Pepsin Egg White Hydrolysate Ameliorates Obesity-Related Oxidative Stress, Inflammation and Steatosis in Zucker Fatty Rats

Regulation of redox enzymes by nutraceuticals: a review of the roles of antioxidant polyphenols and peptides

Redox enzymes are essential components of the cellular defence system against oxidative stress, which is a common factor in various diseases. Therefore, understanding the role of bioactive nutraceuticals in modulating the activity of these enzymes holds immense therapeutic potential. This paper provides a comprehensive review of the regulation of redox enzymes in cell and animal models by food-derived bioactive nutraceuticals, focusing on polyphenols and peptides. Specifically, this paper discusses the regulation of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), NAPDH oxidase, xanthine oxidase (XO), myeloperoxidase (MPO), and haem oxygenase (HO) in cell and animal models. Polyphenols, which are abundant in fruits, vegetables, and beverages, have diverse antioxidant properties, including direct scavenging of reactive oxygen species and regulation of transcription factors such as nuclear factor erythroid 2-related factor 2, which leads to the increased expression of the redoxenzymes SOD, HO, and GPx. Similarly, bioactive peptides from various food proteins can enhance antioxidative enzyme activity by regulating gene expression and directly activating the enzyme CAT. In other cases, an antioxidative response requires the downregulation or inhibition of the redox enzymes XO, MPO, and NAPDH oxidase. This paper highlights the potential of bioactive nutraceuticals in mitigating oxidative stress-related diseases and their mechanisms in modulating the redox enzyme expression or activity. Furthermore, the review highlights the need for further research to uncover new therapeutic strategies using nutraceuticals for enhancing cellular antioxidant defence mechanisms and improving health outcomes.

Effect of food derived bioactive peptides on gut health and inflammatory mediators in vivo: a systematic review

Dietary proteins serve as sources of exogenous peptides, after being released from the protein and absorbed, the bioactive peptides can perform several functions in the body. The objective of the current systematic review is to answer the question "How does food derived bioactive peptides can impact on gut health and inflammatory mediators in vivo?" The search was performed at PubMed, Cochrane, and Scopus databases for experimental studies, and the risk of bias was assessed by the SYRCLE tool. The data analysis was conducted following the PRISMA guidelines. Eleven studies performed in animal models evaluating bioactive peptides derived from animal and plant sources were included and evaluated for limitations in heterogeneity, methodologies, absence of information regarding the allocation process, and investigators' blinding. The bioactive peptides demonstrated potential positive effects on inflammation and gut health. The main results identified were a reduction in TNF-α, NF-κB, and TLR4, an improvement in IgA production and in intestinal morphology, with an increase in villi surface area and goblet cell diameter, and Shannon and Simpson indexes were also increased. However, more in vivo studies are still necessary to better elucidate the anti-inflammatory activity and mechanisms by which peptides regulate gut health. PROSPERO (CRD42023416680).

Egg white hydrolysate protects white adipose tissue against metabolic insult in deoxycorticosterone acetate-salt rats

The purpose of this study was to investigate the effect of an egg white hydrolysate (EWH) to protect white adipose tissue damage from cardiometabolic changes induced by severe hypertension. Male Wistar rats were uninephrectomised and divided: SHAM (weekly subcutaneous vehicle (mineral oil + propylene glycol, 1:1)), SHAM + EWH (subcutaneous vehicle plus EWH via gavage, 1 g/kg per day), DOCA (deoxycorticosterone acetate diluted in vehicle subcutaneously weekly in subsequent doses of 20 mg/kg -1st week, 12 mg/kg - 2–3th week, and 6 mg/kg -4–8th week, respectively, plus 1 % NaCl and 0·2 % KCl in drinking water), and DOCA + EWH. Body weight gain, food and water intake, glucose and lipid metabolism were evaluated. Oxidative stress was assessed by biochemical assay and immunofluorescence for NOX-1, nuclear factor kappa B (NFκB), and caspase-3 in retroperitoneal white adipose tissue (rtWAT). Proinflammatory cytokines (IL-6 and 1β), CD163+ macrophage infiltration, and immunohistochemistry for TNFα and uncoupling protein-1 were evaluated, as well as histological analysis on rtWAT. Glutathione peroxidase and reductase were also determined in plasma. EWH showed hypocholesterolemic, antioxidant, anti-inflammatory, and anti-apoptotic properties in the arterial hypertension DOCA-salt model. The results demonstrated the presence of functional changes in adipose tissue function by a decrease in macrophage infiltration and in the fluorescence intensity of NFκB, NOX-1, and caspase-3. A reduction of proinflammatory cytokines and restoration of antioxidant enzymatic activity and mitochondrial oxidative damage by reducing uncoupling protein-1 fluorescence intensity were also observed. EWH could be used as a potential alternative therapeutic strategy in the treatment of cardiometabolic complications associated with malignant secondary arterial hypertension.

Egg White Hydrolysate Mitigates Cadmium-induced Neurological Disorders and Oxidative Damage

We aimed to investigate whether the consumption of Egg White Hydrolysate (EWH) acts on nervous system disorders induced by exposure to Cadmium (Cd) in rats. Male Wistar rats were divided into (a) Control (Ct): H2O by gavage for 28 days + H2O (i.p. - 15th - 28th day); (b) Cadmium (Cd): H2O by gavage + CdCl2 - 1 mg/kg/day (i.p. - 15th - 28th day); (c) EWH 14d: EWH 1 g/kg/day by gavage for 14 days + H2O (i.p.- 15th - 28th day); (d) Cd + EWH cotreatment (Cd + EWHco): CdCl2 + EWH for 14 days; (e) EWH 28d: EWH for 28 days; (f) EWHpre + Cd: EWH (1st - 28th day) + CdCl2 (15th - 28th day). At the beginning and the end of treatment, neuromotor performance (Neurological Deficit Scale); motor function (Rota-Rod test); ability to move and explore (Open Field test); thermal sensitivity (Hot Plate test); and state of anxiety (Elevated Maze test) were tested. The antioxidant status in the cerebral cortex and the striatum were biochemically analyzed. Cd induces anxiety, and neuromotor, and thermal sensitivity deficits. EWH consumption prevented anxiety, neuromotor deficits, and alterations in thermal sensitivity, avoiding neuromotor deficits both when the administration was performed before or during Cd exposure. Both modes of administration reduced the levels of reactive species, and the lipid peroxidation increased by Cd and improved the striatum's antioxidant capacity. Pretreatment proved to be beneficial in preventing the reduction of SOD activity in the cortex. EWH could be used as a functional food with antioxidant properties capable of preventing neurological damage induced by Cd.

Interaction mechanism of egg derived peptides RVPSL and QIGLF with dipalmitoyl phosphatidylcholine membrane: microcalorimetric and molecular dynamics simulation studies

BACKGROUND

Egg-derived peptides are becoming increasingly popular due to their biological activity and non-toxic effects. The egg-derived peptides Arg-Val-Pro-Ser-Leu (RVPSL) and Gln-Ile-Gly-Leu-Phe (QIGLF) display strong angiotensin-converting enzyme inhibitory activity and they can be taken up by intestinal epithelial cells. The interaction of the egg-derived peptides RVPSL and QIGLF with the membrane remains unclear.

