Source Of Antioxidant Peptides Research Articles

Novel Antioxidant Peptides Derived from Feather Keratin Alleviate H2O2-Induced Oxidative Damage in HepG2 Cells via Keap1/Nrf2 Pathway.

Reactive oxygen species (ROS) are crucial for signal transduction and the maintenance of cellular homeostasis. However, superfluous ROS may engender chronic pathologies. Feather keratin is a promising new source of antioxidant peptides that can eliminate excess ROS and potentially treat oxidative stress-related diseases, but the underlying mechanisms have remained elusive. This study investigated the antioxidant effects and mechanisms against H2O2-induced oxidative damage in HepG2 cells of the two latest discovered antioxidant peptides, CRPCGPTP (CP-8) and ANSCNEPCVR (AR-10), first decrypted from feather keratin. The results revealed that CP-8 and AR-10 did not exhibit cytotoxicity to HepG2 cells while reducing intracellular ROS accumulation. Simultaneously, they enhanced the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px), thus alleviating H2O2-induced cell apoptosis. Molecular docking analysis demonstrated that CP-8, AR-10 interacted well with the key amino acids in the Kelch domain of Keap1, thereby directly disrupting the Keap1-Nrf2 interaction. The peptides' biosafety and antioxidant activity via Keap1/Nrf2 signaling lay the groundwork for further animal studies and applications as functional food additives.

Effects of Silkworm Pupae Protein and Active Peptides on Human Immunity

The escalating global population and the concomitant scarcity of protein resources have heightened the urgency to explore novel sources of protein. Insects, as a taxonomic class of organisms, are abundantly enriched with superior-quality protein and steered by this premise, they present a prodigious opportunity for human employment and scientific investigation in the realm of biologic resources. The larval stage of the domesticated silkworms, extensively cultivated for their silk, give rise to the universally consumed pupae in East Asia that augment the dietary provisions. This paper provides a comprehensive discussion of the immune-boosting, antibacterial, antitumor, and antioxidant properties of silkworm pupae proteins. Additionally, it explores the possible allergic reactions that may arise from silkworm consumption. Silkworm chrysalis protein, which contains a plethora of bioactive peptides such as AKPGVY and AAEYPA, offers a novel source of antioxidant peptides that have been shown to bolster immune function, enhance the body's capacity to fend off bacteria and viruses, reduce the risk of tumor development, and mitigate adverse effects such as free radical oxidative damage. However, it is important to note that some individuals may be susceptible to allergic reactions to silkworm pupae. Consequently, safety concerns related to the use of silkworm pupae proteins and active peptides should be taken into account.

Albumin from Erythrina edulis (Pajuro) as a Promising Source of Multifunctional Peptides.

Multifunctional peptides, capable of acting on different body systems through multiple mechanisms of action, offer many advantages over monofunctional peptides, including lower adverse side effects and costs. Erythrina edulis (pajuro) is a legume with a large number of high-quality proteins, of which their potential as a source of antioxidant peptides has been recently reported. In this study, the behavior of these proteins under a sequential enzymatic hydrolysis with digestive and microbial enzymes was investigated by evaluating the multi-functionality of the hydrolyzates. The albumin hydrolyzates obtained after the action of pepsin, pancreatin, and Alcalase showed antioxidant, angiotensin-converting enzyme (ACE), α-amylase, α-glucosidase, and dipeptidyl peptidase (DPP)-IV inhibitory activities. The radical scavenging properties of the hydrolyzate could be responsible for the potent protective effects observed in FeSO4-induced neuroblastoma cells. The findings support the role of pajuro protein as an ingredient of functional foods or nutraceuticals for health promotion and the prevention of oxidative stress, hypertension, and metabolic alteration-associated chronic diseases.

Purification and characterization of antioxidant peptides from hairtail surimi hydrolysates and their effects on beef color stability.

