Molecular Mechanisms and Applications of Polyphenol-Protein Complexes with Antioxidant Properties: A Review

Mechanistic insights into betanin-protein interactions: Structural and thermal stability enhancement by non-covalent binding with animal- and plant-derived proteins

This study evaluated animal- and plant-derived proteins (whey protein isolate, ovalbumin, soy protein isolate, pea protein) for enhancing betanin's thermal stability. Protein-betanin complex formation was confirmed via particle size, SEM, and UV-Vis spectroscopy. Multi-spectroscopy and molecular dynamics simulations revealed static quenching dominated WPI/ovalbumin-betanin interactions, driven by hydrogen bonds and van der Waals forces, evidenced by negative ΔH0, ΔS0, and ΔG0 values, indicating spontaneous, exothermic binding. Reduced free amino groups, intrinsic tryptophan fluorescence, surface hydrophobicity, and α-helix content, alongside increased β-sheet structures, highlighted the roles of hydrophobic and electrostatic interactions. These forces unfolded proteins, altered tryptophan microenvironments, and stabilized complexes. Findings provide mechanistic insights into betanin stabilization and demonstrate the potential of diverse proteins as effective carriers, broadening betanin's application scope in food and pharmaceuticals.

Tannic acid-mediated covalent effects on the structural and antioxidant properties of dual zein/casein protein complex nanoparticles

Protein-polyphenol conjugates with enhanced antioxidant properties offer significant benefits to multiple food systems, including emulsions, gels, and food packaging systems. In this study, tannic acid (TA)-covalently mediated ternary zein/casein-tannic acid nanoparticles (ZCTPs) were effectively fabricated using a pH-driven method. Results showed that the addition of TA reduced the particle size of ZCTPs (from 93 to 74 nm), with improved uniformities (PDI of 0.25) and greater stabilities (zeta potential of -48 mV) compared to zein/casein nanoparticles (ZCPs). Further, SDS-PAGE confirmed the successful establishment of covalent binding between TA and dual proteins. In ZCTPs, TA exhibited a high affinity (66-93 %) to proteins, obviously inducing rearrangements in the protein secondary and tertiary structures. Afterward, the antioxidant activities of ZCTPs were significantly enhanced to 57 and 79 % against DPPH· and ABTS+·, respectively. This novel protein-polyphenol conjugate holds promising potential as a functional ingredient and delivery system in the food industry.

Deep eutectic solvent extraction of polyphenol from plant materials: Current status and future prospects in food applications

The increasing environmental concerns related to biomass waste have led to the exploration of sustainable methods for extracting bioactive compounds from plant materials, especially polyphenols, which are valued for their health benefits and use in functional foods and natural additives. These bioactive compounds are abundant in fruits, vegetables, tea, and herbs, and encompass flavonoids, phenolic acids, tannins, stilbenes, and lignans. Traditional extraction methods often rely on harmful petrochemical solvents, which pose significant environmental and health risks. In contrast, Deep Eutectic Solvents (DESs) have emerged as an eco-friendly alternative, offering advantages such as low toxicity, cost-efficiency, and a wide range of solubility. This review focused recent advancements in DES-based polyphenol extraction, emphasizing their applications in the food industry. It highlights the potential of DES to efficiently extract polyphenols, improving their bioavailability and stability, and exploring future prospect for enhancing food quality, safety, and functionality through functional foods and natural preservatives.

Investigating the effects of polar and non-polar polyphenols on the physicochemical properties and functional characteristics of camellia oil body emulsions

This study aimed to investigate the effects of polar catechol and non-polar α-tocopherol, either individually or in combination, on the stability and functional properties of camellia oil body emulsions. Catechol showed strong interactions with the polar surface proteins of OBs, while α-tocopherol associated with the non-polar lipid regions, collectively enhancing emulsion stability. Combined use of catechol and α-tocopherol significantly reduced droplet size (2810 to 1360 nm), increased zeta potential (5 to -42 mV), and decreased peroxide values from 45 to 12 meq/kg and TBARS values from 260 to 130 meq/kg after 14 days. Combined effect of polyphenols improved the stability of OB emulsions under stress conditions, maintaining structural integrity at elevated NaCl concentrations, high temperatures (90 °C), and after three freeze-thaw cycles. These findings demonstrate the synergistic effects of combining polar and non-polar polyphenols, offering a promising strategy for enhancing oxidative stability and functionality in food systems.

