A bovine lactoferrin-derived peptide induced osteogenesis via regulation of osteoblast proliferation and differentiation.

Osteoporosis is a disease of aging, characterized by a decrease in bone quality and a reduction in bone strength. Promoting the activity of osteoblasts is a useful strategy for combating the progression of osteoporosis. As a novel bone growth factor, lactoferrin plays a role in the anabolic activity in bone by inducing the proliferation and differentiation of osteoblasts and inhibiting the formation of osteoclasts. However, potential peptides with osteogenic activity from lactoferrin have not been identified. In the present study, a peptide with osteogenic activity-LFP-C, fragment residues 624 to 632, derived from lactoferrin hydrolysates-was identified using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry and screened using molecular docking analysis. The LFP-C peptide significantly increased the proliferation of mouse cell line MC3T3-E1 and had a promoting effect on alkaline phosphatase activity and calcium deposition. Moreover, LFP-C increased the proportion of osteoblasts in the G2 and M phases. The osteogenic mechanism of LFP-C was also studied by molecular docking. We found that LFP-C could bind to the key domain (Lys13-Thr15-Gln16-Leu17-Gly18-Asp22) of epidermal growth factor receptor, a vital receptor tyrosine kinase that leads to the activation of the mitogen-activated protein kinase pathway. The main interaction forces were interpolated charge, hydrophobicity, and hydrogen bonding. Results indicated that LFP-C may play an osteogenic role in a similar way to lactoferrin, by promoting the proliferation and differentiation of osteoblasts. The findings of this in vitro experiment also demonstrated that the molecular docking method could play a role in the screening process; this in silico approach allowed for faster and cheaper identification of a promising bioactive component.

Antioxidant and ACE Inhibitory Activity of Enzymatic Hydrolysates from Ruditapes philippinarum.

Ruditapes philippinarum proteins were hydrolyzed by trypsin, neutrase, and pepsin. The antioxidant activities and ACE inhibitory activity of hydrolysates were analyzed and the antioxidant activities were related to their molecular weight distribution and amino acid compositions. Results indicated the hydrolysis of proteins led to an increase in small peptides and free amino acids. The antioxidant activities of Ruditapes philippinarum hydrolysates against DPPH radical scavenging, inhibition on linoleic acid peroxidation, and reducing power showed that the neutrase hydrolysate exhibited the strongest antioxidant activity. In addition, an ACE inhibition assay revealed that the pepsin hydrolysate had the highest ACE inhibitory ability. Ruditapes philippinarum protein hydrolysates could be a promising source of natural antioxidant and ACE inhibitory.

Bioactive hydrolysates from casein: generation, identification, and in silico toxicity and allergenicity prediction of peptides.

BACKGROUND: Bioactive casein peptides have attracted considerable attention for their applications in industry. However, there is little clarity regarding mass spectrometric profiles for peptides in enzymatic hydrolysates of casein produced under varying conditions. In this study, the compositions of the peptides from casein hydrolysates were compared for different enzyme/substrate ratio (E/S) and hydrolysis times. The toxicity, allergenicity and bioactivity of the identified peptides were assessed in silico. RESULTS: A total of 70 unique peptides were identified, and there were 28, 21, 13 and 8 peptides from αs1 -casein, αs2 -casein, ß-casein and κ-casein respectively. The peptide number decreased with the increase in E/S and hydrolysis time. Moreover, peptides with relative molecular mass Mr ranging from 1000 to 1500 Da occupied the highest proportion of 31.43%, and almost all of the peptides showed Mr less than 5000 Da. In silico analysis showed that all of the peptides were non-toxic and non-allergenic, and several of them were assessed by PeptideRanker as having a relatively high likelihood of being bioactive peptides. CONCLUSIONS: Composition of the peptides in the casein hydrolysates varied with the enzymolysis conditions. This study's results may facilitate the production of target bioactive peptides by controlling E/S and hydrolysis time, which is beneficial for the application of casein peptides in the functional food industry. © 2017 Society of Chemical Industry.

Gelatin/dextran active films incorporated with cinnamaldehyde and α-tocopherol for scallop (Patinopecten yessoensis) adductor muscle preservation.

