Fractionation of Protein Hydrolysates of Fish Waste Using Membrane Ultrafiltration: Investigation of Antibacterial and Antioxidant Activities

In this study, yellowfin tuna (Thunnus albacores) viscera were hydrolyzed with protamex to obtain hydrolysate that is separated by a membrane ultrafiltration into four molecular size fractions (< 3, 3-10, 10-30, and 30 kDa <). Antibacterial and antioxidant properties of the resulting hydrolysates and membrane fractions were characterized, and results showed that the lowermost molecular weight fraction (< 3 kDa) had significantly the highest (P < 0.05) percentage of bacteria inhibition against Gram-positive (Listeria and Staphylococcus) and Gram-negative (E. coli and Pseudomonas) pathogenic and fish spoilage-associated microorganisms and scavenging activity against DPPH and ABTS radical and ferric reducing antioxidant power among the fractionated enzymatic hydrolysates. These results suggest that the protein hydrolysate derived from yellowfin tuna by-products and its peptide fractions could be used as an antimicrobial and antioxidant ingredient in both nutraceutical applications and functional food.

Nobiletin Promotes Megakaryocytic Differentiation through the MAPK/ERK-Dependent EGR1 Expression and Exerts Anti-Leukemic Effects in Human Chronic Myeloid Leukemia (CML) K562 Cells

Differentiation therapy is an alternative strategy used to induce the differentiation of blast cells toward mature cells and to inhibit tumor cell proliferation for cancer treatment. Nobiletin (NOB), a polymethoxyflavone phytochemical, is present abundantly in citrus peels and has been reported to possess anti-cancer activity. In this study, we investigated the anti-leukemic effects of NOB on cell differentiation and its underlying mechanisms in human chronic myeloid leukemia (CML) K562 cells. NOB (100 μM) treatment for 24 and 48 h significantly decreased viability of K562 cells to 54.4 ± 5.3% and 46.2 ± 9.9%, respectively. NOB (10–100 μM) significantly inhibited cell growth in K562 cells. Flow cytometry analysis and immunoblotting data showed that NOB (40 and 80 μM) could modulate the cell cycle regulators including p21, p27, and cyclin D2, and induce G1 phase arrest. NOB also increased the messenger RNA (mRNA) and protein expression of megakaryocytic differentiation markers, such as CD61, CD41, and CD42 as well as the formation of large cells with multi-lobulated nuclei in K562 cells. These results suggested that NOB facilitated K562 cells toward megakaryocytic differentiation. Furthermore, microarray analysis showed that expression of EGR1, a gene associated with promotion of megakaryocytic differentiation, was markedly elevated in NOB-treated K562 cells. The knockdown of EGR1 expression by small interference RNA (siRNA) could significantly attenuate NOB-mediated cell differentiation. We further elucidated that NOB induced EGR1 expression and CD61 expression through increases in MAPK/ERK phosphorylation in K562 cells. These results indicate that NOB promotes megakaryocytic differentiation through the MAPK/ERK pathway-dependent EGR1 expression in human CML cells. In addition, NOB when combined with imatinib could synergistically reduce the viability of K562 cells. Our findings suggest that NOB may serve as a beneficial anti-leukemic agent for differentiation therapy.

Triketone-terpene meroterpenoids from the leaves of Rhodomyrtus tomentosa

Eight new meroterpenoids (1-8) featuring β-triketone-conjugated terpenoids, rtomentones A-H, were isolated from the leaves of Rhodomyrtus tomentosa. Structures of the isolates were unambiguously established by a combination of NMR and ECD spectroscopy and X-ray diffraction analysis. Rtomentone C (3) was the first example of aromadendrane-based meroterpenoid containing an oxa-spiro[5.6] ring. Rtomentone D (4) was obtained as a racemic mixture confirmed by chiral HPLC analysis. The cytotoxicity against MDA-MB-231, A549, and DLD-1 cells of all isolates was evaluated.

Effect of Fructus Mori. bioactive polysaccharide conjugation on improving functional and antioxidant activity of whey protein

Whey protein with high biological and technological values is an excellent source of nutrition. However, the limited functional properties prevent its widespread applications in food industry. In this study, the whey protein functionality was improved via glycation with mulberry fruit polysaccharide by Maillard reaction. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis profile and free amino groups determination confirmed the glycation occurred between whey protein and mulberry fruit polysaccharide. The emulsion capacity and stability of the conjugates were 1.40-fold and 1.52-fold higher than that of whey protein. The conjugates also exhibited remarkably improved antioxidant activity. The fish oil emulsion coated by conjugates demonstrated smaller droplet size, better storage and oxidative stability than that stabilized by whey protein. The findings would be of vital importance for updated understanding of the modification in emulsifying properties of proteins by glycation with natural bioactive polysaccharides as well as for the development of healthy foods.

