (Rp2 = 0.97, RMSEP = 0.35) in black tea. The results of this study provide a new method for the quantitative determination of the bioactive components of black tea.

CONTENT OF CATECHINS IN LEAVES AND ROOTS OF COMARUM SALESOVIANUM AND COMARUM PALUSTRE (ROSACEAE)

The search for additional sources of catechins among the local flora is relevant today. The method for determining the content of catechins by the spectrophotometric method in the leaves of the subshrub Zalesov's cinquefoil (Comarum salesovianum (Steph.) Asch. et Graebn.) from the Rosaceae Juss. family was validated. The content of catechins in terms of (±)-catechin in the leaves and rhizomes of two species of the genus Comarum ‒ C. salesovianum and C. palustre L. (marsh cinquefoil) was studied. The highest content of catechins was found in the roots of C. palustre (4%) and leaves of C. salesovianum (2.58%). A method for determining the composition and content of individual catechins in the leaves and roots of two representatives of the genus Comarum by high-performance liquid chromatography has been proposed. Three catechins [(±)-catechin, epigallocatechin gallate and (-)-epicatechin] were found in leaves and roots. (±)-catechin and (-)-epicatechin are predominant in the leaves and roots of C. palustre and C. salesovianum. The content of epigallocatechin gallate does not exceed 0.1 mg/g. The concentration of (±)-catechin is highest in the roots (1.21 mg/g) of C. palustre, and (-)-epicatechin is highest in the leaves (1.35 mg/g) of C. salesovianum.

Biomimetic Approach for Enhanced Mechanical Properties and Stability of Self-Mineralized Calcium Phosphate Dibasic–Sodium Alginate–Gelatine Hydrogel as Bone Replacement and Structural Building Material

Mineralized materials are gaining increased interest recently in a number of fields, especially in bone tissue engineering as bone replacement materials as well as in the architecture-built environment as structural building materials. Until the moment, there has not been a unified sustainable approach that addresses this multi-scale application objective by developing a self-mineralized material with minimum consumption of materials and processes. Thus, in the current study, a hydrogel developed from sodium alginate, gelatine, and calcium phosphate dibasic (CPDB) was optimized in terms of rheological properties and mineralization capacity through the formation of hydroxyapatite crystals. The hydrogel composition process adopted a three-stage, thermally induced chemical cross-linking to achieve a stable and enhanced hydrogel. The 6% CPDB-modified SA–gelatine hydrogel achieved the best rheological properties in terms of elasticity and hardness. Different concentrations of epigallocatechin gallate were tested as well as a rheological enhancer to optimize the hydrogel and to boost its anti-microbial properties. However, the results from the addition of EPGCG were not considered significant; thus, the 6% CPDB-modified SA–gelatine hydrogel was further tested for mineralization by incubation in various media, without and with cells, for 7 and 14 days, respectively, using scanning electron microscopy. The results revealed significantly enhanced mineralization of the hydrogel by forming hydroxyapatite platelets of the air-incubated hydrogel (without cells) in non-sterile conditions, exhibiting antimicrobial properties as well. Similarly, the air-incubated bioink with osteosarcoma SaOs-2 cells exhibited dense mineralized topology with hydroxyapatite crystals in the form of faceted spheres. Finally, the FBS-incubated hydrogel and FBS-incubated bioink, incubated for 7 and 14 days, respectively, exhibited less densely mineralized topology and less distribution of the hydroxyapatite crystals. The degradation rate of the hydrogel and bioink incubated in FBS after 14 days was determined by the increase in dimensions of the 3D-printed samples, which was between 5 to 20%, with increase in the bioink samples dimensions in comparison to their dimensions post cross-linking. Meanwhile, after 14 days, the hydrogel and bioink samples incubated in air exhibited shrinkage: a 2% decrease in the dimensions of the 3D-printed samples in comparison to their dimensions post cross-linking. The results prove the capacity of the developed hydrogel in achieving mineralized material with anti-microbial properties and a slow-to-moderate degradation rate for application in bone tissue engineering as well as in the built environment as a structural material using a sustainable approach.

