Sulfate glycosaminoglycan from swim bladder exerts immunomodulatory potential on macrophages via toll-like receptor 4 mediated NF-κB signaling pathways

This study explored the immunomodulatory impact and potential mechanisms on macrophages RAW264.7 using a purified macromolecular sulfate glycosaminoglycan (SBSG) from the swim bladder, whose structure was similar to chondroitin sulfate A. The results showed that SBSG at 0.25-1 mg/mL increased the viability and phagocytosis of RAW264.7 cells. Meanwhile, SBSG promoted the secretion of tumor necrosis factor α (TNF-α), interleukin 10 (IL-10), and nitric oxide (NO), as well as the production of reactive oxygen species (ROS). According to the RT-PCR and Western blot data, SBSG activated TLR4-nuclear factor kappa B (NF-κB) signaling pathways, which decreased the relative mRNA and protein levels of Toll-like receptor 4 (TLR4), IκB kinase β (IKKβ), NF-κB p65, and p-NF-κB p65. The molecular docking and molecular dynamic simulation findings revealed that the main binding force between TLR4 and SBSG was conventional hydrogen bond interaction, resulting in more stable ligand receptor complexes. In summary, SBSG exhibits significant immunomodulatory potential, similar to chondroitin sulfate C. The underlying molecular mechanism involved the binding of SBSG through hydrogen bonding to TLR4 receptors, triggering the NF-κB signaling pathway to downregulate the expression of related genes and proteins. This, in turn, regulated the secretion of various cytokines that were mediated by macrophages to exert the immunity of the body.

Bridging neurotrophic factors and bioactive peptides to Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder. As the demographic shifting towards an aging population, AD has emerged as a prominent public health concern. The pathogenesis of AD is complex, and there are no effective treatment methods for AD until now. In recent years, neurotrophic factors and bioactive peptides including brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), irisin, melatonin, have been discovered to exert neuroprotective functions for AD. Bioactive peptides can be divided into two categories based on their sources: endogenous and exogenous. This review briefly elaborates on the pathogenesis of AD and analyzes the regulatory effects of endogenous and exogenous peptides on the pathogenesis of AD, thereby providing new therapeutic targets for AD and a theoretical basis for the application of bioactive peptides as adjunctive therapies for AD.

Effects of Walnut and Pumpkin on Selective Neurophenotypes of Autism Spectrum Disorders: A Case Study

Special diets or nutritional supplements are regularly given to treat children with autism spectrum disorder (ASD). The increased consumption of particular foods has been demonstrated in numerous trials to lessen autism-related symptoms and comorbidities. A case study on a boy with moderate autism who significantly improved after three years of following a healthy diet consisting of pumpkin and walnuts was examined in this review in connection to a few different neurophenotypes of ASD. We are able to suggest that a diet high in pumpkin and walnuts was useful in improving the clinical presentation of the ASD case evaluated by reducing oxidative stress, neuroinflammation, glutamate excitotoxicity, mitochondrial dysfunction, and altered gut microbiota, all of which are etiological variables. Using illustrated figures, a full description of the ways by which a diet high in pumpkin and nuts could assist the included case is offered.

Research Progress on the Preparation and Function of Antioxidant Peptides from Walnuts

Food-derived peptides have good antioxidant activity and are highly safe for humans; consequently, there has been continuous growth in research on antioxidants, with potential applications in food, medicine, cosmetics, and other fields. Among food-derived peptides, walnut-derived peptides have attracted increasing attention as food-derived peptides rich in eight essential amino acids. This review summarizes the progress made in the development and identification of antioxidant peptides in walnut proteins. This article mainly describes the interaction between reactive oxygen species and cellular antioxidant products, modulation of enzyme content and activity, and regulation of the redox signaling pathways and analyzes the mechanisms of reduction in oxidative stress. Finally, the complex structure-activity relationships of walnut-derived peptides are analyzed based on their amino acid composition and secondary structure of the polypeptides. This review provides a theoretical basis for the production of walnut-derived antioxidant peptides and could help promote the development of the walnut industry.

Advanced Insights into Walnut Protein: Structure, Physiochemical Properties and Applications

Facing extreme pressure from an increasing population and climate degeneration, it is important to explore a green, safe and environmentally sustainable food source, especially for protein-enriched diets. Plant proteins have gained much attention in recent years, ascribing to their high nutritional value and environmental friendliness. In this review, we summarized recent advances in walnut protein with respect to its geographical distribution, structural and physiochemical properties and functional attributes. As a worldwide cultivated and largely consumptive crop, allergies and some physicochemical limitations have also led to a few concerns about walnut protein. Through comprehensive analysis and discussion, some strategies may be useful for future research, extraction and processing of walnut protein.

Isolation, Identification, Activity Evaluation, and Mechanism of Action of Neuroprotective Peptides from Walnuts: A Review

As human life expectancy increases, the incidence of neurodegenerative diseases in older adults has increased in parallel. Walnuts contain bioactive peptides with demonstrated neuroprotective effects, making them a valuable addition to the diet. We here present a comprehensive review of the various methods used to prepare, isolate, purify, and identify the neuroprotective peptides found in walnuts. We further summarise the different approaches currently used to evaluate the activity of these peptides in experimental settings, highlighting their potential to reduce oxidative stress, neuroinflammation, and promote autophagy, as well as to regulate the gut microflora and balance the cholinergic system. Finally, we offer suggestions for future research concerning bioavailability and improving or masking the bitter taste and sensory properties of final products containing the identified walnut neuroprotective peptides to ensure successful adoption of these peptides as functional food ingredients for neurohealth promotion.

Phytotherapeutic targeting of the mitochondria in neurodegenerative disorders

Neurodegenerative diseases are characterized by degeneration or cellular atrophy within specific structures of the brain. Neurons are the major target of neurodegeneration. Neurons utilize 75-80% of the energy produced in the brain. This energy is either formed by utilizing the glucose provided by the cerebrovascular blood flow or by the in-house energy producers, mitochondria. Mitochondrial dysfunction has been associated with neurodegenerative diseases. But recently it has been noticed that neurodegenerative diseases are often associated with cerebrovascular diseases. Cerebral blood flow requires vasodilation which to an extent regulated by mitochondria. We hypothesize that when mitochondrial functioning is disrupted, it is not able to supply energy to the neurons. This disruption also affects cerebral blood flow, further reducing the possibilities of energy supply. Loss of sufficient energy leads to neuronal dysfunction, atrophy, and degeneration. In this chapter, we will discuss the metabolic modifications of mitochondria in aging-related neurological disorders and the potential of phytocompounds targeting them.