RESULTS

The position and structure of the peptides in the membrane were calculated. The maximum density values of RVPSL and QIGLF were 2.27 and 1.22 nm from the center of the 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) membrane, respectively, indicating that peptides penetrated the membrane-water interface and were embedded in the membrane. The interaction of RVPSL and QIGLF with the DPPC membrane did not affect the average area per lipid or the lipid sequence parameters. The thermodynamic parameters ΔH, ΔG, and ΔS of the interaction between the peptide RVPSL with the DPPC membrane were 17.91 kJ mol-1 , -17.63 kJ mol-1 , 187.5 J mol-1 ·k-1 , respectively. The thermodynamic parameters ΔH, ΔG, and ΔS of the interaction between peptide QIGLF with DPPC membrane were 17.10 kJ mol-1 , -17.12 kJ mol-1 , 114.8 J mol-1 ·k-1 , respectively.

CONCLUSION

The results indicated that the binding of peptides RVPSL and QIGLF to DPPC is an endothermic, spontaneous, and entropy-driven reaction. The results of the study are relevant to the problem of the low bioavailability of bioactive peptides (BP). © 2023 Society of Chemical Industry.

Cardiovascular Harmful Effects of Recommended Daily Doses (13 µg/kg/day), Tolerable Upper Intake Doses (0.14 mg/kg/day) and Twice the Tolerable Doses (0.28 mg/kg/day) of Copper

Copper is essential for homeostasis and regulation of body functions, but in excess, it is a cardiovascular risk factor since it increases oxidative stress. The objective of this study was to evaluate the effects of exposure to the recommended daily dose (13 µg/kg/day), upper tolerable dose (0.14 mg/kg/day) and twice the upper tolerable dose (0.28 mg/kg/day) via i.p. over 4 weeks on the vascular reactivity of aortic rings and the contraction of LV papillary muscles of male Wistar rats. It was also determined whether the antioxidant peptide from egg white hydrolysate (EWH) prevents these effects. Copper exposure at the doses evaluated did not change weight gain of male Wistar rats, the reactivity of the aortic rings or the cardiac mass. The dose of 0.13 µg/kg/day did not reduce the force of contraction, but it impaired the time derivatives of force. Doses of 0.14 and 0.28 mg/kg/day reduced the force of contraction, the inotropic response to calcium and isoproterenol, the postrest contraction and the peak and plateau of tetanized contractions. EWH treatment antagonized these effects. These results suggest that copper, even at the dose described as upper tolerable, can impair cardiac contraction without altering vascular reactivity. Antioxidative stress therapy with EWH reversed these harmful effects, suggesting a possible strategy for the amelioration of these effects.

The association between egg consumption and metabolic health status in overweight and obese adolescents

Existing evidence examining the relation between egg consumption and metabolic health of overweight/obese adolescents is scarce. We examined the association between egg consumption and metabolic status in Iranian overweight/obese adolescents. Using multistage cluster random sampling approach, overweight/obese adolescents (n = 203) with ages from 12 to 18 years old were selected for the present cross-sectional study. A validated 147-item food frequency questionnaire was adopted to determine usual dietary intakes. Blood pressure and anthropometric data and were assessed, and levels of lipid profile, insulin, and glucose were measured by collecting fasting blood samples. Participants were classified into metabolically healthy obese (MHO) or metabolically unhealthy obese (MUO) based on two methods of International Diabetes Federation (IDF) and the combination of IDF with Homeostasis Model Assessment Insulin Resistance (HOMA-IR). In total, 67 (33.0%) and 79 (38.9%) adolescents were classified as MUO based on IDF/HOMA and IDF definitions, respectively. Considering IDF criteria, the highest intake of egg was related to decreased chance of MUO, in crude (OR 0.22; 95% CI 0.10-0.48) and maximally-adjusted model (OR 0.25; 95% CI 0.10-0.59). Considering IDF/HOMA-IR criteria, similar results were obtained (crude model: OR 0.24; 95% CI 0.11-0.52; fully-adjusted model: OR 0.28; 95% CI 0.11-0.69). Stratified analyses found stronger relation among boys (vs. girls) and overweight (vs. obese) individuals. In conclusion, higher egg consumption was negatively related to decreased chance of being MUO in overweight/obese adolescents, especially in boys and overweight individuals, regardless of MUO definitions. Prospective studies are required to support our results.

An Egg White-Derived Peptide Enhances Systemic Insulin Sensitivity and Modulates Markers of Non-Alcoholic Fatty Liver Disease in Obese, Insulin Resistant Mice

Non-alcoholic fatty liver disease (NAFLD), the hepatic manifestation of the metabolic syndrome, is a global health problem. Currently, no pharmacological treatment is approved for NAFLD. Natural health products, including bioactive peptides, are potential candidates to aid in the management of metabolic syndrome-related conditions, including insulin resistance and obesity. In this study, we hypothesized that an egg-white-derived bioactive peptide QAMPFRVTEQE (Peptide 2) would improve systemic and local white adipose tissue insulin sensitivity, thereby preventing high-fat diet-induced exacerbation of pathological features associated with NAFLD, such as lipid droplet size and number, inflammation, and hepatocyte hypertrophy in high-fat diet-fed mice. Similar to rosiglitazone, Peptide 2 supplementation improved systemic insulin resistance during the hyperinsulinemic-euglycemic clamp and enhanced insulin signalling in white adipose tissue, modulating ex vivo lipolysis. In the liver, compared with high-fat diet fed animals, Peptide 2 supplemented animals presented decreased hepatic cholesterol accumulation (p < 0.05) and area of individual hepatic lipid droplet by around 50% (p = 0.09) and reduced hepatic inflammatory infiltration (p < 0.05) whereas rosiglitazone exacerbated steatosis. In conclusion, Peptide 2 supplementation improved insulin sensitivity and decreased hepatic steatosis, unlike the insulin-sensitizing drug rosiglitazone.

Dietary Egg White Hydrolysate Prevents Male Reproductive Dysfunction after Long-Term Exposure to Aluminum in Rats

Aluminum (Al) is a non-essential metal omnipresent in human life and is considered an environmental toxicant. Al increases reactive oxygen production and triggers immune responses, contributing to chronic systemic inflammation development. Here, we have tested whether an egg white hydrolysate (EWH) with potential bioactive properties can protect against changes in reproductive function in rats exposed to long-term Al dietary levels at high and low doses. Male Wistar rats received orally: low aluminum level group-AlCl₃ at 8.3 mg/kg b.w. for 60 days with or without EWH (1 g/kg/day); high aluminum level group-AlCl₃ at 100 mg/kg b.w. for 42 days with or without EWH (1 g/kg/day). The co-administration of EWH prevented the increased Al deposition surrounding the germinative cells, reducing inflammation and oxidative stress in the reproductive organs. Furthermore, the daily supplementation with EWH maintained sperm production and sperm quality similar to those found in control animals, even after Al exposure at a high dietary contamination level. Altogether, our results suggest that EWH could be used as a protective agent against impairment in the reproductive system produced after long-term exposure to Al at low or high human dietary levels.

TetraSOD®, a Unique Marine Microalgae Ingredient, Promotes an Antioxidant and Anti-Inflammatory Status in a Metabolic Syndrome-Induced Model in Rats

Increased oxidative stress has been linked to the pathogenic process of obesity and can trigger inflammation, which is often linked with the risk factors that make up metabolic syndrome (MetS), including obesity, insulin resistance, dyslipidaemia and hypertension. TetraSOD^®, a natural marine vegan ingredient derived from the microalgae Tetraselmis chuii that is high in the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) has recently demonstrated in vitro increased activity of these key antioxidant enzymes. In the present study, the potential bioactive effects of three dietary dosages of TetraSOD^® in enhancing antioxidant and anti-inflammatory mechanisms to combat the metabolic disturbances that compose MetS were assessed in rats given a cafeteria (CAF) diet. Chronic supplementation with 0.17, 1.7, and 17 mg kg⁻¹ day⁻¹ of TetraSOD^® for 8 weeks ameliorated the abnormalities associated with MetS, including oxidative stress and inflammation, promoting endogenous antioxidant defence mechanisms in the liver (GPx and GSH), modulating oxidative stress and inflammatory markers in plasma (NOx, oxLDL and IL-10), and regulating genes involved in antioxidant, anti-inflammatory and immunomodulatory pathways in the liver, mesenteric white adipose tissue (MWAT), thymus, and spleen. Overall, TetraSOD^® appears to be a potential therapeutic option for the management of MetS.