Exploring electrodialysis with bipolar membranes for water lentil (duckweed) protein purification: A first investigation into process and membrane characterization with products comparison to chemical acidification

Water lentils are free-floating aquatic plants which could be an inexpensive source of protein due to their high leaf protein content and very rapid reproduction. However, the extraction and purification of leaf proteins from their matrix is a necessary step for human consumption, as undesired compounds can reduce their functional or sensorial properties. Therefore, in this study, water lentil proteins were purified for the first time using electrodialysis with bipolar membrane (EDBM), a technology that has been developed as an ecofriendly alternative to chemical acidification. The EDBM of water lentils successfully produced a protein concentrate that had a similar protein content (approximately 47.7 g/100 g) and protein extraction yield (around 39.4 %) compared to chemical precipitation. Moreover, EDBM allowed the demineralization of the protein concentrate by-product compared to chemical precipitation, reducing by 74 % its ash content (58.4 vs 15.2 g/100 g) and doubled its protein content (20.5 vs 41.1 g/100 g). However, during the EDBM process, the system's resistance tripled, and protein deposits were observed inside spacers and on bipolar membrane cation-exchange layer. Hence, while EDBM shows great promise, further optimization is necessary to enhance process efficiency.

Covalent modulation of zein surface potential by gallic acid to enhance the formation of electrostatic-driven ternary antioxidant complex coacervates with chitosan

Despite existing research on the interaction between zein (Z) and chitosan (CS), the formation and mechanisms of ternary electrostatic coacervates incorporating polyphenols remain unclear. Herein, we covalently and non-covalently modified zein with gallic acid (GA). Comparisons revealed that the covalent coupling of Z with GA (forming Z(GA)) reduced zein's surface potential, enabling them to form tightly bound coacervates with cationic polysaccharide chitosan through electrostatic attraction. Turbidity, ζ-potential, and appearance experiments indicated that the maximum yield of insoluble coacervates was achieved at a Z(GA)/CS mass ratio of 7:1 and pH 6.5. Furthermore, the coacervate properties were evaluated using Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and microscopic structure analysis. Electrostatic attraction between the -COO- groups of Z(GA) and the -NH3+ groups of CS triggered complex coacervation, which induced structural modifications and enhanced thermal stability. This study fosters the efficient encapsulation and controlled release of nutraceuticals, enhancing human absorption.

Innovative vibriosis control in open aquaculture: Paratapes undulata as a sustainable growth and resistance enhancer in red tilapia

This study demonstrates the novel therapeutic potential of Paratapes undulata for mitigating Vibrio alginolyticus infection in red tilapia. In vivo, P. undulata significantly improved growth by approximately 362% in group G3 (Clam-treated Control) and 284% in group G4 (Clam-treated Infected), compared to the infected control group (G2), and reduced mortality by 100% in group G3 and 75% in group G4, compared to the infected control group (G2), and alleviated clinical signs, correlating with enhanced hematological and biochemical profiles, and reduced tissue damage. Mechanistically, P. undulata modulated the immune response by shifting cytokine balance towards anti-inflammation, enhanced antioxidant capacity, and directly inhibited Vibrio alginolyticus virulence. Gas Chromatography-Mass Spectrometry and Fourier-Transform Infrared Spectroscopy analyses revealed the presence of bioactive compounds contributing to these effects. These findings establish P. undulata as a promising, natural, and sustainable biocontrol agent for vibriosis in aquaculture, offering a novel strategy for disease management and reducing reliance on antibiotics. This study suggests that P. undulata can be effectively incorporated into aquaculture feed or water treatments to prevent and manage vibriosis outbreaks.

Insight into the binding mechanism of rutin and lysozyme: Based on spectroscopy and molecular simulation technology

Lysozyme (LYZ) is an excellent natural food preservative and can also be used as a bioactive carrier loading small molecules to enhance its stability and antioxidant properties. This research explored the intricate mechanism of interaction between LYZ and rutin. Multiple spectroscopic techniques was used first to confirm that rutin caused a fluorescence burst in LYZ. LYZ amino acid microenvironment was altered. The main driving forces driving the formation of the complex between rutin and LYZ were hydrogen bonding and van der Waals forces. In addition, the incorporation of rutin improved the overall stability and oxidation resistance of the complexes. The results of molecular docking and molecular dynamics simulation further show that rutin and LYZ are stably bound by hydrogen bonds and other interactions. The investigation contributed precious information for the development of novel natural preservatives and the design of advanced small molecular carriers.

Amphipathic regulation of cottonseed protein with the conjugation of bayberry tannin for efficient surface decontamination of uranium

Radioactive substances (Uranium) on the human body or facility surfaces are easy to diffuse in nuclear activity, posing a severe threat to ecological security and human health, especially for personnel working in and around uranium mining and nuclear facilities. In this work, a green protein-based surfactant was synthesized using the free-radical conjugating method to graft bayberry tannin (BT) onto cottonseed protein (CPI) for regulating its amphipathy and removing uranyl ions (UO₂²⁺) in both aqueous environments and solid surfaces. FTIR, CD spectroscopy, intrinsic fluorescence, conductometric titration, and SEM-EDX characterization techniques confirmed the successful covalent conjugation of BT onto CPI, inducing unfolding, conformational changes, and enhanced hydrophilicity of CPI. Thus, leading to improved foaming and emulsifying properties. Notably, the surfactant exhibited high efficiency in UO₂²⁺ removal and selectivity from an aqueous environment, achieving a removal rate of 93 % within 30 minutes and a maximum adsorption capacity of 310.15 mg/g. Additionally, it also demonstrated effectiveness in decontaminating different simulated uranium-contaminated solid surfaces. The synergistic interaction between BT's phenolic-hydroxyl groups and CPI's structural versatility and functional groups facilitated the effective UO₂²⁺ complexation. This study demonstrates the feasibility of using agro-industrial waste-derived CPI-BT as an eco-friendly, sustainable, and cost-effective alternative to synthetic surfactants for mitigating uranium contamination in environments near uranium mining operations and nuclear facilities.