Isolation and Identification of Anti-Inflammatory Peptide from Goose Blood Hydrolysate to Ameliorate LPS-Mediated Inflammation and Oxidative Stress in RAW264.7 Macrophages

This study was designed to isolate an anti-inflammatory activity oligopeptide from goose blood (GBP) for ameliorating LPS-mediated inflammation response and oxidative stress in RAW264.7 macrophages. In this study, GBP was isolated by tangential flow ultrafiltration system (TFUS) combined with size exclusion chromatography (SEC), ion exchange chromatography (IEC), and reversed-phase liquid chromatography (RP-LC), and then identified by liquid chromatography mass spectrometry (LC-MS/MS). The experiment results indicated that the amino acid sequence of oligopeptide with the best anti-inflammatory activity was IIe-Val-Tyr-Pro-Trp-Thr-Gln-Arg (IVYPWTQR), which had a molecular weight of 1062.5720 Da, and was derived from haemoglobin subunit beta OS in goose blood. In addition, IVYPWTQR was confirmed to have satisfactory stability and maintained high anti-inflammatory activity in a simulated gastrointestinal digestion. The mechanism by which the IVYPWTQR protected against LPS-mediated inflammation response was attributed to downregulating the TLR4/NF-kB/iNOS pathway. Moreover, IVYPWTQR ameliorated oxidative stress damage in inflammatory state was attributed to activating antioxidant defence system, which was regulated by Keap-1/NRF2/HO-1 signalling pathway for decreasing the accumulation of reactive oxide species (ROS). In summary, these results indicated GBP could serve as a potential functional factor for prevention and improvement of inflammation mediated by LPS and provided an affordable dietary intervention strategy to prevent inflammation.

Quinoa husk peptides reduce melanin content via Akt signaling and apoptosis pathways

To improve the treatment of pigmentation disorders, looking for natural and safe inhibitors of melanin synthesis has become an area of research interest. The quinoa husk peptides reportedly elicit various biological activities (e.g., anti-cancer, antioxidant, anti-hypertensive, and so forth), but its effects on melanin inhibition remain unknown. In the current study, we purified quinoa husk peptides with 30 and 80% ethanol using a macroporous adsorption resin (DA201-C). Component screening revealed that the 80%-ethanol fraction (i.e., QHP fraction) contained numerous short peptides (84.41%) and hydrophobic amino acids (45.60%), while eliciting a superior tyrosinase [TYR]-inhibition rate, 2,2-diphenyl-1-picryhydrazil-scavenging rate, reducing activity, and chelating capacity compared to the 30% fraction and was thus applied in subsequent analyses. Differentially expressed genes in the QHP fraction were primarily enriched in the Akt-signaling pathways based on transcriptomics. Thus, we assessed the expression of related proteins and genes in A375 cells and rat skin cells following treatment with QHP.

Pharmacotherapeutic potential of walnut (Juglans spp.) in age-related neurological disorders

Global and regional trends of population aging spotlight major public health concerns. As one of the most common adverse prognostic factors, advanced age is associated with a remarkable incidence risk of many non-communicable diseases, affecting major organ systems of the human body. Age-dependent factors and molecular processes can change the nervous system's normal function and lead to neurodegenerative disorders. Oxidative stress results from of a shift toward reactive oxygen species (ROS) production in the equilibrium between ROS generation and the antioxidant defense system. Oxidative stress and neuroinflammation caused by Amyloid-ß protein deposition in the human brain are the most likely pathogenesis of Alzheimer's disease (AD). Walnut extracts could reduce Amyloid-ß fibrillation and aggregation, indicating their beneficial effects on memory and cognition. Walnut can also improve movement disabilities in Parkinson's disease due to their antioxidant and neuroprotective effect by reducing ROS and nitric oxide (NO) generation and suppressing oxidative stress. It is noteworthy that Walnut compounds have potential antiproliferative effects on Glioblastoma (the most aggressive primary cerebral neoplasm). This effective therapeutic agent can stimulate apoptosis of glioma cells in response to oxidative stress, concurrent with preventing angiogenesis and migration of tumor cells, improving the quality of life and life expectancy of patients with glioblastoma. Antioxidant Phenolic compounds of the Walnut kernel could explain the significant anti-convulsion ability of Walnut to provide good prevention and treatment for epileptic seizures. Moreover, the anti-inflammatory effect of Walnut oil could be beneficial in treating multiple sclerosis. In this study, we review the pharmaceutical properties of Walnut in age-related neurological disorders.

Recent Studies on Protective Effects of Walnuts against Neuroinflammation

Neuroinflammation plays a significant role in the aging process and the pathophysiology of neurodegenerative diseases, such as Alzheimer’s disease. Accordingly, possible therapeutic strategies aimed at anti-inflammatory effects may be beneficial to brain health. Walnut kernels contain large quantities of unsaturated fatty acids, peptides, and phenolic compounds that have anti-inflammatory effects. The long-term intake of walnuts has been found to improve cognitive function and memory in rats and humans. However, the modulatory effect of walnuts on neuroinflammation has received much less attention. This review focuses on the potential influence and main regulating mechanisms of walnuts and their active ingredients on neuroinflammation, including the regulation of microglia activation induced by amyloid β or lipopolysaccharides, inhibition of peripheral inflammation mediated by macrophages, reduction in oxidative stress by decreasing free radical levels and boosting antioxidant defenses, and control of gut microbes to maintain homeostasis. However, the majority of evidence of the beneficial effects of walnuts or their components on neuroinflammation and neurodegeneration comes from experimental work, whereas evidence from clinical studies on the beneficial effects is scarcer and less conclusive. This review aims to provide new insights into the neuroinflammation-regulating mechanisms and natural active ingredients of walnuts and the development of walnut-based functional foods for the alleviation of neurodegenerative diseases.