Fine particulate matter aggravates intestinal and brain injury and affects bacterial community structure of intestine and feces in Alzheimer's disease transgenic mice

Fine particulate matter (PM_2.5) was a risk factor for neurological disorders when emerging studies revealed that PM_2.5 affected the bacterial community structure of gut in Alzheimer's disease (AD) patients. The purpose of this study was to explore the effects of PM_2.5 on intestinal and brain injury and on bacterial community structure in the intestine and feces of APP/PS1 transgenic mice exposed to PM_2.5 for eight weeks with a real-world whole-body inhalation exposure system in Taiyuan, China. The brain and intestinal tissues were collected to evaluate histopathological changes by HE staining. TNF-α and IL-6 levels in intestines, brains, and serums, and Aβ-42 levels in brains were detected. Intestinal and fecal samples were subjected to 16S rRNA gene sequencing. Results showed that PM_2.5 significantly aggravated the pathological injury in intestines and brains in AD mice with elevated pro-inflammatory cytokine levels. The estimators of Shannon, Simpson, Chao1, and ACE indexes reflected the diversity and richness of the bacterial community. Compared with the FA-WT group, the FA-AD group had lower diversity and richness when the PM_2.5-AD group had the highest ones. PCA and NMDS revealed the specific influence of PM_2.5 on the bacterial community of intestine and feces because that the PM_2.5-FA and PM_2.5-AD group clumped visibly closer than the other groups in both bacterial communities of intestine and feces. The KEGG pathway analysis predicted the vital functional genes and metabolic pathways in the bacterial community of PM_2.5-AD mice. This study indicated the histopathological changes and inflammation in the intestine and brain were seriously caused in PM_2.5-AD mice when the α-diversity of the bacterial community in intestine and feces was visibly changed.

Effect of Parkin on methamphetamine-induced α-synuclein degradation dysfunction in vitro and in vivo

INTRODUCTION

Methamphetamine (METH) is a psychostimulant drug with complicated neurotoxicity, and abuse of METH is very common. Studies have shown that METH exposure causes alpha-synuclein (α-syn) accumulation. However, the mechanism of α-syn accumulation has not been determined.

METHODS

In this study, we established cell and animal models of METH intoxication to evaluate how METH affects α-syn expression. In addition, to explore METH-induced neurotoxicity, we measured the level of Parkin and the phosphorylation levels of α-syn, Polo-like kinase 2 (PLK2), the proteasome activity marker CD3δ, and the apoptosis-related proteins Caspase-3 and PARP. Parkin is a key enzyme in the ubiquitin-proteasome system. In addition, the effect of Parkin on METH-induced neurotoxicity was investigated by overexpressing it in vitro and in vivo.

RESULTS

METH exposure increased polyubiquitin and α-syn expression, as did MG132. Furthermore, the level of Parkin and the interaction between Parkin and α-syn decreased after METH exposure. Importantly, the increases in α-syn expression and neurotoxicity were relieved by Parkin overexpression.

CONCLUSIONS

By establishing stable cell lines and animal models that overexpress Parkin, we confirmed Parkin as an important factor in METH-induced α-syn degradation dysfunction in vitro and in vivo. Parkin may be a promising target for the treatment of METH-induced neurotoxicity.

Evaluation of antifatigue and antioxidant activities of the marine microalgae Isochrysis galbana in mice

The present work aimed to estimate the possible anti-fatigue effect and potential mechanism of Isochrysis galbana (IG) in mice. The anti-fatigue activity of IG (100, 200, and 400 mg/kg) was elucidated by a weight-loaded forced swimming test, and the potential mechanism was explored by determination of fatigue-related biochemical parameters. The results showed that pretreatment with IG significantly extended the exhaustive swimming time and increased the levels of liver glycogen, muscle glycogen and blood glucose in a dose-dependent manner. Besides, the increased levels of alanine aminotransferase, aspartate aminotransferase, blood lactic acid, lactic dehydrogenase, creatine kinase, and blood urea nitrogen by exhausted swimming, were dramatically attenuated by pretreatment with IG. Furthermore, supplementation with IG significantly enhanced the glutathione peroxidase and superoxide dismutase levels, while attenuated the level of malonaldehyde. Taken together, IG possessed appreciable efficacy to alleviate fatigue, and the mechanism might be associated with favorably modulating the process of energy consumption, metabolism, and attenuating oxidative stress injury.