ROS Suppression by Egg White Hydrolysate in DOCA-Salt Rats—An Alternative Tool against Vascular Dysfunction in Severe Hypertension

This study aimed to evaluate the potential for lowering blood pressure and beneficial effects on mesenteric resistance arteries (MRA) and conductance vessels (aorta) produced by dietary supplementation of an egg white hydrolysate (EWH) in rats with severe hypertension induced by deoxycorticosterone plus salt treatment (DOCA-salt), as well as the underlying mechanisms involved. The DOCA-salt model presented higher blood pressure, which was significantly reduced by EWH. The impaired acetylcholine-induced relaxation and eNOS expression observed in MRA and aorta from DOCA-salt rats was ameliorated by EWH. This effect on vessels (MRA and aorta) was related to the antioxidant effect of EWH, since hydrolysate intake prevented the NF-κB/TNFα inflammatory pathway and NADPH oxidase-induced reactive oxygen species (ROS) generation, as well as the mitochondrial source of ROS in MRA. At the plasma level, EWH blocked the higher ROS and MDA generation by DOCA-salt treatment, without altering the antioxidant marker. In conclusion, EWH demonstrated an antihypertensive effect in a model of severe hypertension. This effect could be related to its endothelium-dependent vasodilator properties mediated by an ameliorated vessel’s redox imbalance and inflammatory state.

Health Functions of Egg Protein

Egg protein is a remarkably abundant source of protein, with an amino acid score of 100 and the highest net protein utilization rate. However, there have been relatively fewer studies investigating the health benefits of egg protein. In this review, we have summarized the available information regarding the health benefits of egg proteins based on human studies. In particular, studies conducted on the characteristics of egg whites, as they are high in pure protein, have reported their various health functions, such as increases in muscle mass and strength enhancement, lowering of cholesterol, and visceral fat reduction. Moreover, to facilitate and encourage the use of egg white protein in future, we also discuss its health functions. These benefits were determined by developing an egg white hydrolysate and lactic-fermented egg whites, with the latter treatment simultaneously improving the egg flavor. The health benefits of the protein hydrolysates from the egg yolk (bone growth effect) and eggshell membrane (knee join pain-lowering effect) have been limited in animal studies. Therefore, the consumption of egg protein may contribute to the prevention of physical frailty and metabolic syndromes.

Potential benefits of egg white hydrolysate in the prevention of Hg-induced dysfunction in adipose tissue

Aim: To investigate the effects of egg white hydrolysate (EWH) on the lipid and glycemic metabolism disruption in the white adipose tissue (WAT) dysfunction induced by mercury (Hg). Experimental: Wistar rats were treated for 60 days: control (saline, intramuscular - i.m.); hydrolysate (EWH, gavage, 1 g kg^-1 day^-1); mercury (HgCl₂, i.m., 1^st dose 4.6 μg kg^-1, subsequent doses 0.07 μg kg^-1 day^-1) and hydrolysate-mercury (EWH-HgCl₂). Hg level and histological analyses were performed in epididymal WAT (eWAT), pancreas and liver. GRP78, CHOP, PPARα, PPARγ, leptin, adiponectin, and CD11 mRNA expressions were analyzed in eWAT. The plasma lipid profile, glucose, and insulin levels were measured. Antioxidant status was also evaluated in the plasma and liver. Results: EWH intake prevented the reduced eWAT weight, adipocyte size, insulin levels, and antioxidant defenses and the increased glucose and triglyceride levels induced by Hg exposure; hepatic glutathione levels were higher in rats co-treated with EWH. The increased mRNA expression of CHOP, PPARα, and leptin induced by Hg was reduced in co-treated rats. EWH did not modify the elevated mRNA expression of GRP78, PPARγ and adiponectin in Hg-treated rats. Increased levels of Hg were found in the liver; the co-treatment did not alter this parameter. EWH prevented the morphological and metabolic disorder induced by Hg, by improving antioxidant defenses, inactivating pro-apoptotic pathways and normalizing the mRNA expression of PPARs and adipokines. Its effects enabled an increase in insulin levels and a normal balance between the fat storage and expenditure mechanisms in WAT. Conclusions: EWH may have potential benefits in the prevention and management of Hg-related metabolic disorders.

Preparation of reductive polypeptides from fresh placentas of dairy cows

In order to prepare reductive polypeptides from the placenta of dairy cows' fresh placentas from healthy Chinese Holstein cows were obtained and homogenized. Response surface model was established to optimize the hydrolysis condition for the extraction of the placental polypeptides. Specifically, the placental tissue homogenate was treated with both trypsin and pepsin for 348 min and 329 min; at 35.00% and 35.75% of substrate concentration; with an enzyme-substrate ratio of 3.33% and 3.92%, respectively, based on the models. The treated samples were then demineralized and freeze-dried to obtain the hydrolyzed polypeptides. In order to identify the molecular mass distribution and reducibility of polypeptides, matrix-assisted laser desorption ionization (MALDI) and Prussian blue methods were used. The concentrations of placental polypeptides after hydrolysis by trypsin or pepsin were 5.52% and 5.97%, respectively; the vitamin C (Vit C) equivalents were 36.26 μg mg^-1 or 61.15 μg mg^-1, respectively. Both groups showed intensity peaks of MALDI patterns in the range of 300 - 400 Da, and polypeptides hydrolyzed by pepsin had higher Vit C equivalent anti-oxidant activity than trypsin hydrolyzed polypeptide, suggesting that the proteins in the placental tissues were hydrolyzed to di-peptides and tri-peptides completely. In conclusion, both trypsin and pepsin hydrolysis performed well in preparation of reductive polypeptides from the fresh placentas of dairy cows; while, pepsin is more effective than trypsin. The primary reductive ingredients may be the oligopeptides with molecular mass less than 1000 Da.

Anti-Obesity and Anti-Hyperglycemic Effects of Meretrix lusoria Protamex Hydrolysate in ob/ob Mice

Meretrix lusoria (M. lusoria) is an economically important shellfish which is widely distributed in South Eastern Asia that contains bioactive peptides, proteins, and enzymes. In the present study, the extracted meat content of M. lusoria was enzymatic hydrolyzed using four different commercial proteases (neutrase, protamex, alcalase, and flavourzyme). Among the enzymatic hydrolysates, M. lusoria protamex hydrolysate (MLPH) fraction with MW ≤ 1 kDa exhibited the highest free radical scavenging ability. The MLPH fraction was further purified and an amino acid sequence (KDLEL, 617.35 Da) was identified by LC-MS/MS analysis. The purpose of this study was to investigate the anti-obesity and anti-hyperglycemic effects of MLPH containing antioxidant peptides using ob/ob mice. Treatment with MLPH for 6 weeks reduced body and organ weight and ameliorated the effects of hepatic steatosis and epididymal fat, including a constructive effect on hepatic and serum marker parameters. Moreover, hepatic antioxidant enzyme activities were upregulated and impaired glucose tolerance was improved in obese control mice. In addition, MLPH treatment markedly suppressed mRNA expression related to lipogenesis and hyperglycemia through activation of AMPK phosphorylation. These findings suggest that MLPH has anti-obesity and anti-hyperglycemic potential and could be effectively applied as a functional food ingredient or pharmaceutical.

