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•Polyphenols were able to covalently bond with glycated myofibrillar protein (MP).•Physicochemical properties of ternary conjugates depended on nature of polyphenols.•Adducted ...polyphenols altered the conformation characteristics of glycated MP.•MP-dextran (DX)-polyphenol ternary adducts had higher thermal stability.•MP-DX-polyphenol ternary adducts had higher antioxidative capacity.
In the present study, three types of polyphenols, namely, (−)-epigallocatechin-3-gallate (EGCG), catechin (C), and gallic acid (GA), were grafted to myofibrillar protein (MP)-dextran (DX) conjugate through a free radical-mediated adduction method. The analysis of secondary structure showed that conjugation of polyphenols induced a decrease in contents of α-helix structures. The surface hydrophobicity of MP-DX conjugate was increased after polyphenols were covalently adducted, while that of the free amino, thiol groups, and tyrosine residues were decreased, especially with the addition of EGCG (p < 0.05). Analysis of rheological properties showed that covalently linking of polyphenols decreased the thermal gelling capacity by inhibiting myosin-head aggregation and myosin tails interaction. Moreover, polyphenol adduction was able to remarkably improve the thermal stability and antioxidant activity of MP-DX conjugate. The findings regarding enhanced functionalities evidence potential of applying the ternary adduct as a novel antioxidant.
Acute kidney injury causes significant morbidity and mortality in the community and clinic. Various pathologies, including renal and cardiovascular disease, traumatic injury/rhabdomyolysis, sepsis, ...and nephrotoxicity, that cause acute kidney injury (AKI), induce general or regional decreases in renal blood flow. The ensuing renal hypoxia and ischemia promotes the formation of reactive oxygen species (ROS) such as superoxide radical anions, peroxides, and hydroxyl radicals, that can oxidatively damage biomolecules and membranes, and affect organelle function and induce renal tubule cell injury, inflammation, and vascular dysfunction. Acute kidney injury is associated with increased oxidative damage, and various endogenous and synthetic antioxidants that mitigate source and derived oxidants are beneficial in cell-based and animal studies. However, the benefit of synthetic antioxidant supplementation in human acute kidney injury and renal disease remains to be realized. The endogenous low-molecular weight, non-proteinaceous antioxidant, ascorbate (vitamin C), is a promising therapeutic in human renal injury in critical illness and nephrotoxicity. Ascorbate may exert significant protection by reducing reactive oxygen species and renal oxidative damage via its antioxidant activity, and/or by its non-antioxidant functions in maintaining hydroxylase and monooxygenase enzymes, and endothelium and vascular function. Ascorbate supplementation may be particularly important in renal injury patients with low vitamin C status.
Mangrove endophytic fungi can produce impressive quantities of metabolites with promising antioxidant activities that may be useful to humans as novel physiological agents. In this study, we ...investigated the phylogenetic diversity and antioxidant potential of 46 fungal endophytes derived from the mangrove species Rhizophora stylosa and R. mucronata from the South China Sea. The fungal isolates were identified using a combination of morphological characteristics and phylogenetic analysis of the internal transcribed spacer (ITS) sequences. Seventeen genera belonging to 8 taxonomic orders of Ascomycota were discovered, specifically, Botryosphaeriales, Capnodiales, Diaporthales, Eurotiales, Glomerellales, Hypocreales, Pleosporales, and Xylariales. The most abundant fungal orders included Xylariales (35.49%) and Diaporthales (27.61%), which were predominantly represented by the culturable species Pestalotiopsis sp. (34.54%) and Diaporthe sp. (18.62%). The stems showed more frequent colonization and species diversity than the roots, leaves, hypocotyls, and flower tissues of the host plant. The antioxidant activities of all the isolated fungal extracts on four different culture media were assessed using improved 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonicacid) (ABTS) methods. A relatively high proportion (84.8%) of the isolates displayed antioxidant capacity (%RSA > 50%). Further research also provided the first evidence that HQD-6 could produce flufuran as a significant radical scavenger with IC50 values of 34.85±1.56 and 9.75±0.58 μg/mL, respectively. Our findings suggest that the utilization of a biotope such as that of the endophytic fungal community thriving on the mangrove plants R. stylosa and R. mucronata may be suitable for use as a sustainable resource for natural antioxidants.
