Concentrations Of Epigallocatechin-3-gallate Research Articles

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.

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 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.

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.

Shade responses and resistant mechanisms in Spatholobus suberectus

The medicinal plant Spatholobus suberectus Dunn is easily exposed to shade stress during growth, but its shade responses and shade stress resistant mechanisms have not been clarified. In this study, shade treatments including four attenuated sunlight intensities (100%, 60%, 40%, and 10%) and three shade durations (30 d, 45 d, and 60 d) were applied to S. suberectus. The shade-induced morphological indicators, phytohormonal regulations, metabolic flavonoids contents, transcriptomic flavonoid pathway gene expressions, and stress physiological changes of S. suberectus were analyzed. The putative promoter cis-regulatory elements (CREs) of 18 flavonoid biosynthetic pathway genes were identified. Results showed the stem growth indicators of S. suberectus were better at 40% light intensity. Phytohormones were involved in the shade-induced responses. Short-term shade (30 d) increased total flavonoids, gallated catechins and especially epigallocatechin gallate contents and favored for boosting medicinal value. Long-term shade (45 d, 60 d) tended to decrease flavonoids. The shade-induced flavonoids changes were attributed to their corresponding biosynthesizing genes expression variations. The high antioxidant capacity and the presence of phytohormone-, stress-, and development-related CREs provided the basis for stress resistance. In conclusion, the multiple responses under shade and the CREs analysis elucidated S. suberectus’ shade tolerance.

The antibacterial mechanism of (-)-epigallocatechin-3-gallate (EGCG) against Campylobacter jejuni through transcriptome profiling.

(-)-Epigallocatechin-3-gallate (EGCG) has been shown antibacterial activity against Campylobacter jejuni; however, the relevant antibacterial mechanism is unknown. In this study, phenotypic experiments and RNA sequencing were used to explore the antibacterial mechanism. The minimum inhibitory concentration of EGCG on C. jejuni was 32µg/mL. EGCG-treated was able to increase intracellular reactive oxygen species levels and decline bacterial motility. The morphology and cell membrane of C. jejuni after EGCG treatment were observed collapsed, broken, and agglomerated by field emission scanning electron microscopy and fluorescent microscopy. The RNA-seq analysis presents that there are 36 and 72 differential expressed genes after C. jejuni was treated by EGCG with the concentration of 16 and 32µg/mL, respectively. EGCG-treated increased the thioredoxin expression, which was a critical protein to resist oxidative stress. Moreover, downregulation of the flgH and flgM gene in flagellin biosynthesis of C. jejuni was able to impair the flagella, reducing cell motility and virulence. The primary antibacterial mechanism revealed by RNA-seq is that EGCG with iron-chelating activity competes with C. jejuni for iron, causing iron deficiency in C. jejuni, which potentially impacts the survival and virulence of C. jejuni. The results suggested a new direction for exploring the activity of EGCG against C. jejuni in the food industry. PRACTICAL APPLICATION: A deeper understanding of the antibacterial mechanism of EGCG against C. jejuni was more beneficial in improving the food safety, eliminating concerns about human health caused by C. jejuni in future food, and promoting the natural antibacterial agent EGCG application in the food industry.

Effect of epigallocatechin-3-gallate modification on the structure and emulsion stability of rice bran protein in the presence of soybean protein isolate

For improving the emulsion stability of rice bran protein (RBP), RBP was modified by different concentrations of epigallocatechin-3-gallate (EGCG) in the presence of soybean protein isolate (SPI), and RBP-EGCG-SPI conjugate was prepared by alkaline pH-shifting. The results showed that the addition of EGCG led to an increase in the bound phenol content and the flexibility of the secondary structure, a decrease in the free sulfhydryl and disulfide bond content of the RBP-EGCG-SPI conjugate. EGCG covalently bound to RBP and SPI through non-disulfide bonds. When the concentration of EGCG was 10 % (w/v), the emulsifying activity index and emulsion stability index of conjugate reached the maximum value (36.61 m2/g and 255.61 min, respectively), and the conjugate had the best emulsion stability. However, an EGCG concentration above 10 % (w/v) negatively affected the emulsion stability, with increasing particle size due to protein aggregation. Summarily, the modification of EGCG improved the emulsion stability of conjugate by regulating the spatial structure of RBP-EGCG-SPI conjugate. The work provided an important guide to further improve the emulsion stability of RBP.