Scallops are rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid but perishable due to their microbial growth and lipid oxidation. In this study, gelatin/dextran films containing cinnamaldehyde and α-tocopherol (0% + 0%, 0.3% + 0.3%, 0.6% + 0.6%, 0.9% + 0.9%, and 1.2% + 1.2%, w/w) as active fillers were developed by solution casting method, and their preservation effects on scallop adductor muscle refrigerated at 4°C for 0, 3, 6, 9, and 12 days were evaluated. Inclusion of the two active fillers did not influence the thermal stability of the films but created heterogenous and discontinuous film microstructure and increased the film hydrophobicity. Increase in the concentrations of active fillers lowered the mechanical properties and water vapor permeability of the films but increased their crystallinity, thickness, water contact angle, opacity, antibacterial property, and antioxidant property. The longest release times for both cinnamaldehyde and α-tocopherol were found in 95% (v/v) ethanol solution. The gelatin/dextran films containing 1.2% (w/w) of active fillers (Gelatin [Ge]/Dextran [Dx]/1.2 film) improved the chemical stability of refrigerated scallop adductor muscle. The total viable count (TVC) of the unpackaged scallop adductor muscle exceeded the recommended limit of 7 lg CFU/g on day 6 (7.07 ± 0.50 lg CFU/g), whereas the TVC of the Ge/Dx/1.2 film-packaged scallop adductor muscle was still below the limit on day 9 (5.60 ± 0.50 lg CFU/g). Thus, the Ge/Dx/1.2 film can extend the shelf life of refrigerated scallop adductor muscle by at least 3 days. Overall, the developed gelatin/dextran active packaging films are promising for the preservation of aquatic food products.

Unlocking the Therapeutic Potential of a Manila Clam-Derived Antioxidant Peptide: Insights into Mechanisms of Action and Cytoprotective Effects against Oxidative Stress.

Reactive oxygen species (ROS) are implicated in various pathological conditions due to their ability to induce oxidative damage to cellular components. In this study, we investigated the antioxidant properties of a peptide isolated from the hydrolysate of Manila clam (Ruditapes philippinarum) muscle. Purification steps yielded RPTE2-2-4, exhibiting potent scavenging activities against DPPH•, HO•, and O2•-, akin to Vitamin C. Structural analysis showed that the isolated peptide, LFKKNLLTL, exhibited characteristics associated with antioxidant activity, including a short peptide length and the presence of aromatic and hydrophobic amino acid residues. Moreover, our study demonstrated the cytoprotective effects of the peptide against H2O2-induced oxidative stress in HepG2 cells. Pretreatment with the peptide resulted in a dose-dependent reduction in intracellular ROS levels and elevation of glutathione (GSH) levels, indicating its ability to modulate cellular defense mechanisms against oxidative damage. Furthermore, the peptide stimulated the expression of the cytoprotective enzyme heme oxygenase-1 (HO-1), further reinforcing its antioxidant properties. Overall, our findings highlight the potential of the Manila clam-derived peptide as a natural antioxidant agent with therapeutic implications for oxidative stress-related diseases. Further investigation into its mechanisms of action and in vivo efficacy is warranted to validate its therapeutic potential.

Simultaneous determination of subspecies and geographic origins of 110 rice cultivars by microsatellite markers.

Rice varieties of different subspecies types (indica rice and japonica rice) across various geographical origins (Hunan, Jiangsu, and Northeast China) were monitored using microsatellite markers (simple sequence repeats, SSR). 110 representative rice cultivars were collected from the main crop areas. Multiple methods including clustering analysis (neighbor-joining (NJ) method, unweighted pair-group method with arithmetic mean (UPGMA) method), principal component analysis (PCA) and model-based grouping were applied. The study revealed that 25 pairs of SSR markers exhibited a broad range of polymorphism information content (PIC) values, ranging from 0.240 to 0.830. Furthermore, our study successfully achieved a higher overall mean correct rate of 99.09% in determining the geographical origin of rice. Simultaneously, it accurately classified indica rice and japonica rice. These findings are significant as they provide an SSR fingerprint of 110 high-quality rice cultivars, serving as a valuable scientific resource for the detection of rice adulteration and traceability of its origin.