Interactions between β-lactoglobulin and polyphenols: Mechanisms, properties, characterization, and applications

β-lactoglobulins (βLGs) have a wide range of applications in food because of their ability to emulsify, foam, and gel. This makes them good functional additives. However, their performance depends on temperature, pH, and mineral levels, so their functional qualities are limited in particular applications. How polyphenols (PPs) interact with βLG is crucial for the functional characteristics and quality of dietary compounds. In most food systems, a spontaneous interaction between proteins and PPs results in a "protein-PP conjugate," which is known to affect the sensory, functional, and nutraceutical qualities of food products. The βLG-PP conjugates can be used to enhance the quality of food. This article emphasizes analytical techniques for describing the characteristics of βLG-PP complexes/conjugates. It also goes over the functions of βLG-PP conjugates, including their solubility, thermal stability, emulsifying, and antioxidant qualities. The majority of βLG-PPs interactions is due to non-covalent (H-bonding, electrostatic interactions) or covalent bonds that are mostly caused by βLG or PP oxidation through enzymatic or non-enzymatic mechanisms. Furthermore, the conformation or type of proteins and PPs, as well as environmental factors like pH and temperature, have a significant impact on proteins-PPs interactions. Higher thermal stability, antioxidant activities, and superior emulsifying capabilities of the βLG-PP conjugates make them useful as innovative additives to enhance the quality and functions of food products.

Improvement of the Structure and Antioxidant Activity of Protein-Polyphenol Complexes in Barley Malts Using Roasting Methods

Proteins and polyphenols are important components in barley malt. During the roasting process of barley malt, proteins and polyphenols interact and influence each other, ultimately altering the nutritional profile and functional properties of barley malt. In this research, polyphenol-free proteins and protein-polyphenol complexes were extracted from barley malt subjected to varying degrees of roasting. The antioxidant activity of protein-polyphenol complexes was assessed by ABTS, FRAP, and ORAC assays. The structural characteristics of the proteins were examined through UV, FL, CD, FTIR, and SEM. We found that roasting enhances the solubility of globulin, prolamin, and glutenin and facilitates the binding of these proteins with polyphenols. Conversely, the impact of roasting on albumin exhibits a trend opposite to that observed in the other three proteins. The antioxidant activity of protein-polyphenol complexes was significantly higher than that of polyphenol-free proteins. Additionally, the microenvironment of the amino acid residues of the four proteins exhibited increased polarity following the roasting process, and the structural conformation of albumin, globulin, and glutelin transitioned from an ordered to a disordered state. Our results indicate that roasting enhances the antioxidant activity of protein-polyphenol complexes by altering the secondary and tertiary structures of these proteins, thereby exposing more hydrophobic side-chain groups inside the proteins and offering more binding sites for polyphenols.

Inhibition of amyloid formation of prion fragment (106-128) by polyphenolic compounds

Prion diseases are characterized by the self-association and amyloid formation of misfolded prion proteins. Developing effective inhibitors of protein aggregation is critical for therapeutic intervention. In this study, we systematically evaluated a range of polyphenolic compounds as potential inhibitors of amyloid fibril formation of PrP(106-128), a prion fragment crucially involved in prion aggregation and propagation. Our findings demonstrate that the basic aromatic backbone structure of flavone alone is insufficient to inhibit PrP(106-128) amyloid formation. Remarkably, flavone molecules containing adjacent hydroxyl groups on the phenolic B or A ring efficiently inhibited PrP(106-128) fibrillization, whereas compounds lacking vicinal hydroxyl groups were less effective in inhibiting amyloid formation. Epigallocatechin-3-gallate (EGCG) was one of the most potent inhibitors found in this study, with the gallate moiety playing an active role in the inhibitory function. Our findings indicate a structure-dependent inhibition activity of the phenolic small molecules, where the number and positioning of hydroxyl groups on the phenyl ring play a pivotal role in inhibiting the aggregation of the peptide. The auto-oxidation of the catechol or pyrogallol moieties to form quinone structures, followed by their reaction with amino acid side chains of the peptide to form covalent adducts, likely account for the inhibitory activity of these phenolic compounds on PrP(106-128) amyloidogenesis. These results will help the design of novel polyphenolic molecules with optimized structural features as potent inhibitors of amyloid formation of both PrP(106-128) and the full-length prion proteins.