•SePPs prepared by Neutrase-Alcalase hydrolysis showed high antioxidant ability.•SePPs attenuated TNF-α and d-gal-induced oxidant stress via MAPK/NF-κB pathway.•Bioavailability of Se in the forms of ...SePPs was better than other Se supplements.•SePPs exerted antioxidant activity by the synergistic effects of Se and peptides.•Eighty-five Se-peptide sequences were characterized by HPLC-ESI-MS/MS.
Present study aimed to prepare and identify antioxidative peptides from selenium-containing soybeans, and to investigate their bioavailability and protective effects against oxidative stress-related diseases. Selenium-containing soybean antioxidative peptides (Mw < 1 kDa, SePPs) hydrolyzed by Neutrase and Alcalase reached the highest cellular antioxidant activity (EC50 value 320.5 ± 39.71 μg/L). SePPs could be efficiently absorbed through Caco-2 monolayer, and then significantly reverse the tumor necrosis factor-α (TNF-α)-induced inflammatory cytokine, phosphorylated c-Jun N-terminal kinases (p-JNK) and nuclear factor-kappa B (NF-κB) levels in EA. hy926 cells (p < 0.05). d-galactose-induced aging mice model showed that liver superoxidase dismutase (SOD) and glutathione peroxidase-1 (GPx-1) were enhanced, while aspartate aminotransferase (AST), alanine aminotransferase (ALT) and NF-κB were decreased by SePPs significantly (p < 0.05). SePPs could inhibit brain oxidative stress via regulating MAPK/NF-κB pathway. Comparing with Na2SeO3, selenomethionine (SeMet) and selenium-free peptides, SePPs was found to present synergistic effects of selenium and peptides in antioxidant activity.
The beneficial effects of polyphenols, predominantly in the context of oxidative stress-related diseases such as cancer, cardiovascular diseases and neurological conditions including Alzheimer's and ...Parkinson's diseases, have been documented by a number of papers and reviews. The antioxidant/prooxidant properties of phenolic compounds are related mainly to the number and positions of hydroxyl groups and to their redox metal (Cu, Fe) chelating capacity. In this work we studied structurally distinct phenolic molecules such as myricetin, morin, 3',4'-dihydroxy-flavone, taxifolin and 4-hydroxycoumarin, either alone or as interacting with Cu
ions. EPR and UV-Vis spectroscopy confirmed that the effective binding of cupric ions to phenolic compounds requires the presence of the 3-OH and 4-CO groups on the flavonoid C ring and unsaturated C2-C3 bond of the C-ring, which permits through-conjugation with the B-ring. An ABTS assay revealed that radical scavenging activities of phenolic compounds are related to their number of hydroxyl groups, planarity of the molecular skeleton, extent of delocalization and they decrease in the order: myricetin > morin > 3',4'-dihydroxyflavone ~ 4-hydroxy coumarin > taxifolin. Absorption titrations indicate that copper ions can modulate the DNA binding affinity of flavonoids via the formation of their Cu-chelates. Gel electrophoresis measurements indicated that the protective effect of the phenolic compounds decreases in the order: 3',4'-dihydroxyflavone > 4-OH coumarin > morin > taxifolin ~ myricetin. This can be explained by the fact that myricetin, taxifolin and morin form stable Cu(II) complexes capable of causing DNA damage via interaction with DNA and ROS formation via the Fenton reaction. Application of ROS scavengers revealed the formation of singlet oxygen, superoxide and hydroxyl radicals and their concerted synergistic effect on the DNA. The overall results suggest that the most pronounced DNA damage has been observed for flavonoids containing higher number of hydroxyl groups (including 3-OH group of the C ring), such as myricetin (six hydroxyl groups), morin and taxifolin (five hydroxyl groups) in the presence of Cu(II) ions. The proposed mechanism of action by which Cu(II) complexes of myricetin, morin and taxifolin interact with DNA predispose these substances to act as potential anticancer agents. The anticancer activity of phenolic compounds can be explained by their moderate prooxidant properties, which can boost ROS formation and kill cancer cells. Alternatively, slight prooxidant properties may activate antioxidant systems, including antioxidant enzymes and low molecular antioxidants such as glutathione and thus act as preventive anticancer agents.
Oxidative stress is at the forefront of Alzheimer disease (AD) research. While its implications in the characteristic neurodegeneration of AD are vast, the most important aspect is that it seems ...increasingly apparent that oxidative stress is in fact a primary progenitor of the disease, and not merely an epiphenomenon. Moreover, evidence indicates that a long “dormant period” of gradual oxidative damage accumulation precedes and actually leads to the seemingly sudden appearance of clinical and pathological AD symptoms, including amyloid-β deposition, neurofibrillary tangle formation, metabolic dysfunction, and cognitive decline. These findings provide important insights into the development of potential treatment regimens and even allude to the possibility of a preventative cure. In this review, we elaborate on the dynamic role of oxidative stress in AD and present corresponding treatment strategies that are currently under investigation.
