Anti-fatigue activity of sea cucumber peptides prepared from Stichopus japonicus in an endurance swimming rat model

EPA-enriched lipid from Apostichopus japonicus byproducts mitigates UVB-induced oxidative stress and inflammation by gut-skin axis

The tremendous byproducts from sea cucumber processing discarded as waste bring serious environmental and economic challenges. The abundant EPA in sea cucumber intestines indicates the potential for lipid development. However, there is little study on how these lipids affect skin health. Using REM techniques, this study prepared lipids from Apostichopus japonicus intestines (AJIL) with a 26.63 % EPA content, which displayed DPPH scavenging capacity in vitro. Administration of AJIL showed significant skin repair effects by reducing the symptoms of UVB-induced skin tissue damage, preventing epidermal thickening and increasing hydroxyproline content to protect collagen. AJIL suppressed oxidative stress and inflammation by significantly reducing ROS and MDA levels and enhancing GPx and CAT activity, as well as inhibiting the expression of inflammatory cytokines such as TNF-α, NF-κB, IL-1β and IL-6. By upregulating Nrf2, HO-1 and NQO-1 and downregulating Keap1, AJIL activated the Keap1-Nrf2 signaling pathways. Furthermore, AJIL regulated the composition and structure of gut microbiome, especially significantly increasing the SCFA-producing and anti-inflammatory bacteria like Muribacuclaceae, Alloprevotella, Bacteroides and Prevotellaceae, then improved key metabolic pathways. Overall, AJIL mediated the gut-skin axis to prevent UVB-induced skin damage and revealed potential as a natural skin protection candidate, which transformed discarded sea cucumber intestines into valuable resources for skin health.

Quinoa protein and its hydrolysate improve the fatigue resistance of mice: a potential mechanism to relieve oxidative stress and inflammation and improve energy metabolism

Fatigue is commonly marked by reduced endurance and impaired function, often linked to overexertion and chronic conditions. Quinoa (Chenopodium quinoa Willd.), with its rich amino acids and resilience to harsh conditions, offers a novel strategy for combating fatigue. This study explored the antifatigue effects of quinoa protein (QPro) and its hydrolysate (QPH) in weight-loaded swimming mice. After 4 weeks of oral administration, QPro and QPH significantly prolonged swimming duration, reduced serum fatigue biomarkers (lactic acid, urea nitrogen, lactate dehydrogenase, creatine kinase), and elevated glycogen reserves in the liver and muscle. RT-qPCR analysis indicated that QPH activated hepatic gluconeogenesis via G6Pase and PEPCK signaling and enhanced mitochondrial function through PGC-1α/NRF1/TFAM signaling in muscle. Additionally, QPro and QPH boosted antioxidant defenses by improving antioxidant enzyme activity, reducing malondialdehyde through the Nrf2/HO-1 pathway, and suppressing inflammation by reducing TNF-α and IL-6 levels. Network pharmacology identified 31 key targets involved in energy metabolism and inflammation, providing novel insights into the molecular mechanisms underlying the antifatigue properties of quinoa peptides. These findings highlight the potential of QPro and QPH as natural and bioactive ingredients in functional foods for enhancing endurance and mitigating fatigue.

Cucumaria frondosa intestines and ovum hydrolysates intervention ameliorates the symptoms of dextran sulfate sodium-induced colitis by modulating gut microbiota and its metabolites

Colitis, a troublesome inflammatory disease that significantly impacts daily life, has garnered considerable attention in recent times. Protolysates play a crucial role in the treatment of colitis, and the intestines and ovum of Cucumaria frondosa represent a readily available source of these hydrolysates. However, the effects of C. frondosa intestines and ovum hydrolysates (CFHs) on colitis have not been thoroughly investigated. We initially examined the molecular weight distribution of CFHs and found that the fraction of molecules with a weight less than 1000 Da accounted for 86.98%, indicating that the hydrolysis primarily produced oligopeptides. Subsequently, we employed a dextran sulfate sodium-induced experimental colitis model to assess the therapeutic potential of CFHs. The findings indicated that preventive administration of CFHs dramatically attenuated the pathological manifestations associated with colitis in mice, including weight loss, colon shortening, and tissue damage. Furthermore, CFHs suppressed the secretion of pro-inflammatory cytokines IL-6, TNF-α, and IL-1β, as well as MPO in colon tissue. Metagenomic sequencing demonstrated that CFHs could restore balance to the dysregulated gut microbiota by reinforcing Bacteroidota and suppressing Verrucomicrobia populations, impacting various microbial functions. Metabolomic analyses further revealed that CFHs exhibited a more efficacious modulatory effect on DSS-induced metabolic abnormalities, including amino acid biosynthesis, linoleic acid metabolism, and dopaminergic synapses. In conclusion, CFHs showed promise in alleviating colitis, laying the groundwork for the development and application of CFHs as functional food for colitis relief.