Antioxidant Stress and Anti-Inflammatory Activities of Egg White Proteins and Their Derived Peptides: A Review

Oxidative stress and chronic inflammation are the common pathological bases of chronic diseases such as atherosclerosis, cancer, and cardiovascular diseases, but most of the treatment drugs for chronic diseases have side effects. There is an increasing interest to identify food-derived bioactive compounds that can mitigate the pathological pathways associated with oxidative stress and chronic inflammation. Egg white contain a variety of biologically active proteins, many of which have antioxidant and anti-inflammatory activities and usually show better activity after enzymatic hydrolysis. This review covers the antioxidative stress and anti-inflammatory activities of egg white proteins and their derived peptides and clarifies their mechanism of action in vivo and in vitro. In addition, the link between oxidative stress and inflammation as well as their markers are reviewed. It suggests the potential application of egg white proteins and their derived peptides and puts forward further research prospects.

New Method for Obtaining a Bioactive Essence Extracted from Iberian Ham Fat Rich in MUFA and Antioxidants

Iberian ham is one of the most representative Spanish products and presents an excellent nutritional and sensory quality. Iberian ham trimming fat is considered a by-product and to give a new use to this remaining part could represent a healthy and innovative option for obtaining sustainable foods. The purpose of this work was to obtain a new bioactive ingredient from Iberian ham trimming fat with the highest amount of antioxidants and monounsaturated fatty acids (MUFA), using a new non-invasive solvent-free method. To obtain the essence, two different extraction procedures were carried out. After fatty acid characterization, degree of acidity, peroxide index and a basic sensory analysis were performed. Antioxidant in vitro activity and total phenolic compounds (TPC) were also determined. This new ingredient showed a better sensory profile than raw ham fat, a lower degree of acidity, a higher content of MUFAs, and also showed a higher antioxidant capacity and an increase in phenolic compounds compared to the raw material. This bioactive essence could be used as a food, a cosmetic or a nutraceutical ingredient to prevent certain diseases related to oxidative stress and could also contribute to the maintenance of the circular economy.

The Role of Bioactive Peptides in Diabetes and Obesity

Bioactive peptides are present in most soy products and eggs and have essential protective functions. Infection is a core feature of innate immunity that affects blood pressure and the glucose level, and ageing can be delayed by killing senescent cells. Food also encrypts bioactive peptides and protein sequences produced through proteolysis or food processing. Unique food protein fragments can improve human health and avoid metabolic diseases, inflammation, hypertension, obesity, and diabetes mellitus. This review focuses on drug targets and fundamental mechanisms of bioactive peptides on metabolic syndromes, namely obesity and type 2 diabetes, to provide new ideas and knowledge on the ability of bioactive peptide to control metabolic syndromes.

The Role of Bioactive Peptides in Diabetes and Obesity

Bioactive peptides are present in most soy products and eggs and have essential protective functions. Infection is a core feature of innate immunity that affects blood pressure and the glucose level, and ageing can be delayed by killing senescent cells. Food also encrypts bioactive peptides and protein sequences produced through proteolysis or food processing. Unique food protein fragments can improve human health and avoid metabolic diseases, inflammation, hypertension, obesity, and diabetes mellitus. This review focuses on drug targets and fundamental mechanisms of bioactive peptides on metabolic syndromes, namely obesity and type 2 diabetes, to provide new ideas and knowledge on the ability of bioactive peptide to control metabolic syndromes.

Antioxidant Properties of Egg White Hydrolysate Prevent Mercury-Induced Vascular Damage in Resistance Arteries

Aim: We investigated the antioxidant protective power of egg white hydrolysate (EWH) against the vascular damage induced by mercury chloride (HgCl2) exposure in resistance arteries. Methods: Male Wistar rats received for 60 days: (I) intramuscular injections (i.m.) of saline and tap water by gavage - Untreated group; (II) 4.6 μg/kg of HgCl2 i.m. for the first dose and subsequent doses of 0.07 μg/kg/day and tap water by gavage - HgCl2 group; (III) saline i.m. and 1 g/kg/day of EWH by gavage - EWH group, or (IV) the combination of the HgCl2 i.m. and EWH by gavage - EWH + HgCl2 group. Blood pressure (BP) was indirectly measured and dose-response curves to acetylcholine (ACh), sodium nitroprusside (SNP), and noradrenaline (NE) were assessed in mesenteric resistance arteries (MRA), as in situ production of superoxide anion, nitric oxide (NO) release, vascular reactive oxygen species (ROS), lipid peroxidation, and antioxidant status. Results: Egg white hydrolysate prevented the elevation in BP and the vascular dysfunction after HgCl2 exposure; restored the NO-mediated endothelial modulation and inhibited the oxidative stress and inflammatory pathways induced by HgCl2. Conclusion: Egg white hydrolysate seems to be a useful functional food to prevent HgCl2-induced vascular toxic effects in MRA.

Exploring the Role of a Novel Peptide from Allomyrina dichotoma Larvae in Ameliorating Lipid Metabolism in Obesity

The aim of this study was to identify an anti-obesity peptide from Allomyrina dichotoma and investigate the lipid metabolic mechanism. Enzymatically hydrolyzed A. dichotoma larvae were further separated using tangential flow filtration and consecutive chromatographic processes. Finally, an anti-obesity peptide that showed the highest inhibitory effect on lipid accumulation was obtained, and the sequence was Glu-Ile-Ala-Gln-Asp-Phe-Lys-Thr-Asp-Leu (EIA10). EIA10 decreased lipid aggregation in vitro and significantly reduced the accumulation of body weight gain, liver weight, and adipose tissue weight in high-fat-fed mice. Compared with the control group, the levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL), insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) in the high-fat diet (HFD) group increased significantly, and the content of high-density lipoprotein cholesterol (HDL) in the serum decreased significantly. On the contrary, the levels of TC, TG, and insulin in the EIA10 group decreased significantly, and the HDL content increased significantly compared with the HFD group. Additionally, EIA10 dramatically decreased mRNA and protein levels of transcription factors involved in lipid adipogenesis. Taken together, our results suggest that EIA10 could be a promising agent for the treatment and prevention of obesity.

Whole egg consumption increases gene expression within the glutathione pathway in the liver of Zucker Diabetic Fatty rats

Nutrigenomic evidence supports the idea that Type 2 Diabetes Mellitus (T2DM) arises due to the interactions between the transcriptome, individual genetic profiles, lifestyle, and diet. Since eggs are a nutrient dense food containing bioactive ingredients that modify gene expression, our goal was to examine the role of whole egg consumption on the transcriptome during T2DM. We analyzed whether whole egg consumption in Zucker Diabetic Fatty (ZDF) rats alters microRNA and mRNA expression across the adipose, liver, kidney, and prefrontal cortex tissue. Male ZDF (fa/fa) rats (n = 12) and their lean controls (fa/+) (n = 12) were obtained at 6 wk of age. Rats had ad libitum access to water and were randomly assigned to a modified semi-purified AIN93G casein-based diet or a whole egg-based diet, both providing 20% protein (w/w). TotalRNA libraries were prepared using QuantSeq 3' mRNA-Seq and Lexogen smallRNA library prep kits and were further sequenced on an Illumina HighSeq3000. Differential gene expression was conducted using DESeq2 in R and Benjamini-Hochberg adjusted P-values controlling for false discovery rate at 5%. We identified 9 microRNAs and 583 genes that were differentially expressed in response to 8 wk of consuming whole egg-based diets. Kyto Encyclopedia of Genes and Genomes/Gene ontology pathway analyses demonstrated that 12 genes in the glutathione metabolism pathway were upregulated in the liver and kidney of ZDF rats fed whole egg. Whole egg consumption primarily altered glutathione pathways such as conjugation, methylation, glucuronidation, and detoxification of reactive oxygen species. These pathways are often negatively affected during T2DM, therefore this data provides unique insight into the nutrigenomic response of dietary whole egg consumption during the progression of T2DM.

