Structure-Functional Study of Tyrosine and Methionine Dipeptides: An Approach to Antioxidant Activity Prediction

Walnut oil as a dietary intervention for atherosclerosis: Efficacy and mechanistic pathways

BACKGROUND AND AIMS

Walnut oil (WO) and peanut oil (PO) are common vegetable oils rich in unsaturated fatty acids, known to alleviate atherosclerosis (AS) and reduce the risk of cardiovascular diseases (CVD). WO contains a higher proportion of polyunsaturated fatty acids (PUFAs) compared to PO. This study aimed to explore the influence of WO on AS and elucidate its potential mechanisms, providing a theoretical basis for enhancing the application of WO in functional foods and pharmaceuticals.

METHODS

AS was established in rats using a high-fat diet and vitamin D3 injections. Rats with AS were administered WO or PO via gavage at a dose of 1.2 g/kg for 4 weeks. Serum lipid levels and arterial injury were assessed, and transcriptomic and metabolomic analyses of the rat vasculature were performed.

RESULTS

Both WO and PO significantly lowered serum lipid levels and the atherogenic index (AI) in rats, reducing arterial wall injury and plaque formation. WO exhibited a more pronounced effect, particularly in decreasing serum levels of TG, TC, HDLC, and LDL-C. Transcriptomic analysis indicated that fatty acid, amino acid metabolism were crucial in AS development due to a high-fat diet. Metabolomic analysis indicated significant changes in the metabolism of arginine, proline, cysteine, methionine, glycine, serine and threonine in rats treated with WO.

CONCLUSION

WO and PO help alleviate AS by regulating lipid metabolism and influencing pivotal metabolic pathways like TCA cycle and cysteine-methionine metabolism. The more significant impact of WO indicates its potential as a dietary supplement for preventing and treating AS.

Hydrophobic corn zein-modified cellulose nanofibril (CNF) films with antioxidant properties

Cellulose nanofibrils (CNFs) can form strong biodegradable films; however, due to their hydrophilicity, moisture can degrade their mechanical and barrier properties. Corn zein (CZ) is a hydrophobic protein that when covalently linked with CNF films through peptide bonds, may improve their hydrophobicity. CZ was covalently linked to aminophenylacetic acid and aminobenzoic acid esterified CNF films which were then assessed for evidence of modification, hydrophobicity, mechanical properties, and antioxidant activity. Upon modification, an increase in hydrophobicity and an increase in antioxidant activity as evidenced by 57% higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 26% higher (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) ABTS scavenging activities when compared to control CNF films, and reduced thio barbituric acid reactive substances (TBARS) values in canola oil during 14 days of 50 °C storage were noted. Results demonstrate that modification of CNF films with a hydrophobic protein such as CZ can increase the hydrophobicity of these biodegradable films while providing active antioxidant functionality.

Theoretical Design of New Grafted Molecules d-Glucosamine-Oxyresveratrol-Essential Amino Acids: DFT Evaluation of the Structure-Antioxidant Activity

In the pursuit of innovative high-performance materials suitable for antioxidant applications, the density functional theory was employed to design a series of compounds derived from small biodegradable organic molecules. This study involved grafting the negatively charged unit d-glucosamine (GleN) and essential amino acids onto the 3 and 4' carbons of the backbone of trans-2,4,3',5'-tetrahydroxystilbene (trans-OXY), respectively. The aim was to prevent trans-OXY degradation into the cis region and enhance its electronic and antioxidant properties. Theoretical calculations using DFT/PW91/TZP in water revealed that the designed biomolecules (GleN-OXY-AA) outperformed both free OXY units and essential amino acids in terms of antioxidant efficacy, as indicated by the bond dissociation energy (BDE) findings. Notably, GleN-OXY-Ile and GleN-OXY-Trp compounds exhibited an average BDE of 66.355 kcal/mol, translating to 1.82 times the activity of t-OXY and 1.55 times the action of ascorbic acid (Vit C). AIM analysis demonstrated that the proposed biomaterials favored the formation of quasi-rings through intramolecular H···O hydrogen bonds, promoting π-electron delocalization and stabilization of radical, cationic, and anionic forms. Quantum calculations revealed the release of hydrogen atoms or electrons from sites of reduced electronegativity, visually identified by MEP maps and estimated by Hirshfeld atomic charges.

