Exploring the role of γ-Oryzanol on stabilization mechanism of Pickering emulsion gels loaded by α-Lactalbumin or ß-Lactoglobulin via multiscale approaches.

The research explored the role of γ-oryzanol (γs) on stabilization behavior of Pickering emulsion gels (PEGs) loaded by α-lactalbumin (α-LA) or ß-lactoglobulin (ß-LG), being analyzed by experimental and computer methods (molecular dynamic simulation, MD). Primarily, the average particle size of ß-LG-γS was expressed 100.07% decrease over that of α-LA-γS. In addition, γs decreased the dynamic interfacial tension of two proteins with the order of ß-LG < α-LA. Meanwhile, quartz crystal microbalance with dissipation proved that ß-LG-γS exhibited higher adsorption mass and denser rigid interface layer than α-LA-γS. Moreover, the hydrophobic group of γS had electrostatic repulsion with polar water molecules in the aqueous phase, which spread to the oil phase. ß-LG-γS had lower RMSD/Rg value and narrower fluctuation compared with α-LA-γS. This work strength the exploration of interfacial stabilization mechanism of whey protein-based PEGs, which enriched its theoretical research for industrial-scale production as the replacement of trans fat and cholesterol.

Alleviating Effect of Lacticaseibacillus rhamnosus 1.0320 Combined with Dihydromyricetin on Acute Alcohol Exposure-Induced Hepatic Impairment: Based on Short-Chain Fatty Acids and Adenosine 5'-Monophosphate-Activated Protein Kinase-Mediated Lipid Metabolism Signaling Pathway.

Excessive drinking has been listed by the World Health Organization as the fifth major risk factor; especially the liver, as the core organ of alcohol metabolism, is prone to organic lesions. Probiotics have received attention due to their bioactivity for liver protection. The beneficial effects of probiotics on hosts are related to their physiological functions. Therefore, based on the concept of second-generation synbiotes, this study explored the protective effects of four dietary polyphenols on the stress tolerance, hydrophobicity, adhesion, and digestive characteristics of L. rhamnosus 1.0320. L. rhamnosus 1.0320 had the best synergistic effect with dihydromyricetin (DMY). Therefore, this combination was selected as a synbiotic supplement to explore the protective effect on acute alcohol exposure-induced hepatic impairment. The results showed that L. rhamnosus 1.0320 combined with DMY restored the intestinal barrier by upregulating short-chain fatty acid levels and activated the adenosine 5'-monophosphate-activated protein kinase-mediated lipid metabolism pathway to inhibit oxidative stress, inflammation, and lipid accumulation in the liver. Furthermore, 109 CFU/mouse/d L. rhamnosus 1.0320 and 50 mg/kg/d DMY by gavage were identified as the optimal doses for protection against acute alcohol expose-induced hepatic impairment. This study provides new insights into alleviating acute alcoholic hepatic impairment by targeting intestinal metabolites through the gut-liver axis.

Protective Effect of Polyphenols, Protein, Peptides, and Polysaccharides on Alcoholic Liver Disease: A Review of Research Status and Molecular Mechanisms.

Alcoholic liver disease (ALD) has emerged as an important public health problem in the world. The polyphenols, protein, peptides, and polysaccharides have attracted attention for prevention or treatment of ALD. Therefore, this paper reviews the pathogenesis of ALD, the relationship between polyphenols, peptides, polysaccharides, and ALD, and expounds the mechanism of gut microbiota on protecting ALD. It is mainly found that the hydroxyl group of polyphenols endows it with antioxidation to protect ALD. The ALD protection of bioactive peptides is related to amino acid composition. The ALD protection of polysaccharides is related to the primary structure. Meanwhile, polyphenols, protein, peptides, and polysaccharides prevent or treat ALD by antioxidation, anti-inflammatory, antiapoptosis, lipid metabolism, and gut microbiota regulation. This contribution provides updated information on polyphenols, protein, peptides, and polysaccharides in response to ALD, which will not only facilitate the development of novel bioactive components but also the future application of functional food raw materials will be promoted.

Non-perfectly Amphipathic α-Helical Structure Containing the XXYXX Sequence Improves the Biological Activity of Bovine αs2-Casein Antimicrobial Peptides.

Non-amphiphilic WIQPKTKVIPYVRYL (WI-6) derived from bovine αs2-casein f (193-207) was modified by a defined mutation method to obtain five engineered peptides with mirror symmetry structures. The five engineered peptide sequences were WF-1 (WFQVKTRVRTKVQFW), FW-2 (FWRRYKKVKKYRRWF), FW-3 (FWQVIKKVKKIVQWF), FK-4 (FKQFYRRVRRYFQKF), and FR-5 (FRQWYRRVRRYWQRF). However, FW-2, FW-3, FK-4, and FR-5 had obvious XXYXX sequences. Among these, FW-3 was demonstrated to have the highest antibacterial activity, which indicates that the non-perfectly amphipathic α-helical structure containing the XXYXX sequence has a better bactericidal effect. Therefore, peptide FW-3 could be widely used as a substitute for antibiotics in food, medicine, and other fields. These findings provide a potential method for designing novel antimicrobial peptides.