Characteristics, Antioxidant Activity Stability, and Anti-Fatigue Activity of Hydrolysates from Cucumaria frondosa Tentacles

This study aimed to assess the impact of alcalase, trypsin, flavourzyme, and neutrase on the characteristics, antioxidant activity stability, and anti-fatigue activity of hydrolysates derived from Cucumaria frondosa tentacles (CFTHs). The results demonstrate that favourzyme hydrolysates exhibited the highest degree of hydrolysis (DH). Zeta potential and particle size measurements indicated that hydrolyzed peptides treated with favourzyme appeared aggregated and exhibited larger particle sizes. The antioxidant properties of CFTHs demonstrated good thermal stability, pH stability, and enhanced simulated gastrointestinal digestive stability. The anti-fatigue activity of CFTHs was examined using an acute exercise fatigue model. The results indicate that CFTHs extended the exhaustive swimming time of mice to 17.81 min. Additionally, CFTHs significantly elevated (p < 0.01) blood glucose (Glu) and liver glycogen (LG) levels, while also decreasing (p < 0.05) the concentrations of metabolites such as lactic acid (LA), urea nitrogen (BUN), creatine kinase (CK), lactate dehydrogenase (LDH), and ammonia (NH3). This reduction contributed to the alleviation of fatigue in the body. Furthermore, the levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were significantly increased (p < 0.05), which aided in mitigating oxidative damage induced by strenuous exercise. These findings strongly support the potential utilization of CFTHs in food products as natural antioxidant and anti-fatigue alternatives.

Progress in Preparation Technology and Functional Research On Marine Bioactive Peptides

Marine bioactive peptides are a class of peptides derived from marine organisms that can optimize the body's metabolic environment and benefit the body's health. These peptides have attracted increasing amounts of attention due to their wide range of health-promoting effects. Additionally, they have the potential to ameliorate diseases such as hypertension, diabetes, influenza viruses, and inflammation and can be used as functional foods or nutritional supplements for the purpose of treating or alleviating diseases. This paper reviews the recent research progress on marine bioactive peptides, focusing on their production technologies and functions in biomaterials and drug development.

Anti-Fatigue Activity of Corn Protein Hydrolysate Fermented by Lactic Acid Bacteria

OBJECTIVES

This study aimed to clarify the effect of lactic acid bacteria-fermented corn protein hydrolysate (FCH) on fatigue in mice and explore the connection between fatigue-related indicators and intestinal microbial flora.

METHODS

The fatigue model of mice was constructed by exercise endurance experiment. The anti-fatigue level of FCH was evaluated by measuring physiological and biochemical indexes in mouse serum, liver and skeletal muscle. The relationship between FCH, intestinal flora and fatigue was explored through the analysis of intestinal microbial diversity in mice, and the anti-fatigue mechanism of FCH was further analyzed.

RESULTS

The results showed that the weight-bearing swimming time of mice was prolonged by 1.96 times, and the running time of mice was prolonged by 2.63 times in the high-dose FCH (FCH-H) group. Moreover, the lactic acid contents in the blood were reduced by 16.00%, and lactate dehydrogenase activity and urea nitrogen contents basically returned to the normal level. Meanwhile, the malondialdehyde contents were reduced by 31.24%, and superoxide dismutase activity and glutathione contents were increased by 1.84 times and 1.72 times, respectively. In addition, the glycogen contents of the body were restored, and the muscle glycogen and liver glycogen were increased by 1.81 and 5.81 times, respectively. Analysis of intestinal microbial flora diversity in mice showed that the highest relative abundance was Lactobacillus, and the FCH group could recover and even increase its relative abundance. Lactobacillus was significantly positively correlated with muscle glycogen and SOD.

CONCLUSIONS

FCH can alleviate fatigue by regulating fatigue-related indicators and improving the intestinal microbial flora of the organism.

