Properties and functions of acylated starch with short-chain fatty acids: a comprehensive review.

Short-chain fatty acids (SCFAs) are the primary energy source of colonic epithelial cells, but oral SCFAs are digested, absorbed, or degraded before reaching the colon. The acylated starch with SCFAs can be fermented and release specific SCFAs under the action of colonic intestinal microbiota. This review first introduces the preparation method, reaction mechanism, and substitution factors. Second, the structure, physical and chemical properties, in vitro function, and mechanism of acylated starch were expounded. Finally, the application of acylated starch in foods is introduced, and its safety is evaluated, providing a basis for the further development of acylated starch-based foods. The acylated starch obtained by different acylation types and preparation methods is different in particle, molecular, and crystal structures, leading to changes in the function and physicochemical properties. Meanwhile, acylated starch has the functional potential of targeted delivery of SCFAs to the colon, which can increase SCFAs in feces and intestine, selectively regulate the intestinal microbiota, and produce a prebiotic effect conducive to host health. The safety of acetylated starch has been supported by relevant studies, which have been widely used in various food fields and have great potential in the food industry.

Effects of steam explosion pretreatment on the digestive properties and gut microbiota of Laminaria japonica polysaccharide.

BACKGROUND: Laminaria japonica polysaccharide, which is an important bioactive substance of Laminaria japonica with anti-inflammatory and antioxidant effects. In this study, the molecular weight, functional groups and surface morphology were investigated to evaluate the digestive properties of Laminaria japonica polysaccharide before and after steam explosion. RESULTS: The results indicated that the Laminaria japonica polysaccharide entered the large intestine to be utilized by the gut microbiota after passing through the oral, gastric and small intestinal. Meanwhile, Laminaria japonica polysaccharide of steam explosion promoted the growth of beneficial bacteria Phascolarctobacterium and Intestinimonas, and increased the content of acetic, propionic and butyric acids, which was 2.29-folds, 2.60-folds and 1.63-folds higher than the control group after 48 h of fermentation. CONCLUSION: This study reveals that the effect of steam explosion pretreatment on the digestion in vitro and gut microbiota of Laminaria japonica polysaccharide will provide a basic theoretical basis for the potential application of Laminaria japonica polysaccharide as a prebiotic in the food industry. © 2024 Society of Chemical Industry.

Prokaryotic Expression, Purification, and Antibacterial Activity of the Hepcidin Peptide of Crescent Sweetlips (Plectorhinchus cinctus).

The hepcidin peptide of crescent sweetlips (Plectorhinchus cinctus) is a cysteine-rich, cationic antimicrobial peptide that plays a crucial role in the innate immune system's defense against invading microbes. The aim of this study was to identify the optimal parameters for prokaryotic expression and purification of this hepcidin peptide and characterize its antibacterial activity. The recombinant hepcidin peptides were expressed in Escherichia coli strain Arctic Express (DE3), with culture and induction conditions optimized using response surface methodology (RSM). The obtained hepcidin peptides were then purified before tag cleavage, and their antibacterial activity was determined. The obtained results revealed that induction temperature had the most significant impact on the production of soluble recombinant peptides. The optimum induction conditions were determined to be an isopropylthio-ß-galactoside (IPTG) concentration of 0.21 mmol/L, induction temperature of 18.81 °C, and an induction time of 16.01 h. Subsequently, the recombinant hepcidin peptide was successfully purified using Ni-IDA affinity chromatography followed by SUMO protease cleavage. The obtained hepcidin peptide (without His-SUMO tag) demonstrated strong antimicrobial activity in vitro against V. parahaemolyticus, E. coli, and S. aureus. The results showed prokaryotic (E. coli) expression is a feasible way to produce the hepcidin peptide of crescent sweetlips in a cost-effective way, which has great potential to be used as an antimicrobial agent in aquaculture.

Marine glycoproteins: a mine of their structures, functions and potential applications.

