Catechin Research Articles

Influence of Melatonin Coating on Physiochemical Qualities and Enzymatic Activities in Banana Pericarp under Cold Storage

Banana pericarp is highly susceptible to chilling injury (CI), negatively affecting its quality and shelf life. Melatonin (MT), a plant tryptophan derivative, has shown promising effects in mitigating CI and related physiological disorders in tropical and subtropical fruits. This study investigated the efficacy of MT at different concentrations (0, 50, and 100 µM/L) in the coating of banana pericarp to control CI and physicochemical degradation during storage at 7 °C for five days, and on each day, fruits were assessed for quality. The MT100 treatment significantly (p < 0.05) mitigated the severity of the CI index, electrolytic leakage (EL), and malondialdehyde (MDA) levels. Reactive oxygen species (ROS) levels were substantially higher in control samples, whereas MT treatments notably suppressed their increase. Glutathione (GSH) and ascorbic acid (AA) levels were elevated in those banana pericarps treated with higher MT concentrations. Although total phenolic content (TPC) and total carotenoid contents (TCC) were increased in MT-treated samples, the MT concentrations did not significantly affect them. The level of phenolic compounds, such as gallic acid (GA), chlorogenic acid (CA), quinic acid (QA), protocatechuic acid (PA), and catechin (CC), exhibited continuous growth during the storage period, with the highest levels found in MT100-treated samples. Activities of enzymes such as lipoxygenase (LOX), phospholipase D (PLD), phenylalanine ammonia-lyase (PAL), and polyphenol oxidase (PPO) were significantly (p < 0.05) higher in control samples and rose continuously over time, yet were effectively reduced in MT-treated pericarps. This study shows that applying a higher MT coating (100 µM/L) to bananas is an effective post-harvest strategy to considerably lower the incidence of CI and associated losses.

(−)-Epigallocatechin-3-O-gallate or (−)-epicatechin enhances lipid catabolism and antioxidant defense in common carp (Cyprinus carpio L.) fed a high-fat diet: Mechanistic insights from the AMPK/Sirt1/PGC-1α signaling pathway

Long-term high-fat diets (HF) lead to lipid accumulation and an oxidative stress response, which deteriorates the chemical and physical characteristics of fish muscle. Green tea extracts, such as (−)-epigallocatechin-3-O-gallate (EGCG) and (−)-epicatechin (EC), have been found to regulate antioxidant ability and lipid metabolism. However, the effects of EGCG and EC on alleviating oxidative stress and lipid metabolism disorders caused by HF are unclear. Furthermore, the underlying mechanisms remain unknown. In this study, a total of 360 carp (average weight: 9.75 ± 0.09 g) were provided with four experimental diets: a control diet (CN, 6.15% dietary lipids), a high-fat diet (HF, 14.05% dietary lipids), HF supplemented with EGCG (HF + EGCG, 14.05% dietary lipids +50 mg/kg EGCG), and a HF diet supplemented with EC (HF + EC, 14.05% dietary lipids +1000 mg/kg EC) for a duration of 84 days. The results indicated that EGCG or EC ameliorated the negative effects of the HF diet on muscle tissue. Apart from muscle physical characteristics, EGCG decreased yellowness (b*), redness (a*), and dripping loss (P < 0.05). Apart from muscle nutritional composition and antioxidant status, EC mitigated the reduction in protein levels in the muscle induced by the HF diet. Similarly, EGCG and EC mitigated the excessive accumulation of lipids and reactive oxygen species (ROS) in the muscle induced by the HF diet (P < 0.05). Further study showed that EGCG or EC facilitated the phosphorylation of AMP-activated protein kinase (AMPK) and increased silent information regulator 1 (Sirt1) and PPARγ coactivator-1 alpha (PGC-1α) expression in muscle. Taken together, the results of this study revealed that EGCG or EC enhance lipid metabolism and antioxidant capacity in the muscle of common carp (Cyprinus carpio L.) via the AMPK/Sirt1/PGC-1α pathway.