Antioxidant, Polyphenol, Physical, and Sensory Changes in Myofibrillar Protein Gels Supplemented with Polyphenol-Rich Plant-Based Additives

BACKGROUND

Plant-based additives such as blackcurrant juice and pomace, as well as herbal extracts from Melissa officinalis and Centella asiatica, possess well-established health-promoting properties. This study aimed to investigate how the incorporation of polyphenol-rich plant-based additives into a myofibrillar protein matrix could enhance the nutritional value, antioxidant potential, and sensory quality of novel food gels.

METHODS

Myofibrillar protein gels were enriched with selected plant-based additives. Antioxidant properties were assessed using the ABTS radical cation decolorization assay, DPPH radical scavenging assay, and the Ferric Reducing Antioxidant Power (FRAP) assay. Polyphenol profiles were determined with emphasis on flavonols, flavan-3-ols, and chlorogenic acids. Physicochemical properties including pH, color, texture, energetic value, dry matter, and ash contents were measured. Sensory evaluation was conducted using consumer preference tests and descriptive sensory profiling.

RESULTS

Enriched gels contained bioactive compounds such as catechins, procyanidins, chlorogenic acids, and anthocyanins, whose presence correlated with distinct antioxidant activities. Blackcurrant pomace significantly elevated both total polyphenol content and antioxidant capacity, imparting a vivid red-purple color that influenced consumer perception. Melissa officinalis extract enhanced antioxidant potential and introduced a mild, pleasant aroma. Centella asiatica extract further improved the nutritional profile and oxidative stability of the gels, demonstrating additive and synergistic effects in both functional and sensory dimensions.

CONCLUSIONS

Polyphenol-rich plant-based additives, particularly blackcurrant pomace and extracts from M. officinalis and C. asiatica, markedly improve the antioxidant capacity, nutritional value, and sensory appeal of myofibrillar protein-based food gels. These findings support their potential application in the development of functional food products tailored to consumer expectations.

Antioxidant High-Fluorescent Silkworm Silk Development Based on Quercetin-Induced Luminescence

The fluorescent silk produced by feeding silkworms with traditional fluorescent dyes is limited in functionality and suffers from fluorescence quenching, rendering it unsuitable for long-term stable performance as a medical implant material in the human body. This work introduces an innovative strategy to develop a novel multifunctional fluorescent silk composite by incorporating quercetin (QR), a naturally occurring molecule with aggregation-induced emission (AIE) characteristics, into the diet of silkworms. Silk derived from QR-fed silkworms presents significant enhancements in fluorescence, antioxidant, and mechanical properties, with the QR-2.5% group presenting the best overall performance. The resulting silk exhibits superstrong blue fluorescence when exposed to 405 nm laser light, with a breaking strength of 4.26 ± 0.42 cN/D and a breaking energy of 5.96 ± 1.32 cN/cm, improvements of 15.76% and 18.25%, respectively, in comparison with regular silk. Fourier transform infrared spectroscopy (FTIR) analysis indicates that QR induces a structural transformation of fibroin protein from α-helix and random coil to β-sheet configuration, thereby increasing silk crystallinity. Additionally, compared with regular silk, the antioxidant properties of both sericin and silk fibroin increased by 88.66% and 17.25%, respectively. At the same time, this multifunctional silk has excellent biocompatibility and strong cell adhesion. The high-strength, uniformly luminescent silk developed in this study has outstanding antioxidant and mechanical properties. It effectively avoids the fluorescence quenching issue common in traditional fluorescent silk materials and introduces new functionalities. This advancement is significant for increasing the utility of functionally modified silk.

Functional, structural, and rheological properties of the complexes containing sunflower petal extract with dairy and plant-based proteins

This study aims to investigate the impact of sunflower petal extract (SFE) on the functional and structural properties of sodium caseinate and chickpea proteins. For this purpose, 3.5 % of sodium caseinate solution and 3.5 % of protein extracted from chickpea powder were prepared in phosphate buffer (pH = 7). SFE was used at different concentrations, from 1 to 3 % in different protein solutions and functional, structural and rheological properties were measured. The results revealed that complexation of SFE with different proteins can enhance the antioxidant, foaming properties, solubility, emulsion activity, emulsion stability, viscoelastic behavior, and can decrease surface hydrophobicity. FTIR and docking results showed that the most bonding type was non-covalent bonds. Major phenolic compounds containing heliannone A, B, and kaempferol had strong affinity with sodium caseinate, and then chickpea protein. Therefore, the results demonstrated that SFE and its complexes had appropriate emulsifying properties that reduces interfacial tension in the water/oil interface.