Many bioactive compounds are reported from marine organisms, which are significantly different from those found in terrestrial organisms regarding their chemical structures and pharmacological activities. Marine glycoproteins (MGs) have aroused increasing attention as a good nutrient source owing to their potential applications in medicine, cosmetics and food. However, there is a lack of a comprehensive study on MGs to help readers understand the current state of research on marine-derived glycoproteins. The current review compiles the recent progress made on the structures and functions of MGs with future perspectives to maximize their value and applications via bibliometric analysis methods for the first time. The current research on MGs appears mostly limited to the laboratory, with no large-scale production of marine glycoproteins developed. The sugar chains are bound to proteins through covalent bonds that can readily be cleaved leading to difficultly in their separation and purification. Health effects attributed to MGs include treatment of inflammatory diseases, as well as anti-oxidant, immune modulation, anti-tumor, hypolipidemic, hypoglycemic, anti-bacterial and anti-freeze activities. This review can not only deepen the understanding of the functions of MGs, but also lay an important foundation for the further development and utilization of marine resources.

Overview on isolation, structural and functional properties of marine glycoproteins (MGs) via bibliometric analysis methods for the first time.Marine glycoproteins (MGs) have various biological activities and potential health applications.glycoproteins from marine organisms (MGs) significantly enhanced anti-oxidant and anti-inflammatory activities.

Polyoxometalate K6[P2Mo18O62] Inactivates Escherichia coli O157:H7 by Inducing recA Expression and Apoptosis-like Bacterial Death.

Polyoxometalates have emerged as promising bactericidal agents. In the current study, the bactericidal activity of polyoxometalate K6[P2Mo18O62] against Escherichia coli (E. coli) O157:H7 and its possible underlying mechanisms were explored. The obtained results demonstrated that K6[P2Mo18O62] could effectively kill E. coli O157:H7 at millimolar levels. Moreover, K6[P2Mo18O62] treatment also induced significant increases in recA protein expression and further triggered characteristic apoptosis-like bacterial death events such as DNA fragmentation and phosphatidylserine exposure. In conclusion, polyoxometalate K6[P2Mo18O62] possesses a desirable antibacterial activity, and induction of bacterial apoptosis-like death might be involved in its underlying bactericidal mechanisms.

Anti-Aging Effects of R-Phycocyanin from Porphyra haitanensis on HUVEC Cells and Drosophila melanogaster.

Aging has become a global public health challenge. Many studies have revealed that the excessive generation of ROS and oxidative stress could be the major causative factors contributing to aging. In this study, R-phycocyanin (R-PC) was isolated from Porphyra haitanensis, and its anti-aging ability was explored by natural aging Drosophila melanogaster and H2O2-induced HUVEC cells as the aging model. Results showed that R-PC α and ß subunits expressed have antioxidant activity and can inhibit the generation of radicals, exhibiting a protective effect against H2O2-induced apoptotic HUVEC cells death. R-PC prevented the H2O2-induced HUVEC cell cycle phase arrest by regulating cell cycle-related protein. Furthermore, R-PC prevented the H2O2-induced HUVEC cell cycle phase arrest by regulating cell-cycle-related protein expression. In vivo study also indicated that R-PC significantly increased the survival time and alleviated the oxidative stress of Drosophila melanogaster. Moreover, R-PC notably decreased levels of ROS in natural aging flies and inhibited lipid peroxidation by enhancing the expressions of the endogenous stress marker genes (SOD1, SOD2, CAT of Drosophila melanogaster). Taken together, a study on the antioxidation extract from Porphyra haitanensis, such as R-PC, may open a new window for the prevention of anti-aging.

High-Amylose Corn Starch Regulated Gut Microbiota and Serum Bile Acids in High-Fat Diet-Induced Obese Mice.

High-amylose corn starch is well known for its anti-obesity activity, which is mainly based on the regulatory effects on gut microbiota. Recently, the gut microbiota has been reported to improve metabolic health by altering circulating bile acids. Therefore, in this study, the influence of high-amylose corn starch (HACS) on intestinal microbiota composition and serum bile acids was explored in mice fed with a high fat diet (HFD). The results demonstrated HACS treatment reduced HFD-induced body weight gain, hepatic lipid accumulation, and adipocyte hypertrophy as well as improved blood lipid profiles. Moreover, HACS also greatly impacted the gut microbiota with increased Firmicutes and decreased Bacteroidetes relative abundance being observed. Furthermore, compared to ND-fed mice, the mice with HFD feeding exhibited more obvious changes in serum bile acids profiles than the HFD-fed mice with the HACS intervention, showing HACS might restore HFD-induced alterations to bile acid composition in blood. In summary, our results suggested that the underlying mechanisms of anti-obesity activity of HACS may involve its regulatory effects on gut microbiota and circulating bile acids.