Revealing the variances in color formation and bioactivities of seven catechin monomers throughout the enzymatic reaction by colorimetric and mass spectrometry

The capacity differences of seven catechin monomers to produce colors after treating with catechin-free extract were investigated. After 240-min reaction, only (-)-epicatechin (EC) and (+)-catechin (C) presented obvious luminous red color with L* values of 63.32–71.73, a* values of 37.13–46.44, and b* values of 65.64–69.99. Meanwhile, the decrease rate of EC and C was 43.52 %−50.35 %, which were significantly lower than those of other catechin monomers (85.91 %−100 %). The oxidized products of catechin monomers were analyzed by ultra-high performance liquid chromatography-quadrupole-time of flight-mass spectrometry coupled with diode array detector, wherein dehydro-dimers and -trimers (oxidative coupling products of catechins’ A-B ring) were found to be the major chromogenic compounds of EC and C. Additionally, the antioxidant capacity of catechin monomers only decreased after 30-min reaction, while along with further enzymatic reaction, catechin monomers presented comparable oxyradical scavenging ability (e.g., the DPPH inhibitory rates of catechin monomers were in the range of 24.42 %–50.77 %) to vitamin C (positive control, DPPH inhibitory rate was 27.66 %). Meanwhile, the inhibitory effects of most catechin monomers on α-glucosidase were enhanced in different degrees. These results provided basis for the development of enzymatically-oxidized catechin monomers as functional food color additives.

Effect of the combined binding of topotecan and catechin/protocatechuic acid to a pH-sensitive DNA tetrahedron on release and cytotoxicity: Spectroscopic and calorimetric studies

The therapeutic efficacy of chemotherapy drugs can be effectively improved through the dual effects of their combination with natural polyphenols and the delivery of targeted DNA nanostructures. In this work, the interactions of topotecan (TPT), (+)-catechin (CAT), or protocatechuic acid (PCA) with a pH-sensitive DNA tetrahedron (MUC1-TD) in the binary and ternary systems at pHs 5.0 and 7.4 were investigated by fluorescence spectroscopy and calorimetry. The intercalative binding mode of TPT/CAT/PC to MUC1-TD was confirmed, and their affinity was ranked in the order of PCA > CAT > TPT. The effects of the pH-sensitivity of MUC1-TD and different molecular structures of CAT and PCA on the loading, release, and cytotoxicity of TPT were discussed. The weakened interaction under acidic conditions and the co-loading of CAT/PCA, especially PCA, improved the release of TPT loaded by MUC1-TD. The targeting of MUC1-TD and the synergistic effect with CAT/PCA, especially CAT, enhanced the cytotoxicity of TPT on A549 cells. For L02 cells, the protective effect of CAT/PCA reduced the damage caused by TPT. The single or combined TPT loaded by MUC1-TD was mainly concentrated in the nucleus of A549 cells. This work will provide key information for the combined application of TPT and CAT/PCA loaded by DNA nanostructures to improve chemotherapy efficacy and reduce side effects.

Identification of Antiviral Phytocompounds as Potential Anti‐Dengue Agents against DENV NS2B/NS3 Protease: An Integrated Molecular Modelling and Dynamics Approach