Green Tea Catechins Decrease Solubility of Raloxifene In Vitro and Its Systemic Exposure in Mice.

Green tea is a widely consumed beverage. A recent clinical study reported green tea decreased systemic exposure of raloxifene and its glucuronide metabolites by 34-43%. However, the underlying mechanism(s) remains unknown. This study investigated a change in raloxifene's solubility as the responsible mechanism. The effects of green tea extract, (-)-epigallocatechin gallate (EGCG), and (-)-epigallocatechin (EGC) on raloxifene's solubility were assessed in fasted state simulated intestinal fluids (FaSSIF) and fed state simulated intestinal fluids (FeSSIF). EGCG and EGC represent green tea's main bioactive constituents, flavan-3-gallate and flavan-3-ol catechins respectively, and the tested concentrations (mM) match the µg/mg of each compound in the extract. Our mouse study (n = 5/time point) evaluated the effect of green tea extract and EGCG on the systemic exposure of raloxifene. EGCG (1mM) and EGC (1.27mM) decreased raloxifene's solubility in FaSSIF by 78% and 13%, respectively. Micelle size in FaSSIF increased with increasing EGCG concentrations (> 1000% at 1mM), whereas EGC (1.27mM) did not change micelle size. We observed 3.4-fold higher raloxifene solubility in FeSSIF compared to FaSSIF, and neither green tea extract nor EGCG significantly affected raloxifene solubility or micelle size in FeSSIF. The mice study showed that green tea extract significantly decreased raloxifene Cmax by 44%, whereas EGCG had no effect. Green tea extract and EGCG did not affect the AUC0-24h of raloxifene or the metabolite-to-parent AUC ratio. This study demonstrated flavan-3-gallate catechins may decrease solubility of poorly water-soluble drugs such as raloxifene, particularly in the fasted state.

Epigallocatechin-3-gallate combination on the growth of Enterococcus faecalis and cytotoxicity on fibroblast cells

Background: Calcium hydroxide is an ingredient that is often used in pulp capping procedures. Calcium hydroxide can cause chronic inflammation and has weak antibacterial properties against Enterococcus faecalis. Epigallocatechin-3-gallate (EGCG) has anti-inflammatory properties and antibacterial properties against Enterococcus faecalis bacteria. Materials applied to the oral cavity were non-cytotoxic, biocompatible and antibacterial. Purpose: To determine the inhibitory effect against Enterococcus faecalis bacterial growth and cytotoxic to fibroblast cells of calcium hydroxide and EGCG combination with various concentrations of EGCG solution 5 µg/mL, 10 µg/mL, 20 µg/mL. Method: Calcium hydroxide mixed with EGCG with EGCG concentration in distilled water, at 5 µg/mL, 10 µg/mL, 20 µg/mL concentrations. The inhibitory test was tested using Petri dishes with Mueller-Hinton agar, using a dilution method. Observation of the inhibition zone at Petri dishes was carried out by measuring the diameter around the well using calipers. The cytotoxicity test was tested on BHK-21 fibroblast cells using the MTT assay test. The Formazan optical density test indicated the number of live cells. Result: The result of the inhibitory test showed a significant difference between the calcium hydroxide-EGCG group. The cytotoxicity test showed that there was no significant difference in the percentage of living fibroblasts, after administration of the calcium hydroxide-EGCG combination.

Mechanisms underlying the effect of walnut pellicle extracts and its four representative polyphenols on in vitro digestion of walnut protein isolate

