Purification of novel angiotensin converting enzyme inhibitory peptides from beef myofibrillar proteins and analysis of their effect in spontaneously hypertensive rat model

Ameliorative effect of mussel-derived ACE inhibitory peptides on spontaneous hypertension rats

PURPOSE

The purpose of this study was to prepare the novel mussel-derived ACE inhibitory peptides (MEPs) by enzymatic hydrolysis of Mytilus edulis and investigate their antihypertensive effects in vivo.

METHODS

After assessing the stability of MEPs in vitro, we investigated the effect of MEPs on hypertension using spontaneously hypertensive rats (SHRs). Subsequently, MEPs were purified and identified by ultrafiltration, gel filtration chromatography and liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

Our study demonstrated that MEPs could keep stable ACE inhibitory activity after treatment with heat, acid, alkali, metal ions and simulated gastrointestinal digestive fluid. Additionally, the animal experiments showed that both short-term and long-term treatment with MEPs resulted in a significant reduction in systolic and diastolic blood pressure in SHRs. Mechanistically, the results suggested that MEPs could reduce vascular remodeling, regulate renin-angiotensin system (RAS), and inhibit kidney and myocardial fibrosis. Finally, we isolated and identified five peptides from MEPs, with the peptide Ile-Leu-Thr-Glu-Arg showed the highest ACE inhibition rate.

CONCLUSION

Our findings demonstrate the potential use of MEPs as active components in functional foods designed to lower blood pressure.

Application of Plant Proteases in Meat Tenderization: Recent Trends and Future Prospects

Papain, bromelain, and ficin are commonly used plant proteases used for meat tenderization. Other plant proteases explored for meat tenderization are actinidin, zingibain, and cucumin. The application of plant crude extracts or powders containing higher levels of compounds exerting tenderizing effects is also gaining popularity due to lower cost, improved sensory attributes of meat, and the presence of bioactive compounds exerting additional benefits in addition to tenderization, such as antioxidants and antimicrobial effects. The uncontrolled plant protease action could cause excessive tenderization (mushy texture) and poor quality due to an indiscriminate breakdown of proteins. The higher cost of separation and the purification of enzymes, unstable structure, and poor stability of these enzymes due to autolysis are some major challenges faced by the food industry. The meat industry is targeting the recycling of enzymes and improving their stability and shelf-life by immobilization, encapsulation, protein engineering, medium engineering, and stabilization during tenderization. The present review critically analyzed recent trends and the prospects of the application of plant proteases in meat tenderization.

Produksi Hidrolisat Protein Kacang Koro Benguk dengan Aktivitas Penghambat Kerja Enzim Pengkonversi Angiotensin melalui Kombinasi Fermentasi dan Hidrolisis Enzimatik

Mucuna bean (Mucuna pruriens L.) is a legume having high protein content which has the potential as a source of bioactive peptides. One of the bioactive peptides is an angiotensin-converting enzyme (ACE) inhibitor, thus, mucuna beans might be used as a potential source of antihypertensive compounds. This study aimed to increase the functionality of proteins from mucuna beans as ACE inhibitors using a combination of fermentation and enzymatic hydrolysis followed by membrane filtration. The mucuna beans were fermented for 0, 24, 48, 96, and 144 h. The highest ACE inhibitory activity of 54.37%, was obtained by fermentation of the beans at 48 h, with a protein content of 20.82 mg/mL. The 48 h fermented mucuna beans were further hydrolyzed using alcalase or neutrase and subsequently filtered with UF membranes having 20,10 and 5 kDa cut-off. The enzymatic hydrolysis followed by membrane filtration increased the ACE inhibitory activity of mucuna beans. The neutrase hydrolysates resulting from 5 kDa membrane filtration showed the best ACE inhibitory activity (62.96% with a protein content of 10.39 mg/mL). A combination of fermentation and enzymatic hydrolysis followed by filtration using UF-membrane was able to produce ACE inhibitory peptides from mucuna beans. The potential of mucuna beans peptides as ACE inhibitors was due to the presence of negatively charged amino acid residues such as Asp and Glu, positively charged amino acids such as Arg and Lys, and hydrophobic amino acids such as Val, Leu, Ala, and Ile.