AbstractDengue fever is one of the most dreaded viral diseases caused by the bite of female Aedes aegypti and Aedes albopictus mosquitoes infected with the Dengue virus (DENV). No DENV antiviral drugs have been approved, yet they are desperately needed. The current study focuses on finding potential therapeutics from 8 medicinal plants reported to have activity against the DENV NS2B/NS3 protease in vitro. Eighty‐two phytocompounds were selected from eight different medicinal plants like Vernonia cinerea, Tridax procumbens, Cassia angustifolia, Lawsonia inermis, Dryobalanops aromatic, Punica granatum, Zingiber zerumbet and Zizyphus‐jujuba. The top five phytocompounds (Epicatechin (EPI), Chrysoeriol (CHR), Apigenin (API), Quercetin‐3,4′‐Dimethylether (QUE), and Caffeic acid (CAF)) identified from toxicity evaluation and docking studies were further subjected to 100 ns long Molecular Dynamics (MD) simulations to study their structural stability and binding affinity through MM‐PBSA based free‐energy calculations. MD results revealed overall conformational stability with all the five phytocompounds. Furthermore, MM‐PBSA results suggest binding free energy values of −154.415 kJ/mol, −151.154 kJ/mol, −139.048 kJ/mol, −122.827 kJ/mol), and −120.622 kJ/mol for compound EPI, QUE, API, CAF, and CHR respectively by interacting with essential binding site residues. These compounds could thus be studied extensively to develop nature‐based therapeutic compounds as anti‐dengue agents for DENV2.

Effect of Some Ecological Factors on Stomata and Phenolic Compounds Production in Aloe Vera L. Gel and Effect Gel to the Adult of Flour Beetle: Tribolium Castaneum (Coleoptera : Tenebriodae)

This search presents the effect of some ecological factors such as (ultraviolet –B radiation , temperature , salinity ) on stomatal index and stomatal frequency and phenolic compounds after exposure to Aloe vera L. UV-B radiation , temperature and salinity . Ultraviolet – B radiation is one of the important abiotic factors that can stimulate the production of secondary metabolites, including phenolic compounds. Aloe vera (Asphodelaceae) is a medicinal plant used in Iraq for treating sunburn, wounds, and heartburn. The flour beetle: Tribolium castaneum is one of the inset causes of loss storage food yield in the world. The study aims the effect of some ecological factors such as (ultraviolet –B radiation , temperature , salinity ) on stomatal index and stomatal frequency and phenolic compounds after exposure to Aloe vera L. UV-B radiation , temperature and salinity and investigate the insecticidal and repellency effect of leaf gel for Aloe vera to estimate the percentage of the insecticidal effect for concentrations 25, 50, 75, and 100 % of alcoholic extract within seven days on adult insects. The gel in leaf exposure to UV-B radiation contained a higher diversity of phenolic compounds and flavonoids. This search showed a high percent kill for an adult with 100% of the alcoholic extract compared with control and an excellent effect of Aloe vera gel at a concentration of 50 % for a repellency effect with a value of 10.842%. Phenolic compounds showed after exposure to UV as : (dioxyflavone ,kampferol, catechuic acid, flavonol glucuronic acid, gabardine isoflavone, isoquercitrin, p-coumaric acid, hispaglabridine ) with a high percentage in the gel after exposure to UV-B compared by control.

(−)-Epicatechin ameliorates type 2 diabetes mellitus by reshaping the gut microbiota and Gut–Liver axis in GK rats

As one of the most abundant plant polyphenols in the human diet, (−)-epicatechin (EC) can improve insulin sensitivity and regulate glucose homeostasis. However, the primary mechanisms involved in EC anti-T2DM benefits remain unclear. The present study explored the effects of EC on the gut microbiota and liver transcriptome in type 2 diabetes mellitus (T2DM) Goto–Kakizaki rats for the first time. The findings showed that EC protected glucose homeostasis, alleviated systemic oxidative stress, relieved liver damage, and increased serum insulin. Further investigation showed that EC reshaped gut microbiota structure, including inhibiting the proliferation of lipopolysaccharide (LPS)-producing bacteria and reducing serum LPS. In addition, transcriptome analysis revealed that the insulin signaling pathway may be the core pathway of the EC anti-T2DM effect. Therefore, EC may modulate the gut microbiota and liver insulin signaling pathways by the gut–liver axis to alleviate T2DM. As a diet supplement, EC has promising potential in T2DM prevention and treatment.