Protective Effects of a Discontinuous Treatment with Alpha-Lipoic Acid in Obesity-Related Heart Failure with Preserved Ejection Fraction, in Rats

Obesity induces hemodynamic and humoral changes that are associated with functional and structural cardiac remodeling, which ultimately result in the development of heart failure (HF) with preserved ejection fraction (HFpEF). In recent years, pharmacological studies in patients with HFpEF were mostly unsatisfactory. In these conditions, alternative new therapeutic approaches are necessary. The aim of our study was (1) to assess the effects of obesity on heart function in an experimental model and (2) to evaluate the efficacy of an alpha-lipoic acid (ALA) antioxidant treatment. Sprague-Dawley rats (7 weeks old) were either included in the control group (n = 6) or subjected to abdominal aortic banding (AAB) and divided into three subgroups, depending on their diet: standard (AAB + SD, n = 8), hypecaloric (AAB + HD, n = 8) and hypecaloric with discontinuous ALA treatment (AAB + HD + ALA, n = 9). Body weight (BW), glycemia, echocardiography parameters and plasma hydroperoxides were monitored throughout the study. After 36 weeks, plasma adiposity (leptin and adiponectin) and inflammation (IL-6 and TNF-alpha) markers, together with B-type natriuretic peptide and oxidative stress markers (end-products of lipid peroxidation and endogenous antioxidant systems) were assessed. Moreover, cardiac fiber diameters were measured. In our experiment, diet-induced obesity generated cardiometabolic disturbances, and in association with pressure-overload induced by AAB, it precipitated the onset of heart failure, cardiac hypertrophy and diastolic dysfunction, while producing a pro-oxidant and pro-inflammatory plasmatic status. In relationship with its antioxidant effects, the chronic ALA-discontinuous treatment prevented BW gain and decreased metabolic and cardiac perturbations, confirming its protective effects on the cardiovascular system.

Adverse impact of egg consumption on fatty liver is partially explained by cardiometabolic risk factors: A population-based study

BACKGROUND AND AIMS

We evaluated the association of egg consumption with liver tests (LTs) and non-alcoholic fatty liver disease (NAFLD). This relationship is poorly documented.

METHODS

The National Health and Nutrition Examination Survey (NHANES, 2005-2010) database was used. Analysis of covariance, adjusted linear and logistic regression models were used.

RESULTS

Of the 14,369 participants, 46.8% were men and 45.2% had NAFLD. After correction for several variables including: age, gender, race, education, poverty to income ratio, alcohol intake, energy intake, smoking, and physical activity - fatty liver index (FLI), serum aspartate aminotransferase (AST) alanine aminotransferase (ALT) were 36.9, 25.8 (U/L) and 23.9 (U/L), respectively, in the first tertile (T1) reaching 68.7, 34.9 and 36.5, respectively, in the third tertile (T3) (p < 0.001 for all comparisons). In the model with same covariates, there was significant positive linear relationship between FLI (standard β coefficient (β): 0.196), AST (β: 0.099) and ALT (β: 0.112) with egg consumption and participants in the highest tertile (T3) of egg consumption had 11% higher chance of NAFLD compared with T1 (odds ratio: 1.11 and 95% confidence interval: 1.07-1.17). Of note, after more correction for triglycerides, hypertension and diabetes, the significant link between egg consumption and LTs and/or NAFLD attenuated and disappeared.

CONCLUSION

Our findings highlight the adverse role of egg consumption on LTs and likelihood of NAFLD. These associations seem to be attributable to cardio-metabolic risk factors. These findings require confirmation to improve our understanding of the role of egg consumption in the pathogenesis of NAFLD.

A comparative study of the modulation of the gut microbiota in rats by dietary intervention with different sources of egg-white proteins

BACKGROUND

Gut microflora dysbiosis has been related closely to a variety of diseases including obesity and inflammatory bowel disease. Proteins and peptides in egg white have been found to alleviate inflammation but the role played by the intestinal flora is still unclear. Using casein as a dietary protein control, we investigated the effects of diets composed of hen egg white, duck egg white, and preserved egg white on gut microbiota in the rat cecum.

RESULTS

The gut microbiota in rats were altered after egg-white consumption. The results showed that rats fed with egg white had a similar overall structure of cecal bacterial communities, which was different from those fed with casein. The relative abundance of Akkermansia in the group of rats fed with hen egg white was highest among all groups. Rats fed with duck egg white had significantly higher relative abundance of Proteobacteria and Peptostreptococcaceae, and lower relative abundance of Lachnospiraceae. In addition, the levels of lipopolysaccharide (LPS) and lipopolysaccharide-binding protein (LBP) in rats fed with duck egg white and preserved egg white were lower than the levels in rats fed with hen egg white.

CONCLUSION

Our results indicated the possible positive effect on homeostasis of the intestinal flora brought about by the intake of duck egg white. This study provides an insight into the potential positive impact of preserved egg white on health by changing gut microbiota and affecting the antigen load. © 2020 Society of Chemical Industry.

Chicken Egg Proteins and Derived Peptides with Antioxidant Properties

In addition to their high nutritional value, some chicken egg proteins and derivatives such as protein hydrolysates, peptides and amino acids show antioxidant properties which make them prominent candidates for the development of functional foods, drawing attention to both the food and biopharmaceutical industries. This review summarizes current knowledge on antioxidant activity of chicken egg proteins and their derived peptides. Some egg proteins such as ovalbumin, ovotransferrin and lysozyme from egg white or phosvitin from yolk have shown antioxidant properties, although derived peptides have higher bioactive potential. The main process for obtaining egg bioactive peptides is enzymatic hydrolysis of its proteins using enzymes and/or processing technologies such as heating, sonication or high-intensity-pulsed electric field. Different in vitro assays such as determination of reducing power, DPPH and ABTS radical-scavenging activity tests or oxygen radical absorbance capacity assay have been used to evaluate the diverse antioxidant mechanisms of proteins and peptides. Similarly, different cell lines and animal models including zebrafish, mice and rats have also been used. In summary, this review collects all the knowledge described so far regarding egg proteins and derived peptides with antioxidant functions.

Glucagon-like peptide-1, insulin-like growth factor-1, and adiponectin in insulin-dysregulated ponies: effects of feeding a high nonstructural carbohydrate diet and association with prospective laminitis

Endocrinopathic laminitis, related to equine metabolic syndrome and insulin dysregulation, causes marked pain and suffering in horses and represents a substantial cost to the horse industry. This study investigated the effect of feeding a diet high in nonstructural carbohydrates on concentrations of active glucagon-like peptide-1 (aGLP-1), total insulin-like growth factor-1 (IGF-1), and high-molecular-weight (HMW) adiponectin, in insulin-dysregulated ponies. Thirty-seven ponies were challenged with this diet for up to 18 d to induce hyperinsulinemia. Hormone concentrations were measured in selected samples on day 2 of the diet challenge period, over 4 h after feeding. Fourteen of the ponies developed mild laminitis induced by the diet challenge. Insulin and glucose responses to the diet have been reported previously. Feeding increased the concentrations of aGLP-1 (P < 0.05) and HMW adiponectin (P < 0.001), but there was no difference between the laminitic and nonlaminitic groups for either hormone. Concentrations of IGF-1 and insulin were inversely related, with IGF-1 being 32% lower in hyperinsulinemic/laminitic ponies compared with nonlaminitic ponies (P = < 0.05). These results indicate that unlike insulin and possibly IGF-1, concentrations of aGLP-1 and HMW adiponectin do not have a strong association with, or play a major role in, the pathogenesis of equine laminitis.