Bioactive peptides from meat: Current status on production, biological activity, safety, and regulatory framework

By-products of the meat processing industry which are often discarded as waste are excellent protein substrates for producing bioactive peptides through enzymatic hydrolysis. These peptides have tremendous potential for the development of functional food products but there is scanty information about the regulations on bioactive peptides or products in various parts of the world. This review focuses on the diverse bioactive peptides identified from different meat and meat by-products, their bioactivity and challenges associated in their production as well as factors limiting their effective commercialization. Furthermore, this report provides additional information on the possible toxic peptides formed during production of the bioactive peptides, which enables delineation of associated safety and risk. The regulatory framework in place for bioactive peptide-based foods in different jurisdictions and the future research directions are also discussed. Uniform quality, high cost, poor sensory acceptance, lack of toxicological studies and clinical evidence, paltry stability, and lack of bioavailability data are some of the key challenges hindering commercial advancement of bioactive peptide-based functional foods. Absorption, distribution, metabolism and excretion (ADME) studies in rodents, in vitro genotoxicity, and immunogenicity data could be considered as absolute pre-requisites to ensure safety of bioactive peptides. In the absence of ADME and genotoxicity data, long term usage to evaluate safety is highly warranted. Differences in legislations among countries pose challenge in the international trade of bioactive peptides-based functional foods. Harmonization of regulations could be a way out and hence further research in this area is encouraged.

Ensemble-AHTPpred: A Robust Ensemble Machine Learning Model Integrated With a New Composite Feature for Identifying Antihypertensive Peptides

Hypertension or elevated blood pressure is a serious medical condition that significantly increases the risks of cardiovascular disease, heart disease, diabetes, stroke, kidney disease, and other health problems, that affect people worldwide. Thus, hypertension is one of the major global causes of premature death. Regarding the prevention and treatment of hypertension with no or few side effects, antihypertensive peptides (AHTPs) obtained from natural sources might be useful as nutraceuticals. Therefore, the search for alternative/novel AHTPs in food or natural sources has received much attention, as AHTPs may be functional agents for human health. AHTPs have been observed in diverse organisms, although many of them remain underinvestigated. The identification of peptides with antihypertensive activity in the laboratory is time- and resource-consuming. Alternatively, computational methods based on robust machine learning can identify or screen potential AHTP candidates prior to experimental verification. In this paper, we propose Ensemble-AHTPpred, an ensemble machine learning algorithm composed of a random forest (RF), a support vector machine (SVM), and extreme gradient boosting (XGB), with the aim of integrating diverse heterogeneous algorithms to enhance the robustness of the final predictive model. The selected feature set includes various computed features, such as various physicochemical properties, amino acid compositions (AACs), transitions, n-grams, and secondary structure-related information; these features are able to learn more information in terms of analyzing or explaining the characteristics of the predicted peptide. In addition, the tool is integrated with a newly proposed composite feature (generated based on a logistic regression function) that combines various feature aspects to enable improved AHTP characterization. Our tool, Ensemble-AHTPpred, achieved an overall accuracy above 90% on independent test data. Additionally, the approach was applied to novel experimentally validated AHTPs, obtained from recent studies, which did not overlap with the training and test datasets, and the tool could precisely predict these AHTPs.

Assessment of quality attributes of porcine blood and liver hydrolysates incorporated pork loaves stored under aerobic and modified atmospheric packaging

Lipid oxidation and microbial proliferations were studied in pork loaves prepared with incorporation of blood and liver protein hydrolysates stored in aerobic and MAP packaging for 28 and 42 days at 4 ± 1 ºC. In in-vitro trials selected levels i.e. blood hydrolysate (T1 and T3-600 mg/g), and liver hydrolysate (T2 and T4-600 mg/g), control without hydrolysate (C1-00 and C2-00 mg/g) w/w of emulsion, were added into pork loaves and packaged under aerobic (C1, T1 and T2) and MAP (C2, T3 and T4) condition. Physico-chemicals as pH, water activity_, titratable acidity, lipid-oxidations, color profile, textural indices, microbial qualities and sensorial properties were analyzed. Significant (p < 0.05) lower lipid oxidation, microbial proliferations and decrease in sensory attributes were seen for tested groups and MAP than aerobic packaging. It can be concluded that pork loaves containing porcine blood and liver hydrolysates can be successfully stored upto 28th days in aerobically packed and 42 days in MAP condition at refrigerated storage with acceptable physico-chemical, oxidative stability, microbiological and sensory quality. Whereas, pork loves prepared with blood hydrolysate (T3-600 mg/g), packaged under MAP condition were superior for all studied attributes than other groups. Blood and liver hydrolysate might be used as an alternative to synthetic preservative for meat preservation.