Zein and gum arabic nanoparticles: potential enhancers of immunomodulatory functional activity of selenium-containing peptides.

Food-derived nanomaterials optimizing bioactive peptides is an emerging route in the functional food field. Zein and gum arabic (GA) possess favorable encapsulation properties for controlled release, targeted delivery and stabilization of food bioactive ingredients, and thus are considered as promising carriers for delivery systems. In order to improve the bioavailability of rice selenium-containing peptide TSeMMM (T), the nanoparticles (ZTGNs) containing peptide T, zein and GA have been previously prepared. This study focused on evaluating the immunomodulatory capacity of ZTGNs. The results showed that ZTGNs significantly alleviated cyclophosphamide-induced reduction in immune organ indices and liver glutathione content of mice. There was a significant upregulation observed in the levels of immune-related cytokines IL-6, TNF-α, and IFN-γ as well as their mRNA expression. Moreover, ZTGNs enriched the diversity of the intestinal flora and promoted the proportion of beneficial bacteria. In conclusion, ZTGNs have potential as immunomodulatory enhancers for food bioactive ingredients, providing prospects for further optimization of dietary supplements.

Potentials of dietary fiber and polyphenols in whole grain wheat flour to release the liver function and intestinal tract injury in lead-induced mice.

The presence of lead as an environmental pollutant is widespread. However, safe and effective treatments for the resulting intestinal and liver damage from high levels of lead exposure remain limited. The study aimed to investigate the protective effects of dietary fiber and polyphenols in whole grain wheat flour on lead-induced mice. The results indicated that the daily intake of 12 mg of polyphenols, 0.5 g of dietary fiber, and their combination effectively reduced blood and liver lead accumulation by approximately 50 % in mice exposed to lead, while also mitigating lead-induced oxidative stress though a reduction in malondialdehyde levels and an enhancement in antioxidant enzyme activities including superoxide dismutase, catalase, and glutathione peroxidase. Furthermore, all three treatments enhanced cytokine secretion with the combined treatment exhibiting the highest efficacy. Specifically, the combination treatment decreased tumor necrosis factor-α and interleukin 1ß by 56.78 %, 47.86 % in intestinal tissue while increasing increased interleukin 4 and interleukin 10 by 81.84 %, 145.14 %. Additionally, it promoted the expression of tight junction proteins like Zonula occludens-1, Occludin and Claudin-1. The study presented a potential strategy for alleviating liver and intestinal tract damage from high-dose lead exposure.

Effect of gluconic acid rinsing on cadmium decontamination from rice protein.

Cadmium (Cd) accumulation in rice protein has long been considered a significant threat to human health. In the present study, a costless and effective method based on gluconic acid (GA) rinsing of rice protein was developed to reduce Cd contamination in rice protein. Moreover, the effect of GA on the structural and functional properties of rice protein was evaluated. With liquid-solid ratio of 30 mL/g and oscillation time of 120 min, 96.0% and 93.6% of Cd were eliminated from rice protein-H and rice protein-L, respectively. In addition, the results of scanning electron microscopy, Fourier transform infrared, and sodium dodecyl sulfate polyacrylamide gel electrophoresis analyses showed that GA treatment did not significantly change the structural properties of rice protein. However, GA treatment increased foaming properties, water holding capacity, and oil holding capacity of the rice protein, without affecting its further applicability. Thus, the proposed GA rinsing method can be considered a green and efficient strategy to solve the issue brought by Cd residual contamination in rice protein. PRACTICAL APPLICATION: Given the advantages of green and efficient agriculture, gluconic acid (GA) has emerged as a powerful strategy for removing the Cd from rice protein. The method developed herein showed great potentials for applications in the manufacture of rice-based products.

Facile synthesis of chitosan-tartaric acid biosorbents for removal of Cu(II) and Cd(II) from water and tea beverages.