The antioxidant peptides extracted from plants or animals have shown great potential in preventing food quality deterioration caused by oxidization. Here, peptide fractions obtained from hairtail surimi hydrolysates (HSH) were investigated for structure and color-protective effect. The results showed the<3kDa fraction obtained from HSH by ultrafiltration could be separated into five major fractions (A-E) by gel chromatography, among which fraction A possessed the highest antioxidant activities. This fraction A could be further separated into two fractions (A1 and A2 ) by the reversed-phase high-performance liquid chromatography, and fraction A2 with lower α-helix content exhibited the higher antioxidant activities. The amino acids sequence of fraction A2 was identified as DLYANTVLSGGTTMYPGIADR (2214.0627Da). The synthetic peptide with this sequence was also found to exhibit obvious antioxidant activity. Moreover, both HSH, fractions A1 and A2 , and synthetic peptide demonstrated color-protective effects during the beef preservation. Taken together, the results obtained showed that the natural antioxidant peptides could be isolated from HSH, which can be used in meat preservation for inhibiting color deterioration. PRACTICAL APPLICATION: This study demonstrated the potential of hairtail surimi hydrolysates (HSH) as a source of antioxidant peptides. Furthermore, these antioxidant peptides purified from HSH exhibited the potential for prevention of beef color deterioration of beef, providing a potential application for meat preservation. Particularly, using the antioxidant peptides sourced from fish surimi for meat preservation may not only ease the safety concerns about artificial preservatives but also create a unique selling proposition, especially in far eastern Asian countries, since consumers in these countries believe "umami" is the combination of "fish" and "meat."

The effect of in vitro digestion on antioxidant properties of water-soluble and insoluble protein fractions of traditional Serbian white- brined cheeses

The influence of simulated in vitro digestion on antioxidant potential of protein fractions of traditional Serbian white-brined cheeses was investigated. Water-soluble (WSF) and water-insoluble fractions (WINF) of three cow’s and three ovine white-brined cheeses were fractionated. Total antioxidant capacity, reducing power and iron (II) chelating properties of these fractions before and after in vitro digestion were assayed. The investigated protein fractions had different antioxidant properties. WSFs had a better total antioxidant capacity and reducing power and less pronounced iron (II) chelating properties than WINFs. A strong negative correlation (-0.818, P&amp;lt;0.05) between the total antioxidant capacities of undigested WSF and WINF of traditional cheeses were observed. In vitro digestion greatly improved the total antioxidant capacities of WINFs (by 16.61-34.18 times), their reducing power (up to 95.77 %) and except in the case of Svrljig ovine cheese, the iron (II) chelating ability as well. A less pronounced increase (up to 71.29 %) of the total antioxidant capacity of WSFs was induced by in vitro digestion. In vitro digestion reduced reducing power of WSF of investigated ovine cheeses as well as reducing power of WSF of Homolje cow’s cheese. Since there was no significant correlation between the investigated antioxidant properties of digested WSFs and their free amino acids and mineral contents the observed differences should be attributed to different composition and properties of low molecular weight peptides. Thus, further investigations related to their isolation and characterization needs to be conducted. However, these results indicate that Serbian white-brined cheeses have great potential as source of antioxidant peptides.

Dromedary Milk Protein Hydrolysates Show Enhanced Antioxidant and Functional Properties.

SUMMARYResearch backgroundMilk protein hydrolysates have received particular attention due to their health-promoting effects. Dromedary milk differs from the milk of other dairy animals in the composition and structure of its protein components, which give it unique properties. The bioactivity and functionality of whole dromedary milk proteins and their enzymatic hydrolysates have not received much attention, hence this study aims to investigate the effect of enzymatic hydrolysis of dromedary milk proteins on their antioxidant activities and functional properties.Experimental approachDromedary milk proteins were treated using four proteolytic enzymes (pepsin, trypsin, α-chymotrypsin and papain) and two mixtures of enzymes (pancreatin and pronase). The degree of hydrolysis was measured to verify the hydrolysis of the proteins. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography served to determine the molecular mass distribution of the hydrolysates while reversed phase-high performance liquid chromatography (RP-HPLC) was conducted to explore their hydrophobicity. The antioxidant activities were evaluated using various in vitro tests, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging capacities, iron(III) reducing ability and chelating activity. Besides, functional properties such as solubility, foaming and emulsification were assessed.Results and conclusionsDromedary milk protein hydrolysates exhibited different degrees of hydrolysis ranging from 17.69 to 41.86%. Apart from that, the hydrolysates showed different electrophoretic patterns, molecular mass distribution and RP-HPLC profiles demonstrating the heterogeneity of the resulting peptides in terms of molecular mass and polarity. The hydrolysates displayed significantly higher antioxidant capacities than the undigested proteins at all the tested concentrations. Iron(II) chelating activity was the most improved assay after proteolysis and the hydrolysate generated with pancreatin had the highest chelating power. Dromedary milk protein hydrolysates possessed good solubility (>89%). Further, foaming and emulsifying properties of dromedary milk proteins were enhanced after their proteolysis. These interfacial properties were influenced by the enzymes employed during proteolysis.Novelty and scientific contributionEnzymatic hydrolysis of dromedary milk proteins is an effective tool to obtain protein hydrolysates with great antioxidant and functional properties. These results suggest that dromedary milk protein hydrolysates could be used as a natural source of antioxidant peptides to formulate functional foods and nutraceuticals.