Comparison of wheat, soybean, rice, and pea protein properties for effective applications in food products

Pea and rice proteins are promising to substitute allergenic proteins, and increasingly, play important roles in the food industry because of their hypoallergenic characteristics and nutritional value. However, manufacturers generally provide limited functionality information on these proteins. Therefore, this study comprehensively compared functional properties of wheat, soybean, rice, and pea proteins for their industrial applications and illustrated correlation among various functionalities. Results showed that protein solubility (PS) was highly related to its water absorption (WA) capacity, emulsifying activity index (EAI), and emulsion stability index (ESI). The overall functionality of pea protein was close to that of soybean protein while rice protein cannot match with all other proteins. sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis indicated the composition of each protein was unique. While the deconvolution of the amide I band of the Raman spectra indicated soybean and pea proteins that shared similar features, but they were different from that of wheat and rice proteins. PRACTICAL APPLICATIONS: Due to the allergenicity of wheat and soybean proteins, food manufacturers are looking for alternative protein sources. Rice and Pea proteins are promising substitutes because of their "allergen-friendly" as well as their emergence in the food market. This study provided a comprehensive comparison of the functionality of commercially available wheat, soybean, rice, and pea proteins. The information presented in this study would be helpful to food scientists, scholars, or engineers when they develop appropriate application of various proteins in food products.

Effect of multi-frequency countercurrent ultrasound treatment on extraction optimization, functional and structural properties of protein isolates from Walnut (Juglans regia L.) meal

This study evaluated the effects of ultrasound treatment on walnut meal protein (WMP) extraction and techno-functional properties. The Box-Behnken Design (BBD) was adopted for the optimization of the traditional and ultrasound-assisted extraction (UAE) processes. Standard protocols were used to assay the techno-functional characteristics. The extraction models' statistical results exhibited adequacy with the least desirability index of 95.8%. The UAE enhanced the WMP extraction yield, purity, and chemical score by 30.15%, 16.27%, and 9.74%, respectively, while reducing the extraction time by 25% over the control. The emulsion and foam stabilities and bulk density increased by 34.5%, 39.8%, and 6.1%, respectively, over the control. The α-helix decreased while β-sheet, β-turns and random coil secondary structure components increased significantly (p < .05) by 95.76%, 101.3%, 105.1%, and 85.7% correspondingly. The dual-frequency combination (20/40 kHz/kHz) was the best frequency mode. WMP could serve as a functional additive in manufactured foods as texture and flavor enhancer. PRACTICAL APPLICATIONS: Walnut meal protein (WMP) has a well-balanced amino acid profile and its economic use could be practically increased as a food ingredient by ultrasound-assisted extraction. By this technique, WMP could be employed for the development of enhanced food ingredients rather than being discarded as animal feed. This study showed a positive effect of ultrasonic-assisted alkaline pretreatment on WMP extraction, functionality and structure characteristics. In addition to process improvement, ultrasound is energy efficient and environmentally friendly. Therefore, the applicability of this technique to improve the functionality of plant proteins from industrial by-products to be included in food products is promising.

Pearl powder reduces sleep disturbance stress response through regulating proteomics in a rat model of sleep deprivation

Aims

This study aimed to explore whether pearl could help prevent cognitional morbidity and improve the metabolic processes of hippocampus.

Methods

Rats were divided into group of control (CTL), sleep deprivation (SD) and pearl powder (PP). The sleeplessness was introduced to all rats except control. Before and after administration with vehicle or pearl powder, cognition was evaluated by Morris water maze (MWM). The protein expression in hippocampus among all groups was examined using iTRAQ‐based global proteomic analysis.

Results

Morris water maze tests revealed improvements of insomnia‐induced cognitive deficit in both PP‐ and ES‐treated rats, as compared to SD rats. However, proteomic analysis indicates that the pharmacological impact on gene expression of these two medicines is quite different: pearl is more capable of correcting aberrant gene expression caused by SD than estazolam. Therefore, pearl is more suitable for treatment of insomnia. These data, together with protein‐protein interaction analysis, indicate that several pathways, affected by sleep deprivation, may be rescued by pearl powder: retrograde endocannabinoid signalling pathway, and the protein interaction or network enrich in oxidative phosphorylation Parkinson's disease and Huntington disease, etc

Conclusions

Sleep deprivation can mimic cognition decline caused by insomnia with altered protein expression in the hippocampus; such behavioural and pathological changes can be significantly ameliorated by pearl powder.

Recovery of Yam Soluble Protein from Yam Starch Processing Wastewater

Over the past two decades, many studies have shown that the yam storage protein dioscorin, which is abundant in the wastewater of starch processing, exhibits many biological activities both in vitro and in vivo. In the present study, the acid-precipitation method was optimized using Box-Behnken design (BBD) combined with response surface methodology (RSM) for the recovery of yam soluble protein (YSP) from wastewater. The experimental yield of YSP reached 57.7%. According to relative quantitative proteomics (LC-MS/MS), the crude YSP was mainly composed of 15 dioscorin isoforms, which was further verified by anion-exchange and size-exclusion chromatography. YSP was found to be rich in glutamic acid and aspartic acid, and the eight essential acids made up approximately 33.7% of the YSP. Moreover, the YSP demonstrated antioxidant activity, including scavenging DPPH, hydroxyl and superoxide anion radicals, and the possible structure-activity relationships were discussed. These results indicated that YSP produced by acid precipitation may be used as a protein source with antioxidant properties.