Versatile inulin/trans-ferulic acid/silk sericin nanoparticles-nourished probiotic complex with prolonged intestinal retention for synergistic therapy of inflammatory bowel disease

To achieve effective long-term synergistic treatment of inflammatory bowel disease (IBD) with probiotics, we developed a versatile inulin/trans-ferulic acid/silk sericin nanoparticles-nourished probiotic complex. Inulin/TFA/SS nanoparticles were fabricated by inulin, trans-ferulic acid (TFA), and silk sericin (SS), and then loaded onto the surface of poly-l-lysine (PLL) and poly-glutamic acid (PGA)-coated Bifidobacterium longum (BL) to obtain BL@PLL-PGA-Inulin/TFA/SS NPs (BL@PP-NPs). This design simultaneously endowed the complex with excellent gastrointestinal resistance, antioxidant, and anti-inflammation abilities. Moreover, the inulin in the nanoparticles acts as a prebiotic, promoting the Bifidobacterium's rapid proliferation to exert effects within a short period. Compared with uncoated BL, BL@PP-NPs exhibited excellent gastric acid tolerance and up to 31.32-fold colonic colonization, and the ROS scavenging and proliferative capacity were increased by 5.61- and 1.39-fold, respectively. In a mouse model of dextran sulfate sodium (DSS)- and trinitrobenzene sulfonic acid (TNBS)-induced colitis, the components of Inulin/TFA/SS NPs synergized with probiotics to efficiently treat IBD by attenuating oxidative stress, decreasing inflammation, repairing intestinal barrier, and promoting the rapid proliferation of probiotics to reverse gut microbial disorders. Collectively, food-grade BL@PP-NPs represent a novel approach to probiotic modification that offers an effective, safe, and synergistic therapy for IBD.

Enhancement of Physicochemical and Functional Properties of Chicken Breast Protein Through Polyphenol Conjugation: A Novel Ingredient for Protein Supplements

Polyphenol conjugation has emerged as a promising approach to enhance the technological properties and physiological benefits of food proteins. This study investigated the effects of polyphenol conjugation on the technological properties, antioxidant capacity, and in vitro digestibility of chicken breast (CB) proteins. Conjugation with (-)-epigallocatechin 3-gallate (EGCG) and tannic acid (TA) significantly reduced sulfhydryl content. EGCG conjugates exhibited higher turbidity and greater molecular weight aggregates (>245 kDa). Fourier-transform infrared spectroscopy (FTIR) revealed alterations in protein secondary structures, with shifts in amide I and II bands. Polyphenol conjugation significantly enhanced the water-holding capacity of chicken muscle proteins, particularly for CB-TA (3.29 g/g) and CB-EGCG (3.13 g/g) compared to the control (2.25 g/g). The emulsion stability index improved notably in CB-EGCG (96.23 min) and CB-TA (87.24 min) compared to the control (69.05 min). Color analysis revealed darker and more intense hues for CB-EGCG, while CB-TA maintained a lighter appearance, making it potentially preferable for industrial applications requiring neutral-colored powders. Moreover, polyphenol conjugation could enhance antioxidant capacity, particularly in conjugates with EGCG (p < 0.05). In vitro protein digestibility remained comparable across treatments (p > 0.05). Our findings could indicate the potential of chicken muscle protein-polyphenol conjugates as innovative ingredients for high-quality protein supplements.

Formulation and Characterization of Sodium Caseinate/Phloretin Complexes as Antioxidant Stabilizers in Oil-in-Water Emulsions

Emulsifiers with antioxidant properties, such as protein/polyphenol complexes, adsorb at the oil-water interface and improve the physical and oxidative stability of emulsions. Here, 2% (w/w) sodium caseinate and varying concentrations of phloretin (0-10 mM) were used to stabilize oil-in-water emulsions. Control emulsions with protein alone showed poor stability with increased droplet sizes from 0.33 µm to 5.18 µm after 30 days, while no significant change was observed in emulsions containing phloretin (remaining below 400 nm). The in vitro antioxidant activities increased with increasing phloretin concentrations (0 to 10 mM). In the ABTS assay, the antioxidant activity improved from 14.02 ± 8.33% to 95.09 ± 1.31%, and in the DPPH assay, it increased from 32.59 ± 2.73% to 99.03 ± 0.14%. Similarly, the oxidative stability of the emulsions improved with increasing phloretin concentrations (0 to 10 mM). After 30 days of storage, PV decreased from 38.22 ± 2.58 µM to 11.81 ± 2.55 µM, and MDA content reduced from 48.43 ± 0.31 µM to 7.24 ± 0.21 µM. Measuring the apparent viscosity demonstrated a reduction in viscosity with the addition of phloretin. These findings demonstrate that incorporating phloretin into sodium caseinate-stabilized emulsions as a novel antioxidant emulsifier can be an effective strategy to extend the shelf life of emulsified food products prone to oxidative deterioration.