Perspectives on the Potential Benefits of Antihypertensive Peptides towards Metabolic Syndrome

In addition to the regulation of blood pressure, the renin-angiotensin system (RAS) also plays a key role in the onset and development of insulin resistance, which is central to metabolic syndrome (MetS). Due to the interplay between RAS and insulin resistance, antihypertensive compounds may exert beneficial effects in the management of MetS. Food-derived bioactive peptides with RAS blocking properties can potentially improve adipose tissue dysfunction, glucose intolerance, and insulin resistance involved in the pathogenesis of MetS. This review discusses the pathophysiology of hypertension and the association between RAS and pathogenesis of the MetS. The effects of bioactive peptides with RAS modulating effects on other components of the MetS are discussed. While the in vivo reports on the effectiveness of antihypertensive peptides against MetS are encouraging, the exact mechanism by which these peptides infer their effects on glucose and lipid handling is mostly unknown. Therefore, careful design of experiments along with standardized physiological models to study the effect of antihypertensive peptides on insulin resistance and obesity could help to clarify this relationship.

Peptides from Natural or Rationally Designed Sources Can Be Used in Overweight, Obesity, and Type 2 Diabetes Therapies

Overweight and obesity are among the most prominent health problems in the modern world, mostly because they are either associated with or increase the risk of other diseases such as type 2 diabetes, hypertension, and/or cancer. Most professional organizations define overweight and obesity according to individual body-mass index (BMI, weight in kilograms divided by height squared in meters). Overweight is defined as individuals with BMI from 25 to 29, and obesity as individuals with BMI ≥30. Obesity is the result of genetic, behavioral, environmental, physiological, social, and cultural factors that result in energy imbalance and promote excessive fat deposition. Despite all the knowledge concerning the pathophysiology of obesity, which is considered a disease, none of the existing treatments alone or in combination can normalize blood glucose concentration and prevent debilitating complications from obesity. This review discusses some new perspectives for overweight and obesity treatments, including the use of the new orally active cannabinoid peptide Pep19, the advantage of which is the absence of undesired central nervous system effects usually experienced with other cannabinoids.

Optimization of Antioxidant Hydrolysate Produced from Tibetan Egg White with Papain and Its Application in Yak Milk Yogurt

The objective of the present study was to produce antioxidant hydrolysate from Tibetan egg white protein hydrolyzed with papain, and to investigate the effect of added papain egg white hydrolysate (PEWH) on the quality characteristics and amino acid profiles of yak milk yogurt. A response surface methodology (RSM) was utilized to analyze the effects of hydrolysis time (X₁), the ratio of enzymes to substrates, and enzyme dosage (X₃) on the superoxide anion radical (O₂⁻) scavenging activity of hydrolysates. The predicted maximum value of O₂⁻ scavenging activity (89.06%) was obtained an X₁ of 2.51 h, X₂ of 4.13%, and X₃ of 4500 U/g of substrate, almost approaching the experimental value (88.05 ± 1.2%). Furthermore, it was found that the addition of PEWH to yak milk can enhance acidification, sensory score, the number of lactic acid bacteria (LAB), and the amino acid content in yak milk yogurt. The results suggested that PEWH displayed an exceptional potential to be developed as a functional food ingredient that could be applied during the manufacturing process of yak milk yogurt.

Egg white hydrolysates improve vascular damage in obese Zucker rats by its antioxidant properties

Metabolic Syndrome (MS) is related to increased risk of early death due to cardiovascular complications, among others. Dietary intervention has been suggested as the safest and most cost-effective alternative for treatment of those alterations in patients with MS. The aim of this study was to investigate the effects of different egg white hydrolysates (HEW1 and HEW2) in obese Zucker rats, focus on the development of cardiovascular complications. Blood pressure, heart rate, basal cardiac function and vascular reactivity in aorta and mesenteric resistance arteries were evaluated. Reactive oxygen species production by dihydroethidium-emitted fluorescence, NOX-1 mRNA levels by qRT-PCR, angiotensin-converting enzyme activity by fluorimetry and kidney histopathology were also analysed. Both hydrolysates improve the endothelial dysfunction occurring in resistance arteries. Additionally, HEW2 reduced vascular oxidative stress. PRACTICAL APPLICATIONS: Egg white is a good source of bioactive peptides, some of them with high antioxidant activity. They may be used as functional foods ingredients and could serve as an alternative therapeutic option to decrease some Metabolic Syndrome-related complications. This study suggests that these hydrolysates could be an interesting non-pharmacological tool to control cardiovascular complications related to Metabolic Syndrome.

Egg White Hydrolysate: A new putative agent to prevent vascular dysfunction in rats following long-term exposure to aluminum

Aluminum (Al) is toxic for humans and animals. Here, we have tested the potential for Egg White Hydrolysate (EWH) to protect against cardiovascular changes in rats exposed to both high and low dietary levels of Al. Indeed, EWH has been previously shown to improve cardio metabolic dysfunctions induced by chronic exposure to heavy metals. Male Wistar rats received orally: Group 1) Low aluminum level (AlCl₃ at a dose of 8.3 mg/kg b.w. during 60 days) with or without EWH treatment (1 g/kg/day); Group 2) High aluminum level (AlCl₃ at a dose of 100 mg/kg b.w. during 42 days) with or without EWH treatment. After Al treatment, rats co-treated with EWH did not show vascular dysfunction or increased blood pressure as was observed in non EWH-cotreated animals. Indeed, co-treatment with EWH prevented the following effects observed in both aorta and mesenteric arteries: the increased vascular responses to phenylephrine (Phe), the decreased ACh-induced relaxation, the reduction on endothelial modulation of vasoconstrictor responses and the nitric oxide bioavailability, as well as the increased reactive oxygen species production from NAD(P)H oxidase. Altogether, our results suggest that EWH could be used as a protective agent against the harmful vascular effects after long term exposure to Al.

Changes in the diet composition of fatty acids and fiber affect the lower gastrointestinal motility but have no impact on cardiovascular parameters: In vivo and in vitro studies

BACKGROUND

Food and diet are central issues for proper functioning of the cardiovascular (CV) system and gastrointestinal (GI) tract. We hypothesize that different types of dietary FAs affect CV parameters as well as GI motor function and visceral sensitivity.

METHODS

Male Wistar rats were fed with control diet (CTRL), diet supplemented with 7% soybean oil (SOY), SOY + 3.5% virgin coconut oil (COCO), and SOY + 3.5% evening primrose oil (EP) for 4 weeks. The content of insoluble fiber in CTRL was higher than in SOY, COCO, or EP. Body weight gain and food/water intake were measured. At day 28, biometric, biochemical, CV parameters, GI motor function (X-ray and colon bead expulsion test), and visceral sensitivity were evaluated. Changes in propulsive colonic activity were determined in vitro. The colon and adipose tissue were histologically studied; the number of mast cells (MCs) in the colon was calculated.