Generation and Characterization of Novel Bioactive Peptides from Fish and Beef Hydrolysates

Bioactive peptides were successfully produced from fish (Gadidae) and beef skeletal muscles after being hydrolyzed for 8 h with pepsin. Subsequently, they were purified using a Sep-Pak C18 cartridge and reversed-phase high-performance liquid chromatography (RP-HPLC). The molecular weights of pure fish and beef peptides were determined to be 2364.4 and 3771.8, respectively. According to Edman degradation, the fish peptide was composed of 21 amino acid residues (F21), while the beef peptide was composed of 34 amino acid residues (B34). F21 and B34 displayed angiotensin-converting enzyme inhibitory activity with a half maximal inhibitory concentration (IC50) values of 7.3 µg/mL and 5.8 µg/mL, respectively. F21 exhibited antioxidant activity with an IC50 value of 389.9 µg/mL, whereas B34 exhibited no antioxidant activity. Moreover, F21 and B34 displayed antimicrobial effects against a wide spectrum of food-borne pathogens and spoilage bacteria. Bioactive peptides derived from muscle proteins are a promising strategy for the production of functional food materials and safe food preservatives.

Angiotensin I-converting enzyme inhibitory peptide: an emerging candidate for vascular dysfunction therapy

Abnormal vasoconstriction, inflammation, and vascular remodeling can be promoted by angiotensin II (Ang II) in the renin-angiotensin system (RAS), leading to vascular dysfunction diseases such as hypertension and atherosclerosis. Researchers have recently focused on angiotensin I-converting enzyme inhibitory peptides (ACEIPs), that have desirable efficacy in vascular dysfunction therapy due to Ang II reduction by inhibiting ACE activity. Promising methods for the large-scale preparation of ACEIPs include selective enzymatic hydrolysis and microbial fermentation. Thus far, ACEIPs have been widely reported to be hydrolyzed from protein-rich sources, including animals, plants, and marine organisms, while many emerging microorganism-derived ACEIPs are theoretically biosynthesized through the nonribosomal peptide synthase (NRPS) pathway. Notably, vasodilatation, anti-inflammation, and vascular reconstruction reversal of ACEIPs are strongly correlated. However, the related molecular mechanisms underlying signal transduction regulation in vivo remain unclear. We provide a comprehensive update of the ACE-Ang II-G protein-coupled type 1 angiotensin receptor (AT1R) axis signaling and its functional significance for potential translation into therapeutic strategies, particularly targeting AT1R by ACEIPs, as well as specific related signaling pathways. Future studies are expected to verify the biosynthetic regulatory mechanism of ACEIPs via the NRPS pathway, the effect of gut microbiota metabolism on vascular dysfunction and rigorous studies of ACE-Ang II-AT1R signaling pathways mediated by ACEIPs in large animals and humans.

Anti-inflammatory and Antioxidant Activity of Peptides From Ethanol-Soluble Hydrolysates of Sturgeon (Acipenser schrenckii) Cartilage

Research has shown that cartilage containing chondroitin sulfate and protein presents versatile bioactivities. Chondroitin sulfate in cartilage is beneficial to activate the immune system while the protein/peptide has not been fully understood. The current study investigated the antioxidant and anti-inflammatory properties of ethanol-soluble hydrolysates of sturgeon cartilage (ESCH) prepared through hot-pressure, enzymatic hydrolysis and ethanol extraction. UV spectrum, IR and agarose gel electrophoresis results suggested the successful exclusion of chondroitin sulfate from peptides. Nitric oxide (NO) floods in cells activated by inflammation. It was inhibited when administrated with ESCH. To further explain the observed anti-inflammatory activity, ESCH was separated with Sephadex G-15 into 3 components, among which F3 showed a higher NO inhibition rate and significantly reduced the production of the proinflammatory cytokine IL-6. In addition, the yield of IL-10 increased. Western blotting suggested that F3 downregulated the NO content and IL-6 level by suppressing Mitogen-activated protein kinases (MAPK) channels. Moreover, both ESCH and F3 showed DPPH and ABTS free radical scavenging abilities which was possibly related to the anti-inflammatory property. These results indicated that ESCH behaved anti-inflammatory and antioxidant activities. Cartilage may be a good source to produce anti-inflammatory peptides.