Purification and characterization of antioxidant peptides from enzymatic hydrolysate of mungbean protein.

In this study, the antioxidant activity of mungbean protein hydrolysate (MPH) was systematically investigated. MPH was fractionated by ultrafiltration into two major fractions (MPH-1 <3kDa, MPH-2 >3kDa). Fraction MPH-1, which exhibited the highest antioxidant activity, was further fractionated by gel column into three fractions (MPH-1A, MPH-1B, and MPH-1C). The antioxidant activity of the MPH-1B fraction was stronger than that of the other fractions. Eight mungbean peptides (P1-P8) were identified in fraction MPH-1B by UPLC-Q-TOF-MS. Among them, peptides Trp-Gly-Asn (WGN, P2), Ala-Trp (AW, P4), Arg-Gly-Trp-Tyr-Glu (RGWYE, P5), and Gly-Val-Pro-Phe-Trp (GVPFW, P7) had high antioxidant activity. Moreover, these four peptides exerted protective effects against H2 O2 -induced cytotoxicity and regulated the MDA content, CAT activity, and total GSH content in HepG2 cells with specific observation. This study demonstrated the potential of MPH as a source of antioxidant peptides. This provides a scientific basis for the preparation of antioxidant peptides from mungbean protein. PRACTICAL APPLICATION: This study demonstrated the potential of the hydrolysate of mungbean protein as a source of antioxidant peptides and provided a scientific basis for the preparation of antioxidant peptides from mungbean protein.

Белки молочной сыворотки как источник антиоксидантных пептидов

Белки молочной сыворотки как источник антиоксидантных пептидов

Barrel Jellyfish (Rhizostoma pulmo) as Source of Antioxidant Peptides.

The jellyfish Rhizostoma pulmo, Macrì 1778 (Cnidaria, Rhizostomae) undergoes recurrent outbreaks in the Mediterranean coastal waters, with large biomass populations representing a nuisance or damage for marine and maritime activities. A preliminary overview of the antioxidant activity (AA) of R. pulmo proteinaceous compounds is provided here based on the extraction and characterization of both soluble and insoluble membrane-fractioned proteins, the latter digested by sequential enzymatic hydrolyses with pepsin and collagenases. All jellyfish proteins showed significant AA, with low molecular weight (MW) proteins correlated with greater antioxidant activity. In particular, collagenase-hydrolysed collagen resulted in peptides with MW lower than 3 kDa, ranging 3–10 kDa or 10–30 kDa, with AA inversely proportional to MW. No cytotoxic effect was detected on cultured human keratinocytes (HEKa) in a range of protein concentration 0.05–20 μg/mL for all tested protein fractions except for soluble proteins higher than 30 kDa, likely containing the jellyfish venom compounds. Furthermore, hydrolyzed jellyfish collagen peptides showed a significantly higher AA and provided a greater protective effect against oxidative stress in HEKa than the hydrolyzed collagen peptides from vertebrates. Due to a high reproductive potential, jellyfish may represent a potential socioeconomic opportunity as a source of natural bioactive compounds, with far-reaching beneficial implications. Eventually, improvements in processing technology will promote the use of untapped marine biomasses in nutraceutical, cosmeceutical, and pharmaceutical fields, turning marine management problems into a more positive perspective.

Antioxidant activity of peptides in postmortem aged duck meat as affected by cooking and in vitro digestion

ABSTRACT The objective of this study was to investigate the effect of cooking and in vitro digestion on antioxidant activity of peptides in duck meat after 7 days postmortem aging. The 1, 1-diphenyl-2- picrylhydrazyl (DPPH) free radical scavenging activity and reducing power of the obtained peptides were evaluated. Results showed that the cooked sample possessed higher antioxidant activity than the raw sample and upon cooking at different temperatures, sample aged for 7 days had significantly higher antioxidant activity than that of unaged (day 0). The samples which showed higher antioxidant activity after cooking (65°C–30 min, 100°C–20 min, 121°C–10 min) were selected for in vitro digestion, and it is found that their DPPH radical scavenging activity decreased significantly but the reducing power increased significantly after gastrointestinal digestion. These results show the potential of aged duck meat as a good source of antioxidant peptides with high bioactivity after cooking and gastrointestinal digestion.