PH-Responsive Carrier-Free Polyphenol Nanoparticles Assembled by Oxidative Polymerization with Enhanced Stability and Antioxidant Activity for Improved Bioaccessibility.

Encapsulation of plant polyphenols with micro-/nano-carriers for enhanced bioavailability has been well documented, but the preparation of these carriers and subsequent loading of polyphenols is a multiple process, which is generally complicated with potentially unexpected negative effects on the bioactivity of the polyphenols. Here, we reported a convenient method to assemble carrier-free polyphenol nanoparticles (NPs) based on oxidative coupling polymerization. The effectiveness was assessed with five different polyphenols including pyrocatechol (PY), catechin (CA), epigallocatechin gallate (EGCG), tannic acid (TA), and proanthocyanidin (PC). The structural characteristics of these assembled nanoparticles (PY NPs, CA NPs, EG NPs, TA NPs, and PC NPs) were systematically analyzed with dynamic light scattering (DLS), transmission electron microscopy (TEM), UV-visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR). All NPs were colloidally stable with varying NaCl concentrations from 0 to 300 mM, were acid-resistant and alkali-intolerant, and were suitable for oral administration. An array of antioxidant assays further confirmed the superior antioxidant capabilities of NPs over Trolox and polyphenol monomers, indicating that the oxidative polymerization of polyphenols did not compromise the polyphenol activity of NPs. The in vitro simulated digestion studies validated that these responsive NPs were actually gastrointestinal pH-responsive and applicable to the gastrointestinal physiological environment. The bioaccessibility assessments by using a static in vitro digestion model revealed that better results were achieved with NPs than polyphenol monomers, with TA NPs showing about 1.5-fold higher bioaccessibility than other polyphenol nanoparticles. The present study with five polyphenols demonstrated that the oxidative polymerization of polyphenols provides an effective platform to assemble various carrier-free NPs with enhanced antioxidant activity, favorable stability, and improved bioaccessibility, which could be used promisingly as a functional food ingredient in food matrices or as oral drug delivery candidates for helping to manage human health or treating various gastrointestinal disorders in both the pharmaceutical and nutritional fields.

Elucidating the inhibitory effects of natural organic matter on the photodegradation of organic micropollutants: Atrazine as a probe compound

Natural organic matter (NOM) is a complex mixture of heterogeneous compounds with varying functional groups and molecular sizes. Understanding the impact of NOM on the generation of photochemically produced reactive intermediates (PPRIs) and their potential inhibitory effects on photolysis has remained challenging due to the variations in the reactivities and concentrations of these functional groups. To address this gap, tannic acid (TA), gallic acid (GA), catechin (CAT), and tryptophan (Trp), were chosen as potential substitutes for NOM. Their effects on the photochemical transformation process were evaluated and compared with the widely used Suwannee River NOM (SRNOM). Atrazine (ATZ) was selected as a probe organic micropollutant (OMP). In this investigation, a significantly higher concentration of HO• was observed compared to O21, and the triplet excited state ( NOM*3). The findings suggest that the substituted phenols, particularly those with carboxylate-substitutions, played a substantial role in HO• formation, while electron-rich moieties acted as antioxidants, consuming NOM*3. Hydroxyl, carboxylic, and amino acid were the active groups for O21 formation. However, the inhibitory effects induced by the NOM surrogates were significant and mainly attributed to the direct photolysis inhibition caused by the inner filter effect. The scope of this work was further extended to include SRNOM, where similar trends with less pronounced formation of PPRIs and inner filter effects were observed. Therefore, this study sheds some light on the role of the functional groups in NOM during photochemical transformations of OMPs, thereby deepening our understanding of their fate in aqueous systems.