Comparison in bioactivity and characteristics of Ginkgo biloba seed polysaccharides from four extract pathways.

The effects of hot-water extraction (HWE), ultrasound-treated extraction (UTE), enzyme-treated extraction (ETE) and ultrasound-enzyme treated extraction (UETE) on the α-glucosidase inhibitory activity, antioxidant activities and characteristics of Ginkgo biloba seed polysaccharides were investigated and compared in this study. Among the four extracted polysaccharides, the UETE-polysaccharide initially exhibited the highest α-glucosidase inhibitory activity and antioxidant activities. The HWE-polysaccharide showed a large number of small compact spherical structures, and the UTE-polysaccharide exhibited an irregular pleated porous shape; meanwhile, the ETE-polysaccharide and UETE-polysaccharide were spongy with smooth surface topography, as observed by scanning electron microscopy (SEM). The four polysaccharides varied in monosaccharide composition. The HWE-polysaccharide mainly consisted of homogeneous mannose; the UETE-polysaccharide was primarily composed of mannose, rhamnose, and glucose in a molar ratio of 8.25:1.00:1.53. The HWE-polysaccharide had the largest molecular weight (4.2 × 105 Da), reduced by the order of the UETE-polysaccharide (2.02 × 104 Da), ETE-polysaccharide (1.72 × 104 Da), and UTE-polysaccharide (1.34 × 104 Da). Thus, the four extract methods exerted significant effects on the bioactivity and characteristics of the polysaccharides. The UETE-polysaccharide from G. biloba seeds showed the highest bioactive activities and distinctive structural characteristics.

Study of the alleviation effects of a combination of Lactobacillus rhamnosus and inulin on mice with colitis.

Ulcerative colitis (UC) is a common inflammatory bowel disease (IBD) that has serious harmful effects on human health. Lactobacillus rhamnosus, a probiotic, has a strong colonization and adhesion effect and improves the intestinal health of the host. Inulin has good anti-inflammatory effects and can promote the proliferation of beneficial intestinal bacteria. The purpose of this study was to investigate the alleviating effects of L. rhamnosus 1.0320 in combination with inulin on UC, examining the resulting changes in intestinal flora. A UC model was established by having mice freely drink a 3% (w/v) dextran sodium sulphate (DSS) solution for seven days. After successful modeling, the mice were given antibiotics, L. rhamnosus 1.0320 by itself, inulin by itself, and L. rhamnosus 1.0320 combined with inulin as an intragastric intervention for 28 days. The abundance and structural changes of bacteria in the intestinal content of mice were analyzed by 16S rDNA high-throughput sequencing. The study found that male BALB/c mice can successfully establish a typical model of small intestinal inflammation by freely drinking a 3% DSS solution for one week. L. rhamnosus 1.0320 combined with inulin can alleviate DSS-induced colitis, reduce the Disease Activity Index (DAI) score of the pathological damage of colon tissue, decrease myeloperoxidase (MPO) activity, increase hemoglobin content, and regulate the expression levels of inflammatory cytokines IL-1ß, IL-6, TNF-α and IL-10. The intestinal flora of mice is reduced after enteritis, and its structure gets disordered. The combination of L. rhamnosus 1.0320 and inulin can increase the abundance and diversity of intestinal flora, and increase the content of beneficial bacteria. Prebiotics promote the colonization ability of probiotics. L. rhamnosus 1.0320 combined with inulin can change the intestinal flora to relieve ulcerative colitis, providing a new theoretical basis for the study of UC mechanism.

Novel Angiotensin-Converting Enzyme-Inhibitory Peptides From Fermented Bovine Milk Started by Lactobacillus helveticus KLDS.31 and Lactobacillus casei KLDS.105: Purification, Identification, and Interaction Mechanisms.

Fermented milks with strong angiotensin I-converting enzyme (ACE)-inhibitory activity were obtained through a culture with Lactobacillus helveticus KLDS.31 and Lactobacillus casei KLDS.105 with a fermentation and storage temperature of 37 °C. Ultrafiltration fractions with a molecular weight less than 3 kDa in fermented milk whey exhibited the strongest inhibitory activity. Correspondingly, a gastrointestinal digestion experiment showed retention of the bioactivity of these fractions with pepsin and trypsin treatment. Four ACE-inhibitory peptides from fermented milk were isolated, purified by two-step reverse chromatography, and sequenced. Furthermore, the interaction mechanisms between ACE and four isolated peptides were investigated by a molecular docking method and the Independent Gradient Model. Experimental determination of IC50 was done to verify theoretical results. The inhibitory peptide interacted with ACE as follows: Lys-Pro-Ala-Gly-Asp-Phe > Lys-Ala-Ala-Leu-Ser-Gly-Met > Lys-Lys-Ala-Ala-Met-Ala-Met > Leu-Asp-His-Val-Pro-Gly-Gly-Ala-Arg.