Identification of key gene modules and hub genes of human mantle cell lymphoma by coexpression network analysis

Purpose

Mantle cell lymphoma (MCL) is a rare and aggressive subtype of non-Hodgkin lymphoma that is incurable with standard therapies. The use of gene expression analysis has been of interest, recently, to detect biomarkers for cancer. There is a great need for systemic coexpression network analysis of MCL and this study aims to establish a gene coexpression network to forecast key genes related to the pathogenesis and prognosis of MCL.

Methods

The microarray dataset GSE93291 was downloaded from the Gene Expression Omnibus database. We systematically identified coexpression modules using the weighted gene coexpression network analysis method (WGCNA). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis were performed on the modules deemed important. The protein-protein interaction networks were constructed and visualized using Cytoscape software on the basis of the STRING website; the hub genes in the top weighted network were identified. Survival data were analyzed using the Kaplan-Meier method and were compared using the log-rank test.

Results

Seven coexpression modules consisting of different genes were applied to 5,000 genes in the 121 human MCL samples using WGCNA software. GO and KEGG enrichment analysis identified the blue module as one of the most important modules; the most critical pathways identified were the ribosome, oxidative phosphorylation and proteasome pathways. The hub genes in the top weighted network were regarded as real hub genes (IL2RB, CD3D, RPL26L1, POLR2K, KIF11, CDC20, CCNB1, CCNA2, PUF60, SNRNP70, AKT1 and PRPF40A). Survival analysis revealed that seven genes (KIF11, CDC20, CCNB1, CCNA2, PRPF40A, CD3D and PUF60) were associated with overall survival time (p < 0.05).

Conclusions

The blue module may play a vital role in the pathogenesis of MCL. Five real hub genes (KIF11, CDC20, CCNB1, CCNA2 and PUF60) were identified as potential prognostic biomarkers as well as therapeutic targets with clinical utility for MCL.

Targeting drug delivery system for platinum(Ⅳ)-Based antitumor complexes

Classical platinum(II) anticancer agents are widely-used chemotherapeutic drugs in the clinic against a range of cancers. However, severe systemic toxicity and drug resistance have become the main obstacles which limit their application and effectiveness. Because divalent cisplatin analogues are easily destroyed in vivo, their bioavailability is low and no selective to tumor tissues. The platinum(IV) prodrugs are attractive compounds for cancer treatment because they have great advantages, e.g., higher stability in biological media, aqueous solubility and no cross-resistance with cisplatin, which may become the next generation of platinum anticancer drugs. In addition, platinum(IV) drugs could be taken orally, which could be more acceptable to cancer patients, breaking the current situation that platinum(II) drugs can only be given by injection. The coupling of platinum(IV) complexes with tumor targeting groups avoids the disadvantages such as instability in blood, irreversible binding to plasma proteins, rapid renal clearance, and non-specific distribution in normal tissues. Because of the above advantages, the combination of platinum complexes and tumor targeting groups has become the hottest field in the research and development of new platinum drugs. These approaches can be roughly categorized into two groups: active and passive targeted strategies. This review concentrates on various targeting and delivery strategies for platinum(IV) complexes to improve the efficacy and reduce the side effects of platinum-based anticancer drugs. We have made a summary of the related articles on platinum(IV) targeted delivery in recent years. We believe the results of the studies described in this review will provide new ideas and strategies for the development of platinum drugs.

Preparation of soy sauce by walnut meal fermentation: Composition, antioxidant properties, and angiotensin-converting enzyme inhibitory activities

Remaining walnut meal after oil extraction still contains many nutrients. However, these by‐products have not been effectively used. In this study, walnut meal and Aspergillus oryzae (3.042) were used in combination to prepare a soy sauce‐like material with high amino nitrogen content (ANC). The optimal conditions for the preparation of walnut soy sauce (ratio of brine:koji of 1.7:1 for 6 days at 45°C) were determined using response surface experiments (RSE), which showed maximum ANC of 855 mg/100 ml. The results of amino acid analysis indicated that walnut soy sauce had a similar amino acid composition compared with three commercial soy sauces. It contained all the essential amino acids and had a high content of umami amino acids such as Glu and Asp, which may give it a stronger umami taste. Moreover, the crude walnut soy sauce was extracted sequentially using ethyl acetate, n‐butanol, acetone and water, and the total phenols, total flavonoids, reducing sugars, and the peptides of different solvent extracts were measured. Results showed that the total phenolic and flavonoid contents were highest in the ethyl acetate extracts. However, water residue had the highest levels of reducing sugars and peptides. In vitro, the water residue showed the highest antioxidant capacity and angiotensin‐converting enzyme (ACE) inhibitory activity, due to more reducing sugars and peptides. These results indicated that walnut soy sauce may have significant antioxidant and ACE inhibitory activity. The findings provide a scientific basis for developing a replacement for soy sauce and broaden the beneficial application of walnut meal.