Construction, characterization, and in vitro hypolipidemic activity of Auricularia auricula-judae soluble dietary fiber-phenol complexes

To investigate the interaction between polyphenols and soluble dietary fiber, we prepared complexes of Auricularia auricula-judae soluble dietary fiber (ASDF) with catechin (CC) and chlorogenic acid (CGA) using the isothermal adsorption method. The resulting complexes were ASDF-CC complex (ASDF-CC) and ASDF-CGA complex (ASDF-CGA). Spectral analysis confirmed the successful construction of ASDF-polyphenol complexes. The results of the sugar composition analysis indicate that the monosaccharide composition of ASDF is not altered by the non-covalent binding of CC and CGA. The molecular weights of ASDF-CC and ASDF-CGA were 102.26 × 103 Da and 99.87 × 103 Da, respectively, which were significantly larger than the molecular weight of ASDF. Thermal analyses showed that ASDF-CC and ASDF-CGA are more thermally stable than ASDF. Morphological analysis revealed that the particle size of ASDF-polyphenol complexes decreased, while the specific surface area increased, and the surface became sparser and more uniformly arranged compared to ASDF. The results of the cholesterol and bile acid salt adsorption capacity assays showed that both complexes exhibited increased in vitro hypolipidemic activity compared to ASDF. Notably, the ASDF complex with CC and CGA effectively enhanced the bio-accessibility of CC and CGA. In conclusion, the interaction between soluble dietary fibers and phenolic compounds through non-covalent bonds is a feasible approach to enhance their bioactivity.

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.

(-)-Epicatechin protects against myocardial ischemia/reperfusion injury via autophagy-dependent ferroptosis.

(-)-Epicatechin (EPI) has physiological activities such as antioxidant, anti-inflammatory and immune enhancement. In this study, we elucidated the protective effects of EPI in myocardial ischemia/reperfusion injury (MI/RI) and its mechanisms. An in vivo I/R model was constructed by performing left anterior descending coronary artery surgery on rats, and an in vitro I/R model was constructed by subjecting hypoxia/reperfusion treatment on H9C2 cells. The damage of cardiac tissues was detected by 2,3,5-triphenyltetrazolium chloride (TTC) and hematoxylin-eosin (H&E) staining, and expressions of ferroptosis-related proteins were examined by Western blot. Changes in the number of autophagosomes, the levels of oxidative stress and Fe2+ were also examined. EPI reduced abnormal electrocardiogram waveform and infarct size caused by MI/RI in rats. The increasing trend of levels of reactive oxygen species (ROS) and Fe2+ was reversed by EPI, suggesting that EPI can reduce ferroptosis in vivo. Moreover, the levels of lipid ROS and LC3 in H9C2 cells were decreased with EPI treatment, and autophagy and ferroptosis were also alleviated in a dose-dependent manner in vitro. Co-cultivation of USP14 inhibitor IU1 and EPI further revealed that EPI regulates ferroptosis through the USP14-autophagy pathway. EPI can reduce the level of oxidative stress by promoting USP14 to reduce autophagy, thus inhibiting autophagy dependent ferroptosis and reducing oxidative stress, and has a protective effect on myocardial infarction/myocardial infarction.

Effect of soybean protein-isolate-catechin edible film and coating on the storage quality of bean bun

This study focused on creating an edible film and coating using soy isolate protein (SPI) and catechin (CC) composite, which were then applied to bean buns. The objective was to assess the changes in quality during storage. Initially, SPI films were enriched with different concentrations of CC (1%, 2%, 3%, and 4%) and were examined for their optical and barrier properties. The addition of CC improved the optical barrier of SPI films, resulting in reduced water vapor permeability (WVP) and oxygen permeability (OP), thereby enhancing their suitability for food preservation. Subsequently, the produced edible coatings were applied to bean buns to evaluate their impact on quality attributes and sensory evaluation. The results of the scanning electron microscopy (SEM) analysis showed that the SPI/CC coating exhibited a smoother and more compact surface compared to the uncoated sample. After 15 days of storage, the SPI/CC 3% coated samples displayed the lowest moisture loss of 4.6% and the lowest hardness of 342.97 ± 8.17 N. Additionally, the Avrami equation revealed a significant 31% reduction in crystallinity (K) when comparing the SPI/CC 3% coated samples to the uncoated samples. XRD measurements further confirmed the decrease in crystallinity of the coated samples, indicating that the SPI/CC coating effectively inhibits the aging of bean buns. Moreover, the SPI/CC coating enhances the antioxidant activity of the bean buns and prevents microbial deterioration. These findings suggest that the utilization of SPI/CC coating holds great promise for the preservation of bean buns.