Consumption of water and tea beverages leads to the intake of heavy metals by humans. Development of technology for decontamination greatly reduces the risks of the heavy metal exposure. In this study, environment-friendly chitosan-tartaric acid biosorbents (CTBs) were synthesized by a facile one-step cross-linking strategy to mitigate the Cu(II) and Cd(II) contamination in water and tea beverages. The cross linkage of tartaric acid and chitosan endowed CTBs with excellent properties in aspects of surface roughness, mechanical strength, and acid resistance. Adsorption performance and mechanism of CTBs were studied, and the Langmuir isotherm model and pseudo-second-order kinetic model were adhered during adsorption. Up to 90 % removal efficiencies of Cu(II) and Cd(II) from water and tea beverages by CTBs were achieved. Moreover, the adsorption showed only a slight reduction in the quality of tea beverages. This study offers a new insight for reduction of heavy metals-pollution in beverages.

Characterization of the physiochemical properties, microstructure, and molecular interactions of a novel rice-pea protein gel.

The application of rice and pea proteins in food production is limited due to their undesirable processing performance. The objective of this research was to develop a novel rice-pea protein gel using alkali-heat treatment. This gel had a higher solubility, stronger gel strength, better water retention capacity, and denser bilayer network. This is due to the alkali-heat induced modifications for the secondary structures of proteins (i.e., a decrease in the α-helix, and an increase in the ß-sheets) and the interactions between protein molecules. The network structure of gel was more compact by adding 2% and 4% alkali-heat rice protein (AH-RP). This resulted in a stable double-layer network structure of gel. Adding 4% AH-RP significantly improved the hardness and elasticity of gel. This gel will have a good potential use for being the ingredient to produce the functional foods and meat analogs.

Encapsulation of selenium-containing peptides in xanthan gum-lysozyme nanoparticles as a powerful gastrointestinal delivery system.

In this study, nanoparticles (NPs) prepared with xanthan gum and lysozyme were established as a powerful delivery system for two Se-containing peptides: TSeMMM (STP) and SeMDPGQQ (SHP). NPs-STP and NPs-SHP had relatively small particle sizes (145 nm and 148 nm) and negative zeta potentials (-47 mV and -49 mV). The encapsulation efficiency of NPs-STP and NPs-SHP was determined to be 34.35% and 41.35%, respectively. The stability and antioxidant activity of Se-containing peptides were greatly enhanced due to encapsulation. NPs-STP and NPs-SHP exhibited controlled release of Se-containing peptides under in vitro gastrointestinal conditions. NPs-STP and NPs-SHP showed low toxicity and entered Caco-2 cells through clathrin-mediated endocytosis, contributing to a significant increase in the apparent permeability coefficient of STP (2.19 × 10-6 cm/s) and SHP (2.21 × 10-6 cm/s). Thus, NPs-STP and NPs-SHP are considered promising delivery systems for Se-containing peptides and have good potential applications in the food and pharmaceutical industries.

Effect of ultrasonic treatment on the stability and release of selenium-containing peptide TSeMMM-encapsulated nanoparticles in vitro and in vivo.

Rice selenium-containing peptide TSeMMM (T) with immunomodulatory functions was isolated from selenium-enriched rice protein hydrolysates. However, its biological activity is difficult to be protected in complex digestive environments. In this study, T was encapsulated within zein and gum arabian (GA) through ultrasound treatment to improve its bioactivity and bioavailability. The zein@T/GA nanoparticles were formed using ultrasonic treatment at 360 W for 5 min with a 59.9% T-encapsulation efficiency. In vitro digestion showed that the cumulative release rate of zein@T/GA nanoparticles reached a maximum of 80.69% after 6 h. In addition, short-term animal studies revealed that the nanoparticles had an effect on the levels of tissue glutathione and improved peptides' oral bioavailability. Conclusively, these findings suggest that the ultrasonicated polysaccharide/protein system is suitable for encapsulating active small molecular peptides. Furthermore, it provides a novel foundation for studying the bioavailability of active substances in functional foods.

Novel green chitosan-pectin gel beads for the removal of Cu(II), Cd(II), Hg(II) and Pb(II) from aqueous solution.