Mitigating Effect of Lepidium sativum Seeds Oil on Ovarian Oxidative Stress, DNA Abnormality and Hormonal Disturbances Induced by Acrylamide in Rats

Acrylamide (ACR), an industrial compound, causes both male and female reproductive toxicity. Lepidium sativum seeds (L. sativum) (Garden cress) are known for their health benefits as antioxidant, antiasthmatic, anticoagulant, anti-inflammatory, and analgesic agents. Therefore, this study aimed to investigate the phytochemistry and nutritional value of L. sativum seeds oil for attenuating the ovarian damage induced by acrylamide in rats. The phytochemical investigation of the seeds revealed the presence of vitamins, potassium, iron, sugar and amino acids. Twenty eight compounds from the unsaponifiable fraction and twenty three compounds from the saponifiable fraction were identified. Three sterols and two triterpenes were isolated and identified as β-sitosterol (1), ▵5-avenasterol (2), friedelanol (3), stigmasta-4, 22-dien-3-one (4), and ursolic acid (5). Treatment of acrylamide-induced rats with L. sativum seeds oil ameliorated prolactin (PRL), progesterone (P4), estradiol (E2), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF- α) with variable degrees. The histopathological findings of ovaries supported these results. In conclusion, compounds (3-5) were isolated for the first time from L. sativum seeds oil. The seeds oil attenuated the ovarian damage and could potentially be a new supplemental agent against female infertility.

Stability of Protein Pharmaceuticals: Recent Advances

There have been significant advances in the formulation and stabilization of proteins in the liquid state over the past years since our previous review. Our mechanistic understanding of protein-excipient interactions has increased, allowing one to develop formulations in a more rational fashion. The field has moved towards more complex and challenging formulations, such as high concentration formulations to allow for subcutaneous administration and co-formulation. While much of the published work has focused on mAbs, the principles appear to apply to any therapeutic protein, although mAbs clearly have some distinctive features. In this review, we first discuss chemical degradation reactions. This is followed by a section on physical instability issues. Then, more specific topics are addressed: instability induced by interactions with interfaces, predictive methods for physical stability and interplay between chemical and physical instability. The final parts are devoted to discussions how all the above impacts (co-)formulation strategies, in particular for high protein concentration solutions.'

Black soldier fly (Hermetia illucens L.): A potential small mighty giant in the field of cosmeceuticals

Background and Aims

Natural products are widely used in the pharmaceutical and cosmetics industries due to their high-value bioactive compounds, which make for "greener" and more environmentally friendly ingredients. These natural compounds are also considered a safer alternative to antibiotics, which may result in antibiotic resistance as well as unfavorable side effects. The development of cosmeceuticals, which combine the cosmetic and pharmaceutical fields to create skincare products with therapeutic value, has increased the demand for unique natural resources. The objective of this review is to discuss the biological properties of extracts derived from larvae of the black soldier fly (BSF; Hermetia illucens), the appropriate extraction methods, and the potential of this insect as a novel active ingredient in the formulation of new cosmeceutical products. This review also addresses the biological actions of compounds originating from the BSF, and the possible association between the diets of BSF larvae and their subsequent bioactive composition.

Methods

A literature search was conducted using PubMed and Google Scholar to identify and evaluate the various biological properties of the BSF.

Results

One such natural resource that may be useful in the cosmeceutical field is the BSF, a versatile insect with numerous potential applications due to its nutrient content and scavenging behavior. Previous research has also shown that the BSF has several biological properties, including antimicrobial, antioxidant, anti-inflammatory, and wound healing effects.

Conclusion

Given the range of biological activities and metabolites possessed by the BSF, this insect may have the cosmeceutical potential to treat a number of skin pathologies.