Proteomic analysis of body wall and coelomic fluid in Sipunculus nudus.

In order to make clear the protein compositions of Sipunculus nudus and investigate its immune-related proteins, proteomic analysis was performed on body wall and coelomic fluid of Sipunculus nudus. A total of 1659 proteins were identified, and 539 proteins were differentially expressed in the coelomic fluid compared to those in the body wall, of which 415 proteins were up-regulated while 124 proteins were down-regulated. Gene Ontology (GO) analysis showed that the GO terms involved in the two parts of Sipunculus nudus were similar, with metabolic processes, catalytic activity and cell occupying the top categories of biological process, molecular function and cellular component, respectively. KEGG pathway analysis showed that 49 pathways in body wall and 48 in coelomic fluid were mapped respectively, and these pathways were mainly related to cellular processes, environmental information processing, genetic information processing and metabolism. The COG analysis showed that 757 proteins from body wall and 889 from coelomic fluid were classified into 26 COG categories, respectively. Pfam annotation revealed the mainly immune-related proteins contained in Sipunculus nudus, such as insulin-like growth factor binding protein, catalase, basement membrane proteoglycan, titin. Our research provides the first proteomic information of Sipunculus nudus, which contributes to the study of functional proteins in Sipunculus nudus and is of great significance for the application of Sipunculus nudus in functional foods and medicines.

Application of X-ray diffraction and energy dispersive spectroscopy in the isolation of sulfated polysaccharide from Porphyra haitanensis and its antioxidant capacity under in vitro digestion.

BACKGROUND: The separation and purification of Porphyra haitanensis polysaccharide (PHP), and the determination of changes in molecular weight (Mw) and antioxidant capacity after in vitro digestion, were undertaken. RESULTS: Analysis of two polysaccharide fractions (PHP0.5-1-UF and PHP1.0-1-UF) by various techniques showed that they were very pure sulfated polysaccharides without pigment or protein. PHP0.5-1-UF was filamentous or 'tape-like' sheets, whereas PHP1.0-1-UF had some filaments and large numbers of rounded aggregates. The Mw of PHP, PHP0.5-1-UF and PHP1.0-1-UF was 2.06 × 106 (±2.02%), 6.68 × 106 (±3.17%), and 1.14 × 106 (±3.44%) (g mol-1 ), respectively. After in vitro digestion, the Mw of PHP, PHP0.5-1-UF, and PHP1.0-1-UF decreased. Their antioxidant capacities were markedly higher than before digestion, especially PHP0.5-1-UF and its digestion products, which might be related to the reductions in Mw. CONCLUSION: These findings provide a greater understanding of the separation and purification of sulfated polysaccharides and the influence of digestion on biological activity. They also contribute to the practical application of sulfated polysaccharides in functional foods. © 2021 Society of Chemical Industry.

Structural and physicochemical properties of lotus seed starch-chlorogenic acid complexes prepared by microwave irradiation.

Lotus seed (LS) has a high starch content and possesses many useful functional properties, which are mainly attributed to its phenolic compound content. The objective of this study was to investigate the effect of microwave irradiation (MW) treatment on the structural and physicochemical properties of a lotus seed starch-chlorogenic acid (CA) blend. MW treatment appeared to promote the formation of LS-CA complexes and the modified starch displayed more rougher structures than native starch. The particle size distribution of starch remained approximately constant when the microwave power was 200 W, but increased sharply with further increases in microwave power; a similar trend was observed in the swelling and solubility of starch. XRD and FT-IR spectra show that MW treatment degraded the ordered crystalline structure of starch, facilitating exposure of the starch chains originally buried in the crystalline and amorphous regions within the grains. During this treatment, CA interacted with starch molecules by hydrogen bonding and form a LS-CA complex, which inhibited the self-assembly process of starch chains. These findings demonstrated the potential use of MW treatment in controlling the storage and processing quality of lotus seed, or other starchy foods rich in polyphenols.

Preparation of "Ion-Imprinting" Difunctional Magnetic Fluorescent Nanohybrid and Its Application to Detect Cadmium Ions.