Assessment of Novel Oligopeptides from Rapeseed Napin (Brassica napus) in Protecting HepG2 Cells from Insulin Resistance and Oxidative Stress

Oligopeptides (Thr-His-Leu-Pro-Lys (THLPK), His-Pro-Leu-Lys (HPLK), Leu-Pro-Lys (LPK), His-Leu-Lys (HLK), and Leu-His-Lys (LHK)) are newly identified from rapeseed napin (Brassica napus) protein-derived hydrolysates with the capability of upregulating glucose transporter-4 (GLUT4) expression and translocation. However, whether each of them enhances GLUT4 expression and translocation and their specific mechanisms remain unclear. Here, we assess the effects of the oligopeptides against insulin resistance (IR) and oxidative stress in hepatocytes and screen out the most antidiabetic one. Specifically, compared with other oligopeptides, LPK not only remarkably elevated glucose consumption to 8.45 mmol/L protein; superoxide dismutase (SOD) activity to 319 U/mg protein; GLUT4 expression and translocation; and phosphorylated level of insulin receptor substrate-1 (IRS-1), phosphatidylinositol 3-kinase (PI3K), and protein kinase B (Akt) (P < 0.05) but also remarkably attenuated the reactive oxygen species (ROS) level to 2255, lactate dehydrogenase (LDH) activity to 20.5 U/mg protein, malondialdehyde (MDA) content to 241 nmol/mg protein, and NO content to 1302 μmol/mL protein (P < 0.05). These findings demonstrated that antidiabetic oligopeptide LPK possessed the most potential to protect HepG2 cells from IR and oxidative stress via activating IRS-1/PI3K/Akt/GLUT4 and regulating common oxidative markers in vitro.

Walnut Prevents Cognitive Impairment by Regulating the Synaptic and Mitochondrial Dysfunction via JNK Signaling and Apoptosis Pathway in High-Fat Diet-Induced C57BL/6 Mice

This study was conducted to evaluate the protective effect of Juglans regia (walnut, Gimcheon 1ho cultivar, GC) on high-fat diet (HFD)-induced cognitive dysfunction in C57BL/6 mice. The main physiological compounds of GC were identified as pedunculagin/casuariin isomer, strictinin, tellimagrandin I, ellagic acid-O-pentoside, and ellagic acid were identified using UPLC Q-TOF/MS analysis. To evaluate the neuro-protective effect of GC, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), 2′,7′-dichlorodihydrofluorecein diacetate (DCF-DA) analysis were conducted in H₂O₂ and high glucose-induced neuronal PC12 cells and hippocampal HT22 cells. GC presented significant cell viability and inhibition of reactive oxygen species (ROS) production. GC ameliorated behavioral and memory dysfunction through Y-maze, passive avoidance, and Morris water maze tests. In addition, GC reduced white adipose tissue (WAT), liver fat mass, and serum dyslipidemia. To assess the inhibitory effect of antioxidant system deficit, lipid peroxidation, ferric reducing antioxidant power (FRAP), and advanced glycation end products (AGEs) were conducted. Administration of GC protected the antioxidant damage against HFD-induced diabetic oxidative stress. To estimate the ameliorating effect of GC, acetylcholine (ACh) level, acetylcholinesterase (AChE) activity, and expression of AChE and choline acetyltransferase (ChAT) were conducted, and the supplements of GC suppressed the cholinergic system impairment. Furthermore, GC restored mitochondrial dysfunction by regulating the mitochondrial ROS production and mitochondrial membrane potential (MMP) levels in cerebral tissues. Finally, GC ameliorated cerebral damage by synergically regulating the protein expression of the JNK signaling and apoptosis pathway. These findings suggest that GC could provide a potential functional food source to improve diabetic cognitive deficits and neuronal impairments.

Mechanism of Ser-Ala-Gly-Pro-Ala-Phe treatment with a pulsed electric field to improve ethanol-induced gastric mucosa injury in mice

This paper focused on the mechanism of Ser-Ala-Gly-Pro-Ala-Phe (SAGPAF) treatment to improve gastric mucosal injury in mice. A gastric mucosa injury model induced by ethanol was established, and the superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, nitric oxide (NO) content and myeloperoxidase (MPO) level were determined. We performed macroscopic and histopathological evaluation of the gastric organs. Moreover, we analyzed the mechanism of SAGPAF treatment by western blotting. Compared with the model group, the SOD activity and NO content in the medium-dose and high-dose SAGPAF groups of treated with 10 kV cm^-1 field intensity were significantly increased. The MDA content and MPO level were decreased significantly. They significantly reduced the gastric mucosal injury induced by ethanol (21.17 ± 3.51% and 13.99 ± 2.00%) and the histopathological scores (3.83 ± 0.40 and 4.33 ± 0.37) (P < 0.05). Western blotting analysis showed that SAGPAF after pulsed electric field (PEF) treatment improved gastric injury by reducing protein phosphorylation. These findings provided strong evidence that PEF-treated SAGPAF enhanced the gastric mucosal barrier function by inhibiting the activation of the mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) signaling pathways, reducing the ethanol-induced inflammatory response and oxidative stress.

The anti-inflammatory effects of apigenin and genistein on the rat intestinal epithelial (IEC-6) cells with TNF-α stimulation in response to heat treatment

The aims of the present study were to investigate the anti-inflammatory function of two flavonoids apigenin and genistein in rat intestinal epithelial (IEC-6) cells stimulated by tumor necrosis factor-alpha (TNF-α) and to clarify whether the heat treatment of the flavonoids might affect flavonoid activity. The flavonoids at lower dosage (e.g. 5 μmol/L) had no toxic effect but growth promotion on the cells. Meanwhile, the flavonoid pretreatment of the cells before TNF-α stimulation could maintain cellular morphology, decrease the production of prostaglandin E₂ and two pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-6, but increase the production of two anti-inflammatory cytokines IL-10 and transforming growth factor-β. Additionally, the flavonoids could block off the nuclear translocation of nuclear factor-kappaB (NF-κB) p65, and suppress the expression of phosphorylated IκBα and p65 induced by TNF-α. Meanwhile, the NF-κB inhibitor BAY 11-7082 shared a similar function with the flavonoids to mediate the production of IL-6/IL-10. Furthermore, in silico analysis also declared that the flavonoids could interact with the IκBα-NF-κB complex at the binding pockets to yield the binding energies ranging from -31.7 to -34.0 kJ/mol. However, the heated flavonoids were consistently less effective than the unheated counterparts to perform these anti-inflammatory effects. It is thus proposed that both apigenin and genistein have anti-inflammatory potential to the TNF-α-stimulated IEC-6 cells by inactivating the NF-κB pathway, while heat treatment of the flavonoids caused a negative impact on these assessed anti-inflammatory effects.