Mendelian randomization analysis reveals causal associations of serum metabolites with sepsis and 28-day mortality

Metabolic disorder has been found to be an important factor in the pathogenesis and progression of sepsis. However, the causation of such an association between serum metabolites and sepsis has not been established. We conducted a two-sample Mendelian randomization (MR) study. A genome-wide association study of 486 human serum metabolites was used as the exposure, whereas sepsis and sepsis mortality within 28 days were set as the outcomes. In MR analysis, 6 serum metabolites were identified to be associated with an increased risk of sepsis, and 6 serum metabolites were found to be related to a reduced risk of sepsis. Furthermore, there were 9 metabolites positively associated with sepsis-related mortality, and 8 metabolites were negatively correlated with sepsis mortality. In addition, "glycolysis/gluconeogenesis" (p = 0.001), and "pyruvate metabolism" (p = 0.042) two metabolic pathways were associated with the incidence of sepsis. This MR study suggested that serum metabolites played significant roles in the pathogenesis of sepsis, which may provide helpful biomarkers for early disease diagnosis, therapeutic interventions, and prognostic assessments for sepsis.

Human blood metabolites and risk of sepsis: A Mendelian randomization investigation

BACKGROUND

Evidence supports the observational correlations between human blood metabolites and sepsis. However, whether these associations represent a causal relationship is unknown. In this study, we applied two-sample Mendelian randomization (MR) analyses to examine causality between genetically proxied 486 blood metabolites and sepsis risk.

METHODS

We used summary data from genome-wide association studies (GWAS) on 486 metabolites involving 7824 individuals as exposure and a sepsis GWAS including 11,643 cases and 474,841 controls as the outcome. The inverse-variance weighted (IVW) was the primary method to estimate the causal relationship between exposure and outcome, with MR-Egger and weighted median serving as supplements. Sensitivity analyses were implemented with Cochrane's Q test, MR-Egger intercept, MR-PRESSO and leave-one-out analysis. In addition, we performed replication MR, meta-analysis, Steiger test, linkage disequilibrium score (LDSC) regression and multivariable MR (MVMR) to thoroughly verify the causation.

RESULTS

We identified that genetically determined high levels of 1-oleoylglycerophosphoethanolamine (odds ratio (OR) = .52, 95% confidence interval (CI): .31-.87, p = .0122), alpha-glutamyltyrosine (OR = .75, 95% CI: .60-.93, p = .0102), heptanoate (7:0) (OR = .51, 95% CI: .33-.81, p = .0041) and saccharin (OR = .84, 95% CI: .74-.94, p = .0036) were causally associated with a lower risk of sepsis. MVMR analysis demonstrated the independent causal effect of these metabolites on sepsis.

CONCLUSIONS

These findings indicated that four blood metabolites have a protective impact on sepsis, thus providing novel perspectives into the metabolite-mediated development mechanism of sepsis by combining genomics and metabolomics.

Antioxidant and Angiotensin-Converting Enzyme Inhibitory Activity of Faba Bean-Derived Peptides After In Vitro Gastrointestinal Digestion: Insight into Their Mechanism of Action

Faba bean flour, after in vitro gastrointestinal digestion, showed important antioxidant and angiotensin-converting enzyme (ACE) inhibitory activities. In the present study, 11 faba bean- derived peptides were synthesized to confirm their bioactivities and provide a deeper understanding of their mechanisms of action. The results revealed that 7 peptides were potent antioxidants, namely, NYDEGSEPR, TETWNPNHPEL, TETWNPNHPE, VIPTEPPH, VIPTEPPHA, VVIPTEPPHA, and VVIPTEPPH. Among them, TETWNPNHPEL had the highest activity in the ABTS (EC50 = 0.5 ± 0.2 mM) and DPPH (EC50 = 2.1 ± 0.1 mM) assays (p < 0.05), whereas TETWNPNHPE had the highest activity (p < 0.05) in the ORAC assay (2.84 ± 0.08 mM Trolox equivalent/mM). Synergistic and/or additive effects were found when selected peptides (TETWNPNHPEL, NYDEGSEPR, and VVIPTEPPHA) were combined. Four peptides were potent ACE inhibitors, where VVIPTEPPH (IC50 = 43 ± 1 μM) and VVIPTEPPHA (IC50 = 50 ± 5 μM) had the highest activity (p < 0.05), followed by VIPTEPPH (IC50 = 90 ± 10 μM) and then VIPTEPPHA (IC50 = 123 ± 5 μM) (p < 0.05). These peptides were noncompetitive inhibitors, as supported by kinetic studies and a molecular docking investigation. This study demonstrated that peptides derived from faba beans have multifunctional bioactivities, making them a promising food-functional and nutraceutical ingredient.