In this work, we have fabricated a novel difunctional magnetic fluorescent nanohybrid (DMFN) for the determination of cadmium ions (Cd2+) in water samples, where the "off-on" model and "ion-imprinting" technique were incorporated simultaneously. The DMFN were composed of CdTe/CdS core-shell quantum dots (QD) covalently linked onto the surface of polystyrene magnetic microspheres (PMM) and characterized using ultraviolet-visible spectroscopy (UV-Vis), fluorescence spectroscopy, and transmission electron microscopy (TEM). Based on the favorable magnetic and fluorescent properties of the DMFN, the chemical etching of ethylene diamine tetraacetic acid (EDTA) at the surface produced specific Cd2+ recognition sites and quenched the red fluorescence of outer CdTe/CdS QD. Under optimal determination conditions, such as EDTA concentration, pH, and interfering ions, the working curve of determining Cd2+ was obtained; the equation was obtained Y = 34,759X + 254,894 (R = 0.9863) with a line range 0.05-8 µM, and the detection limit was 0.01 µM. Results showed that synthesized magnetic fluorescent microspheres had high sensitivity, selectivity, and reusability in detection. Moreover, they have significant potential value in fields such as biomedicine, analytical chemistry, ion detection, and fluorescence labeling.

Lotus seed skin proanthocyanidin extract exhibits potent antioxidant property via activation of the Nrf2-ARE pathway.

Lotus seed is well known as traditional food and medicine, but its skin is usually discarded. Recent studies have shown that lotus seed skin contains a high concentration of proanthocyanidins that have multi-functions, such as antioxidation, anti-inflammation, and anti-cancer effects. In the present study, we aimed to isolate and purify the proanthocyanidins from lotus seed skin by acetone extraction and rotary evaporation, identify their chemical structures by HPLC-MS-MS and NMR, and further investigate the antioxidant properties of the extract purified by macroporous resin (PMR) from lotus seed skin both in vitro and in vivo. The results showed that PMR mainly contained oligomeric proanthocyanidins, especially dimeric procyanidin B1 (PB1), procyanidin B2 and procyanidin B4. Although it had limited ability to directly scavenge radicals in vitro, PMR could significantly enhance the expressions of antioxidant proteins via activation of nuclear factor-E2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway in HepG2 cells. Molecular data revealed that PB1, a major component in PMR, stabilized Nrf2 by inhibiting the ubiquitination of Nrf2, which led to subsequent activation of the Nrf2-ARE pathway, including the enhancements of Nrf2 nuclear translocation, Nrf2-ARE binding and ARE transcriptional activity. Moreover, the in vivo results in high fat diet-induced mice further verified the powerful antioxidant property of PMR. These results revealed that lotus seed skin is a promising resource for functional food development.

Inhibition Effect of Triglyceride Accumulation by Large Yellow Croaker Roe DHA-PC in HepG2 Cells.

The phospholipids (PLs) of large yellow croaker (Pseudosciaena crocea, P. crocea) roe contain a high level of polyunsaturated fatty acids, especially docosahexaenoic acid (DHA), which can lower blood lipid levels. In previous research, PLs of P. crocea roe were found able to regulate the accumulation of triglycerides. However, none of these involve the function of DHA-containing phosphatidylcholine (DHA-PC), which is the main component of PLs derived from P. crocea roe. The function by which DHA-PC from P. crocea roe exerts its effects has not yet been clarified. Herein, we used purified DHA-PC and oleic acid (OA) induced HepG2 cells to establish a high-fat model, and the cell activity and intracellular lipid levels were then measured. The mRNA and protein expression of Fatty Acid Synthase (FAS), Carnitine Palmitoyl Transferase 1A (CPT1A) and Peroxisome Proliferator-Activated Receptor α (PPARα) in HepG2 cells were detected via RT-qPCR and western blot as well. It was found that DHA-PC can significantly regulate triglyceride accumulation in HepG2 cells, the effect of which was related to the activation of PPARα receptor activity, upregulation of CPT1A, and downregulation of FAS expression. These results can improve the understanding of the biofunction of hyperlipidemia mediated by DHA-PC from P. crocea roe, as well as provide a theoretical basis for the utilization of DHA-PC from P. crocea roe as a functional food additive.

Ratiometric Fluorescent Nanoprobe for Highly Sensitive Determination of Mercury Ions.

