Interaction Of Polyphenols Research Articles

A review of polyphenol and whey protein-based conjugates

Proteins act as a primary food component obtained from different food sources. In contrast, polyphenols are metabolites and are abundantly present in plants, so their combination plays a crucial role in defining the functional properties of a food product. In the current review, the protein-polyphenol interactions have been briefly reviewed, along with the changes that occur because of their interaction. The mechanisms and the factors affecting the functionalities of the protein-polyphenol conjugates, e.g., the solubility, antioxidant, and gelling properties, have also been briefly reviewed. In addition, the interaction of polyphenols with whey proteins was been reviewed with various applications within the food industry, e.g., emulsifiers, foaming agents, and antioxidants. To end the review, future challenges were also highlighted.

Analysis of Iron Complexes of Tannic Acid and Other Related Polyphenols as Revealed by Spectroscopic Techniques: Implications in the Identification and Characterization of Iron Gall Inks in Historical Manuscripts.

In this work, a structural analysis of the polyphenol complexes with iron and copper at several conditions is reported. The investigated polyphenols were tannic acid, gallic acid, pyrogallol, and syringic acid, being components and molecular models of the gallnuts usually employed in the past in fabrication of iron gall inks (IGIs). Commercial tannic acid extracted from gallnuts, which is a complex mixture of different gallotannins and simpler galloylglucoses, was also employed in this analysis. This analysis comprised the use of Raman, Fourier-transform infrared (FTIR), UV–vis absorption, and fluorescence spectroscopy. The complexation of iron with these molecules leads to a strong change in color due to the deep restructuring of the polyphenol that can be clearly seen by Raman and FTIR spectra. Three main Raman bands appeared at 1450–1490 cm–1 (ν1), 1320–1345 cm–1 (ν2), and 400–650 cm–1 (ν3), which are characteristic of the metal complexes. The structural changes of the polyphenol complexes with iron were also investigated at different pHs and different polyphenol/iron stoichiometries. Other effects of the interaction of polyphenols with iron are the pH decrease of the mixture upon metal complexation and fluorescence quenching induced by the interaction of iron. This quenching is important since it facilitates the Raman inspection of manuscripts since polyphenols show a strong fluorescence emission that overlaps the Raman spectrum. Furthermore, DFT calculations were performed for the first time on the gallic acid complex with iron in order to elaborate a detailed assignment of the vibrational modes of polyphenols and their metal complexes, something that was missed in previous applications of Raman to IGIs.

Interaction of Pyrogallol-Containing Polyphenols with Mucin Reinforces Intestinal Mucus Barrier Properties.

High consumption of polyphenol-rich green tea, coffee, fruits, and vegetables is associated with a low risk of human chronic diseases. Recent studies highlight the relevance of polyphenol-mediated gut microbiota modulation and its impact on mucus barrier. Herein, we study the direct interaction of epicatechin (EC), epigallocatechin gallate (EGCG), and tannic acid (TA) with intestinal mucin by isothermal titration calorimetry and multiple particle tracking and the impact on mucus barrier using ex vivo mucus and Caco-2/HT29-MTX cocultures. Results show that pyrogallol-containing polyphenols EGCG and TA exhibit strong binding to intestinal mucin and reinforce mucus barrier, whereas EC does not. ECGG and TA also mitigate gliadin-mediated cytotoxicity and inflammation. The chemical binding of EGCG and TA to the nucleophilic thiol groups of mucins shows their roles as cross-linkers of mucin networks. These results bring a novel understanding of the health benefits of polyphenols and provide support for the consumption of pyrogallol-containing beverages like green tea as a potential dietary therapy for gluten-related disorders.

Covalent modification of zein with polyphenols: A feasible strategy to improve antioxidant activity and solubility.

Covalent modification of protein with polyphenols is an attractive research topic, since it is an effective way to improve the properties and broaden the applications of protein. However, the majority of prolamin-polyphenol reactions were carried out in alcohol aqueous solution, and this study aimed to investigate the covalent interaction of zein and polyphenols in water. Chlorogenic acid (CGA), gallic acid (GA), and caffeic acid (CA) were used as polyphenol models. The grafting ratio revealed that zein interacted more strongly with CGA and CA than with GA, which was probably due to the larger molecular weight of CGA and the hydroxycinnamic acid structure of CA. Afterward, the differences in structural and functional properties between control zein and zein-polyphenol complexes were compared. Covalent interaction with polyphenols induced great changes in the morphology and secondary structure of zein. Compared with control zein and non-covalent complexes, covalent zein-polyphenol complexes exhibited better solubility, antioxidant activity, and thermal stability. PRACTICAL APPLICATION: Covalent modification of zein with polyphenols in water is a simple and efficient method, which can ameliorate the antioxidant activity as well as the hydrophilicity of zein and improve its application value. The findings of this research carry important implications for using zein-polyphenol complexes as novel food additives, or to design more efficient delivery systems.