Novel Antioxidant Collagen Peptides of Siberian Sturgeon (Acipenser baerii) Cartilages: The Preparation, Characterization, and Cytoprotection of H2O2-Damaged Human Umbilical Vein Endothelial Cells (HUVECs)

For making full use of aquatic by-products to produce high value-added products, Siberian sturgeon (Acipenser baerii) cartilages were degreased, mineralized, and separately hydrolyzed by five kinds of proteases. The collagen hydrolysate (SCH) generated by Alcalase showed the strongest 2,2-diphenyl-1-picrylhydrazyl radical (DPPH·) and hydroxide radical (HO·) scavenging activity. Subsequently, thirteen antioxidant peptides (SCP1-SCP3) were isolated from SCH, and they were identified as GPTGED, GEPGEQ, GPEGPAG, VPPQD, GLEDHA, GDRGAEG, PRGFRGPV, GEYGFE, GFIGFNG, PSVSLT, IELFPGLP, LRGEAGL, and RGEPGL with molecular weights of 574.55, 615.60, 583.60, 554.60, 640.64, 660.64, 885.04, 700.70, 710.79, 602.67, 942.12, 714.82, and 627.70 Da, respectively. GEYGFE, PSVSLT, and IELFPGLP showed the highest scavenging activity on DPPH· (EC₅₀: 1.27, 1.05, and 1.38 mg/mL, respectively) and HO· (EC₅₀: 1.16, 0.97, and 1.63 mg/mL, respectively), inhibiting capability of lipid peroxidation, and protective functions on H₂O₂-damaged plasmid DNA. More importantly, GEYGFE, PSVSLT, and IELFPGLP displayed significant cytoprotection on HUVECs against H₂O₂ injury by regulating the endogenous antioxidant enzymes of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) to decrease the contents of reactive oxygen species (ROS) and malondialdehyde (MDA). Therefore, the research provided better technical assistance for a higher-value utilization of Siberian sturgeon cartilages and the thirteen isolated peptides—especially GEYGFE, PSVSLT, and IELFPGLP—which may serve as antioxidant additives for generating health-prone products to treat chronic diseases caused by oxidative stress.

Production, bioactivities and bioavailability of bioactive peptides derived from walnut origin by-products: a review

Walnut-origin by-products obtained from walnut oil extraction industry are high in proteins with various physiological functions and pharmacological properties and an extensive potential for usage in producing bioactive peptides. This review presents the current research status of bioactive peptides derived from walnut by-products, including preparation, separation, purification, identification, bioactivities, and bioavailability. A plethora of walnut peptides with multiple biological activities, including antioxidative, antihypertensive, neuroprotective, antidiabetic, anticancer, and antihyperuricemia activities, were obtained from walnut-origin by-products by enzymatic hydrolysis, fermentation, and synthesis. Different bioactive peptides show various structural characteristics and amino acid composition due to their diverse mechanism of action. Furthermore, walnut protein and its hydrolysate present a high bioavailability in human gastrointestinal digestive system. Improving the bioavailability of walnut peptides is needful in the development of walnut industry. However, future research still needs to exploit energy conservation, high efficiency, environmentally friendly and low-cost production method of walnut bioactive peptide. The molecular mechanisms of different bioactive walnut peptides still need to be explored at the cell and gene levels. Additionally, the digestion, absorption, and metabolism processes of walnut peptides are also the focus of future research.

Protective effects of functional foods against Parkinson's disease: A narrative review on pharmacology, phytochemistry, and molecular mechanisms

In Persian Medicine (PM), PD (brain-based tremor) is a known CNS disorder with several therapeutic and preventive options. In their medical textbooks and pharmacopeias, Persian great scientists such as Rhazes (854-925 AD), Avicenna (980-1037 AD), and Jorjani (1042-1136 AD), have discussed pharmacological and nutritional strategies for the prevention, slowing progression, and treatment of PD. In the present study, we surveyed plant- and animal-based foods recommended by PM for the prevention and treatment of CNS-related tremors. In vivo and in-vitro pharmacological evidence supporting the beneficial effects of PM-recommended foods in prevention and alleviating PD, major active phytochemicals along with the relevant mechanisms of action were studied. Several PM plants possess potent antioxidant, antiinflammatory, and PD preventing properties. Garlic and allicin, cabbage and isothiocyanates, chickpea seed and its O-methylated isoflavones biochanin A and formononetin, cinnamon, and cinnamaldehyde, saffron and its crocin, crocetin, and safranal, black cumin and its thymoquinone, black pepper and piperine, pistachio and genistein and daidzein, and resveratrol are among the most effective dietary itemsagainst PD. They act through attenuating neurotoxin-induced memory loss and behavioral impairment, oxidative stress, and dopaminergic cell death. PM-recommended foods can help alleviate PD progression and also discovering and developing new neuroprotective anti-PD pharmaceuticals.

Walnut-Derived Peptide Enhances Mitophagy via JNK-Mediated PINK1 Activation to Reduce Oxidative Stress in HT-22 Cells

Mitophagy has a neuroprotective effect on reactive oxygen species (ROS)-induced neurodegenerative diseases. The walnut-derived polypeptide (TW-7) has antioxidant activity and protects nerves by promoting autophagy. However, its action mechanism against oxidative stress through mitophagy remains obscure. Therefore, we aimed to assess the effects of TW-7 on HT-22 cells under oxidative stress. Mitochondrial ultrastructure and cristae number were observed by transmission electron microscopy. The results showed that TW-7 (100 μM) restored the fluorescence intensity of the mitochondrial membrane potential to 0.99 ± 0.04 (P < 0.05), decreased H₂O₂-induced opening of mitochondrial permeability transition pores, and inhibited mitochondrial bioenergetic deficits. Moreover, it significantly increased activities of antioxidant enzymes to 186.88 ± 5.40 U/mgprot, 40.08 ± 0.87 mU/mgprot, and 23.57 ± 0.77 U/mgprot (P < 0.05), based on superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) assay results, respectively. Consistently, it decreased cellular and mitochondrial ROS levels by 51.71 ± 0.81 and 49.75 ± 0.69% (P < 0.05). TW-7 also downregulated C-Jun N-terminal kinase (JNK) phosphorylation and activated PTEN-induced putative kinase 1 (PINK1)-mediated mitophagy in H₂O₂-induced HT-22 cells treated with JNK activator (anisomycin) and inhibitor (SP600125). Furthermore, TW-7 inhibited the mitochondrial apoptosis pathway by downregulation of the cytoplasmic cytochrome C, caspase-9, and cleaved-caspase-3 expression. Additionally, BDNF and SNAP-25 levels significantly increased to protect the synaptic function. Collectively, TW-7 improved oxidative stress-mediated nerve cell injury via JNK-regulated PINK1-mediated mitophagy.