Self-Assembled Pt/Honokiol Nanomicelles for the Treatment of Sepsis-Associated Acute Kidney Injury

Sepsis is a severe and complex systemic infection that can result in multiple organ dysfunction. Sepsis-associated acute kidney injury (SAKI), caused by inflammatory response, oxidative stress, and cellular apoptosis, is a common complication that seriously impacts patient survival rates. Herein, a potent and novel metal-polyphenol nanomicelle can be efficiently self-assembled with Pt4+ and honokiol (HK) by the chelation, π-π conjugation, hydrophobic action, and the surfactant properties of Tween-80. These nanomicelles not only enhance drug bioavailability (encapsulation rates: Pt─49%, HK─70%) and reduce drug toxicity (safety dose: <20 μg/g) but also improve targeting toward damaged renal tissues. Furthermore, Pt4+ and HK in the nanomicelles exert a synergistic physiological effect by scavenging free radicals to alleviate oxidative damage, inhibiting macrophage activation and the release of inflammatory factors to regulate inflammation, and displaying broad-spectrum antimicrobial activity to control infection. These actions collectively protect renal tissue and restore its functionality. Here, we constructed metal-polyphenol nanomicelles (Pt/HK-NMs) via ingenious and efficient self-assembly, providing a new strategy to compensate for deficiencies in the hemodialysis and antibiotic treatment of SAKI.

Antioxidant and Anti-Obesity Properties of Acidic and Alkaline Seaweed Extracts Adjusted to Different pH Levels

This research examined antioxidant and anti-obesity effects of Palmaria palmata extracts obtained through acidic or alkaline treatments and subsequent pH adjustments. After two rounds of acidic or alkaline extraction, the extracts were separated from biomass and adjusted to different pH values: for acidic extracts, pH 3 (no adjustment), pH 6, pH 9, and pH 12; for alkaline extracts, pH 12 (no adjustment), pH 9, pH 6, and pH 3. The findings revealed that extraction medium as well as subsequent pH adjustments significantly influenced composition of the extracts in terms of protein content and recovery, amino acids, and phenolic compounds (p < 0.05). Acidic conditions produced extracts with potent radical scavenging, especially at pH 6 (IC50 = 0.30 ± 0.04 mg.mL-1), while alkaline conditions favored metal chelating, with the highest Fe2+ chelation at pH 12 (IC50 = 0.65 ± 0.03 mg.mL-1). Moreover, extracts showed inhibitory activities against porcine pancreatic lipase and α-amylase, with the acidic extract at pH 9 showing the best anti-obesity properties (IC50 = 5.38 ± 0.34 mg.mL-1 for lipase and IC50 = 5.79 ± 0.30 mg.mL-1 for α-amylase). However, the highest α-amylase activity was in the alkaline extract at pH 12 (IC50 = 3.05 ± 0.66 mg.mL-1). In conclusion, adjusting the pH of seaweed extracts notably influences their bioactive properties, likely due to changes in the reactivity and interactions of bioactive compounds such as peptides, carbohydrates, and polyphenols.

Phenolic Profiling, In Vitro Antiglycation, Antioxidant Activities, and Antidiabetic Effect of Algerian Trigonella Foenum-Graecum L. in Rats Administered a β-Cell Toxicant

This study sought to quantitatively assess individual and total polyphenols, mineral composition, antioxidant and antiglycation activities of Algerian fenugreek seeds (AFS) as well as the antidiabetic effect of its supplementation on streptozotocin-induced diabetic rats. Forty rats were divided into four groups (i) non diabetic rats, (ii) non diabetic rats +10 % AFS, (iii) diabetic rats, (iv) diabetic rats +10 % AFS. Flame-SAA analysis revealed a rich content in micro-elements, HPLC DAD-FLD analysis revealed twenty components with rutin and ferulic acid being the major compounds in AFS hydro-methanolic extract while spectrophotometric assays scrutinized moderate contents in total phenolics and flavonoids. The extract was potent in scavenging ABTS⋅+ and DPPH+ (42.06±2.14 and 55.84±4.14 mg TE/g), reducing Fe3+ and Mo6+ (35.12±2.45 and 29.89±3.12 mg TE/g) and inhibiting AGEs (IC50=1.03±0.02 mg/ml). In vivo, 10 %AFS- supplemented diet (w/w) was found to elicit a significant reduction in glycemia (66.74 %), TNF α (9.4 %), IL-6 (23.74 %), CRP (31.10 %), liver enzymes, lipid peroxidation (MDA) (47.24 %;30 %), protein carbonyl (PCO) (28.35 %; 27.15 %), improvement in insulin level (79.74 %), reduced glutathione amount (GSH) (41.01 %; 16.55 %), glutathione peroxidase (GPx) (45.80 %; 56.37 %), catalase (CAT) (24.44 %; 35.42 %) and glutathione-S-transferase (GST) (22.78 %; 22.90 %) activities, in liver and pancreas respectively, along with a rejuvenation of hepatic and pancreatic histological features. These outcomes disclosed that AFS is endowed with biologically effective components which could be decent applicant to attain the objective of mitigating glycation, oxidative stress and diabetes-related complications.