RESULTS

SOY, COCO, and EP had increased body weight gain but decreased food intake vs CTRL. Water consumption, biometric, biochemical, and CV parameters were comparable between groups. SOY increased the sensitivity to colonic distention. All groups maintained regular propulsive neurogenic contractions; EP delayed colonic motility (P < 0.01). SOY, COCO, and EP displayed decreased size of the cecum, lower number and size of fecal pellets, and higher infiltration of MCs to the colon (P < 0.001).

CONCLUSIONS AND INFERENCES

Dietary FAs supplementation and lower intake of insoluble fiber can induce changes in the motility of the lower GI tract, in vivo and in vitro, but CV function and visceral sensitivity are not generally affected.

Sargassum hystrix as a Source of Functional Food to Improve Blood Biochemistry Profiles of Rats under Stress

This study was conducted to determine the influence of Sargassum hystrix powder (SHP) as an alternative source of functional food for treating in vivo stress by measuring levels of glucose, triacylglycerol, total cholesterol, and cortisol, and liver histopathology. Wistar rats aged 3 months and weighing 150~200 g were divided into 7 groups: normal control, fasting control, negative control (stress without adaptogen), and 4 experimental conditions (stress+0.18 mg/kg diazepam, stress+450 mg/kg pellet, stress+mixture of pellet with SHP 450 mg/kg, and stress+450 mg/kg of SHP). Intake of liquids and and body weight were measured daily. Blood samples were collected on day 0 (baseline), day 5, and day 10 to analyze levels of glucose, triacylglycerol, cholesterol, and cortisol. On day 10, rats were euthanized and livers were collected to observe the severity of inflammation. The results indicated that rats receiving SHP 450 mg/kg and the mixture of pellet with SHP 450 mg/kg showed a similar ability as those receiving diazepam 0.18 mg/kg to cope with stress, indicated by an improvement in all blood biochemistry parameters. Supplementation with SHP 450 mg/kg can be used as an alternative source of functional food for overcoming oxidative stress, as indicated by its ability to improve levels of blood glucose, triacylglycerol, total cholesterol, and cortisol, and to improve liver histology by decreasing severity of liver inflammation.

Egg white hydrolysate enhances insulin sensitivity in high-fat diet-induced insulin-resistant rats via Akt activation

Agents that block the renin-angiotensin system (RAS) improve glucoregulation in the metabolic syndrome disorder. We evaluated the effects of egg white hydrolysate (EWH), previously shown to modulate the protein abundance of RAS component in vivo, on glucose homeostasis in diet-induced insulin-resistant rats. Sprague-Dawley rats were fed a high-fat diet (HFD) for 6 weeks to induce insulin resistance. They were then randomly divided into four groups receiving HFD or HFD supplemented with different concentrations of EWH (1, 2 and 4 %) for another 6 weeks in the first trial. In the second trial, insulin-resistant rats were divided into two groups receiving only HFD or HFD+4 % EWH for 6 weeks. Glucose homeostasis was assessed by oral glucose tolerance and insulin tolerance tests. Insulin signalling and protein abundance of RAS components, gluconeogenesis enzymes and PPARγ were evaluated in muscle, fat and liver. Adipocyte morphology and inflammatory markers were evaluated. In vivo administration of EWH increased insulin sensitivity, improved oral glucose tolerance (P < 0·0001) and reduced systemic inflammation (P < 0·05). EWH potentiated insulin-induced Akt phosphorylation in muscle (P = 0·0341) and adipose tissue (P = 0·0276), but minimal differences in the protein abundance of tissue RAS components between the EWH and control groups were observed. EWH treatment also reduced adipocyte size (P = 0·0383) and increased PPARγ2 protein abundance (P = 0·0237). EWH treatment yielded positive effects on the inflammatory profile, glucose tolerance, insulin sensitivity and adipocyte differentiation in HFD-induced insulin resistance rats. The involvement of local RAS activity requires further investigation.

Peptides and Peptidomimetics as Potential Antiobesity Agents: Overview of Current Status

There is a high occurrence of obesity worldwide without many new medications being approved for its treatment. Therefore, there is an urgent need to introduce new approaches for treating obesity. Bioactive peptides have been used to treat metabolic disorders- such as type-2 diabetes and obesity; while also possessing anti-oxidant, anti-inflammatory, anti-microbial, and anti-viral properties. However, the development of these peptides has taken backstage due to their size, reduced stability, poor delivery and bioavailability, fast rate of degradation etc. But with the emergence of newer techniques for multifunctional peptides, mimetics, peptide analogs, and aptamers, there is a sudden revival in this therapeutic field. An increased attention is required for development of the natural peptides from food and marine sources which can mimic the function of mediators involved in weight management to avoid obesity. Herein, the search for the structures of anti-obesity peptides was carried out in order to establish their potential for drug development in future. An extensive search for the current status of endogenous, food and marine peptides, with reference to novel and interesting experimental approaches based on peptidomimetics for controlling obesity, was performed. Apolipoprotein A-I (apoA-I), melanocortin-4 receptor (MC4R)-specific agonist, GLP-1 dual and triple agonists, neuropeptides and prolactin-releasing peptide mimetics were specifically examined for their anti-obesity role. Novel peptides, mimetics, and synthesis interventions are transpiring and might offer safer alternatives for otherwise scarcely available safe antiobesity drug. A deeper understanding of peptides and their chemistry through the use of peptide engineering can be useful to overcome the disadvantages and select best mimetics and analogs for treatment in future.

Egg White Hydrolysate as a functional food ingredient to prevent cognitive dysfunction in rats following long-term exposure to aluminum

Aluminum (Al), which is omnipresent in human life, is a potent neurotoxin. Here, we have tested the potential for Egg White Hydrolysate (EWH) to protect against changes in cognitive function in rats exposed to both high and low levels of Al. Indeed, EWH has been previously shown to improve the negative effects induced by chronic exposure to heavy metals. Male Wistar rats received orally: Group 1) Low aluminum level (AlCl3 at a dose of 8.3 mg/kg b.w. during 60 days) with or without EWH treatment (1 g/kg/day); Group 2) High aluminum level (AlCl3 at a dose of 100 mg/kg b.w. during 42 days) with or without EWH treatment (1 g/kg/day). After 60 or 42 days of exposure, rats exposed to Al and EWH did not show memory or cognitive dysfunction as was observed in Al-treated animals. Indeed, co-treatment with EWH prevented catalepsy, hippocampal oxidative stress, cholinergic dysfunction and increased number of activated microglia and COX-2-positive cells induced by Al exposure. Altogether, since hippocampal inflammation and oxidative damage were partially prevented by EWH, our results suggest that it could be used as a protective agent against the detrimental effects of long term exposure to Al.

High Fat/High Glucose Diet Induces Metabolic Syndrome in an Experimental Rat Model

Metabolic syndrome (MetS) is defined as a constellation of many metabolic disorders such as hypertension, impaired glucose tolerance, dyslipidemia and obesity, being this last disorder a key factor in the etiology of the syndrome. The widespread of MetS in actual society, mainly in developed countries, is becoming an important health problem and is increasing the need to develop new treatments against this pathology is increasing fast. The main objective of the present study was to evaluate the MetS-associated alterations developed in a new glucose diet-induced-obesity (DIO) rodent model. These alterations were also compared to those alterations developed in a fructose-DIO rodent model. Wistar rats were divided into four groups: Control (C), High-fat (HF), High-fat/high-fructose (HFF) and High-fat/high-glucose (HFG). The animals were fed ad libitum for 20 weeks. At the end of the study, HFG animals showed lower expression of energy expenditure genes when compared to the other DIO groups. Oxidative stress biomarkers such as MDA and mitochondrial RT-qPCR analyses showed an increase of oxidative damage together with mitochondrial dysfunction in HFG group. This group also showed increased insulin and glucose plasma levels, though HFF animals showed the greatest increase on these parameters. All DIO groups showed increased plasma levels of triglycerides. Altogether, our results indicated a better impact of glucose than fructose, when combined with a high-fat diet, to induce most of the alterations associated with MetS in rats. In addition, our research facilitates a new animal model to evaluate future treatments for MetS.