Antiproliferative Effects of Roylea cinerea (D. Don) Baillon Leaves in Immortalized L6 Rat Skeletal Muscle Cell Line: Role of Reactive Oxygen Species Mediated Pathway

Roylea cinerea (D. Don) Baill. (Lamiaceae) is an indigenous plant of Western Himalayas, and has been used by the native population for the treatment of various diseases such as fever, malaria, diabetes, jaundice, and skin ailments. However, limited proportion of pharmacological and toxicological information is available on the bioactive properties of this plant. Therefore, the present study was designed to explore the anti-oxidant and anti-proliferative activities of Roylea cinerea. Methanolic extracts of leaves and stem of Roylea cinerea were prepared through maceration procedure and evaluated for the antioxidant activity using hydrogen/electron donating and hydroxyl radical scavenging assay. Significant antioxidant activity was observed for the methanolic extract of leaves in DPPH (EC₅₀ 239 µg/ml), molybdate ion reduction assay (29.73 µg ascorbic acid equivalent/mg dry weight of extract) as well as in plasmid nicking assay. Anti-proliferative and apoptotic activity in L6 rat skeletal muscle cell line was done using in vitro assays, i.e., MTT, Lactate dehydrogenase, mitochondrial membrane potential assay along with phase contrast, confocal, and scanning electron microscopy. The methanol extract of leaves and stem inhibited the growth of L6 cells with IC₅₀ value of 69.41µg/ml and 124.93 µg/ml, respectively, and the lactate dehydrogenase activity was 20.29% and 0.3%, respectively. Cell cycle analysis by flow cytometry exhibited the arrest of cells in G1 and sub-G1 phase by methanolic leaves extract. Furthermore, the results of microscopic and docking analysis strengthened the observation made in the present study regarding the apoptotic mode of cell death in the L6 cell line. The in vitro findings of our studies revealed that the bioactive ingredients present in the methanolic extract of leaves and stem of Roylea cinerea have the anticancer potential. Further in vivo studies are needed to verify the in vitro results.

Bioactive Peptides from Walnut Residue Protein

Walnut residue is a kind of high-quality plant protein resource. The bioactive peptide prepared from walnut residue has excellent health care functions such as antioxidation and antihypertensive activity, but at present, walnut residue is often regarded as waste or low value feed, fertilizer and other materials. The uneconomical use of walnut residue has hindered the development of the walnut industry to some extent. Effective utilization of walnut residue protein to develop bioactive peptides and other products is of great significance to realize the comprehensive utilization of walnut residue, improve the added value of by-products, and change the current low utilization rate of walnut residue. In this paper, the preparation, purification and structure identification of walnut protein bioactive peptides are reviewed, and different functional walnut active peptides (WBPs) are introduced. The potential effects of these bioactivities on human health and their different uses in food, medicine and other industries are discussed. The purpose is to provide reference information for the effective utilization of walnut residue resources and the development of walnut industry.

Antimicrobial Resistance in Veterinary Medicine: An Overview

Antimicrobial resistance (AMR) represents one of the most important human- and animal health-threatening issues worldwide. Bacterial capability to face antimicrobial compounds is an ancient feature, enabling bacterial survival over time and the dynamic surrounding. Moreover, bacteria make use of their evolutionary machinery to adapt to the selective pressure exerted by antibiotic treatments, resulting in reduced efficacy of the therapeutic intervention against human and animal infections. The mechanisms responsible for both innate and acquired AMR are thoroughly investigated. Commonly, AMR traits are included in mobilizable genetic elements enabling the homogeneous diffusion of the AMR traits pool between the ecosystems of diverse sectors, such as human medicine, veterinary medicine, and the environment. Thus, a coordinated multisectoral approach, such as One-Health, provides a detailed comprehensive picture of the AMR onset and diffusion. Following a general revision of the molecular mechanisms responsible for both innate and acquired AMR, the present manuscript focuses on reviewing the contribution of veterinary medicine to the overall issue of AMR. The main sources of AMR amenable to veterinary medicine are described, driving the attention towards the indissoluble cross-talk existing between the diverse ecosystems and sectors and their cumulative cooperation to this warning phenomenon.

Antioxidant Peptides from Collagen Hydrolysate of Redlip Croaker (Pseudosciaena polyactis) Scales: Preparation, Characterization, and Cytoprotective Effects on H2O2-Damaged HepG2 Cells