Enhanced Antioxidant and Digestive Enzyme Inhibitory Activities of Pacific White Shrimp Shell Protein Hydrolysates via Conjugation with Polyphenol: Characterization and Application in Surimi Gel

Pacific white shrimp shell protein hydrolysates (SSPHs) produced using alcalase (UAH) and papain (UPH), and polyphenols (PPNs) conjugates were prepared using variable concentrations (0.5-3% w/v) of different polyphenols (EGCG, catechin, and gallic acid). When 2% (v/v) of a redox pair was used for conjugation, 0.5% (w/v) of PPNs resulted in the highest conjugation efficiency (CE), regardless of the polyphenol types. However, CE decreased further with increasing levels of PPNs (p < 0.05). SSPHs at 2% retained the highest CE when combined with the selected PPN and redox pair concentrations (p < 0.05). FTIR and 1H-NMR analysis confirmed the successful conjugation of PPNs with the SSPHs. Among all the conjugates, EGCG conjugated with UAH (A-E) or UPH (P-E) exhibited the highest DPPH/ABTS radical scavenging, and metal chelating activities, respectively. The highest FRAP activity was noticed for A-E conjugate followed by UAH-catechin (A-C) and UPH-catechin (P-C) conjugates. The A-C sample (6 mg/mL) demonstrated the strongest inhibition efficiency against α-amylase, α-glucosidase, and pancreatic lipase (89.29, 81.23, and 80.69%, respectively) than other conjugates (p < 0.05). When A-C conjugate was added into surimi gels prepared from Indian mackerel (IM) and threadfin bream (TH) mince at various levels (2-6%; w/w), gel strength, and water holding capacity was increased in a dose-dependent manner, regardless of surimi type. However, whiteness decreased with increasing A-C levels. After the in vitro digestion of surimi gels, antioxidant and enzyme inhibitory activities were also increased as compared to the digest prepared from control surimi gels (added without A-C conjugate). Thus, waste from the shrimp industry in conjugation with plant polyphenols could be utilized to produce antioxidant and antidiabetic or anti-obesity agents, which could be explored as a promising additive in functional foods and nutraceuticals.

Rethinking Nanoparticle Synthesis: A Sustainable Approach vs. Traditional Methods

This review portrays a comparison between green protocols and conventional nanoparticle (NP) synthesis strategies, highlighting each method's advantages and limitations. Various top-down and bottom-up methods in NP synthesis are described in detail. The green chemistry principles are emphasized for designing safe processes for nanomaterial synthesis. Among the green biogenic sources plant extracts, vitamins, enzymes, polysaccharides, fungi (Molds and mushrooms), bacteria, yeast, algae, and lichens are discussed. Limitations in the reproducibility of green protocols in terms of availability of raw material, variation in synthetic protocol, and selection of material due to geographical differences are elaborated. Finally, a conclusion is drawn utilizing green chemical principles, & a circular economy strategy to minimize waste generation, offering a promising framework for the synthesis of NPs emphasizing sustainability.

Microencapsulation of green tea polyphenols: Utilizing oat oil and starch-based double emulsions for improved delivery

The stability and bioavailability of green tea polyphenols, crucial for their health benefits, are compromised by environmental sensitivity, limiting their use in functional foods and supplements. This study introduces a novel water-in-oil-in-water double emulsion technique with microwave-assisted extraction, significantly enhancing the stability and bioavailability of these compounds. The primary objective of this study was to assess the effectiveness of several encapsulating agents, such as gum Arabic as control and native and modified starches, in improving encapsulated substances' stability and release control. Native and modified starches were chosen for their outstanding film-forming properties, improving encapsulation efficiency and protecting bioactive compounds from oxidative degradation. The combination of maltodextrin and tapioca starch improved phenolic content retention, giving 46.25 ± 2.63 mg/g in tapioca starch microcapsules (GTTA) and 41.73 ± 3.24 mg/g in gum arabic microcapsules (GTGA). Besides the control, modified starches also had the most potent antioxidant activity, with a 45 % inhibition (inh%) in the DPPH analysis. Oat oil was utilized for its superior viscosity and nutritional profile, boosting emulsion stability and providing the integrity of the encapsulated polyphenols, as indicated by the microcapsules' narrow span index (1.30 ± 0.002). The microcapsules' thermal behavior and structural integrity were confirmed using advanced methods such as Differential Scanning Calorimetry (DSC) and Fourier-Transform Infrared Spectroscopy (FT-IR). This study highlights the critical role of choosing appropriate wall materials and extraction techniques. It sets a new standard for microencapsulation applications in the food industry, paving the way for future innovations.

A metal-phenolic coordination framework nanozyme exhibits dual enzyme mimicking activity and its application is effective for colorimetric detection of biomolecules

Biomolecules play vital roles in many biological processes and diseases, making their identification crucial. Herein, we present a colorimetric sensing method for detecting biomolecules like cysteine (Cys), homocysteine (Hcy), and glutathione (GSH). This approach is based on a reaction system whereby colorless 3,3',5,5'-tetramethylbenzidine (TMB) undergoes catalytic oxidation to form blue-colored oxidized TMB (ox-TMB) in the presence of hydrogen peroxide (H2O2), utilizing the peroxidase and catalase-mimicking activities of metal-phenolic coordination frameworks (MPNs) of Cu-TA, Co-TA, and Fe-TA nanospheres. The Fe-TA nanospheres demonstrated superior activity, more active sites and enhanced electron transport. Under optimal conditions, the Fe-TA nanospheres were used for the detection of biomolecules. When present, biomolecules inhibit the reaction between TMB and H2O2, causing various colorimetric responses at low detection limits of 0.382, 0.776 and 0.750 μM for Cys, Hcy and GSH. Furthermore, it was successfully applied to real water samples with good recovery results. The developed sensor not only offers a rapid, portable, and user-friendly technique for multi-target analysis of biomolecules at low concentrations but also expands the potential uses of MPNs for other targets in the environmental field.