Roles of Dietary Bioactive Peptides in Redox Balance and Metabolic Disorders

Bioactive peptides (BPs) are fragments of 2-15 amino acid residues with biological properties. Dietary BPs derived from milk, egg, fish, soybean, corn, rice, quinoa, wheat, oat, potato, common bean, spirulina, and mussel are reported to possess beneficial effects on redox balance and metabolic disorders (obesity, diabetes, hypertension, and inflammatory bowel diseases (IBD)). Peptide length, sequence, and composition significantly affected the bioactive properties of dietary BPs. Numerous studies have demonstrated that various dietary protein-derived BPs exhibited biological activities through the modulation of various molecular mechanisms and signaling pathways, including Kelch-like ECH-associated protein 1/nuclear factor erythroid 2-related factor 2/antioxidant response element in oxidative stress; peroxisome proliferator-activated-γ, CCAAT/enhancer-binding protein-α, and sterol regulatory element binding protein 1 in obesity; insulin receptor substrate-1/phosphatidylinositol 3-kinase/protein kinase B and AMP-activated protein kinase in diabetes; angiotensin-converting enzyme inhibition in hypertension; and mitogen-activated protein kinase and nuclear factor-kappa B in IBD. This review focuses on the action of molecular mechanisms of dietary BPs and provides novel insights in the maintenance of redox balance and metabolic diseases of human.

Changes in the stability and antioxidant activities of different molecular weight bioactive peptide extracts obtained from beef during in vitro human digestion by gut microbiota

This study was conducted to determine changes in the stability and antioxidant activity of extracts of bioactive peptides with different molecular weights (<3 and <10 kDa) obtained from beef myofibrillar protein using commercial enzymes (alkaline-AK and papain) during in vitro human digestion by gut microbiota. After the digestion in the large intestine, the stability of the bioactive peptide extracts decreased regardless of their molecular weight. However, the peptides obtained following alkaline-AK treatment were less stable than those obtained following papain digestion. The radical scavenging activities of the peptide extracts also decreased during in vitro human digestion, regardless of the molecular weights of the peptides and the commercial enzymes used. These results indicate that the stability and antioxidative activity of the bioactive peptides were affected by the digestion process by the gut microbiota. This study provides data supporting the changes in the stability and bioavailability of functional materials within the human body.

Rational design of mimetic peptides based on the interaction between Inga laurina inhibitor and trypsins for Spodoptera cosmioides pest control

The interaction of Inga laurina Kunitz inhibitor with insect trypsins is an example of protein-protein interaction with potential application for the pest control. However, the crop field application of proteins as inhibitors is limited due to high production cost, the large molecular size and low environmental stability. The use of mimetic peptides that have molecular features associated with the protein inhibitor can result in a product with lower cost and higher efficiency for the agricultural application. Here, we designed mimetic peptides deriving from globular domains of ILTI that are predicted to interact with trypsin enzymes of Lepidoptera pest. Two linear peptides were identified and synthetized from the interface of interaction between trypsin-ILTI complexes. These peptides were derived due to its high-energy contribution for the biding affinity between the enzyme-protein inhibitor. The peptides showed structural stability, propensity to adopt the bound conformation also without the context of the protein, inhibitory activity of digestive trypsins and toxic effects on the S. cosmioides, indicating that they can be used as potential inhibitor for pest control.

Current Trends of Bioactive Peptides-New Sources and Therapeutic Effect

Generally, bioactive peptides are natural compounds of food or part of protein that are inactive in the precursor molecule. However, they may be active after hydrolysis and can be transported to the active site. Biologically active peptides can also be synthesized chemically and characterized. Peptides have many properties, including antihypertensive, antioxidant, antimicrobial, anticoagulant, and chelating effects. They are also responsible for the taste of food or for the inhibition of enzymes involved in the development of diseases. The scientific literature has described many peptides with bioactive properties obtained from different sources. Information about the structure, origin, and properties of peptides can also be found in many databases. This review will describe peptides inhibiting the development of current diseases, peptides with antimicrobial properties, and new alternative sources of peptides based on the current knowledge and documentation of their bioactivity. All these issues are part of modern research on peptides and their use in current health or technological problems in food production.