Drug-Tea Polyphenol Interaction (III) Incompatibility between Aripiprazole Oral Solution and Green Tea.

The details of incompatibility between aripiprazole (ARIP) oral solution and green tea were examined. When the ARIP oral solution was mixed with a commercial PET bottled green tea beverage, the residual rate of ARIP in the mixed solution decreased to 15.7-17.6%. Mixing with ARIP reduced the content of gallate-type green tea polyphenols (GTPs) in the mixed solution but not the content of non-gallate-type GTPs. Furthermore, using pH 3.0 lactic acid buffer, 2.23 mM ARIP solution and 2.23 mM GTP solution were prepared, and the same volumes of ARIP solution and GTP solution were mixed. When the gallate-type GTP solution was mixed, the residual rate of ARIP in the mixed solution decreased. On the other hand, when the non-gallate-type GTP solution was mixed, the residual rate of ARIP in the mixed solution did not decrease. From the above results, it was found that the main reason for the incompatibility between ARIP oral solution and green tea was the formation of an insoluble substance composed of ARIP and gallate-type GTPs in green tea. Furthermore, experimental results using the continuous variation method revealed that ARIP and (-)-epigallocatechin gallate, which is the most representative gallate-type GTP, interact at a molar ratio of 3 : 2.

Non-covalent interaction of soy protein isolate and catechin: Mechanism and effects on protein conformation

Understanding the molecular mechanism behind protein–polyphenol interactions is critical for the application of protein–polyphenol compounds in foods. The purpose of this research was to investigate the non-covalent interaction mechanism between soy protein isolate (SPI) and catechin and its effect on protein conformation. We observed that particle size, ζ-potential, and polyphenol bound equivalents of SPI increased significantly after non-covalent modification with catechin. These changes caused SPI to aggregate and form a network-like structure. Fourier transform infrared spectroscopy (FTIR) indicated that increased catechin concentrations caused SPI to become looser and more disordered as its α-helix and β-sheet transformed into β-turn and random coil. Furthermore, internal structure of SPI was opened and its hydrophobic groups were exposed to a polar environment, which was demonstrated by decreased surface hydrophobicity. Thermodynamic analysis and molecular docking results showed that the main forces present between SPI and catechin were hydrophobic interactions and hydrogen bonds.

Green Synthesis of Robust Selenium Nanoparticles via Polysaccharide–Polyphenol Interaction: Design Principles and Structure–Bioactivity Relationship

Selenium is an essential micronutrient and is well known for its role in regulating metabolism. However, it is also highly toxic in some of its forms and above certain concentration levels. Amorphous selenium nanoparticles (SeNPs) are extremely unstable and convert into non-bioactive or gray elemental selenium with crystal-type structures due to aggregation, which limits its antioxidant and anti-tumor activities. To overcome these limitations, monodisperse SeNPs were obtained by stabilizing SeNPs with glucan and rosmarinic acid (RA) via Se–O bonds and polysaccharide–polyphenol interactions. The prepared glucan-RA-SeNPs were found much more stable than both SeNPs and glucan-stabilized SeNPs. Meanwhile, glucan-RA-SeNPs displayed enhanced bioactivities including an improved free radical scavenging ability and an increased cytotoxicity toward cancer cells. The underlying mechanism might be related to caspase activation by glucan-RA-SeNPs, thus overproducing intracellular reactive oxygen species and eventually resulting in cancer cell apoptosis. Our work proposes a feasible strategy for improving the structure–bioactivity of SeNPs through polysaccharide–polyphenol interaction.

Investigating the interaction between dietary polyphenols, the SARS CoV-2 spike protein and the ACE-2 receptor.

The global spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has called for an urgent need for the identification of compounds able to control, prevent or slow down the global pandemic. Several dietary polyphenols were assayed against binding to the SARS CoV-2 S1 spike protein and the human ACE-2 receptor, the target of the SARS CoV-2 virus using nano differential scanning fluorimetry, suggesting interaction of dietary polyphenols with both proteins. Following this initial screening the two dietary polyphenols with the strongest affinity were evaluated in a second functional binding assay. The assay was based on the thermophoresis of a fluorescently labelled spike protein and the ACE-2 receptor in the presence of dietary concentrations of the polyphenol in question. It could be experimentally shown that 5-caffeoyl quinic acid and epicatechin reduce the binding constant between SARS CoV-2 spike protein of the alpha variant and the ACE-2 receptor by a factor of ten. The finding could as well be applied to black tea and a coffee beverage with dietary 5-CQA concentrations for the alpha variant Spike protein. Hence it can be speculated that a cup of coffee reduces binding of the virus to its human target, therefore reducing the likelihood of infection with SARS CoV-2, acting as a virus entry-inhibitor.