Bioactive peptides from fish collagens with antioxidant properties have become a topic of great interest for health, food, and processing/preservation industries. To explore the high-value utilized way of scales produced during the fish processing, collagen hydrolysates of redlip croaker (Pseudosciaena polyactis) scales were prepared using six different proteases, and the hydrolysate (RSCH) prepared using neutrase showed the highest degree of hydrolysis (21.36 ± 1.18%) and 2,2-diphenyl-1-picrylhydrazyl (DPPH·) radical scavenging activity (30.97 ± 1.56%) among the six hydrolysates. Subsequently, six antioxidant peptides were purified from RSCH using membrane ultrafiltration and serial chromatography, and their amino acid sequences were identified as DGPEGR, GPEGPMGLE, EGPFGPEG, YGPDGPTG, GFIGPTE, and IGPLGA with molecular masses of 629.61, 885.95, 788.96, 762.75, 733.80, and 526.61 Da, respectively. Among six collagen peptides, GPEGPMGLE, EGPFGPEG, and GFIGPTE exhibited the strongest scavenging activities on DPPH· radical (EC₅₀ 0.59, 0.37, and 0.45 mg/mL), hydroxyl radical (EC₅₀ 0.45, 0.33, and 0.32 mg/mL), and superoxide anion radical (EC₅₀ 0.62, 0.47, and 0.74 mg/mL). GPEGPMGLE, EGPFGPEG, and GFIGPTE showed high inhibiting ability on lipid peroxidation in a linoleic acid model system and protective activities on oxidation-damaged DNA. More importantly, GPEGPMGLE, EGPFGPEG, and GFIGPTE could protect HepG2 cells from H₂O₂-induced oxidative damage through decreasing the levels of reactive oxygen species (ROS) and MDA and activating intracellular antioxidant enzymes of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). These results suggested that six collagen peptides (RCP1–RCP6), especially GPEGPMGLE, EGPFGPEG, and GFIGPTE, might serve as potential antioxidants applied in nutraceutical and pharmaceutical products.

Antioxidant Peptides from the Protein Hydrolysate of Monkfish (Lophius litulon) Muscle: Purification, Identification, and Cytoprotective Function on HepG2 Cells Damage by H2O2

In the work, defatted muscle proteins of monkfish (Lophius litulon) were separately hydrolyzed by pepsin, trypsin, and in vitro gastrointestinal (GI) digestion methods, and antioxidant peptides were isolated from proteins hydrolysate of monkfish muscle using ultrafiltration and chromatography processes. The antioxidant activities of isolated peptides were evaluated using radical scavenging and lipid peroxidation assays and H2O2-induced model of HepG2 cells. In which, the cell viability, reactive oxygen species (ROS) content, and antioxidant enzymes and malondialdehyde (MDA) levels were measured for evaluating the protective extent on HepG2 cells damaged by H2O2. The results indicated that the hydrolysate (MPTH) prepared using in vitro GI digestion method showed the highest degree of hydrolysis (27.24 ± 1.57%) and scavenging activity on a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical (44.54 ± 3.12%) and hydroxyl radical (41.32 ± 2.73%) at the concentration of 5 mg protein/mL among the three hydrolysates. Subsequently, thirteen antioxidant peptides (MMP-1 to MMP-13) were isolated from MPTH. According to their DPPH radical and hydroxyl radical scavenging activity, three peptides with the highest antioxidant activity were selected and identified as EDIVCW (MMP-4), MEPVW (MMP-7), and YWDAW (MMP-12) with molecular weights of 763.82, 660.75, and 739.75 Da, respectively. EDIVCW, MEPVW, and YWDAW showed high scavenging activities on DPPH radical (EC50 0.39, 0.62, and 0.51 mg/mL, respectively), hydroxyl radical (EC50 0.61, 0.38, and 0.32 mg/mL, respectively), and superoxide anion radical (EC50 0.76, 0.94, 0.48 mg/mL, respectively). EDIVCW and YWDAW showed equivalent inhibiting ability on lipid peroxidation with glutathione in the linoleic acid model system. Moreover, EDIVCW, MEPVW, and YWDAW had no cytotoxicity to HepG2 cells at the concentration of 100.0 µM and could concentration-dependently protect HepG2 cells from H2O2-induced oxidative damage through decreasing the levels of reactive oxygen species (ROS) and MDA and activating intracellular antioxidant enzymes of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). These present results indicated that the protein hydrolysate and isolated antioxidant peptides from monkfish muscle, especially YWDAW could serve as powerful antioxidants applied in the treatment of some liver diseases and healthcare products associated with oxidative stress.

Self-assembled hydrophobic Ala-Aib peptide encapsulating curcumin: a convenient system for water insoluble drugs

The exploitation of self-assembled systems to improve the solubility of drugs is getting more and more attention. Among the different types of self-assembled biomaterials, peptides and in particular peptides containing non-coded amino acids (NCAPs) are promising because their use opens the door to more stable materials inducing increased stability to proteolysis. New classes of NCAP, Ac-Ala-X-Ala-Aib-AlaCONH2 (X = alpha-aminoisobutyric acid (Aib) or X = cyclopentane amino acid (Ac5c)) have been prepared and the correlation between the different secondary peptide structure and solvent (i.e. CD3CN, CD3OH, H2O/D2O) verified by NMR. Furthermore, the formation of a nanocolloidal system in water was deeply studied by DLS and the morphology of the obtained spherical aggregates with nanometric dimensions was assessed by TEM. Aib containing pentapeptide was selected for greater ease of synthesis. Its ability to encapsulate curcumin, as a model insoluble drug molecule, was investigated using fluorescence emission and confocal microscopy analyses. Two different approaches were used to study the interaction between curcumin and peptide aggregates. In the first approach peptide aggregates were formed in the presence of curcumin, while in the second approach curcumin was added to the already formed peptide aggregates. We succeeded in our challenge by using the second approach and 53.8% of added curcumin had been encapsulated.