Characteristics of New Peptides GQLGEHGGAGMG, GEHGGAGMGGGQFQPV, EQGFLPGPEESGR, RLARAGLAQ, YGNPVGGVGH, and GNPVGGVGHGTTGT as Inhibitors of Enzymes Involved in Metabolic Syndrome and Antimicrobial Potential

The aim of this study was to determine the cytotoxic properties, influence on enzyme activity involved in metabolic syndrome, and antimicrobial activity of synthetic peptides with GQLGEHGGAGMG, GEHGGAGMGGGQFQPV, EQGFLPGPEESGR, RLARAGLAQ, YGNPVGGVGH, and GNPVGGVGHGTTGT sequences. Peptides have no cytotoxic effect on cells. The highest inhibitory effect on angiotensin converting enzyme I was noted for peptide GT-14 (IC50 = 525.63 µg/mL). None of the tested peptides had an influence on α-glucosidase. The highest α-amylase and lipase inhibitory activity was noted for GG-12 (IC50 = 56.72 and 60.62 µg/mL, respectively). The highest lipoxidase inhibitory activity was determined for peptide ER-13 (IC50 = 84.35 µg/mL). Peptide RQ-9 was characterized by the highest COX inhibitory activity (0.31 and 4.77 µg/mL for COX-1 and COX-2, respectively). Only peptide RQ-9 inhibited S. enteritidis ATCC 4931 growth (42%-48%) in all tested concentrations (15.62-250 mg/mL).

Isolation of novel ACE-inhibitory peptide from naked oat globulin hydrolysates in silico approach: Molecular docking, in vivo antihypertension and effects on renin and intracellular endothelin-1

Naked oat globulin was hydrolyzed by alcalase, flavourzyme, pepsin, and trypsin in sequence. The hydrolysates (NOGH) were purified using gel chromatography, reversed-phase high performance liquid chromatography (RP-HPLC). Finally, fraction D7d with the highest ACE-inhibitory was subjected to liquid chromatography-mass spectrometry analysis and 14 peptides were identified. Of which, peptide SSYYPFK (890.4 Da) was chose to synthesize based on in silico analysis. The SSYYPFK demonstrated high ACE-inhibitory activity (IC₅₀ : 91.82 µM) with competitive inhibition mode, and could effectively (P < 0.05) lower the systolic blood pressure and diastolic pressure of spontaneously hypertensive rats at the concentration of 100 to 150 mg/kg body weight. Molecular docking simulation demonstrated that SSYYPFK could bind with the active site S1 of ACE via short hydrogen bonds. It could remain the ACE-inhibitory activity after simulated gastrointestinal hydrolysis. Moreover, SSYYPFK showed acceptable renin and endothelin-1 suppressing capacity (47.59% and 27.88% at 1.5 mg/mL, respectively). These results indicated that SSYYPFK may have similar antihypertensive mechanism with captopril, and could be develop to natural antihypertensive products. PRACTICAL APPLICATION: One novel ACE-inhibitory peptide SSYYPFK (890.4 Da) was identified from naked oat globulin hydrolysates. It exhibited relatively high renin and intracellular endothelin-1 suppressing capacity, and could effectively (P < 0.05) lower the systolic blood pressure and diastolic pressure of spontaneously hypertensive rats. This peptide could be used as natural and safe nutraceuticals and/or functional ingredients.

Efficacy of a Novel ACE-Inhibitory Peptide from Sargassum Maclurei in Hypertension and Reduction of Intracellular Endothelin-1

Sargassum maclurei is a potential protein resource because of its high protein content and relatively balanced amino acid composition. To promote its usage in food, medical, or other industries, S. maclurei protein was hydrolyzed by pepsin and papain to obtain bioactive peptides. The S. maclurei protein hydrolysates (SMPHs) were purified using gel chromatography and reversed-phase high performance liquid chromatography (RP-HPLC), and 12 major fractions were obtained. The fraction D11 with the highest angiotensin I-converting enzyme (ACE) inhibition (61.59%, at 1 mg/ mL) was subjected to liquid chromatography-mass spectrometry (LC-MS/MS) analysis, and about 17 peptides were identified, of which the RWDISQPY (1063.5 Da) was chosen to be synthesized based on in silico analysis. The RWDISQPY demonstrated high ACE inhibition ability (IC50: 72.24 μM) with competitive inhibition mode, and could effectively (p < 0.05) lower the systolic blood pressure and diastolic pressure of spontaneously hypertensive rats at the concentration of 150 mg/kg body weight. The results of the molecular docking simulation demonstrated that RWDISQPY could bind with the active sites S1 and S2 of ACE via short hydrogen bonds. Moreover, RWDISQPY showed acceptable endothelin-1 suppressing capacity (26.21% at 1.5 mg/mL). These results indicate that S. maclurei could be developed into functional foods such as antihypertensive products.