The differential non-covalent binding of epicatechin and chlorogenic acid to ovotransferrin and the enhancing efficiency of immunomodulatory activity

Seeking safe and environmentally friendly natural immunomodulators is a pressing requirement of humanity. This study investigated the differential binding characteristics of two polar polyphenols (PP), namely epicatechin (EC) and chlorogenic acid (CA), to ovotransferrin (OVT), and explored the relationship between structural transformations and immunomodulatory activity of OVT-PP complexes. Results showed that CA exhibited a stronger affinity for OVT than EC, mainly driven by hydrogen bonds and van der Waals forces. Complexation-induced conformational variations in OVT, including static fluorescence quenching, increased microenvironment polarity surrounding tryptophan and tyrosine residues, and the transition from disordered α-helix to stable β-sheet. Furthermore, the structural conformation transformation of OVT-PP complexes facilitated the enhancement of immunomodulatory activity, with the OVT-CA (10:2) complex demonstrating the best immunomodulatory activity. Principal component analysis (PCA) and Pearson correlation analysis revealed the immunomodulatory activities of the OVT-PP complexes were influenced by surface hydrophobicity (negatively correlated), β-sheet percentage and polyphenol binding constants. It could be inferred that PP complexation increased the surface polarity of OVT, consequently enhancing its immunomodulatory activity by promoting cell membrane affinity and antigen recognition. This study provides valuable guidance for effectively utilizing polyphenol-protein complexes in enhancing immunomodulatory activity.

Insights into the Neuroprotective Potential of Epicatechin: Effects against Aβ-Induced Toxicity in Caenorhabditis elegans.

Medical therapies to avoid the progression of Alzheimer's disease (AD) are limited to date. Certain diets have been associated with a lower incidence of neurodegenerative diseases. In particular, the regular intake of foods rich in polyphenols, such as epicatechin (EC), could help prevent or mitigate AD progression. This work aims to explore the neuroprotective effects of EC using different transgenic strains of Caenorhabditis elegans, which express human Aβ1-42 peptides and contribute to elucidating the mechanisms involved in the effects of EC in AD. The performed assays indicate that this flavan-3-ol was able to reduce the signs of β-amyloid accumulation in C. elegans, improving motility and chemotaxis and increasing survival in transgenic strain peptide producers compared to nematodes not treated with EC. The neuroprotective effects exhibited by EC in C. elegans could be explained by the modulation of inflammation and stress-associated genes, as well as autophagy, microgliosis, and heat shock signaling pathways, involving the regulation of cpr-5, epg-8, ced-7, ZC239.12, and hsp-16 genes. Overall, the results obtained in this study support the protective effects of epicatechin against Aβ-induced toxicity.

Studies on the orange red color development on the surface of the dried Ume (Prunus mume Sieb. et Zucc.) in a drying system equipped with full spectrum artificial sunlight