Antioxidant Metabolism Pathways in Vitamins, Polyphenols, and Selenium: Parallels and Divergences

Free radicals (FRs) are unstable molecules that cause reactive stress (RS), an imbalance between reactive oxygen and nitrogen species in the body and its ability to neutralize them. These species are generated by both internal and external factors and can damage cellular lipids, proteins, and DNA. Antioxidants prevent or slow down the oxidation process by interrupting the transfer of electrons between substances and reactive agents. This is particularly important at the cellular level because oxidation reactions lead to the formation of FR and contribute to various diseases. As we age, RS accumulates and leads to organ dysfunction and age-related disorders. Polyphenols; vitamins A, C, and E; and selenoproteins possess antioxidant properties and may have a role in preventing and treating certain human diseases associated with RS. In this review, we explore the current evidence on the potential benefits of dietary supplementation and investigate the intricate connection between SIRT1, a crucial regulator of aging and longevity; the transcription factor NRF2; and polyphenols, vitamins, and selenium. Finally, we discuss the positive effects of antioxidant molecules, such as reducing RS, and their potential in slowing down several diseases.

Antibacterial Activity of Plant Polyphenols Belonging to the Tannins against Streptococcus mutans-Potential against Dental Caries

Dental caries (DC) is the most common oral pathology. The main bacteria responsible for DC is Streptococcus mutans. One of the strategies that can decrease or eliminate the risk of DC development is using compounds that will inhibit both the growth and virulence factors of S. mutans. Tannins are plant polyphenols that have strong antibacterial activity. The purpose of this study was to assess the antibacterial activity of three tannins against S. mutans. In this investigation, microbiological tests (MIC and MBC) and physicochemical techniques like the fluorescence measurements of tannins' interaction with S. mutans cell membrane and membrane proteins, zeta potential, and thermodynamic analyses were used to obtain knowledge about the antibacterial potential of the investigated compounds against S. mutans as well as about the mechanisms associated with antibacterial activity. The obtained results demonstrate that the used compounds exhibit high antibacterial activity against S. mutans. The mechanisms of their antibacterial activity are linked to the strong change in the S. mutans membrane fluidity and potential, and to their interaction with membrane proteins that can result in great disturbance of bacterial physiology and ultimately the inhibition of bacterial growth, triggering their death. Therefore, it can be concluded that the investigated compounds can be potentially used as natural factors in the prevention of dental caries.

Tannic acid adsorption properties of cellulose nanocrystalline/fish swim bladder gelatin composite sponge

Foods and beverages with excessive tannins acid (TA) content taste astringent and bitter. The overconsumption of TA could result in nutritional and digestive problems. In this study, the cellulose nanocrystals (CNC)/fish swim bladder gelatin (FG) composite sponge was prepared with glutaraldehyde as a crosslinking agent. The TA adsorption performance of the sponge was discussed. The freeze-dried CNC/FG composite sponge had a porous network structure. CNC was combined into the FG matrix as a reinforcing phase. The mechanical strength, thermal stability, and swelling properties of the composite sponge were improved with the addition of an appropriate amount of CNC. Although CNC decreased the porosity of composite sponge, the increase in active adsorption sites resulted in an overall positive effect on its TA adsorption properties. Under the optimal adsorption conditions, the TA removal rate of 1.0 % CNC composites reached 80.4 %. Furthermore, the sponge retained a TA removal rate of 54 % after five cycles of adsorption and desorption using 50 % ethanol. The results demonstrated that CNC/FG composite sponge has application potential in the field of adsorption materials for TA.

The Pharmacological Properties of Red Grape Polyphenol Resveratrol: Clinical Trials and Obstacles in Drug Development

Resveratrol is a stilbenoid from red grapes that possesses a strong antioxidant activity. Resveratrol has been shown to have anticancer activity, making it a promising drug for the treatment and prevention of numerous cancers. Several in vitro and in vivo investigations have validated resveratrol's anticancer capabilities, demonstrating its ability to block all steps of carcinogenesis (such as initiation, promotion, and progression). Additionally, resveratrol has been found to have auxiliary pharmacological effects such as anti-inflammatory, cardioprotective, and neuroprotective activity. Despite its pharmacological properties, several obstacles, such as resveratrol's poor solubility and bioavailability, as well as its adverse effects, continue to be key obstacles to drug development. This review critically evaluates the clinical trials to date and aims to develop a framework to develop resveratrol into a clinically viable drug.