Artocarpus heterophyllus Lam. leaf extracts added to pectin-based edible coating for Alternaria sp. control in tomato

The use of pectin edible coatings has been receiving great attention due to their availability, non-toxic, and physicochemical properties. However, few reports showed their antifungal activity against phytopathogens such as Alternaria spp., one of the main causes of tomato production losses. This work was aimed to evaluate the effect of low methoxy pectin (LMP)-based coating with and without JLE, to control Alternaria sp. in fruit, including the study of tomato quality parameters behavior. LMP showed dose-dependent activity against two Alternaria spp. strains. JLE with 243.6 ± 6.3 GAE/g dried weight of total soluble polyphenols and 20.6 ± 1.1 RE/g dried weight of total flavonoids, and high antioxidant capacity caused 39.9% of growth inhibition. The interaction of polyphenols with coating (PGW) was evidenced by FTIR. During in vivo preventive treatments (12 days, 20 °C, 75–80% RH), a decrease of infection severity and fruit firmness improvement were observed. PGW decreases the maturation rate of fruit Cordinate a * and hue angle presented the greatest changes. According this behavior, the use of LMP coatings added with JLE could be a convenient strategy to control Alternaria spp. and improve the tomato shelf-life.

Characterization of Soybean Protein Isolate-Food Polyphenol Interaction via Virtual Screening and Experimental Studies.

(1) Background: Protein–polyphenol interactions have been widely studied regarding their influence on the properties of both protein and the ligands. As an important protein material in the food industry, soybean protein isolate (SPI) experiences interesting changes through polyphenols binding. (2) Methods: In this study, a molecular docking and virtual screening method was established to evaluate the SPI–polyphenol interaction. A compound library composed of 33 commonly found food source polyphenols was used in virtual screening. The binding capacity of top-ranking polyphenols (rutin, procyanidin, cyanidin chloride, quercetin) was validated and compared by fluorescence assays. (3) Results: Four out of five top-ranking polyphenols in virtual screening were flavonoids, while phenolic acids exhibit low binding capacity. Hydrogen bonding and hydrophobic interactions were found to be dominant interactions involved in soybean protein–polyphenol binding. Cyanidin chloride exhibited the highest apparent binding constant (Ka), which was followed by quercetin, procyanidin, and rutin. Unlike others, procyanidin addition perturbed a red shift of SPI fluorescence, indicating a slight conformational change of SPI. (4) Conclusions: These results suggest that the pattern of SPI–polyphenol interaction is highly dependent on the detailed structure of polyphenols, which have important implications in uncovering the binding mechanism of SPI–polyphenol interaction.

Noncovalent Interactions of Sea Buckthorn Polyphenols with Casein and Whey Proteins: Effect on the Stability, Antioxidant Potential, and Bioaccessibility of Polyphenols

In this work, effect of casein and whey protein interaction on the stability, antioxidant potential, and bioaccessibility of sea buckthorn polyphenols was investigated. The results revealed that casein–polyphenol and whey protein–polyphenol interaction both decreased the in vitro antioxidant capacity of polyphenols. On the other hand, the protein–polyphenol complexes increased the stability of sea buckthorn polyphenols during simulated in vitro digestion. Moreover, both the casein–polyphenol and whey protein–polyphenol complexes exhibited an increased bioaccessibility of polyphenols (60.97–64.97%) in comparison to that of free polyphenolic extract (40.01%). The main bonding force between sea buckthorn polyphenols and the proteins was found to be a hydrophobic interaction, as revealed by ATR-FTIR, UV–vis, and fluorescence spectroscopy. The particle size of casein–polyphenol and whey protein–polyphenol complexes was in the nanosize region (650–983 nm). The low span factors of polyphenol–protein complexes revealed the narrow range of particle size distribution and thus more homogeneity in the particle size. This finding highlights that the interaction between casein and whey proteins with sea buckthorn polyphenols could protect these bioactive compounds against the influence of simulated digestion.