An orange-red fraction was obtained from fully sun-dried Ume (Prunus mume Sieb. et Zucc.) using a layer extraction method with acetone, methanol, and chloride as organic solvents. Liquid chromatography tandem-mass spectrometry (LC-MS/MS) analysis revealed a series of (-)-epicatechin (EC) dimers and trimers. The polymers were compared with published m/z negative mode and their fragments were characterized as procyanidin B2–2 (A-type dimer), procyanidin C1–2 (A-type trimer), and procyanidin C1–4 (dehydrotriepicatechin B1). High-performance liquid chromatography coupled with diode array detection (HPLC-DAD) analysis showed that the dehydrotriepicatechin B1 peak had an absorption maximum of 425 nm in the visible light range (400–600 nm). Similar results were obtained when salted Ume were subjected to simulated sunlight drying conditions using a low-temperature artificial drying system. Testing of blue light in an (-)-epicatechin (EC) model system showed the strongest catalytic effect. This study suggests that during sun-drying of salted Ume, (-)-epicatechin (EC) concentrates on the epidermis and undergoes photooxidative polymerization after sufficient sun exposure, further producing double bonds that cause the surface of sun-dried Ume to appear orange-red. This research has led to an innovative drying system that can replace sun-drying and avoid external factors such as insects, bacteria, meteorology, and food nutrition improvement that affect the quality of dried products.

Effects of (-)-epicatechin on hepatic triglyceride metabolism.

(-)-Epicatechin (EC) consumption is associated with an improvement of hyperlipemia and other metabolic changes linked to obesity and western-style diets. This work investigated the effects of EC on triglyceride (TG) metabolism both in vivo, where mice were supplemented with EC (2 and 20 mg EC per kg body weight), and in vitro, when human HepG2 hepatocytes were incubated in the presence of EC and the main EC metabolites found in human plasma. Increased hepatic TG levels were only observed after 24 weeks supplementation with EC (20 mg per kg body weight), with a preserved liver structure and absence of inflammation or oxidative stress. EC caused increased expression of diacylglycerol acyltransferases (DGAT2), key enzymes in TG synthesis, and the upregulation of PPARα, which promotes free fatty acid (FFA) oxidation. On the other hand, incubation of HepG2 cells in the presence of high concentrations of EC (1-10 μM) did not affect TG deposition nor DGAT2 expression. In summary, in mouse liver, EC upregulated mechanisms that can neutralize the potential toxicity of FFA, i.e. TG synthesis and FFA β-oxidation. Results in mouse liver and HepG2 cells stress the safety of EC in terms of TG metabolism and development of hepatopathies in doses within the limits given by a rational time and dose for human consumption.

Microwave-assisted synthesis of nickel-oxide/cobalt-oxide/reduced graphene oxide nanocomposite for highly sensitive electrochemical determination of epicatechin in food samples

The determination of bioactive compounds in food samples has received significant attention in recent years due to their potential health benefits. Epicatechin (EC) is one of the flavanol compounds naturally present in various foods such as tea, cocoa, grapes, and berries. It has various potential health benefits, including antioxidant, anti-inflammatory, and anti-cancer properties. However, excessive intake of EC can also have negative effects on health. The accurate and reliable detection of EC in food samples is crucial for ensuring consumer safety and maintaining quality control standards in the food industry. Therefore, developing a sensitive and reliable sensor for detecting EC in food samples is of significant importance. This research presents a novel method for detecting EC in various food samples. The method involves the use of a nickel-oxide/cobalt-oxide/reduced-graphene-oxide composite material (NiO/CoO/rGO) synthesized through a microwave-assisted technique which is then applied to a glassy carbon electrode to fabricate NiO/CoO/rGO/GCE sensor for sensitive determination of EC. The structural, morphological, and electrochemical characteristics of the electrode materials were analyzed using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The morphological results confirmed the formation of well-dispersed NiO/CoO nanoparticles on the surface of rGO sheets. The electrochemical results revealed that the NiO/CoO/rGO/GCE sensor has exceptional electron-transport properties and electrocatalytic activity towards EC, with an Rct value of 90.85 kΩ that is lower than that of the Bare/GCE and GO/GCE electrodes, which attributed to the synergistic effect of NiO/CoO nanoparticles and rGO sheets. The method was found to have a detection limit of 0.0012 μM for EC, with a linear range of 0.05–65 μM. The sensor was also reliable, stable, reproducible, and selective, and yielded excellent recoveries (near to 100 %) with low RSD values for detecting EC in food samples.