l-Me-thion-yl-l-tyrosine monohydrate

The study of the oxidation of various proteins necessitates scrutiny of the amino acid sequence. Since me-thio-nine (Met) and tyrosine (Tyr) are easily oxidized, peptides that contain these amino acids are frequently studied using a variety of oxidation methods, including, but not limited to, pulse radiolysis, electrochemical oxidation, and laser flash photolysis. To date, the oxidation of the Met-Tyr dipeptide is not fully understood. Several investigators have proposed a mechanism of intra-molecular electron transfer between the sulfide radical of Met and the Tyr residue. Our elucidation of the structure and absolute configuration of l-Met-l-Tyr monohydrate, C14H20N2O4S·H2O (systematic name: (2S)-2-{[(2S)-2-amino-4-methyl-sulfanyl-butano-yl]amino}-3-(4-hy-droxy-phen-yl)propanoic acid monohydrate) is presented herein and provides information about the zwitterionic nature of the dipeptide. We suspect that the zwitterionic state of the dipeptide and its inter-action within the solvent medium may play a major role in the oxidation of the dipeptide. In the crystal, all the potential donor atoms inter-act via strong N-H⋯O, C-H⋯O, O-H⋯S, and O-H⋯O hydrogen bonds.

Formation of a Purple Product upon the Reaction of ABTS Radicals with Proteins

The reaction of the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) free radical (ABTS^●) with proteins (bovine serum albumin, blood plasma, egg white, erythrocyte membranes, and Bacto Peptone) leads not only to a reduction of ABTS^● but also to the appearance of a purple color (absorption maximum at 550-560 nm). The aim of this study was to characterize the formation and explain the nature of the product responsible for the appearance of this color. The purple color co-precipitated with protein, and was diminished by reducing agents. A similar color was generated by tyrosine upon reaction with ABTS^●. The most feasible explanation for the color formation is the addiction of ABTS^● to proteins' tyrosine residues. The product formation was decreased by nitration of the bovine serum albumin (BSA) tyrosine residues. The formation of the purple product of tyrosine was optimal at pH 6.5. A decrease in pH induced a bathochromic shift of the spectra of the product. The product was not a free radical, as demonstrated by electrom paramagnetic resonance (EPR) spectroscopy. Another byproduct of the reaction of ABTS^● with tyrosine and proteins was dityrosine. These byproducts can contribute to the non-stoichiometry of the antioxidant assays with ABTS^●. The formation of the purple ABTS adduct may be a useful index of radical addition reactions of protein tyrosine residues.

Preparation and identification of a novel peptide with high antioxidant activity from corn gluten meal

The antioxidant activity of corn peptides is related to their molecular weight and structure. Corn gluten meal (CGM) was hydrolyzed using a combination of Alcalase, Flavorzyme and Protamex, and the hydrolysates were subjected to antioxidant activity analysis after further fractionation. Corn peptides with molecular weights less than 1 kDa (CPP1) exhibited excellent antioxidant activity. A novel peptide, Arg-Tyr-Leu-Leu (RYLL), was identified from CPP1. RYLL displayed preferable scavenging capacities for ABTS radicals and DPPH radicals, with IC₅₀ values of 0.122 mg/ml and 0.180 mg/ml, respectively. Based on quantum calculations, RYLL had multiple antioxidant active sites, and tyrosine was the main active site due to the highest energy of the highest occupied molecular orbit (HOMO). Moreover, the simple peptide structure and hydrogen bond network of RYLL contributed to the exposure of the active site. This study elucidated the antioxidant mechanism of corn peptides, which could provide an understanding for CGM hydrolysates as natural antioxidants.