In this study, a novel dual-emission ratiometric fluorescent nanoprobe (RFN) was synthesized and ultilized for highly sensitive determination of mercury ions. In this nanoprobe, fluorescein isothiocyanate (FITC) doped silica (SiO2) served as a reference signal, FITC-SiO2 microspheres were synthesized and modified with amino groups, and then Au Nanoclusters (AuNCs) were combined with the amino groups on the surface of the FITC-SiO2 microspheres to obtain the RFN. The selectivity, stability, and pH of the RFN were then optimized, and the determination of mercury ions was performed under optimal conditions. The probe fluorescence intensity ratio (F520 nm/F680 nm) and Hg2+ concentration (1.0 × 10-10 mol/L to 1.0 × 10-8 mol/L) showed a good linear relationship, with a correlation coefficient of R2 = 0.98802 and a detection limit of 1.0 × 10-10 mol/L, respectively. The probe was used for the determination of trace mercury ion in water samples, and the recovery rate was 98.15~100.45%, suggesting a wide range of applications in monitoring pollutants, such as heavy metal ion and in the area of environmental protection.

Modified xanthan gum for crystal violet uptake: kinetic, isotherm, and thermodynamic behaviors.

Modified xanthan gum (XG-AM-TTE) was employed as an adsorbent to study the adsorption behavior, thermodynamics and kinetics of crystal violet (CV) from an aqueous solution. Fourier transform infrared spectroscopy analysis indicates that the functional groups present in the adsorbent, such as carboxyl, ester and hydroxyl groups, are included on the external surface of the material, and these groups are potential active sites for interaction with CV. According to X-ray diffraction results, the structure of XG-AM-TTE after CV adsorption became more disordered, and the microstructure change is an indication of effective adsorption of CV to the surface, with CV becoming remarkably dispersed in the adsorbent according to the scanning electron microscopy observations. The adsorption kinetics and adsorption equilibrium were best described by the pseudo-second-order model and Freundlich isotherms, respectively. The thermodynamic parameters, as the Gibbs-free energy (ΔG), enthalpy (ΔH) and entropy (ΔS), indicated that the adsorption is a spontaneous, endothermic and entropy increase process. The maximum adsorption capacity of XG-AM-TTE was 183 ± 12 mg/g, suggesting that XG-AM-TTE is an efficient adsorbent.

Short-chain fatty acids in control of energy metabolism.

Short-chain fatty acids (SCFAs), especially acetate, propionate and butyrate, are the end products from the intestinal microbial fermentation of dietary fibers and resistant starch. It has been well documented that plasma and colonic SCFAs are associated with metabolic syndromes. Recently, the involvement of SCFAs in energy homeostasis regulation has been extensively studied. The importance of SCFAs on energy metabolism has highlighted the potential of modulating SCFAs as a nutritional target to prevent and counteract metabolism disorders and its associated diseases such as obesity and type 2 diabetes. Here, we summarize the current knowledge about the biological properties of SCFAs with their impact on the energy homeostasis.

Phenotypic, fermentation characterization, and resistance mechanism analysis of bacteriophage-resistant mutants of Lactobacillus delbrueckii ssp. bulgaricus isolated from traditional Chinese dairy products.

Bacteriophage infection is a large factor in dairy industrial production failure on the basis of pure inoculation fermentation, and developing good commercial starter cultures from wild dairy products and improving the environmental vigor of starter cultures by enhancing their phage resistance are still the most effective solutions. Here we used a spontaneous isolation method to obtain bacteriophage-resistant mutants of Lactobacillus delbrueckii ssp. bulgaricus strains that are used in traditional Chinese fermented dairy products. We analyzed their phenotypes, fermentation characteristics, and resistance mechanisms. The results showed that bacteriophage-insensitive mutants (BIM) BIM8 and BIM12 had high bacteriophage resistance while exhibiting fermentation and coagulation attributes that were as satisfying as those of their respective parent strains KLDS1.1016 and KLDS1.1028. According to the attachment receptor detection, mutants BIM8 and BIM12 exhibited reduced absorption to bacteriophage phiLdb compared with their respective bacteriophage-sensitive parent strains because of changes to the polysaccharides or teichoic acids connected to their peptidoglycan layer. Additionally, genes, including HSDR, HSDM, and HSDS, encoding 3 subunits of a type I restriction-modification system were identified in their respective parent strains. We also discovered that HSDR and HSDM were highly conserved but that HSDS was variable because it is responsible for the DNA specificity of the complex. The late lysis that occurred only in strain KLDS1.1016 and not in strain KLDS1.1028 suggests that the former and its mutant BIM8 also may have an activatable restriction-modification mechanism. We conclude that the L. bulgaricus BIM8 and BIM12 mutants have great potential in the dairy industry as starter cultures, and their phage-resistance mechanism was effective mainly due to the adsorption interference and restriction-modification system.