Walnut pellicle extracts (WPE) is rich in phenolic acids. The effects of WPE and its monomeric phenolics (ellagic acid (EA), (+)-catechin (CA), chlorogenic acid (CLA), and epigallocatechin gallate (EGCG)) on in vitro digestion of walnut protein isolate (WPI) were studied. The underlying mechanisms on WPI enzymatic digestion through WPE and pure phenolic compounds with digestive enzymes (pepsin and trypsin) therein using Michaelis-Menten kinetics, fluorescence quenching, molecules docking, and surface plasmon resonance (SPR). The in vitro digestibility of WPI decreased significantly by the addition of WPE. WPE had the strong inhibitory effect on WPI digestion and pepsin and trypsin activities. The effects of polyphenols on WPI digestibility were mainly manifested in the interaction between polyphenols and digestive enzymes. SPR as well as fluorescence quenching indicated that WPE bound to pepsin and trypsin was the strongest. Among the four phenolic compounds abundant in the tested WPE, EGCG inhibited pepsin and trypsin more strongly than the other three compounds. SPR showed that EGCG was bound more tightly to pepsin and trypsin than CLA, CA, and EA. In vitro WPI digestion was strongly inhibited by WPE, mainly due to its high content of EGCG, CLA, CA, and EA causing strong inhibition of pepsin and trypsin. The study investigated the influence of plant protein by phenolic acids in the human digestive system and providing a theoretical basis for the processing and manufacturing of polyphenol-rich nut-based functional foods.

Stability of Flavan-3-ols, Theaflavins, and Methylxanthines in 30 Industrial Green, Black, and White Tea (Camellia sinensis L.) Extracts Characterized via Liquid Chromatography Techniques.

Commercially available tea extracts for dietary supplements and nutraceuticals are standardized to characteristic components of Camellia sinensis L., such as epigallocatechin gallate (EGCG) and total catechins or polyphenols. However, since most commercial tea extracts are highly concentrated into only one molecule such as EGCG, the comparatively less stable catechin, the oxidative stability of the extract during the 24-month shelf life was questioned. It was hypothesized that the overall oxidative stability is reduced for highly purified/concentrated tea extracts due to the absence of other natural antioxidants stabilizing the complex mixture. Via liquid chromatographic analysis, the individual chromatographic profiles of 30 commercial white, green, and black tea extracts were evaluated and compared regarding oxidative stability and functional properties. The contents of bioactive flavan-3-ols, theaflavins, and methylxanthines differed much from what was claimed by the suppliers. At the end of the product shelf life, most of the commercial green and black tea extracts showed a decrease in the flavan-3-ol content, the main bioactive components of tea. A high EGCG content to the detriment of other possibly stabilizing flavan-3-ols or antioxidants in tea was found to explain the lower oxidative stability of such tea extract products. A natural overall composition of molecular structures was found to be superior to a strong enrichment in just one molecule.

#236 : Alleviating Effects of EGCG on Ovarian Hyperstimulation Syndrome and the Potential Modulating Mechanism

Background and Aims: Ovarian hyperstimulation syndrome (OHSS) is one of the most severe complications of COH during IVF treatment. Increased capillary permeability is a hallmark of the pathophysiology of OHSS, vascular endothelial growth factor (VEGF) is an important mediator in OHSS, and studies have established a correlation between serum VEGF levels and the severity of the OHSS. (-)-epigallocatechin-3-gallate (EGCG), the most prevalent and biologically active polyphenolic catechin in green tea, has been reported to produce a number of beneficial effects on humans. Numerous studies have shown that in many pathological processes, EGCG could inhibit VEGF and its receptor expression and have an angiogenesis effect. Herein, EGCG might have a therapeutic effect on OHSS. Methods: We investigated the role of EGCG in OHSS both in vitro and in vivo. Primary human granulosa-lutein (hGL) cells and a human granulosa-like tumor (KGN) cell line were cultured and treated for 24 hours with various concentrations of EGCG. In SD rats, an animal OHSS model was established by injecting pregnant mare serum gonadotropin (PMSG) and randomly assigning them to receive vehicle only or EGCG for three days. For comparison, all experiments were repeated 3-8 times. The effect of EGCG on KGN and hGL cells was determined by MTT assay. The body weight of rats was measured every day, and the ovary size and weight were measured after removal. Evans-blue was used to determine permeability. ELISA was used to measure serum estrogen and VEGF levels in rats. RNA and protein expressions of VEGF, VEGFR-2, TGF-[Formula: see text]1, and T[Formula: see text]R II were detected by qPCR and Western-blotting and immunostaining in vitro and in vivo experiments. Results: Our research found that giving rats EGCG prevented the development of OHSS, as evidenced by histological examination, ovarian weight, and morphology. When compared to the OHSS group, the EGCG treatment group had significantly lower ovary weight (147.9 vs 206.5 mg) (Fig. 1). Furthermore, when compared to OHSS rats, EGCG-treated rats have lower ovarian VEGF expression as measured by IHC and RT-qPCR. VEGF and E2 protein levels in the serum of the EGCG treatment group are significantly lower. EGCG exerted inhibitory effects on cell growth only in high dose (50 uM) and longtime (48 h) treatment in KGN and hGL cells. In KGN cells and hGL cells, EGCG significantly reduces the expression of VEGF and TGF-[Formula: see text] at the RNA and protein levels. Furthermore, EGCG inhibits TGF-[Formula: see text]1-induced VEGF production and secretion in KGN cells by suppressing TGF-[Formula: see text] expression and its traditional Smad signaling pathway. EGCG also downregulates VEGF expression through the 67-kDa laminin receptor-mediated PKA-CREB pathway (Fig. 2). Conclusions: EGCG inhibited VEGF via the TGF-[Formula: see text]1 classical-SMAD pathway and the 67LR-mediated CREB pathway, reducing ovarian inflammation and slowing the progression of OHSS in a rat model.