Rapid qualitative profiling and quantitative analysis of Juglandis Mandshuricae Cortex and seven flavonoids by ultra-high performance liquid chromatography-quadrupole/orbitrap high-resolution mass spectrometry

Juglandis Mandshuricae Cortex is the bark of Juglans mandshurica Maxim., which has been used as a folk medicine plant in China and India. In this study, an ultra-high performance liquid chromatography-quadrupole/orbitrap high-resolution mass spectrometry method was developed to clarify and quantify the chemical profiling of Juglandis Mandshuricae Cortex rapidly. A total of 113 compounds were characterized. Among them, seven flavonoids were simultaneously quantified in 15 min, including myricetin, myricetrin, taxifolin, kaempferol, quercetin, quercitrin, and naringenin. The method was validated for accuracy, precision, and the limits of detection and quantification. All calibration curves showed a good linear relationship (r > 0.9990) within test ranges. The intra- and inter-day relative standard deviations were less than 2.16%. Accuracy validation showed that the recovery was between 95.6% and 101.3% with relative standard deviation values below 2.85%. The validated method was successfully applied to determine the contents of seven flavones in Juglandis Mandshuricae Cortex from seven sources and the contents of these places were calculated respectively. This method provides a theoretical basis for further developing the medicinal value of Juglandis Mandshuricae Cortex.

Tricholoma matsutake-Derived Peptides Ameliorate Inflammation and Mitochondrial Dysfunction in RAW264.7 Macrophages by Modulating the NF-κB/COX-2 Pathway

Tricholoma matsutake is an edible fungus that contains various bioactive substances, some of them with immunostimulatory properties. Presently, there is limited knowledge about the functional components of T. matsutake. Our aim was to evaluate the protective effects and molecular mechanisms of two T. matsutake-derived peptides, SDLKHFPF and SDIKHFPF, on lipopolysaccharide (LPS)-induced mitochondrial dysfunction and inflammation in RAW264.7 macrophages. Tricholoma matsutake peptides significantly ameliorated the production of inflammatory cytokines and inhibited the expression of COX-2, iNOS, IKKβ, p-IκB-α, and p-NF-κB. Immunofluorescence assays confirmed the inhibitory effect of T. matsutake peptides on NF-κB/p65 nuclear translocation. Furthermore, the treatment with T. matsutake peptides prevented the accumulation of reactive oxygen species, increased the Bcl-2/Bax ratio, reversed the loss of mitochondrial membrane potential, and rescued abnormalities in cellular energy metabolism. These findings indicate that T. matsutake peptides can effectively inhibit the activation of NF-κB/COX-2 and may confer an overall protective effect against LPS-induced cell damage.

Role of bioactive peptides derived from food proteins in programmed cell death to treat inflammatory diseases and cancer

Bioactive peptides are specific peptide which usually contains 2-20 amino acid residues and actively exerts various functions and biological activities and ultimately affect health. Programmed cell deaths are some styles of cell death discovered in recent years, which is the key to tissue development and balance, eliminating excess, damaged or aging cells. More importantly, programmed cell death is a potential way to treat inflammatory diseases and cancer. In this review, through screening references from 2015 to present, we introduce the effect of bioactive peptides derived from food proteins on inflammatory diseases or cancer through regulating programmed cell deaths, including apoptosis, autophagy, pyroptosis, ferroptosis, and necroptosis. And this review also introduces the targets of these bioactive peptides to regulate programmed cell death. The purpose of this review is to help to expand the prospective applications of bioactive peptides in the field of inflammatory disease and cancer to provide some guidance.

Anti-osteoporosis effect and purification of peptides with high calcium-binding capacity from walnut protein hydrolysates

The walnut protein hydrolysate (WPH) was prepared via simulated gastrointestinal digestion. The degree of hydrolysis (DH), amino acid composition, and relative molecular weight distribution of WPH were analyzed. The results showed that the DH of WPH was 11.6%, WPH was rich in Glu and Pro, and the relative average molecular weight of 572 Da accounted for 59.78%. The effects of WPH on osteoporosis were evaluated using a model of retinoic acid-induced osteoporosis rat. Treatment with WPH effectively increased the serum calcium and phosphorus contents, alleviated calcium loss, and reduced tartrate-resistant acid phosphate and alkaline phosphatase activities and bone gla protein content. WPH treatment significantly improved the biomechanical properties of the bone and increased the value of bone mineral density. In addition, WPH treatment improved the bone microstructure. WPH was isolated and purified by Sephadex G-25 gel filtration chromatography and semi-preparative reversed-phase high-performance liquid chromatography. A fraction with high calcium-binding activity was obtained and 15 peptides were identified.

Walnut peptide WEKPPVSH in alleviating oxidative stress and inflammation in lipopolysaccharide-activated BV-2 microglia via the Nrf2/HO-1 and NF-κB/p38 MAPK pathways

The peptide WEKPPVSH from walnut protein hydrolyzate was used to evaluate the antioxidant and anti-inflammatory protective effect on lipopolysaccharide (LPS)-activated BV-2 microglia and its possible mechanism. The results indicated that WEKPPVSH significantly decreased nitric oxide (NO) and reactive oxygen species (ROS) generation in a dose-dependent manner, and significantly up-regulated superoxide dismutase and catalase activities (P < 0.01). Results of enzyme-linked immunosorbent assay (ELISA) showed that WEKPPVSH significantly mitigated the secretion of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) (P < 0.01). Immunofluorescence analysis exhibited that WEKPPVSH down-regulated p65 translocation to the cell nucleus. Western blotting showed that WEKPPVSH up-regulated the expression of nuclear factor erythroid 2-related factor (Nrf2) and heme oxygenase-1 (HO-1), and down-regulated the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), p-IκB/IκB, p-p65/p65 and p-p38/p38. In summary, WEKPPVSH might protect against oxidative stress and inflammation in LPS-stimulated BV-2 microglia by enhancing the Nrf2/HO-1 signaling pathway and blocking the nuclear factor-κB/p38 mitogen - activated protein kinase (NF-κB/p38 MAPK) signaling pathway. The results provided an experimental basis for the research and development of walnut peptide products.