Chitosan-pectin gel beads (CPBs) were synthesized via a facile and green method and applied to remove heavy metals from aqueous solution. The structural characteristics of CPBs were investigated by SEM and FTIR, the mechanical strength of CPBs was measured by Texture Analyzer and the stability of CPBs was evaluated in acidic solution. To study the adsorption characteristics, the effect of pH, contact time, initial heavy metals concentration, temperature, adsorption mechanism and regeneration were systematically investigated. The adsorption kinetics fitted well pseudo-second-order model, and the adsorption isotherms were well described by Langmuir model. The maximum adsorption capacities of Cu(II), Cd(II), Hg(II) and Pb(II) were 169.4, 177.6, 208.5 and 266.5 mg/g, respectively. The adsorption-desorption experiments revealed that the CPBs exhibited a great reusability. Thus, the synthesized CPBs in this study had the potential to be utilized as an environment-friendly and green adsorbent for the removal of heavy metals.

Absorption and transport of a Mytilus edulis-derived peptide with the function of preventing osteoporosis.

The YPRKDETGAERT peptide (PME-1) identified from the Mytilus edulis proteins has been shown to promote the proliferation and differentiation of osteoblasts and it has good bone-forming activity in vitro. Further, PME-1 has been shown to prevent osteoporosis in vivo. PME-1 can be absorbed through the gastrointestinal tract, and the passing rate in monolayer Caco-2 cells was 6.57%. PME-1 can also enter the blood circulation and the concentration of PME-1 in serum reached the maximum, 61.06 ± 26.32 ng mL-1, 20 min after feeding. The multifunctional in vivo imager was used to further determine the distribution of the 5-FITC-(Acp)-YPRKDETGAERT peptide (PME-1-FITC) 2 h after feeding the peptide, and the result confirmed the above results and showed that a part of PME-1-FITC can affect bone in vivo. Therefore, PME-1 not only was easily absorbed in the gastrointestinal tract, but also has the potential beneficial effect on preventing osteoporosis.

Inhibition of immunotoxicity of Pb2+-induced RAW264.7 macrophages by selenium species in selenium-enriched rice.

Previous studies have revealed that Selenium-enriched rice protein hydrolysates (SPHs) could alleviate Pb2+-induced apoptosis in RAW264.7 macrophages. The purpose of the current study was to detect the effect of different selenium (Se) species on immunotoxicity of the Pb2+-induced RAW264.7 macrophages and explore the potential immunomodulatory mechanism. Herein, SPHs, an isolated SPHs fraction (SPHs-2), selenomethionine (SeMet), selenite (SeIV) were used to investigate their inhibitory effect and the impacts on the expression of cytokines and related protein kinases in immunomodulatory pathways. The results showed that, compared with Pb2+-only group, Se-containing components significantly enhanced the cell viability and effectively decrease nitric oxide (NO) content in Pb2+-induced RAW264.7 cells. Furthermore, compared with other Se species, SPHs-2 markedly decreased the secretion levels of pro-inflammatory cytokines TNF-α, NF-κB, IL-1ß, MyD88, IL-6 and IL-8. Western blot results demonstrated that SPHs-2 effectively downregulated the expressions of IκB, IKKα, p38, and Erk1/2, and also successfully blocked the phosphorylation of these protein kinases. Our findings suggested that SPHs-2 effectively attenuate inflammatory response and inhibit the immunotoxicity of Pb2+ on RAW264.7 macrophages via regulating NF-κB/MAPK signaling pathways.

Novel Anticoagulant Peptide from Lactoferrin Binding Thrombin at the Active Site and Exosite-I.

Thrombin is currently one of the important targets for the treatment and prevention of thrombosis. At present, there are few reports on the application of lactoferrin peptides in anticoagulation. In this study, a peptide with the amino acid sequence of LRPVAAEIY (LF-LR) derived from lactoferrin was shown to possess antithrombotic activity. LF-LR (5 mM) significantly prolonged activated partial thromboplastin time, prothrombin time, and thrombin time for 13.4, 1.7, and 5.1 s, respectively. It prolonged the coagulation time of fibrinogen from 15.3 ± 0.4 to 20.2 ± 0.5 s by affecting the conformation of thrombin. Using circular dichroism analysis, LF-LR can increase the α-helix content of thrombin from 25.6 to 56.7% and made the ß-sheet disappear. In addition, LF-LR also quenched fluorescence of thrombin at about 346 nm (λEx = 280 nm). By means of molecular docking, it was found that LF-LR could bind to both the active site and the exosite-I of thrombin, and the combined LYS60F, TRP60D, ASP189, LYS36, and ARG77A are typical amino acids in the two domains, respectively.