Properties of Different Varieties of Durian

Durian (Durio zibethinus Murr.), like many other exotic, tropical, and conventional fruits, is important in the prevention of different diseases. In this study, the characterization of the main bioactive compounds of the most popular cultivars of durian and their properties are described. The changes in the quality indices of the antioxidant status were determined by CUPRAC, ABTS, FRAP, DPPH, and ORAC assays. The profiling of phytochemicals was carried out by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). For the first time, in vitro studies were performed by the interaction of extracted durian polyphenols with human serum proteins (HSP) such as human serum albumin (HSAlb), fibrinogen (HSFib) and globulin (HSGlo) as novel biomarkers of coronary artery disease (CAD). The fluorescence measurements of the resulting intensity and calculated binding properties of the interaction of polyphenols with proteins showed that the most reactive was Monthong durian cultivar. This study suggests that durian cultivars have relatively strong antioxidant, binding, and health potentials and could be a significant source of natural antioxidants used in daily fresh consumption and for functional foods.

Conformational analysis of tannic acid: Environment effects in electronic and reactivity properties.

Polyphenols are natural molecules of crucial importance in many applications, of which tannic acid (TA) is one of the most abundant and established. Most high-value applications require precise control of TA interactions with the system of interest. However, the molecular structure of TA is still not comprehended at the atomic level, of which all electronic and reactivity properties depend. Here, we combine an enhanced sampling global optimization method with density functional theory (DFT)-based calculations to explore the conformational space of TA assisted by unsupervised machine learning visualization and then investigate its lowest energy conformers. We study the external environment's effect on the TA structure and properties. We find that vacuum favors compact structures by stabilizing peripheral atoms' weak interactions, while in water, the molecule adopts more open conformations. The frontier molecular orbitals of the conformers with the lowest harmonic vibrational free energy have a HOMO-LUMO energy gap of 2.21 (3.27) eV, increasing to 2.82 (3.88) eV in water, at the DFT generalized gradient approximation (and hybrid) level of theory. Structural differences also change the distribution of potential reactive sites. We establish the fundamental importance of accurate structural consideration in determining TA and related polyphenol interactions in relevant technological applications.

Interactions of polyphenols from traditional apple varieties ‘Bobovac’, ‘Ljepocvjetka’ and ‘Crvenka’ with β-Glucan during in vitro simulated digestion

Interactions between β-glucan and polyphenols might have an effect on polyphenol digestion and bioaccessibility. The influence of β-glucan on in vitro gastrointestinal digestion of polyphenols of traditional apple varieties was studied. Polyphenols were chemically and enzymatically extracted, and identified and quantified with high-performance liquid chromatography. Simulated digestion of peel and flesh of apples was conducted. Polyphenols released in digestion in lower amounts than occur naturally in apples. Their content increased from the oral to the gastric, then decreased in the intestinal phase (up to 21% (peel) and 16% (flesh) were recovered) where anthocyanins and flavan-3-ols were not found. β-glucan decreased (oral and intestinal digestion of peel) or increased (gastric digestion of peel; oral, gastric, intestinal digestion of flesh) the recovered polyphenols. Interactions between β-glucan, polyphenols and enzymes might have influenced these effects. β-glucan is suggested to increase the polyphenol content reaching lower parts of the digestive tract.

SEM morphology, porosity, swelling and hardness test of foam from dried albumin -gambier tannins

Phenolic foam is a product of natural albumin made from gambier tannins, water, and other additional substances. The interaction of albumin and tannin polyphenols can be considered as complex formation because of the secondary bonds that exist between them. Albumin-based foam is produced by a high-speed mixing system, therefore obtaining a homogeneous emulsion of gas dispersion in the oven-dried liquid. The aim of this study was to examine the morphological structure, porosity, swelling, and hardness of a foam made from several concentrations of dried albumin mixed with gambier tannins. The results showed that there werelarge, small, regular and cracked pore structures, with an average porosity of 73.16%, swelling of 45.55% and hardness of 22.09 (N/cm2) depending on albumin concentration used.

Phenolic compounds of mango (Mangifera indica) by-products: Antioxidant and antimicrobial potential, use in disease prevention and food industry, methods of extraction and microencapsulation