Phase I/II clinical trial of efficacy and safety of EGCG oxygen nebulization inhalation in the treatment of COVID-19 pneumonia patients with cancer

BackgroundThe antiviral drug Nirmatrelvir was found to be a key drug in controlling the progression of pneumonia during the infectious phase of COVID-19. However, there are very few options for effective treatment for cancer patients who have viral pneumonia. Glucocorticoids is one of the effective means to control pneumonia, but there are many adverse events. EGCG is a natural low toxic compound with anti-inflammatory function. Thus, this study was designed to investigate the safety and efficacy of epigallocatechin-3-gallate (EGCG) aerosol to control COVID-19 pneumonia in cancer populations.MethodsThe study was designed as a prospective, single-arm, open-label phase I/II trial at Shandong Cancer Hospital and Institute, between January 5, 2023 to March 31,2023 with viral pneumonia on radiographic signs after confirmed novel coronavirus infection. These patients were treated with EGCG nebulization 10 ml three times daily for at least seven days. EGCG concentrations were increased from 1760-8817umol/L to 4 levels with dose escalation following a standard Phase I design of 3–6 patients per level. Any grade adverse event caused by EGCG was considered a dose-limiting toxicity (DLT). The maximum tolerated dose (MTD) is defined as the highest dose with less than one-third of patients experiencing dose limiting toxicity (DLT) due to EGCG. The primary end points were the toxicity of EGCG and CT findings, and the former was graded by Common Terminology Criteria for Adverse Events (CTCAE) v. 5.0. The secondary end point was the laboratory parameters before and after treatment.ResultA total of 60 patients with high risk factors for severe COVID-19 pneumonia (factors such as old age, smoking and combined complications)were included in this phase I-II study. The 54 patients in the final analysis were pathologically confirmed to have tumor burden and completed the whole course of treatment. A patient with bucking at a level of 1760 umol/L and no acute toxicity associated with EGCG has been reported at the second or third dose gradients. At dose escalation to 8817umol/L, Grade 1 adverse events of nausea and stomach discomfort occurred in two patients, which resolved spontaneously within 1 hour. After one week of treatment, CT showed that the incidence of non-progression of pneumonia was 82% (32/39), and the improvement rate of pneumonia was 56.4% (22/39). There was no significant difference in inflammation-related laboratory parameters (white blood cell count, lymphocyte count, IL-6, ferritin, C-reactive protein and lactate dehydrogenase) before and after treatment.ConclusionAerosol inhalation of EGCG is well tolerated, and preliminary investigation in cancer population suggests that EGCG may be effective in COVID-19-induced pneumonia, which can promote the improvement of patients with moderate pneumonia or prevent them from developing into severe pneumonia.Trial registrationClinicalTrials.gov Identifier: NCT05758571. Date of registration: 8 February 2023.

Effects of the Taste Substances and Metal Cations in Green Tea Infusion on the Turbidity of EGCG-Mucin Mixtures.

Astringency has an important impact on the taste quality of tea infusion, a process which occurs when polyphenols complex with salivary proteins to form an impermeable membrane. (-)-Epigallocatechin gallate (EGCG) is the main astringent compound found in green tea and mucin is the main protein present in saliva. Determining the turbidity of EGCG-mucin mixtures is an effective method to quantify the astringency intensity of EGCG solutions. In this study, the effects of taste-related, substances present during green tea infusion, on the turbidity of EGCG-mucin mixtures was investigated under the reacting conditions of a pH value of 5.0, at 37 °C, and for 30 min. The results showed that epicatechins, caffeic acid, chlorogenic acid, and gallic acid reduced the turbidity of EGCG-mucin mixtures, while rutin increased turbidity. Metal ions increased the turbidity of EGCG-mucin mixtures. These can be arranged by effectiveness as Al3+ > K+ > Mg2+ > Ca2+. Caffeine, theanine, and sodium glutamate all decreased the turbidity values of EGCG-mucin mixtures, but sucrose had a weak effect. Further experiments confirmed that the turbidity of green tea infusion-mucin mixture indicated the astringent intensity of green tea infusion, and that the turbidity was significantly correlated with the contents of tea polyphenols and EGCG.

Epigallocatechin gallate modification of physicochemical, structural and functional properties of egg yolk granules

The aim of this study was to prepare protein-polyphenol covalent complexes by treating egg yolk granules (EYG) with alkali in the presence of epigallocatechin gallate (EGCG) and characterize the physicochemical, structural, and functional properties of these covalent complexes. Results revealed that the optimal covalent binding occurred when the concentration of EGCG reached 0.15% (w/w), resulting in a grafting rate of 1.51 ± 0.03%. As the amount of EGCG increased, corresponding increases were observed in the particle size and ζ-potential of the complexes, thereby enhancing their stability. Furthermore, our analysis using fluorescence spectroscopy, FTIR, SEM, and SDS-PAGE collectively demonstrated the formation of a covalent complex between EYG and EGCG. Notably, the covalent complexes exhibited improved antioxidant activity and emulsifying properties. Overall, this study establishes a theoretical framework for the future practical application of EYG, emphasizing the potential of EGCG to modify its structural and functional characteristics.