Effect of Maternal Administration of Edible Bird's Nest on the Learning and Memory Abilities of Suckling Offspring in Mice.

Although human brains continue developing throughout the underage developmental stages, the infancy period is considered the most important one for the whole life. It has been reported that sialic acid from edible bird's nest (EBN) can facilitate the development of brain and intelligence. In this study, by oral administration of EBN to female mice during the pregnancy or lactation period, the effects of EBN on the levels of sialic acid in mouse milk were determined using high-performance liquid chromatography (HPLC). Furthermore, the spatial learning performances of their offspring were assessed using the Morris water maze test. Additionally, cerebral malondialdehyde (MDA), superoxide dismutase (SOD), choline acetyltransferase (ChAT), and acetylcholinesterase (AChE) in cubs nursed by the female mice given the EBN homogenate were examined, while BDNF immunohistochemical staining and neuron count in hippocampi were investigated as well. These results showed that administration with EBN in maternal mice during pregnancy or lactation period can improve the learning and memory functions in their offspring, possibly by increasing the activities of SOD and ChAT and, at the meantime, decreasing the levels of MDA and activities of AChE. Moreover, BDNF levels for CA1, CA2, and CA3 regions in hippocampi and the numbers of dyed neurons in CA1, CA2, CA3, and DG regions among the offspring were significantly enhanced due to the intake of EBN by the maternal mice. We concluded that maternal administration of EBN during the pregnancy and lactation periods can improve the spatial learning performances in the offspring.

Effect of A Polyphenol-Rich Canarium album Extract on the Composition of the Gut Microbiota of Mice Fed a High-Fat Diet.

This study investigated the influence of Canarium album extract (CAext) on intestinal microbiota composition of mice fed a high-fat diet (HFD). Kun Ming (KM) mice were fed either a normal chow diet or a HFD for six weeks. At the seventh week, HFD-fed mice were gavaged daily with saline, or a different dose of CAext for four weeks, respectively. Then, the composition of the gut microbiota was analyzed by high-throughput sequencing technology. Analysis of fecal microbial populations, grouped by phyla, showed significant increases of Firmicutes and Verrucomicrobia, but a decrease of Bacteroidetes in all CAext-fed mice. Particularly, CAext gavage in a low dose or a medium dose caused a significant increase in the proportion of Akkermansia. These findings suggested that CAext can alter the gut microbiota composition of HFD-fed mice, and had a potential prebiotic effects on Akkermansia.

In Vitro Antioxidant Activity and In Vivo Anti-Fatigue Effect of Sea Horse (Hippocampus) Peptides.

This study investigated changes the in vitro antioxidant activity of Hippocampus polypeptides during enzymatic hydrolysis, including the effects of enzyme species, enzyme concentration, material-liquid ratio, hydrolysis time, pH, and temperature of the reaction system. Its in vivo anti-fatigue activity was also studied. Hippocampus peptide prepared by papain digestion exhibited the highest 1,1-diphenyl-2-picryl-hydrazyl free radical scavenging rate (71.89% ± 1.50%) and strong hydroxyl radical scavenging rate (75.53% ± 0.98%), compared to those prepared by five other commonly used enzymes (i.e., trypsin, neutral protease, compound protease, flavorzyme, and alkaline protease). Additionally, maximum antioxidant activity of Hippocampus polypeptide prepared by papain digestion was reached after hydrolysis for 40 min at pH 6.0 and 60 °C of the reaction system by using 2000 U/g enzyme and a material-liquid ratio of 1:15. Moreover, compared with the control group, Hippocampus peptide prolonged the swimming time by 33%-40%, stabilized the blood glucose concentration, increased liver glycogen levels, and decreased blood lactate levels and blood urea nitrogen levels in mice (p < 0.01). In conclusion, these results indicated that Hippocampus polypeptide prepared by papain digestion under optimal conditions exhibited high degrees of antioxidant and anti-fatigue activity.