Evaluation of the Antioxidant Activity In Vitro and in Hippocampal HT-22 Cells System of Protein Hydrolysates of Common Carp (Cyprinus carpio) By-Product

ABSTRACTFish processing by-products may become more than 50% of the starting material. If mismanaged, these large quantities of discarded fish can create serious pollution problems and can also generate cost associated with their disposal. Enzymatic hydrolysis is one of the techniques that is currently being developed in order to recover and add value to these biomolecules. There is an increasing interest in natural antioxidants that are safer for consumers compared with synthetic antioxidants. In this study, common carp by-product was hydrolyzed using the enzymes Alcalase (A) and Protamex (P) to reach degrees of hydrolysis (DH) of 10 and 15%, respectively. Antioxidant capacity against peroxyl radicals (ACAP); 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging; and the measurement of intracellular reactive oxygen species (ROS) concentration after exposure to common carp protein hydrolysates were investigated. The results revealed that the hydrolysate A15 exhibited significantly (p < 0.05) higher antioxidant activity against the DPPH radical. A15 showed the highest in vitro antioxidant competence against peroxyl radicals, whereas P15 showed the lowest activity against peroxyl radicals (p < 0.05). Hydrolysates having the highest and the lowest in vitro antioxidant activity (A15 and P15, respectively) were selected for the determination of antioxidant activity in the HT-22 cells system. Measurement of intracellular ROS concentration revealed that P15 at the concentration of 1.25 mg/mL significantly (p < 0.05) reduced the intracellular ROS concentration. These results showed that common carp by-product protein hydrolysates are a source of antioxidant peptides with a high potential for food and pharmaceutical industries to develop new nutraceuticals and functional foods.

“Antioxidant activity and characterization of protein fractions and hydrolysates from normal and quality protein maize kernels”

Maize is the main crop cultivated worldwide with more than 1 billion metric tons produced annually and is one of the most relevant sources of protein for human consumption in developing countries. Proteins and peptides isolated from maize exert relevant antioxidant activity which is increased by enzymatic hydrolysis. However, there is limited information about the antioxidant potential of proteins isolated from Quality Protein Maize (QPM) varieties and their hydrolysates. The aim of this research was to determine the differences in protein profile and antioxidant activity of protein fractions and hydrolysates between a hybrid white maize (Asgrow 773) and a QPM variety (CML-502). The biophysical evaluation and the total protein quantification by Kjeldahl and fractions by ninhydrin were consistent with the changes due to the breeding process of the QPM material. The antioxidant potential of the hydrolysates obtained from albumins and globulins had a 3-fold increase in both maize varieties. The prolamins hydrolysates presented an increase of 7-fold for the normal variety and 2-fold for the QPM variety. The results of this research allow indicate that the QPM varieties are a source of antioxidant peptides and promising candidates in the search for proteins and peptides with other bioactivities.

Effect of cooking and in vitro digestion on the antioxidant activity of dry-cured ham by-products

Dry-cured ham by-products have been traditionally used in Mediterranean household cooking of broths and stews. The aim of this work was to evaluate the effect of cooking treatments and in vitro gastrointestinal digestion on the antioxidant activity of natural peptides found in bones from Spanish dry-cured hams. The antioxidant activity was tested using five different assays and results demonstrated that cooking using conventional household methods increased the antioxidant activity of ham by-products when assessed using different antioxidant assays with the exception of the ABTS radical scavenging measurement assay. Simulated gastrointestinal digestion showed no significant effect on the antioxidant activity of ham by-products and antioxidant activity decreased when assessed using the ORAC and β-carotene bleaching assays. Analysis by MALDI-TOF MS revealed a considerable breakdown of peptides due to the action of gastrointestinal enzymes, mainly in samples cooked at 100°C for 1h. In addition, 459 peptides derived from 57 proteins were identified and quantified using mass spectrometry in tandem, evidencing that peptides derived from collagen protein were responsible for the differences in antioxidant activities observed between the uncooked and cooked samples after digestion. The results show the potential of dry-cured ham bones as a source of antioxidant peptides that retain their bioactivity after household cooking preparations and gastrointestinal digestion.

A novel hemp seed meal protein hydrolysate reduces oxidative stress factors in spontaneously hypertensive rats.