Exploring the Potential of Black Soldier Fly Larval Proteins as Bioactive Peptide Sources through in Silico Gastrointestinal Proteolysis: A Cheminformatic Investigation

Despite their potential as a protein source for human consumption, the health benefits of black soldier fly larvae (BSFL) proteins following human gastrointestinal (GI) digestion are poorly understood. This computational study explored the potential of BSFL proteins to release health-promoting peptides after human GI digestion. Twenty-six proteins were virtually proteolyzed with GI proteases. The resultant peptides were screened for high GI absorption and non-toxicity. Shortlisted peptides were searched against the BIOPEP-UWM and Scopus databases to identify their bioactivities. The potential of the peptides as inhibitors of myeloperoxidase (MPO), NADPH oxidase (NOX), and xanthine oxidase (XO), as well as a disruptor of Keap1–Nrf2 protein–protein interaction, were predicted using molecular docking and dynamics simulation. Our results revealed that about 95% of the 5218 fragments generated from the proteolysis of BSFL proteins came from muscle proteins. Dipeptides comprised the largest group (about 25%) of fragments arising from each muscular protein. Screening of 1994 di- and tripeptides using SwissADME and STopTox tools revealed 65 unique sequences with high GI absorption and non-toxicity. A search of the databases identified 16 antioxidant peptides, 14 anti-angiotensin-converting enzyme peptides, and 17 anti-dipeptidyl peptidase IV peptides among these sequences. Results from molecular docking and dynamic simulation suggest that the dipeptide DF has the potential to inhibit Keap1–Nrf2 interaction and interact with MPO within a short time frame, whereas the dipeptide TF shows promise as an XO inhibitor. BSFL peptides were likely weak NOX inhibitors. Our in silico results suggest that upon GI digestion, BSFL proteins may yield high-GI-absorbed and non-toxic peptides with potential health benefits. This study is the first to investigate the bioactivity of peptides liberated from BSFL proteins following human GI digestion. Our findings provide a basis for further investigations into the potential use of BSFL proteins as a functional food ingredient with significant health benefits.

Biological Functions of Antioxidant Dipeptides

In the history of modern nutritional science, understanding antioxidants is one of the major topics. In many cases, food-derived antioxidants have π conjugate or thiol group in their molecular structures because π conjugate stabilizes radical by its delocalization and two thiol groups form a disulfide bond in its antioxidative process. In recent years, antioxidant peptides have received much attention because for their ability to scavenge free radicals, inhibition of lipid peroxidation, chelation of transition metal ions, as well as their additional nutritional value. Among them, dipeptides are attracting much interest as post-amino acids, which have residues in common with amino acids, but also have different physiological properties and functions from those of amino acids. Especially, dipeptides containing moieties of several amino acid (tryptophan, tyrosine, histidine, cysteine, and methionine) possess potent antioxidant activity. This review summarizes previous details of structural property, radical scavenging activity, and biological activity of antioxidant dipeptide. Hopefully, this review will help provide a new insight into the study of the biological functions of antioxidant dipeptides.

Modulation of Virulence Gene Expression in Salmonella enterica subsp. enterica typhimurium by Synthetic Milk-Derived Peptides

The hydrolysis of milk proteins produces valuable bioactive peptides, some of which show antivirulence activity. In this study, five synthetic milk-derived peptides (β-LG f(9-18), β-CN f(5-15), β-CN f(17-27), β-CN f(94-106), and β-CN f(129-137)) were shown to decrease the expression of virulence genes in Salmonella enterica subsp. enterica typhimurium when tested at four concentrations (0.02, 0.05, 0.1, and 0.2 mg/ml). A mixture of these synthetic peptides at concentrations of 0.02 and 0.2 mg/ml each significantly downregulated the expression of both hilA and ssrB virulence genes in Salmonella typhimurium after a 3-h incubation. Individually, β-CN f(17-27) at 0.02 mg/ml caused a significant decrease in both hilA and ssrB gene expressions. These results suggest a synergistic interaction between bioactive peptides. Depending on dose and amino acid sequence, these five peptides were able to affect the expression of some virulence genes in Salmonella typhimurium.