Phase Transition Behaviors of Poly(N-isopropylacrylamide) Nanogels with Different Compositions Induced by (−)-Epigallocatechin-3-gallate and Ethyl Gallate

Phase transition behaviors of poly(N-isopropylacrylamide) nanogels with different compositions induced by (−)-epigallocatechin-3-gallate (EGCG) and ethyl gallate (EG) has been investigated systematically. Monodisperse poly(N-isopropylacrylamide-co-N-hydroxymethyl acrylamide) (P(NIPAM-co-NMAM)) and poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate) (P(NIPAM-co-HEMA)) nanogels with different feeding monomer ratios were prepared by emulsion polymerization. P(NIPAM-co-NMAM) nanogels exhibit rapid isothermal phase transition behavior in EGCG solutions with low concentration (10−3 mol/L) in less than 10 minutes. The thermosensitive phase transition behaviors of nanogels are affected not only by the copolymerized monomers but also by the concentrations of EGCG and EG in aqueous solutions. Nanogels remain in a shrunken state and do not exhibit thermosensitive phase transition behaviors in EGCG solutions (≥5 mmol/L), whereas they display thermo-responsive phase transition behaviors in EG solutions. The volume phase transition temperature (VPTT) shifts to lower temperatures with increasing EG concentration. The diameters of P(NIPAM-co-NMAM) nanogels decrease with increasing EG concentration at temperatures between 29 and 33 °C. In contrast, the diameters of P(NIPAM-co-HEMA) nanogels increase with increasing EGCG concentration at temperatures between 37 and 45 °C. The results demonstrate the potential of nanogels for simple detection of EG and EGCG concentrations in aqueous solutions over a wide temperature range, and EGCG can serve as a signal for the burst-release of drugs from the P(NIPAM-co-NMAM)-based carriers at physiological temperature.

Dual action of epigallocatechin-3-gallate in virus-induced cell Injury

BackgroundViral infections cause damage and long-term injury to infected human tissues, demanding therapy with antiviral and wound healing medications. Consequently, safe phytochemical molecules that may control viral infections with an ability to provide wound healing to viral-induced tissue injuries, either topically or systemically, are advantageous. Herein, we hypothesized that epigallocatechin-3-gallate (EGCG), the most abundant polyphenol in green tea, might be effective as a wound healing, antiviral, and antifibrotic therapy. ResultsThe antiviral activities of EGCG against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Herpes simplex virus type 2 (HSV-2) as well as its wound healing activities against different monolayer tissue (continuous and primary) systems were investigated. Consider its possible wound-healing advantages as well. To determine the safe concentrations of EGCG in green monkey kidney (Vero) and Vero-E6 cell lines, MTT assay was performed and showed high CC50 values of 405.1 and 322.9 μM, respectively. The antiviral activities of EGCG against SARS-CoV-2 and HSV-2, measured as half-maximal concentration 50 (IC50) concentrations, were 36.28 and 59.88 μM, respectively. These results confirm that the EGCG has remarkable viral inhibitory activities and could successfully suppress the replication of SARS-CoV-2 and HSV-2 in vitro with acceptable selectivity indices (SI) of 11.16 and 5.39, respectively. In parallel, the EGCG exhibits significant and dose/time-dependent anti-migration effects in human breast cancer cells (MCF-7), its resistant variation (MCF-7adr), and human skin fibroblast (HSF) indicating their potential to heal injuries in different internal and topical mammalian systems. ConclusionsThe EGCG has proven to be an efficient antiviral against SARS-CoV-2 and HSV-2, as well as a wound-healing phytochemical. We assume that EGCG may be a promising option for slowing the course of acute cellular damage induced by systemic (Coronavirus Disease 2019 (COVID-19)) or topical (HSV-2) viral infections.