Theaflavin TF3 Relieves Hepatocyte Lipid Deposition through Activating an AMPK Signaling Pathway by targeting Plasma Kallikrein

Nonalcoholic fatty liver disease (NAFLD) is rapidly becoming the leading cause of chronic liver diseases throughout the world. The deficit of pharmacotherapy for NAFLD calls for an urgent need for a new drug discovery and lifestyle management. Black tea is the most popular and functional drink consumed worldwide. Its main bioactive constituent theaflavin helps to prevent obesity-a major risk factor for NAFLD. To find new targets for the development of effective and safe therapeutic drugs from natural plants for NAFLD, we found a theaflavin monomer theaflavin-3,3'-digallate (TF3), which significantly reduced lipid droplet accumulation in hepatocytes, and directly bound and inhibited the activation of plasma kallikrein (PK), which was further proved to stimulate adenosine monophosphate activated protein kinase (AMPK) and its downstream targets. Taken together, we proposed that the TF3-PK-AMPK regulatory axis is a novel mechanism of lipid deposition mitigation, and PK could be a new target for NAFLD treatment.

Purification and identification of antioxidant peptides from duck plasma proteins

The antioxidant peptides extracted from duck plasma hydrolysate (DPH) was investigated. The antioxidant activity of DPH, which was isolated and purified via ultrafiltration, size exclusion chromatography, and reversed-phase high-performance liquid chromatography, was evaluated using its free radical scavenging ability. Nano-liquid chromatography-tandem mass spectrometry was conducted to identify the DPH fractions with the highest antioxidant ability. Seven novel peptides: LDGP, TGVGTK, EVGK, RCLQ, LHDVK, KLGA, and AGGVPAG (400.43, 561.63, 431.48, 260.14, 610.71, 387.47, and 527.57 Da, respectively) were identified and synthesized using a solid-phase peptide produce to evaluate their antioxidant activities. Of these, EVGK exhibited the highest Fe²⁺ chelating ability (16.35%), and RCLQ presented the highest reducing power, 2,2-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt scavenging activity, and 1,1-diphenyl-2-picrylhydrazyl scavenging rate (0.62, 274.83 mM TE/mg, and 95.12%, respectively). Our results indicated that DPH possessed antioxidant capabilities and could be used to obtain antioxidant peptides, thus adding economic value to duck blood.

The separation and identification of the residual antigenic fragments in soy protein hydrolysates

Soybean is one of the major food allergens. In this study, soy protein isolate was hydrolyzed by Neutrase and Flavourzyme. The hydrolysates were separated by ultrafiltration and ion-exchange chromatography. The antigenicity of proteins was determined by indirect competitive ELISA. The molecular weight distribution was characterized by SDS-PAGE. The amino acid sequence of chromatography fractions was analyzed by LC-MS. The results showed that proteins with >50 kDa in hydrolysates had the highest antigenicity and were further separated into F1 -F5 fragments by ion-exchange chromatography. Fragment F4 , which was the most antigenic, was analyzed by LC-MS. The results of mass spectrometry showed that most of the peptides that contained antigen epitopes in chromatography fraction F4 belonged to glycinin subunits. The antigenicity of soy protein was reduced by enzymatic hydrolysis, but glycinin showed resistance to enzymatic hydrolysis. PRACTICAL APPLICATIONS: The identification of residual antigenicity in soy protein hydrolysates by LC-MS provides important information on the resistance mechanism of enzymatic hydrolysis of soybean protein allergens. In addition, the efficient separation of soy protein hydrolysates could be beneficial for developing low-allergenic soybean products.

Effect on amino acid and mineral content of the loach (Misgurnus anguillicaudatus) by adding Fe (II) chelating hairtail protein hydrolysates (Fe (II)-HPH) to the feed

To study the effect on amino acid and mineral content of the loach meat by adding Fe (II) chelating hairtail protein hydrolysates (Fe (II)-HPH) to the feed. A total of 100 healthy loaches were selected. After 1 week's adaptive feeding, they were randomly divided into five groups and fed with feeds containing of Fe (II)-HPH (0, 0.5, 1, 2, and 4 g/kg). On the 40th day, detection work of general nutrients (moisture, ash, crude protein, and crude fat), mineral elements (Fe, Mn, Cu, Zn, Na, K, and Ca), amino acid and amino acid score (AAS), Chemical Score (CS) and essential amino acid index (EAAI) indexes were done. The results show that crude protein has the highest content while crude fat has the lowest when amount of added Fe (II)-HPH in feed is 2 g/kg. The Fe content is significantly improved while amount of added is 1, 2, 4 g/kg. The Ca content is significantly improved and the Zn content is significantly improved while amount of added was 2 g/kg. Mn contents are significantly lower than control while amount of added is 4 g/kg. Based on analysis of amino acids in each group, the nutritional value of loach meat with 2 g/kg Fe (II)-HPH addition amount is relatively high, total amount of essential amino acids increases significantly, and EAA/TAA and EAA/NEAA improve significantly. In conclusion, adding 2 g/kg Fe (II)-HPH to feed could improve the nutritional values of loach meat.