Antihypertensive Effects of Virgin Olive Oil (Unfiltered) Low Molecular Weight Peptides with ACE Inhibitory Activity in Spontaneously Hypertensive Rats

The low molecular weight peptide composition of virgin olive oil (VOO) is mostly unknown. We hypothesised that unfiltered VOO could possess low molecular weight peptides with antihypertensive activity. We produced unfiltered VOO and obtained a water-soluble peptide extract from it. The peptides were separated by size-exclusion using fast protein liquid chromatography, and the low molecular weight fraction was analysed by nanoscale liquid chromatography-Orbitrap coupled with tandem mass spectrometry and de novo sequencing. We selected 23 peptide sequences containing between 6 and 9 amino acids and molecular masses ranging 698–1017 Da. Those peptides were chemically synthesised and their angiotensin-converting enzyme (ACE) inhibitory activity was studied in vitro. Seven peptides showed a strong activity, with half maximal inhibitory concentration (IC50) <10 µm. The antihypertensive effects of the four most active synthesised ACE inhibitor peptides were studied in spontaneously hypertensive rats (SHR). Acute oral administration of synthetic peptides RDGGYCC and CCGNAVPQ showed antihypertensive activity in SHR. We conclude that unfiltered VOO naturally contains low molecular weight peptides with specific ACE inhibitory activity and antihypertensive effects in SHR.

ACE inhibitory peptides derived from de-fatted lemon basil seeds: optimization, purification, identification, structure–activity relationship and molecular docking analysis

The study determines optimized process conditions to maximize ACE inhibitory peptide production. The two novel hexa-peptides (LGRNLPPI and GPAGPAGL) from de-fatted lemon basil seeds (DLBS) was achieved.

Isolation of Novel ACE-Inhibitory and Antioxidant Peptides from Quinoa Bran Albumin Assisted with an In Silico Approach: Characterization, In Vivo Antihypertension, and Molecular Docking

Albumin is the major fraction of quinoa protein that is characterized as having high nutritional value. However, until now, scant information is available on the bioactivity of quinoa albumin or its hydrolysates. To promote its usage, we extracted albumin in this study from quinoa bran assisted with cellulase and hemicellulose, and hydrolyzed it by alcalase and trypsin to produce bioactive peptides. The hydrolysates (QBAH) were purified by gel filtration and reversed-phase high-performance liquid chromatography (RP-HPLC), followed by identification using liquid chromatography–mass spectrometry (LC-MS/MS). Furthermore, based on in silico analysis, one angiotensin-I converting enzyme (ACE)-inhibitory and antioxidant peptide, RGQVIYVL (946.6 Da), and two antioxidant peptides, ASPKPSSA (743.8 Da), and QFLLAGR (803.5 Da), from QBAH were synthesized. RGQVIYVL showed a high ACE-inhibitory activity (IC₅₀ = 38.16 μM) with competitive mode of inhibition, and showed significant antihypertensive effect in spontaneously hypertensive rats at a concentration of 100–150 mg/kg body weight (bw). Molecular docking simulation showed that it could interact with the active ACE site via hydrogen bonds with high binding power. Moreover, RGQVIYVL, ASPKPSSA, and QFLLAGR all demonstrated high ·OH scavenging activity (IC₅₀ = 61.69–117.46 μM), ABTS⁺ scavenging activity (58.29–74.28%) and Fe²⁺ chelating ability (32.54–82.48% at 0.5 mg/mL). They could also retain activity after gastrointestinal enzyme digestion. These results indicate that quinoa albumin is a potential source of bioactive peptides possessing antioxidant and ACE-inhibitory activities.

Effect of Treatment with Peptide Extract from Beef Myofibrillar Protein on Oxidative Stress in the Brains of Spontaneously Hypertensive Rats

This study was conducted to determine the effect of beef peptide extract on oxidative stress in the brains of spontaneously hypertensive rats (SHRs). A 3-kDa peptide extract was obtained from beef myofibrillar protein using alkaline-AK (AK3K). Oxidative stress in SHR brains was measured by assessing malondialdehyde (MDA) and reactive oxygen species (ROS) concentrations and superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx) activity. The SHR brains treated with the AK3K peptide extract (400 mg/kg body weight, AK3K400) showed a significant decrease in MDA and ROS contents by 0.33 and 23.92 μM, respectively (p < 0.05) compared to the control. The SOD activity for AK3K400 was 61.26%, around 20% higher than the control. Furthermore, the SHRs treated with the AK3K peptide extract showed results similar to those obtained using captopril, a hypertension drug, except for the MDA level. The study demonstrates that the beef peptide extract inhibits the generation of oxidative stress in the SHR brain and could possibly be used for neuronal hypertension therapy.