A Novel Insight into Screening for Antioxidant Peptides from Hazelnut Protein: Based on the Properties of Amino Acid Residues

This study used the properties of amino acid residues to screen antioxidant peptides from hazelnut protein. It was confirmed that the type and position of amino acid residues, grand average of hydropathy, and molecular weight of a peptide could be comprehensively applied to obtain desirable antioxidants after analyzing the information of synthesized dipeptides and BIOPEP database. As a result, six peptides, FSEY, QIESW, SEGFEW, IDLGTTY, GEGFFEM, and NLNQCQRYM were identified from hazelnut protein hydrolysates with higher antioxidant capacity than reduced Glutathione (GSH) against linoleic acid oxidation. The peptides having Tyr residue at C-terminal were found to prohibit the oxidation of linoleic acid better than others. Among them, peptide FSEY inhibited the rancidity of hazelnut oil very well in an oil-in-water emulsion. Additionally, quantum chemical parameters proved Tyr-residue to act as the active site of FSEY are responsible for its antioxidation. This is the first presentation of a novel approach to excavating desired antioxidant peptides against lipid oxidation from hazelnut protein via the properties of amino acid residues.

New insights into the structure-activity relationships of antioxidative peptide PMRGGGGYHY

The sequence and structure of antioxidant peptides play fundamental roles in their antioxidant functions. However, the structural mechanism of antioxidant peptides is still unclear. In this study, we used quantum calculations to reveal the antioxidant mechanism of the peptide PMRGGGGYHY. PMRGGGGYHY has multiple antioxidant active sites, and two tyrosine residues were determined to be the major active sites. Based on the structure-activity relationships of PMRGGGGYHY, the antioxidant activity of the modified peptide significantly improved by 4.8-fold to 9.73 ± 0.61 μmol TE/μmol. In addition, the removal of glycine residues from PMRGGGGYHY would increase the energy of the HOMOs and simplify the hydrogen bonding network, causing a significant increase in antioxidant activity. The intracellular ROS scavenging ability gradually decreased with decreasing glycine content. This same peptide has very different effects in vitro versus as a cellular antioxidant. This paper provides new insights into the structural mechanism and rational design/modification of novel antioxidant peptides.

Effects of Dietary Supplementation with dl-Methionine and dl-Methionyl-dl-Methionine in Breeding Pigeons on the Carcass Characteristics, Meat Quality and Antioxidant Activity of Squabs

This study aimed to investigate the effects of dietary supplementation with dl-methionine (dl-Met) and dl-methionyl-dl-methionine (dl-Met-Met) in breeding pigeons on the carcass characteristics, meat quality and antioxidant activity of squabs. A total of 324 pairs of breeding pigeons were selected and allotted to 9 treatments in a completely randomized design, and the birds were fed dietary treatments for 45 d, including a Met-deficient basal diet (BD, crude protein = 15%, Met = 0.25%) and BD + 0.15%, 0.30%, 0.45%, or 0.60% dl-Met or dl-Met-Met diets. Compared with the diet fed to the BD group, dietary dl-Met or dl-Met-Met supplementation effectively increased the carcass yield, semieviscerated yield, eviscerated yield, breast muscle yield, thigh muscle yield, a* value, catalase activity, total superoxide dismutase activity and glutathione peroxidase activity, but decreased the L* value, malonaldehyde concentration, drip loss and cooking loss of squabs (p < 0.05). The relative bioavailability values of dl-Met-Met relative to those of dl-Met were 467% and 376% based on carcass yield and breast muscle yield, respectively (p < 0.001). Moreover, dl-Met-Met was more effective than dl-Met in decreasing the drip loss and improving the antioxidant activity of the breast and thigh muscles of squabs (p < 0.05). As a source of Met, dl-Met-Met, rather than dl-Met, was more beneficial to squabs.