Umami fractions obtained from water-soluble extracts of red oncom and black oncom-Indonesian fermented soybean and peanut products

Red oncom, a fermented product from solid waste of soybean curd process, and black oncom, a similar fermented product but made from defatted peanut cake, have been known to have umami taste. Umami fractions of red oncom and black oncom that are responsible for umami taste have not been investigated yet. The objective of this research was to characterize umami fractions obtained by ultrafiltration and chromatography of both oncoms. The first step, water-soluble extracts of oncoms were ultrafiltered using a membrane with cutoff 3,000 Da and followed by gel filtration chromatography (Sephadex G-25) to obtain umami fractions. Ultrafiltration fractions of red oncom (molecular weight [MW] less than 3,000 Da) and black oncom (MW more than 3,000 Da) had an intense umami taste. The further fractionation by gel filtration chromatography linked to taste dilution analysis yielded umami fractions. Chemical characterization revealed that free glutamic acid, free phenylalanine, and peptides containing their residual amino acids were present in the fractions. PRACTICAL APPLICATION: Umami fractions of red and black oncoms can be used as a source of umami compounds for food industries and food services. The information from this paper can be used by other researchers who will explore umami peptides.

Inhibitory Effects of Walnut (Juglans regia) Peptides on Neuroinflammation and Oxidative Stress in Lipopolysaccharide-Induced Cognitive Impairment Mice

Increasing level of inflammation and oxidative stress could lead to memory impairment. The purpose of this study was to determine the neuroprotective effects of walnut peptides against memory deficits induced by lipopolysaccharide (LPS) in mice and further to explore the underlying anti-inflammatory mechanisms against LPS-elicited inflammation in BV-2 cells. Results showed that walnut protein hydrolysate (WPH) and its low-molecular-weight fraction (WPHL) could ameliorate the memory deficits induced by LPS via normalizing the inflammatory response and oxidative stress in brain, especially WPHL. Furthermore, 18 peptides with anti-inflammatory activities on LPS-activated BV-2 cells were identified from WPHL and it was found that Trp, Gly, and Leu residues in peptides might contribute to the anti-inflammation. Meanwhile, the strong anti-inflammatory effects of LPF, GVYY, and APTLW might be related to their hydrophobic and aromatic amino acid residues as well. LPF, GVYY, and APTLW could reduce the content of proinflammatory mediators and cytokines by downregulating related enzyme expressions and mRNA expressions. Additionally, ROS and mitochondria homeostasis might also contribute to their anti-inflammatory effects.

Absorption Rates and Mechanisms of Avenanthramides in a Caco-2 Cell Model and Their Antioxidant Activity during Absorption

Avenanthramides (AVNs) are a unique kind of polyphenols that were only detected in the oats and have been demonstrated to exhibit strong antioxidant activities but low bioavailability. The purpose of the present research was to evaluate the absorption rates and mechanisms of AVNs (AVN 2c, AVN 2f, and AVN 2p) using a human colon adenocarcinoma cell line (Caco-2) cell model and clarify the influence of the absorption process on the antioxidant capacities of AVNs. Furthermore, the absorption rates and antioxidant activities of ferulic acid and caffeic acid were compared with those of AVNs. Results showed that the apparent absorption rates (P_app) of AVN 2c, AVN 2f, and AVN 2p were 0.65 ± 0.05 × 10^-6, 1.18 ± 0.16 × 10^-6, and 1.44 ± 0.09 × 10^-6 cm/s, respectively, which were significantly lower than those of caffeic acid (3.76 ± 0.31 × 10^-6 cm/s) and ferulic acid (1.69 ± 0.13 × 10^-5 cm/s). Moreover, the metabolites (caffeic acid, ferulic acid, and AVN 2f) of AVNs after absorption were detected and quantified by high-performance liquid chromatography-mass spectrometry. Before absorption, although the antioxidant capacities of AVNs were significantly stronger than those of ferulic acid and caffeic acid, there was an opposite result after absorption. In addition, AVNs transported the Caco-2 monolayer by paracellular diffusion and were affected by monoamine oxidase and efflux transporters (P-gp, MRP2) during absorption. The co-administration of quercetin could significantly improve the absorption rates of AVNs.