Revealing the mechanism of the lutein protective function of epicatechin-fructan glycosylated soybean protein isolate

Lutein possesses various physiological activities but is susceptible to light degradation, thermal degradation, and oxidative degradation. As such, protecting the activity of lutein-based products using natural extracts has become a current research. In this study, lutein was protected by complexing inulin-type fructan (ITF), soybean protein isolate (SPI), and epicatechin (EC), and the protection mechanism of epicatechin-fructan glycosylated soybean protein isolate (EC-GSPI) toward lutein was elucidated comprehensively. The results showed that the addition of EC delayed the degradation of lutein. The results of light stability experiments showed that increased EC significantly enhanced the storage time of the GSPI-Lutein system from 4 to 13 days. Additionally, the effect of EC on glycosylated soybean 7S globulin (G7S) and glycosylated soybean 11S globulin (G11S) was assessed. The light stability of G11S-Lutein and G7S-Lutein after the addition of EC was from G11S > G7S → G7S > G11S. Furthermore, the proteins purified from SPI interacted differently with EC and ITF, with soybean 7S globulin (7S) mainly interacting with EC and soybean 11S globulin (11S) mainly interacting with ITF. EC-GSPI-Lutein exhibited a good protective effect, probably due to the occurrence of hygrothermal Maillard between ITF and 11S, providing a porous structure for lutein storage. At the same time, the binding of EC to 7S significantly enhanced the antioxidant property of the solution and the stability of the protein secondary structure, thereby prolonging the storage time of lutein.

Green tea extracts and substantial catechin derivatives: Evaluation of their potential against breast cancer

Breast cancer is one of the most predominant types of cancer. Although assorted treatment options are available to cope with breast cancer (e.g. chemotherapy, radiotherapy, surgery, hormone therapy, targeted therapy), chemotherapy regimens still hold vital importance. Studies on the discovery of drug-candidate molecules that can create an alternative in the treatment of breast cancer continue at full speed. At this point, nature has a substantial place offering great diversity. Natural products may exhibit anticancer properties directly through molecular targets such as genes or indirectly through metabolic pathways. Moreover, they may be adjuvant agents and contribute to conventional therapy, and thus, they can enhance the efficacy of chemotherapeutics or even ease their side effects. Green tea, a critical dietary source of polyphenols and flavonoids, is obtained from the minimally fermented or unfermented leaves of the Camellia sinensis L. plant and is used in traditional Chinese medicine for many important conditions, including cancer. The phytochemical content of green tea is extremely rich, including (-)-epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin (EGC); (-)-epicatechin-3-gallate (ECG) and (-)-epicatechin (EC) as the main catechins in the composition of green tea. Within the scope of our study, we proposed the cytotoxicity and toxicity comparison of the water and 80% ethanolic extract of the green tea extracts as well as of (-)-epicatechin (EC) and (-)-epigallocatechin (EGC) in terms of their cytotoxicity and toxicity based on the structure-activity relationship on breast cancer. Therefore, we tested aqueous and 80% ethanolic extracts of green tea and EGC and EC on MDA-MB-231, MDA-BMB-468, MCF-7 and SK-BR-3 breast cancer cells. Their toxicity on healthy rat myoblastoma H9c2 cells was further examined. Resazurin reduction assay was used to detect cytotoxicity and toxicity. Both water and 80% ethanolic extract of green tea exhibited remarkable cytotoxicity on MCF-7 cancer cells deserving further investigation, including phytochemical characterization of the extract. Epigallocatechin was also cytotoxic on MCF-7 cells with an IC50 value of 20.07 µM. The possible therapeutic potentials of green tea extracts and their substantial catechin derivatives were assessed for breast cancer therapy.