Nigella sativa: A Dietary Supplement as an Immune-Modulator on the Basis of Bioactive Components

Nutrients can be considered as functional foods, which exert physiological benefits on immune system. The seeds of Nigella sativa, which have many active constituents, are mainly used for medicine, food spice, and nutritional supplements in Egypt. Much attention has been paid to N. sativa seeds for their anticancer, antibacterial, anti-inflammatory, and immune properties. However, their active constituents and mechanisms underlying functions from N. sativa seeds is unclear. Thus, the bioactive constituents with immune regulation in N. sativa seeds were systematically studied. A new compound (3-methoxythymol-6-O-β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside 1) and 11 known compounds (2–12) were separated from the N. sativa seeds by chromatographic methods. Their structures were then elucidated by spectroscopic analysis of MS, UV, IR, ¹H-, and ¹³C-NMR. Furthermore, immunomodulatory effects of those compounds in RAW 264.7 cells were evaluated by phagocytosis, nitric oxide (NO) and cytokine release, related mRNA transcription, and key proteins expression in vitro. Monosaccharide derivatives, Ethyl-α-D-furaarabinose (5), and Ethyl-β-D-fructofuranoside (8) were shown to played bidirectional regulatory roles in immunity and anti-inflammation through the regulation of nuclear factor-κB (NF-κB) signaling pathways. The results showed the active compounds and mechanisms of immune regulation in N. sativa, thus indicating that N. sativa seeds could be used as dietary supplements in immunomodulation.

Antioxidant Mechanisms of the Oligopeptides (FWKVV and FMPLH) from Muscle Hydrolysate of Miiuy Croaker against Oxidative Damage of HUVECs

In this work, the antioxidant mechanisms of bioactive oligopeptides (FWKVV and FMPLH) from protein hydrolysate of miiuy croaker muscle against H₂O₂-damaged human umbilical vein endothelial cells (HUVECs) were researched systemically. The finding demonstrated that the HUVEC viability treated with ten antioxidant peptides (M1 to M10) at 100.0 μM for 24 h was not significantly affected compared with that of the normal group (P < 0.05). Furthermore, FWKVV and FMPLH at 100.0 μM could very significantly enhance the viabilities (75.89 ± 1.79% and 70.03 ± 4.37%) of oxidative-damaged HUVECs by H₂O₂ compared with those of the model group (51.66 ± 2.48%) (P < 0.001). The results indicated that FWKVV and FMPLH played their protective functions through increasing the levels of antioxidant enzymes including superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and decreasing the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and nitric oxide (NO) in oxidative-damaged HUVECs in a dose-dependent manner. In addition, the comet assay revealed that FWKVV and FMPLH could dose-dependently protect deoxyribonucleic acid (DNA) from oxidative damage in the HUVEC model. These results suggested that antioxidant pentapeptides (FWKVV and FMPLH) could serve as potential antioxidant additives applied in the food products, pharmaceuticals, and health supplements.

Simultaneous Quantification of Diarylheptanoids and Phenolic Compounds in Juglans mandshurica Maxim. by UPLC–TQ-MS

The immature epicarps of Juglans mandshurica and Juglans regia have been used as folk medicine for the treatment of cancer in China. Other parts of the J.mandshurica plant, including leaves, branches, barks, and stems, have reported antitumor activities. We previously found that various diarylheptanoids and phenolic compounds isolated from J. mandshurica epicarps show significant antitumor activities. However, there are no reports of quantitative analysis of diarylheptanoids and phenolic compounds of J. mandshurica. In this study, a validated quantitative method, based on ultraperformance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry, was employed to determine the contents of eight diarylheptanoids and seven phenolic compounds in the epicarps of J. mandshurica during different growth periods, in different parts of the plant, and in the epicarps of two Juglans species. The most successful J. mandshurica epicarp harvesting time fell between Day 12 and Day 27. The leaves of J. mandshurica showed potential for medical use as they had the highest content of the 15 compounds (3.399 ± 0.013 mg/g). We showed for the first time that the total content of diarylheptanoids in J. mandshurica is higher than that in J. regia, though, conversely, J. regia has higher contents of phenolic compounds. The method developed in this study is practical and simple and can be applied for quantitative analysis for evaluating the intrinsic quality of J. mandshurica.

Potential of plant-derived peptides for the improvement of memory and cognitive function

Recently, there has been an increased demand for functional foods, to reduce the risk of age-related cognitive impairment, dementia, and Alzheimer's disease. Among them, plant-derived bioactive compounds, such as phytochemicals and peptides, have notable potential in improving memory and cognitive functions. Many studies have provided potential data concerning the characteristics and structure-activity relationships of memory-enhancing peptides. When considering the proof of efficacy of these plant-based peptides in humans as neurological treatment options, it is necessary to accumulate evidence concerning their bioavailability and permeability through blood-brain barrier (BBB). This review focuses on the memory-enhancing effects of peptides derived from plant proteins and presents a current perspective on their structure-activity relationships and BBB permeability.

Protective effect against d-gal-induced aging mice and components of polypeptides and polyphenols in defatted walnut kernel during simulated gastrointestinal digestion

Defatted walnut kernel with pellicle (WKP) is an industrial byproduct during walnut oil extraction, which is rich in protein and polyphenols. WKP was hydrolyzed by simulated gastrointestinal digestion to obtain WKP hydrolysates (WKPHs). Results showed the protein recovery and hydrolysis degree of WKPH were 82.15 and 10.36%. The total phenol contents in WKP and WKPH were 4.90 and 40.70 mg gallic acid equivalent/g, respectively. The antiaging activity of WKPH was evaluated using a d-gal-induced aging mouse model. Results showed that WKPHs could recover the activities of SOD and T-AOC and the content of MDA in tissues and serum of the aging mice. The histological morphology of liver and kidney sections and the immunohistochemistry of TNF-α, IL-1β, and IL-6 in liver were observed. WKPH could effectively protect the tissue structure of the liver and kidney and reduce the inflammatory expression of liver in aging mice. The polypeptides and polyphenols in WKPH were further analyzed. Fifty polypeptides were identified and 12 of these peptides had Leu-Arg at the C-terminal. Forty-two polyphenols were detected, and most phenolic compounds belonged to ellagitannins. This study provided a theoretical basis for the improved processing and high-value utilization of walnut byproducts. PRACTICAL APPLICATION: Defatted walnut kernel with pellicle was hydrolyzed by simulated gastrointestinal digestion to obtain its hydrolysates. The hydrolysates have good antiaging activity in vivo. Fifty polypeptides were identified and 12 of these peptides had Leu-Arg at the C-terminal. Forty-two polyphenols were detected, and most phenolic compounds belonged to ellagitannins. This study could provide a theoretical basis for high-value utilization of walnut byproducts.