Pulsed electric fields treatment at different pH enhances the antioxidant and anti-inflammatory activity of ovomucin-depleted egg white

This research investigated the effects of pulsed electric fields (PEF) (1.4-1.7 kV/cm, 653-695 kJ/kg) and heating (60 and 80 °C for 10 min) at different pH (4, 5, 7, and 9) on the antioxidant and anti-inflammatory activity of ovomucin-depleted egg white (OdEW) after in vitro gastrointestinal hydrolysis. PEF and heating (80 °C for 10 min) at pH 4 enhanced the antioxidant activity of the whole hydrolysates, chemically determined using DPPH and ORAC assays. Furthermore, the anti-inflammatory activity of protein hydrolysates was assessed in lipopolysaccharide-stimulated HT-29 cells using ELISA assay. PEF and heating at pH 4 enhanced the anti-inflammatory activity of the whole hydrolysates dose-dependently. Hydrolysates at 1 mg/ml showed similar inhibition (35.5% and 35.9%) of interleukin-8 production, due to PEF treatment and heating (80 °C for 10 min), respectively. Results indicated that prior PEF treatment can analogously enhance both antioxidant and anti-inflammatory activity of OdEW hydrolysates to heating, with potentially reduced thermal input.

Pepsin egg white hydrolysate modulates gut microbiota in Zucker obese rats

There is limited information that relates the intake of food-derived bioactive peptides and the gut microbiota. We have previously described a pepsin hydrolysate of egg white (EWH) that ameliorates fat accumulation and dyslipidemia, while reducing oxidative stress and inflammation markers in obese Zucker rats. The aim of this study was to associate the beneficial effects of EWH with gut microbiota changes in these animals. Obese Zucker rats received daily 750 mg kg^-1 EWH in drinking water for 12 weeks and faeces were analysed for microbial composition and metabolic compounds in comparison with Zucker lean rats and obese controls. EWH supplementation modulated the microbiological characteristics of the obese rats to values similar to those of the lean rats. Specifically, counts of total bacteria, Lactobacillus/Enterococcus and Clostridium leptum in EWH fed obese Zucker rats were more similar to the lean rats than to the obese controls. Besides, feeding the obese Zucker rats with EWH reduced (P < 0.05) the faecal concentration of lactic acid. The physiological benefits of EWH in the improvement of obesity associated complications of Zucker rats could be associated with a more lean-like gut microbiota and a tendency to diminish total short-chain fatty acids (SCFA) production and associated obesity complications. The results warrant the use of pepsin egg white hydrolysate as a bioactive food ingredient.

Pepsin egg white hydrolysate ameliorates metabolic syndrome in high-fat/high-dextrose fed rats

The aim of this study was to examine the effect of a pepsin egg white hydrolysate (EWH) on metabolic complications using a high-fat/high-dextrose diet-induced Metabolic Syndrome (MetS) experimental model. Male Wistar rats were divided into 4 groups which received: standard diet and water (C), standard diet and a solution with 1 g kg^-1 day^-1 of EWH (CH), high-fat/high-dextrose diet and water (MS), and high-fat/high-dextrose diet and a solution with 1 g kg^-1 day^-1 of EWH (MSH). EWH consumption normalized body weight gain; abdominal obesity and peripheral neuropathy developed in MetS animals, and adipose tissue and liver weight, as well as plasma glucose were reduced. Oxidative stress and inflammation biomarkers were normalized in MSH animals. In conclusion, the oral administration of EWH could be used as a functional food ingredient to improve some complications associated with MetS induced by unhealthy diets.

Egg and Soy-Derived Peptides and Hydrolysates: A Review of Their Physiological Actions against Diabetes and Obesity

Type 2 diabetes and obesity are two chronic conditions associated with the metabolic syndrome and their prevalences are increasing worldwide. The investigation of food protein-derived bioactive peptides that can improve the pathophysiology of diabetes or obesity while causing minimal side effects is desired. Egg and soy proteins generate bioactive peptides with multiple biological effects, exerting nutritional and physiological benefits. This review focuses on the anti-diabetic and anti-obesity effects of egg- and soy-derived peptides and hydrolysates in vivo and in vitro relevant to these conditions. Studies using the intact protein were considered only when comparing the results with the hydrolysate or peptides. In vivo evidence suggests that bioactive peptides from egg and soy can potentially be used to manage elements of glucose homeostasis in metabolic syndrome; however, the mechanisms of action on glucose and insulin metabolism, and the interaction between peptides and their molecular targets remain unclear. Optimizing the production of egg- and soy-derived peptides and standardizing the physiological models to study their effects on diabetes and obesity could help to clarify the effects of these bioactive peptides in metabolic syndrome-related conditions.

Pepsin Egg White Hydrolysate Improves Glucose Metabolism Complications Related to Metabolic Syndrome in Zucker Fatty Rats

The purpose of this study was to evaluate the effect of the administration of two egg white hydrolysates on glucose metabolism complications related to Metabolic Syndrome (MS) in Zucker fatty rats (ZFR). ZFR were given 750 mg/kg/day of egg white hydrolyzed with pepsin (HEW1) or with aminopeptidase (HEW2) for 12 weeks in their drinking water or just water. Zucker lean rats (ZLR), which received water, were used as a control. The presence of tactile allodynia, which is a sign of peripheral neuropathy, was assessed. Blood samples and pancreas were collected to determine the effect of the hydrolysates on glucose metabolism. The intake of HEW1 significantly lowered plasma insulin levels and improved the quantitative indexes of insulin resistance, insulin sensitivity, and pancreatic β-cell functionality (HOMA-IR, HOMA-β, and QUICKI, respectively), but non-significant changes were observed in group treated with HEW2. Compared to ZLR, ZFR showed tactile allodynia, but the consumption of both hydrolysates significantly increased mechanical sensitivity in ZFR. In conclusion, HEW1 pepsin could improve the glucose metabolism abnormalities associated with MS in obese Zucker rats.

Egg Protein-Derived Bioactive Peptides: Preparation, Efficacy, and Absorption

The hen's egg is an important protein source of human diet. On average one large egg contains ~6g protein, which contributes to ~11% of daily protein intake. As a high-quality protein, egg proteins are well recognized as excellent sources of bioactive peptides. The objectives of this chapter are to introduce generation, bioactivities, and absorption of egg protein-derived bioactive peptides. Research on egg protein-derived bioactive peptides has been progressed during the past decades. Enzymatic hydrolysis is the major technique to prepare bioactive peptides from egg protein. Quantitative structure-activity relationships-aided in silico prediction is increasingly applied as a promising tool for efficient prediction of novel bioactive peptides. A number of bioactive peptides from egg proteins have been characterized for antioxidant, immunomodulatory, antihypertensive, antidiabetic, anticancer, and antimicrobial activities. Egg protein-derived peptides that can improve bone health have been reported as well. However, molecular mechanisms of many peptides are not fully understood. The stability and absorption routes, bioavailability, safety, and production of bioactive peptides await further investigation.