Diet and nutrition contribute to both beneficial and harmful aspects of oxidative processes. The harmful processes, termed oxidative stress, occur with many human diseases. Major advances in ...understanding oxidative stress and nutrition have occurred with broad characterization of dietary oxidants and antioxidants, and with mechanistic studies showing antioxidant efficacy. However, randomized controlled trials in humans with free-radical-scavenging antioxidants and the glutathione precursor N-acetylcysteine have provided limited or inconsistent evidence for health benefits. This, combined with emerging redox theory, indicates that holistic models are needed to understand the interplay of nutrition and oxidative stress. The purpose of this article is to highlight how recent advances in redox theory and the development of new omics tools and data-driven approaches provide a framework for future nutrition and oxidative stress research. Here we describe why a holistic approach is needed to understand the impact of nutrition on oxidative stress and how recent advances in omics and data analysis methods are viable tools for systems nutrition approaches. Based on the extensive research on glutathione and related thiol antioxidant systems, we summarize the advancing framework for diet and oxidative stress in which antioxidant systems are a component of a larger redox network that serves as a responsive interface between the environment and an individual. The feasibility for redox network analysis has been established by experimental models in which dietary factors are systematically varied and oxidative stress markers are linked through integrated omics (metabolome, transcriptome, proteome). With this framework, integrated redox network models will support optimization of diet to protect against oxidative stress and disease.
Velvet antler has a long history in traditional medicine. It is also an important healthy ingredient in food as it is rich in protein. However, there has been no report about antioxidant peptides ...extracted from velvet antler by enzymatic hydrolysis. Thus, the objective of this study was to hydrolyze velvet antler using different commercial proteases (Acalase, Neutrase, trypsin, pepsin, and α-chymotrypsin). Antioxidant activities of different hydrolysates were investigated using peroxyl radical scavenging assay by electron spin resonance spectrometry. Among all enzymatic hydrolysates, Alcalase hydrolysate exhibited the highest peroxyl radical scavenging activity. Alcalase hydrolysate was then purified using ultrafiltration, gel filtration, and reverse-phase high performance liquid chromatography. The purified peptide was identified to be Trp-Asp-Val-Lys (tetrapeptide) with molecular weight of 547.29 Da by Q-TOF ESI mass spectroscopy. This purified peptide exhibited strong scavenging activity against peroxyl radical (IC
value, 0.028 mg/mL). In addition, this tetrapeptide showed significant protection ability against AAPH-induced oxidative stress by inhibiting of reactive oxygen species (ROS) generation in Chang liver cells in vitro and in a zebrafish model in vivo. This research suggests that the tetrapeptide derived from Alcalase-proteolytic hydrolysate of velvet antler are excellent antioxidants and could be effectively applied as functional food ingredients and pharmaceuticals.
•The antioxidant hydrolysates were produced by gastrointestinal digestion.•The antioxidant peptide was identified to be Phe-Leu-Asn-Glu-Phe-Leu-His-Val.•The antioxidant peptide has high radical ...scavenging activity.•The antioxidant peptide protected oxidative stress-induced DNA damage.•The antioxidant peptide protected oxidative stress-induced hepatic damage.
Pectoral fin protein from salmon processing byproduct was hydrolyzed using Alcalase, Flavourzyme, Neutrase, pepsin, Protamex, and trypsin, and the peptic hydrolysate showed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. Antioxidant peptide was purified using consecutive chromatography. The purified antioxidant peptide was identified to be Phe-Leu-Asn-Glu-Phe-Leu-His-Val with molecular weight of 1018.48Da by time of flight-mass spectrometry/mass spectrometry (TOF-MS) analysis. The IC50 values against DPPH and 2,2-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) cation radical scavenging activity were 486 and 152μM, respectively, and the octapeptide showed strong ferric reducing power. In addition, the octapeptide showed significant (p<0.05) protection ability against hydroxyl radical-induced DNA damage and hydrogen peroxide-induced hepatic damage in Chang liver cells. Taken together, the pectoral fin protein hydrolysate and/or its active peptides may be useful ingredients in functional food.
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