Autophagy and Apoptosis Cross-Talk in Response to Epigallocatechin Gallate in NALM-6 Cell Line

Background: Chemotherapy, the primary treatment for acute lymphoblastic leukemia (ALL), often yields inadequate responses. Epigallocatechin gallate (EGCG) has been shown to significantly affect tumor cells through various mechanisms, including cell cycle arrest, apoptosis, and autophagy. Objectives: The objective of this study is to explore the impact of EGCG on autophagy, apoptosis, and the interplay between them in NALM-6, a pre-B-ALL cell line. Methods: NALM-6 cells were subjected to various concentrations of EGCG for 24 and 48 hours. Additionally, NH4Cl 10 mM was used as an autophagy inhibitor to examine this mechanism. The EGCG effect on cell viability and apoptosis was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), trypan blue exclusion assay, and flow cytometry. Moreover, western blot analysis and real-time PCR were performed to investigate autophagy. Results: Our findings demonstrated that EGCG significantly affected cell proliferation and viability. It reduced cell viability by 55.24 ± 8.43% (P < 0.0001) while inducing apoptosis by 51.04 ± 1.88% (P = 0.006). Furthermore, in the presence of NH4Cl, EGCG led to a 3.92 ± 1.76-fold increase in LC3 protein level (P = 0.001). It also resulted in an approximately 1.34 ± 0.34-fold enhancement in DRAM1 mRNA expression levels (P = 0.013), while reducing of LC3B by 33.3 ± 30.5% (P = 0.008), P62/SQSTM1 by 46.5 ± 28.26% (P < 0.001), and Atg2B by 45.5 ± 16.25% (P < 0.001). However, the inhibition of autophagy did not alter the apoptosis rate in either untreated or EGCG-treated cells. Conclusions: Overall, our findings suggest that EGCG can trigger apoptosis and autophagy in the NALM-6 cell line. However, blockage of autophagy does not appear to impact apoptosis in this cell line.

Preparation and characterization of egg white protein film incorporated with epigallocatechin gallate and its application on pork preservation.

The aim of this study was to develop the composite films with antioxidant and biodegradable activity based on egg white protein (EWP) and epigallocatechin gallate (EGCG). Water susceptibility, light transmittance, microstructure and antioxidant properties of the composite films without and with EGCG were fully characterized. It was noted that the addition of EGCG might decrease the moisture content, water solubility and swelling capacity. SEM micrographs revealed that discontinuous blocks and rough surfaces were caused by increasing concentration of EGCG, whereas compact and homogeneous particles appeared when the concentration of EGCG reached to 80μmol/L. Moreover, the biodegradability of the composite films was demonstrated by the soil degradation properties that they can be almost completely degraded within ten days. Experimental results on the application in chilled fresh pork showed that the EWP-based films could play an antioxidant role when incorporated with EGCG, indicating their great potential for food packaging.

Amelioration of ovalbumin gel properties by EGCG via protein aggregation, hydrogen, and van der Waals force.

The mechanism of epigallocatechin gallate (EGCG)-modified ovalbumin gel (EMOG) was investigated. Results indicated that, with the increase of EGCG concentration from 0% to 0.05%, the opacity, hardness, and cohesiveness of EMOG increased significantly from 0.058 to 0.133, 321.0g to 377.6g, and 0.879 to 0.951, respectively, while the soluble protein, surface hydrophobicity, and free sulfhydryl decreased significantly by 41.74%, 28.26%, and 39.36%, respectively. Moreover, EGCG promoted the formation of dense and stable microstructures of EMOG, changed the expansion rate, and improved the stability of EMOG. Moreover, the results of silico simulation showed that EGCG would insert into ovalbumin and interact with the amino acids through van der Waals force and hydrogen bonds, leading to a compact and stable protein structure. In this paper, the mechanism of modification of ovalbumin by EGCG was elucidated at the macro and micro levels, providing insights into the action of polyphenols and proteins.