Potential mechanisms underlying the protective effects of Tricholoma matsutake singer peptides against LPS-induced inflammation in RAW264.7 macrophages

This study aimed to investigate the protective effects of a < 3 kDa Tricholoma matsutake Singer peptide (TMWP) on lipopolysaccharide (LPS)-induced inflammation in RAW264.7 macrophages. The results showed that TMWP significantly upregulated superoxide dismutase (SOD) activity and reduced reactive oxygen species (ROS) generation in RAW264.7 macrophages. Western blotting and immunofluorescence analysis indicated that TMWP inhibited the activation of the mitogen-activated protein kinase (MAPK) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathways, thereby reducing the secretion of IL-1β and IL-6 and the expression of TNF-α, COX-2, and iNOS. Additionally, TMWP improved mitochondrial respiration in LPS-stressed macrophages, counteracting the harmful effects of LPS treatment on mitochondrial function. Three peptides (SDIKHFPF, SDLKHFPF, and WFNNAGP) with the highest predicted scores for potential anti-inflammatory activity were identified using nano-HPLC-MS/MS. These data indicated that T. matsutake peptides could be an attractive natural ingredient for developing novel functional foods.

Promotive role of microRNA‑150 in hippocampal neurons apoptosis in vascular dementia model rats

Cognitive impairment is one of the primary features of vascular dementia (VD). However, the specific mechanism underlying the regulation of cognition function in VD is not completely understood. The present study aimed to explore the effects of microRNA (miR)‑150 on VD. To determine the effects of miR‑150 on cognitive function and hippocampal neurons in VD model rats, rats were subjected to intracerebroventricular injections of miR‑150 antagomiR. The Morris water maze test results demonstrated that spatial learning ability was impaired in VD model rats compared with control rats. Moreover, compared with antagomiR negative control (NC), miR‑150 antagomiR alleviated cognitive impairment and enhanced memory ability in VD model rats. The triphenyltetrazolium chloride, Nissl staining and immunohistochemistry results further demonstrated that miR‑150 knockdown improved the activity of hippocampal neurons in VD model rats compared with the antagomiR NC group. To validate the role of miR‑150 in neurons in vitro, the PC12 cell line was used. The flow cytometry and Hoechst 33342/PI double staining results indicated that miR‑150 overexpression significantly increased cell apoptosis compared with the mimic NC group. Moreover, the dual‑luciferase reporter gene assay results indicated that miR‑150 targeted HOXA1 and negatively regulated HOXA1 expression. Therefore, the present study indicated that miR‑150 knockdown ameliorated VD symptoms by upregulating HOXA1 expression in vivo and in vitro.

Juglans mandshurica Maxim.: A Review of Its Traditional Usages, Phytochemical Constituents, and Pharmacological Properties

Juglans mandshurica Maxim., also known as “Manchurian walnut” (Chinese) and “Onigurumi” (Japanese), is a medicinal plant widely distributed in Western and Central Asia, especially in China. It has been traditionally used to treat cancer, gastric ulcers, diarrhea, dysentery, dermatosis, uterine prolapse, and leukopenia. To date, more than 400 constituents including quinones (e.g. naphthoquinones, anthraquinones, naphthalenones, tetralones), phenolics, flavonoids, triterpenoids, coumarins, lignans, phenylpropanoids, diarylheptanoids, and steroids, were isolated and structurally identified from different plant parts of J. mandshurica. Among them, quinones, phenolics, triterpenoids, and diarylheptanoids, as the major bioactive substances, have been extensively studied and displayed significant bioactivity. Previous studies have demonstrated that J. mandshurica and a few of its active components exhibit a wide range of pharmacologically important properties, such as antitumor, immunomodulatory, anti-inflammatory, neuroprotective, anti-diabetic, antiviral, antimicrobial, and anti-melanogenesis activities. However, many investigations on biological activities were mainly based on crude extracts of this plant, and the major bioactive ingredients responsible for these bioactivities have not been well identified. Further in vitro and in vivo studies on the mechanisms of action of the pure bioactive compounds, and more elaborate toxicity studies as well as clinical studies are needed to ensure safety and effectiveness of the plant for human use. Taken together, the present review will provide some specific useful suggestions guide to further investigations and applications of this plant in the preparation of medicines and functional foods.

A novel amphibian-derived peptide alleviated ultraviolet B-induced photodamage in mice

Although the application potential of amphibian skin-derived active peptides in alleviating ultraviolet B (UVB)-induced damage has attracted increasing attention, research remains in its infancy. In this study, a new peptide (OM-GL15, GLLSGHYGRASPVAC) was identified from the skin of the green odorous frog (Odorrana margaretae). Results showed that OM-GL15 scavenged free radicals (2,2'-diazo-bis-3-ethylbenzothiazoline-6-sulfonic acid and 1,1-diphenyl-2-trinitrophenylhydrazine) and reduced Fe³⁺ to Fe²⁺. Moreover, topical administration of OM-GL15 significantly alleviated UVB-induced skin photodamage in mice. Exploration of the underlying mechanisms further showed that OM-GL15 exerted antioxidant potency. Specifically, the peptide reduced the levels of lipid peroxidation and malondialdehyde and protected epidermal cells from UVB-induced apoptosis by inhibiting DNA damage via down-regulation of p53, caspase-3, caspase-9, and Bax and up-regulation of Bcl-2. Our results highlight the potential application of amphibian skin-derived peptides in protection against UVB-induced photodamage and provide a novel peptide candidate for the development of anti-photodamage agents.

Separation, identification and molecular binding mechanism of dipeptidyl peptidase IV inhibitory peptides derived from walnut (Juglans regia L.) protein

Walnut protein was hydrolyzed with different proteases to evaluate the hydrolytic efficiency and dipeptidyl peptidase IV (DPP-IV) inhibitory activity in vitro. All of walnut protein hydrolysates (WPHs) exhibited DPP-IV inhibitory activity and Alcalase-derived hydrolysate (WPH-Alc) with better DPP-IV inhibitory activity of 33.90% (at 0.50 mg/mL) was subsequently separated by ultrafiltration and cation exchange chromatography on a SP Sephadex C-25 column. The results showed that fractions with lower molecular weight and higher basic amino acid residues possessed stronger DPP-IV inhibitory activity. Comparably, the obtained fraction B with the yield of 19.80% had the highest DPP-IV inhibitory activity of 76.19% at 0.25 mg/mL. Moreover, nine novel DPP-IV inhibitory peptides were identified using MALDI-TOF/TOF-MS. Molecular docking revealed the peptides could interact with DPP-IV through hydrogen bonds, salt bridges, hydrophobic interactions, π-cation bonds and π-π bonds. The walnut DPP-IV inhibitory peptides showed better stability with heating treatment, pH treatment, or in vitro gastrointestinal digestion.