This report shows the antioxidant effects of a hemp seed meal protein hydrolysate (HMH) in spontaneously hypertensive rats (SHR). Defatted hemp seed meal was hydrolyzed consecutively with pepsin and pancreatin to yield HMH, which was incorporated into rat feed as a source of antioxidant peptides. Young (8-week old) SHRs were divided into three groups (8 rats/group) and fed diets that contained 0.0%, 0.5% or 1.0% (w/w) HMH for eight weeks; half of the rats were sacrificed for blood collection. After a 4-week washout period, the remaining 20-week old SHRs were fed for an additional four weeks and sacrificed for blood collection. Plasma total antioxidant capacity (TAC) and superoxide dismutase (SOD), catalase (CAT) and total peroxides (TPx) levels were determined. Results showed that plasma TAC, CAT and SOD levels decreased in the older 20-week old SHRs when compared to the young SHRs. The presence of HMH in the diets led to significant (p < 0.05) increases in plasma SOD and CAT levels in both young and adult SHR groups; these increases were accompanied by decreases in TPx levels. The results suggest that HMH contained antioxidant peptides that reduced the rate of lipid peroxidation in SHRs with enhanced antioxidant enzyme levels and total antioxidant capacity.

Antiapoptotic effect of a novel synthetic peptide from bovine muscle and MPG peptide on H2O2-induced C2C12 cells.

The objective of this study was to evaluate antioxidant and antiapoptotic effects of a novel peptide (T.peptide) isolated from bovine and commercially available MPG peptide. The amino acid sequences of the T.peptide were (Glu-Val-Pro-Glu-Val-His-Glu-Glu-Val). The antioxidant activities of these peptides were determined by measuring the 1,1-diphenyl-2-picrylhydrazyl (DPPH•) and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS+•) radical scavenging assays. The in vitro cytotoxicity of T.peptide and MPG peptide was determined against H2O2-induced C2C12 cells. H2O2-induced apoptosis in C2C12 cells were determined by mRNA expression of caspase-3. Moreover, the mRNA expression of tumor necrosis factor alpha (TNF-α) and nuclear factor kappa B (NF-κB) were assayed by reverse transcription polymerase chain reaction. The findings of the study indicate that the mRNA expression of TNF-α and NF-κB are significantly (p < 0.05) increased in H2O2-induced C2C12 cells, whereas a significant decrease (p < 0.05) in these mRNA expressions are observed when pretreated with T.peptide or MPG peptide. Pretreatment with MPG or T.peptides is also found to significantly (p < 0.05) decrease the mRNA expression of caspase-3 in H2O2-induced C2C12 cells. The results of the study demonstrate that both T.peptide and MPG peptide could reduce the DPPH• and ABTS+• radical and inhibit cytotoxicity against H2O2-induced injury, resulting in prevention of free radical generation and subsequent apoptotic cell death, which indicates the potential of bovine meat as a source of antioxidant peptides.

Purification and characterization of a natural antioxidant peptide from fertilized eggs

Fertilized hen eggs are traditionally considered as dietary supplements in many Asian countries. This work aimed to obtain information on antioxidant peptides derived from fertilized eggs. Antioxidant activities were evaluated by measuring reducing power, DPPH radical scavenging activity and inhibition of pyrogallol autoxidation. During 15days of incubation, the antioxidant activity of peptides increased with increasing incubation time. The peptides on day 15 were employed for isolation of antioxidant peptide. An antioxidant peptide, HLFGPPGKKDPV (MW: 1291.51Da), was purified by consecutive chromatographic methods. The purified peptide was a novel peptide corresponding to the fragment 302–313 of ovotransferrin. The conformational prediction and Fourier transform infrared spectroscopy suggested that the peptide existed in β-sheet. Furthermore, the peptide showed an inhibition ratio of 60.20% on linoleic acid autoxidation and an inhibitory effect on ABTS radicals (IC50: 312μM). These results suggested that fertilized eggs could be explored as a source of antioxidant peptides.

Amaranth proteins as a source of antioxidant peptides: Effect of proteolysis

Abstract The antioxidant activity of peptides present in the phosphate buffer-soluble fraction of: – Amaranthus mantegazzianus protein isolates ( Is ), – protein fractions ( Albs , Globs , GlobPs and Gluts ), alcalase hydrolysates of isolates (hydrolysis degree –HD-: 2.4% ( IH ls ) and 30% ( IH hs ) and protein fractions ( AlbHs , GlobHs , GlobPHs , and GlutHs) was investigated. Fractions separated by molecular exclusion chromatography were also analyzed. ABTS +. scavenging method showed the presence of antioxidant peptides in Is , Albs , Globs , and Gluts , being the last the one with the highest activity. No activity was detected in the GlobPs . After hydrolysis, the scavenging activity of all samples increased, especially at high HD. The GlobPs fraction presented the highest scavenging capacity after hydrolysis. Naturally-occurring peptides and polypeptides presented also the capacity to inhibit the linoleic acid oxidation, which was partially lost after hydrolysis. FPLC fractionation evidenced the appearance of Is and IH hs of several peptides and polypeptides which can act as antioxidants by different mechanisms.