Characterization of the Bioactivity and Mechanism of Bactenecin Derivatives Against Food-Pathogens.

With the emergence of multidrug-resistant bacteria, antimicrobial peptides (AMPs) are regarded as potential alternatives to traditional antibiotics or chemicals. We designed and synthesized six derivatives of bactenecin (L2C3V10C11, RLCRIVVIRVCR), including R2F3W10L11 (RRFRIVVIRWLR), R2W3W10R11 (RRWRIVVIRWRR), K2W3V10R11 (RKWRIVVIRVRR), W2R3V10R11 (RWRRIVVIRVRR), W2K3K10R11 (RWKRIVVIRKRR), and K2R3R10K11 (RKRRIVVIRRKR), by amino acid substitution to increase the net charge and reduce hydrophobicity gradually. The bioactivity and mechanisms of action of the designed peptides were investigated. The results indicated that the antimicrobial activity of the designed peptides was higher than that of bactenecin. The hemolytic activity and cytotoxicity of the designed peptides were significantly lower than those of bactenecin. The designed peptides exhibited a wide range of antimicrobial activity against food-pathogens, particularly peptides K2W3V10R11 and W2R3V10R11; in addition, the activity was maintained under physiological salt and heat conditions. Mechanism studies indicated that AMPs interacted with negatively charged bacterial cell membranes, resulting in the destruction of cell membrane integrity by increasing membrane permeability and changing transmembrane potential, leading to cell death. The present study suggested that peptides K2W3V10R11 and W2R3V10R11 exhibited potential as alternatives to traditional antibiotics or chemicals for the treatment of food-pathogens. These findings lead to the development of a potential method for the design of novel AMPs.

Antibacterial Activity and Mechanism of Action of Bovine Lactoferricin Derivatives with Symmetrical Amino Acid Sequences.

In recent years, the overuse of antibiotics has become very serious. Many pathogenic bacteria have become resistant to them, with serious potential health consequences. Thus, it is urgent that we develop new antibiotic drugs. Antimicrobial peptides (AMPs) are important endogenous antibacterial molecules that contribute to immunity. Most have spectral antibacterial properties and do not confer drug resistance. In this paper, an 11-residue peptide (LFcinB18⁻28) with a sequence of KCRRWQWRMKK was modified by amino acid substitution to form a symmetrical amino acid sequence. The antibacterial activities and mechanisms of action of engineered peptides including KW-WK (KWRRWQWRRWK), FP-PF (FPRRWQWRRPF), FW-WF (FWRRWQWRRWF), and KK-KK (KKRRWQWRRKK) were investigated. The four engineered peptides could more effectively inhibit bacteria than the original peptide, LFcinB18⁻28. This suggested that a symmetrical amino acid sequence might enhance the antibacterial activity of AMPs. However, only peptides KW-WK, FP-PF, and KK-KK were safe; FW-WF displayed hemolytic activity. The engineered peptides shared cationic and amphipathic characteristics that facilitated interactions with the anionic microbial membranes, leading to disruption of membrane integrity and permeabilizing microbial membranes, resulting in cell death. Therefore, a symmetrical amino acid sequence and related structural parameters offer an alternative approach to the design of AMPs. This will provide a scientific basis for the design and synthesis of new AMPs.

Broad-Spectrum Antimicrobial Activity and Low Cytotoxicity against Human Cells of a Peptide Derived from Bovine αS1-Casein.

The primary objective of this study was to improve our understanding of the antimicrobial mechanism of protein-derived peptides and to provide evidence for protein-derived peptides as food bio-preservatives by examining the antimicrobial activities, low cytotoxicity, stabilities, and mechanism of Cp1 (LRLKKYKVPQL). In this study, the protein-derived peptide Cp1 was synthesized from bovine αS1-casein, and its potential use as a food biopreservative was indicated by the higher cell selectivity shown by 11-residue peptide towards bacterial cells than human RBCs. It also showed broad-spectrum antimicrobial activity, with minimum inhibitory concentrations (MICs) of 64⁻640 µM against both gram-positive and gram-negative bacteria. The peptide had low hemolytic activity (23.54%, 512 µM) as well as cytotoxicity. The results of fluorescence spectroscopy, flow cytometry, and electron microscopy experiments indicated that Cp1 exerted its activity by permeabilizing the microbial membrane and destroying cell membrane integrity. We found that Cp1 had broad-spectrum antimicrobial activity, low hemolytic activity, and cytotoxicity. The results also revealed that Cp1 could cause cell death by permeabilizing the cell membrane and disrupting membrane integrity. Overall, the findings presented in this study improve our understanding of the antimicrobial potency of Cp1 and provided evidence of the antimicrobial mechanisms of Cp1. The peptide Cp1 could have potential applications as a food biopreservative.