Synthesis and biological evaluation of quercetin and resveratrol peptidyl derivatives as potential anticancer and antioxidant agents

Quercetin and resveratrol are polyphenolic compounds, members of the flavonoid and the stilbene family, respectively, both medicinally important as dietary anticancer and antioxidant agents. They are present in a variety of foods-including fruits, vegetables, tea, wine, as well as other dietary supplements-and are responsible for various health benefits. Different quercetin and resveratrol esters of Leu/Met-enkephalin and tetrapeptide Leu-Ser-Lys-Leu (LSKL) were synthesized as model systems for monitoring the influence of the peptides on biological activity of resveratrol and quercetin. General formula of the main peptidyl-quercetin derivatives is 2-[3-(aa)_n-4-hydroxyphenyl]-3,5,7-tri-hydroxy-4H-1-benzopyran-4-on, and the general formula of the main peptidyl-resveratrol derivatives is (E)-5-[4-(aa)_n)styryl]benzene-1,3-diol. The antioxidant and anticancer activities of prepared compounds were investigated. Significant anticancer activity was obtained for the LSKL-based both quercetin and resveratrol derivatives. All prepared compounds exhibit antioxidant activity, in particular quercetin derivative containing Met-enkephalin.

Antioxidant Properties of Buffalo-Milk Dairy Products: A β-Lg Peptide Released after Gastrointestinal Digestion of Buffalo Ricotta Cheese Reduces Oxidative Stress in Intestinal Epithelial Cells

Redox signaling regulates different gastrointestinal (G.I.) epithelium functions. At the intestinal level, the loss of redox homeostasis in intestinal epithelial cells (IECs) is responsible for the pathogenesis and development of a wide diversity of G.I. disorders. Thus, the manipulation of oxidative stress in IECs could represent an important pharmacological target for different diseases. In this study, peptides released from in vitro gastro intestinal digestion of different buffalo-milk commercial dairy products were identified and evaluated for their bioactive properties. In particular, six G.I. digests of dairy products were tested in a model of oxidative stress for IECs. Among them, buffalo ricotta cheese was the most active and the presence of an abundant β-lactoglobulin peptide (YVEELKPTPEGDL, f:60-72) was also revealed. The antioxidant potential of the identified peptide was also evaluated in a model of hydrogen peroxide (H₂O₂)-induced oxidative stress in the IEC-6 cell line. The peptide was able to reduce ROS release, while, on the other hand, it increased nuclear factor (erythroid-derived 2)-like 2 (Nrf2) activation and the expression of antioxidant cytoprotective factors, such as heme oxygenase 1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO1), and superoxide dismutase (SOD). These results indicate that buffalo ricotta cheese-isolated peptide could have potential in the treatment of some gastrointestinal disorders.

In silicoassessment and structural characterization of antioxidant peptides from major yolk protein of sea urchinStrongylocentrotus nudus

Sea urchin gonads have been demonstrated to contain major yolk protein (MYP), which can be hydrolyzed by enzymes to release biologically active peptides.

Cheese Whey Catalytic Conversion for Obtaining a Bioactive Hydrolysate With Reduced Antigenicity

Bioinformatics was used to design a procedure for industrial enzymatic proteolysis of cheese whey. The specificity rules for commercial enzymes were applied to in silico proteolysis of cheese whey proteins. The pattern of antigens was considered, along with molecular descriptors of bitter taste, antioxidant capacity, and anti-hypertensive activity. The main objective was to obtain hydrolysates with reduced antigenicity and satisfactory sensory properties; an additional goal was to characterize their bioactivity profiles. Protamex/Alcalase mixtures were first used as multienzyme compositions to obtain non-bitter cheese whey hydrolysates. The multifactor optimization performed for degree of hydrolysis, free amino acid content, and residual antigenicity has revealed the optimal Protamex/Alcalase ratio of 3.5:0.5 and the optimal hydrolysis duration of 90 min. The hydrolysate obtained using Protamex/Alcalase 3.5:0.5 mixture had a double antioxidant capacity and a 15 times lower ACE-I inhibition concentration IC50 compared to cheese whey concentrate, and an 11 times lower β-LG residual antigenicity.