Globally, a large amount of agri-food waste is generated as a result of industrial processes or direct consumption of raw materials, and when discarded, they represent a factor of environmental pollution. Mango by-products have a great bioactive potential, especially because they contain phenolic compounds in which mangiferin predominates, in addition to a great variety of phenolic acids, flavonoids and tannins, which confer antioxidant effects against cancer, cardiovascular and neurological diseases, among others. In addition, it was demonstrated that they have an effect against a broad microbial spectrum, including multiple pathogenic bacteria and fungi such as Escherichia coli and Candida albicans, respectively. According to the literature, mango peel and seed extracts also have potential as an additive, by influencing the sensory and physicochemical characteristics of foods, which has been proven by their addition to products such as shrimp, yogurt and cookies. Considering the importance of mango by-products, this work focused on their phenolic properties, the mechanism of antioxidant and antimicrobial action, their fields of pharmacological and food applications, in addition to evaluating their extraction methods and proposing microencapsulation as a suitable technology to avoid their degradation and control their release under appropriate conditions. Based on the analysis performed, further studies are suggested on the application in different foods and to evaluate the interaction of polyphenols with the compounds of the product, to avoid possible negative effects. It is also recommended to experiment with the use of combined technologies to improve results during extraction and microencapsulation.

Extract isolated from cranberry pomace as functional ingredient in yoghurt production: Technological properties and digestibility studies

Yoghurt is recognized as an excellent delivery vehicle for plant-derived phenolic compounds. This study aimed to examine the effect of polyphenol-rich extract produced from cranberry pomace (CE) on the fermentation, textural characteristics, and digestibility of yoghurt. The addition of 0.25%–0.75% of CE to milk prior to fermentation caused an increase of protein particle size and accelerated the acid-induced gelation time of milk depending on the CE concentration due to the complexation of the polyphenols with the milk proteins. Protein–polyphenol interactions were responsible for forming aggregated protein networks from larger particles with higher viscosity and lower syneresis in yoghurt produced with CE compared to that made without CE. However, the addition of the extract did not affect the viability of the yoghurt bacteria. In gastrointestinal digestion, yoghurt with CE showed slower digestion of proteins than the control and a limited release of phenols at the end of intestinal digestion. The overall findings suggest that addition of CE into yoghurt is a promising method of making yoghurts with good textural properties and high yoghurt bacteria viability. Digestibility studies of the product need to be extended to explain the influence of undigested proteins and non-released phenolic compounds on the colonic microbiota.

Mango (Mangifera indica L.) Polyphenols: Anti-Inflammatory Intestinal Microbial Health Benefits, and Associated Mechanisms of Actions.

Mango is rich in polyphenols including gallotannins and gallic acid, among others. The bioavailability of mango polyphenols, especially polymeric gallotannins, is largely dependent on the intestinal microbiota, where the generation of absorbable metabolites depends on microbial enzymes. Mango polyphenols can favorably modulate bacteria associated with the production of bioactive gallotannin metabolites including Lactobacillus plantarum, resulting in intestinal health benefits. In several studies, the prebiotic effects of mango polyphenols and dietary fiber, their potential contribution to lower intestinal inflammation and promotion of intestinal integrity have been demonstrated. Additionally, polyphenols occurring in mango have some potential to interact with intestinal and less likely with hepatic enzymes or transporter systems. This review provides an overview of interactions of mango polyphenols with the intestinal microbiome, associated health benefits and underlying mechanisms.

Complexation of maltodextrin-based inulin and green tea polyphenols via different ultrasonic pretreatment

Ultrasound has been applied in food processing for various purpose, showing potential to advance the physical and chemical modification of natural compounds. In order to explore the effect of ultrasonic pretreatment on the complexation of inulin and tea polyphenols (TPP), different frequencies (25, 40, 80 kHz) and output power (40, 80, 120 W) were carried out. According to the comparison in particle size distribution and phenolic content of different inulin-TPP complexes, it was indicated that high-intensity ultrasonic (HIU) treatment (25 kHz, 40 W, 10 min) could accelerate the interaction of polysaccharides and polyphenols. Moreover, a series of spectral analysis including UV–Vis, FT-IR and NMR jointly evidenced the formation of hydrogen bond between saccharides and phenols. However, the primary structure of inulin and the polysaccharide skeleton were not altered by the combination. Referring to field emission scanning electron microscopy (FESEM), the morphology of ultrasound treated-complex presented a slight agglomeration in the form of bent sheets, compared to non-treated sample. The inulin-TPP complex also revealed better stability based on thermogravimetric analysis (TGA). Thus, it can be speculated from the identifications that proper ultrasonic treatment is promising to promote the complexation of some food components during processing.

Synergistic Two-Way Interactions of Dietary Polyphenols and Dietary Components on the Gut Microbial Composition: Is There a Positive, Negative, or Neutralizing Effect in the Prevention and Management of Metabolic Diseases?

Synergistic Two-Way Interactions of Dietary Polyphenols and Dietary Components on the Gut Microbial Composition: Is There a Positive, Negative, or Neutralizing Effect in the Prevention and Management of Metabolic Diseases?