Anti-Amnesic Effect of Walnut via the Regulation of BBB Function and Neuro-Inflammation in Aβ1-42-Induced Mice

This study was conducted to assess the protective effect of walnut (Juglans regia L.) extract on amyloid beta (Aβ)_1-42-induced institute of cancer research (ICR) mice. By conducting a Y-maze, passive avoidance, and Morris water maze tests with amyloidogenic mice, it was found that walnut extract ameliorated behavioral dysfunction and memory deficit. The walnut extract showed a protective effect on the antioxidant system and cholinergic system by regulating malondialdehyde (MDA) levels, superoxide dismutase (SOD) contents, reduced glutathione (GSH) contents, acetylcholine (ACh) levels, acetylcholinesterase (AChE) activity, and protein expression of AChE and choline acetyltransferase (ChAT). Furthermore, the walnut extract suppressed Aβ-induced abnormality of mitochondrial function by ameliorating reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and ATP contents. Finally, the walnut extract regulated the expression of zonula occludens-1 (ZO-1) and occludin concerned with blood–brain barrier (BBB) function, expression of tumor necrosis factor-alpha (TNF-α), tumor necrosis factor receptor 1 (TNFR1), phosphorylated c-Jun N-terminal kinase (p-JNK), phosphorylated nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor (p-IκB), cyclooxygenase-2 (COX-2), and interleukin 1 beta (IL-1β), related to neuroinflammation and the expression of phosphorylated protein kinase B (p-Akt), caspase-3, hyperphosphorylation of tau (p-tau), and heme oxygenase-1 (HO-1), associated with the Aβ-related Akt pathway.

Neuroprotective Function of a Novel Hexapeptide QMDDQ from Shrimp via Activation of the PKA/CREB/BNDF Signaling Pathway and Its Structure-Activity Relationship

This study aimed to evaluate the neuroprotective function of shrimp-derived peptides QMDDQ and KMDDQ. Biochemical results revealed that both peptides exhibited neuroprotective effects by increasing acetylcholine (ACh) content and inhibiting acetylcholinesterase (AChE) activity in PC12 cells; QMDDQ was more active than KMDDQ. COSY-NOESY spectroscopic data showed that the superior neuroprotective function of QMDDQ might be attributed to its N-terminal glutamine as it exhibited an extended spatial conformation, facilitating its interactions with AChE. QMDDQ can promote the basic energy metabolism of cells more than KMDDQ. The peptides showed neuroprotective ability due to the activation of the antiapoptosis and PKA/CREB/BNDF signaling pathway. QMDDQ was selected to investigate its memory-enhancing activity in scopolamine-induced amnesic mice, revealing memory protection in mice, as it improved their performance in the Morris water maze experiment. In addition, QMDDQ increased ACh content (4.98 ± 0.51 μg/mg prot) and decreased AChE activity (4.72 ± 0.11 U/mg prot) in the mouse hippocampus. These data indicate the systemic mechanism through which naturally derived QMDDQ improved neuroprotection and memory ability.

Neuroprotection by Walnut-Derived Peptides through Autophagy Promotion via Akt/mTOR Signaling Pathway against Oxidative Stress in PC12 Cells

Natural-derived peptides are effective substances in attenuating oxidative stress. However, their specific mechanisms have not been fully elucidated, especially in peptide-mediated autophagy. In the present study, TWLPLPR, YVLLPSPK, and KVPPLLY, novel peptides from Juglans mandshurica Maxim, prevented reactive oxygen species (ROS) production, elevated glutathione peroxidase (GSH-Px) activity and adenosine 5'-triphosphate (ATP) levels, and ameliorated apoptosis in Aβ_25-35 (at a concentration of 50 μM for 24 h)-induced PC12 cells (P < 0.01). Both western blot and immunofluorescence analysis illustrated that the peptides regulated Akt/mTOR signaling through p-Akt (Ser473) and p-mTOR (S2481) and promoted autophagy by increasing the levels of LC3-II/LC3-I and Beclin-1 while lowering p62 expression (P < 0.01). The autophagy inhibitor (3-methyladenine, 3-MA) and inducer (rapamycin, RAPA) were combined used to confirm the contribution of peptide-regulated autophagy in antioxidative effects. Moreover, the peptides increased the levels of LAMP1, LAMP2, and Cathepsin D (P < 0.05) and promoted the fusion with lysosomes to form autolysosomes, accelerating ROS removal. These data suggested that walnut-derived peptides regulated oxidative stress by promoting autophagy in the Aβ_25-35-induced PC12 cells.

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.

Peptides from walnut (Juglans mandshurica Maxim.) protect hepatic HepG2 cells from high glucose-induced insulin resistance and oxidative stress

Schematic of the mechanism underlying the protection of hepatic HepG2 cells against high glucose-induced insulin resistance and oxidative stress by walnut-derived peptides.

miR‑134‑5p/Foxp2/Syn1 is involved in cognitive impairment in an early vascular dementia rat model

Forkhead box P2 (Foxp2) is a transcription factor involved in vocal learning. However, the number of previous studies that have investigated the role of Foxp2 in early vascular dementia (VD) is limited. The aim of the present study was to determine whether microRNA (miR)‑134‑5p/Foxp2 contributes to cognitive impairment in a chronic ischemia‑induced early VD model. miR‑134‑5p was found to be significantly increased in the cortex in a rat VD model. Intracerebroventricular injection of miR‑134‑5p antagomir into VD rats prevented the loss of synaptic proteins and the development of cognitive impairment phenotypes. Histopathological analysis revealed that miR‑134‑5p aggravated cognitive impairment in VD rats through damage to cortical neurons and loss of synaptic proteins. Bioinformatics analysis predicted that miR‑134‑5p targets Foxp2 mRNA. Dual luciferase analysis and western blotting supported the prediction that miR‑134‑5p targets Foxp2. Furthermore, the silencing of Foxp2 significantly inhibited the effect of miR‑134‑5p on synaptic protein loss. Chromatin immunoprecipitation‑quantitative polymerase chain reaction analysis indicated that Foxp2 binds to the synapsin I (Syn1) promoter at ‑400/‑600 bp upstream of the transcription start site. In conclusion, the miR‑134‑5p/Foxp2/Syn1 axis was found to contribute to cognitive impairment in a chronic ischemia‑induced early VD model, which may enable the development of new therapeutic strategies for the prevention and treatment of VD.