Effect of ultrasonic power on properties of edible composite films based on rice protein hydrolysates and chitosan.

Rice protein hydrolysates (RPH) are incapable of film formation by self-crosslinking due to low molecular mass. Hence, we used chitosan (CS) as a modifier and developed rice protein hydrolysates/chitosan (RPH/CS) edible composite films by means of ultrasound. Results showed that ultrasound treatment decreased the particle size and the viscosity of film-forming solutions. The value of elongation at break of composite films was increased by 125% at 400 W compared with untreated film. The peroxide value of soybean oil was significantly reduced from 16.99 ± 0.78 meq/kg to 2.23 ± 0.09 meq/kg with the increase of ultrasonic power. Ultrasound treatment was efficient in keeping smooth on surface, and the films at ultrasound treatment of 200 W had better compatibility. Moreover, hydrogen bonds and covalent interactions were probably the main forces between RPH and CS and contributed to film formation under ultrasound treatment, which supported by analyses of Fourier transform infrared spectroscopy and X-ray diffraction. These results suggested that ultrasound was an effective method to improve the properties of edible composite films.

Neuroprotective effects of two selenium-containing peptides, TSeMMM and SeMDPGQQ, derived from selenium-enriched rice protein hydrolysates on Pb2+-induced oxidative stress in HT22 cells.

Immunomodulatory peptides with the sequences TSeMMM and SeMDPGQQ from selenium (Se)-enriched rice protein hydrolysates (SPHs) were identified in our previous study. We synthesized these two peptides to study whether they have neuroprotective effects on Pb2+-induced oxidative stress in mouse hippocampal HT22 cells, SPHs and a purified SPH fraction (SPHs-2) were used to compare the effects. Peptides pretreatments significantly suppressed Pb2+-induced cytotoxicity by increasing cell viability and decreasing cell apoptosis. TSeMMM and SeMDPGQQ reduced nitric oxide (NO) levels by 37.47% and 14.72% of Pb2+ group, as well as lactate dehydrogenase (LDH) release by 12.98% and 6.32% of Pb2+ group. TSeMMM and SeMDPGQQ could increase the activities of antioxidant enzymes; for example, the activity of superoxide dismutase (SOD) increased by 47.79% and 13.93%, respectively, and that of glutathione peroxidase (GSH-Px) increased by 94.7% and 78.73% of Pb2+ group. Additionally, nuclear factor erythroid 2-related factor (Nrf2) nuclear translocation and heme oxygenase 1 (HO-1) expression were triggered. These results suggest that TSeMMM and SeMDPGQQ can suppress oxidative damage caused by Pb2+; moreover, TSeMMM showed better neuroprotective potential than SeMDPGQQ.

Potential neuroprotection of wheat alkylresorcinols in hippocampal neurons via Nrf2/ARE pathway.

5-n-Alkylresorcinols (ARs) are abundant in wheat bran and potentially antioxidative, although the neuroprotective mechanism is not fully understood. The neuroprotective effect of wheat bran ARs on H2O2-induced neuronal cells and the relationship between neuroprotection and the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant-response element (ARE) pathway were investigated in this study. Seven homologs were identified in the purified ARs by high-performance liquid chromatography-tandem mass spectrometry. Pretreatment with 80 µg mL-1 ARs alleviated 23% HT22 cell death and the up-regulation of intracellular reactive oxygen species level and malondialdehyde under H2O2 stimulation. The neuroprotection effect was proved by the increase in the Nrf2 nuclear location and up-regulation of mRNA and protein expressions of heme oxygenase-1, NAD(P)H quinone dehydrogenase 1, glutamate-cysteine ligase catalytic subunit, and glutamate-cysteine ligase modifier subunit l. Wheat bran ARs displayed a neuroprotective function, possibly by promoting the endogenous antioxidant defense system. ARs may be regarded as a functional food ingredient for preventing neurodegenerative diseases in the future.