Review: Application of Protein-Based Raw Materials in Health Foods in China

Raw protein materials are beneficial for human health, so they are being increasingly used in health foods. In recent years, there has been more and more research on and applications of raw protein materials, but few teams have conducted a detailed review of the application status of raw protein materials in China's health foods, the basis for their compliance and use, and the research on their health care functions. Therefore, this review evaluates the application of animal and plant proteins in China's health foods, the impact of animal and plant proteins on human health, and future research recommendations for animal and plant proteins. This review analyzes and discusses the data on approved health foods that have been verified to contain raw protein materials (mainly including the number of protein health foods approved over the years, the classification of raw protein materials and types of relevant regulations, the analysis of the frequency of use of raw protein materials, and the functions of approved health foods). Through this process, the application of raw protein materials in health foods in China is systematically reviewed. In short, through data analysis, this study found that in 1996~2024, a total of 1142 health foods containing raw protein materials were approved in China, which are mainly divided into animal proteins, vegetable proteins, microbial proteins, and peptide raw materials, and peptide raw materials comprise the majority. The compliance applications of these ingredients are mainly related to China's five categories of food regulations. The results show the following for health foods containing raw protein materials: in terms of the dosage form, they are mainly solid preparations; according to their functional claims, they mainly help to enhance immunity, help improve bone density, help improve skin moisture, and relieve physical fatigue; and in the application of raw materials, it is found that the use of raw materials such as casein phosphopeptide, soybean protein isolate, whey protein, collagen, spirulina, and other raw materials in products is relatively high. Finally, based on these studies, this paper discusses suggestions for raw protein materials in the future development of health food in China and also discusses the limitations of the current research in this review.

Matrikines of Sea Cucumbers: Structure, Biological Activity and Mechanisms of Action

Matrikines (MKs), the products of enzymatic fragmentation of various extracellular matrix (ECM) proteins, regulate cellular activity by interacting with specific receptors. MKs affect cell growth, proliferation, and migration, can induce apoptosis and autophagy, and are also effectively used in biomedicine and functional nutrition. Recently, there has been great interest in the structural features and biological activity of MKs from various sources. This review summarized and analyzed the results of modern research on MKs from sea cucumbers, primarily from trepang (MKT). Particular attention is paid to the analysis of the existing knowledge on the antioxidant, anti-inflammatory and adaptogenic activities of these MKs and the possible mechanisms of their protective action.

Advances in relieving exercise fatigue for curcumin: Molecular targets, bioavailability, and potential mechanism

Intense and prolonged physical activity can lead to a decrease in muscle capacity, making it difficult to maintain the desired exercise intensity and resulting in exercise fatigue. The long-term effects of exercise fatigue can be very damaging to the body, so it is an urgent problem to be addressed. The intervention of foodborne active substances will be an effective measure. There is growing evidence that the molecular structure and function of curcumin have a positive effect on relieving fatigue. In this review, we summarize curcumin's molecular structure, which enables it to bind to a wealth of molecular targets, regulate signaling pathways, and thus alleviate exercise fatigue through a variety of mechanisms, including reducing oxidative stress, inhibiting inflammation, reducing metabolite accumulation, and regulating energy metabolism. The effects of curcumin on fatigue-related markers were analyzed from the perspective of animal models and human models and based on the bidirectional interaction between curcumin and intestinal microbiota: Intestinal microbiota can transform curcumin, and curcumin regulates gut microbiota through metabolic pathways, providing a new perspective for alleviating fatigue. This review contributes to a more comprehensive understanding of the possible molecular mechanisms of curcumin in anti-fatigue and provides a new possibility for the development of functional foods in the future.

Systematical Investigation on Anti-Fatigue Function and Underlying Mechanism of High Fischer Ratio Oligopeptides from Antarctic Krill on Exercise-Induced Fatigue in Mice

High Fischer ratio oligopeptides (HFOs) have a variety of biological activities, but their mechanisms of action for anti-fatigue are less systematically studied at present. This study aimed to systematically evaluate the anti-fatigue efficacy of HFOs from Antarctic krill (HFOs-AK) and explore its mechanism of action through establishing the fatigue model of endurance swimming in mice. Therefore, according to the comparison with the endurance swimming model group, HFOs-AK were able to dose-dependently prolong the endurance swimming time, reduce the levels of the metabolites (lactic acid, blood urea nitrogen, and blood ammonia), increase the content of blood glucose, muscle glycogen, and liver glycogen, reduce lactate dehydrogenase and creatine kinase extravasation, and protect muscle tissue from damage in the endurance swimming mice. HFOs-AK were shown to enhance Na+-K+-ATPase and Ca2+-Mg2+-ATPase activities and increase ATP content in muscle tissue. Meanwhile, HFOs-AK also showed significantly antioxidant ability by increasing the activities of superoxide dismutase and glutathione peroxidase in the liver and decreasing the level of malondialdehyde. Further studies showed that HFOs-AK could regulate the body's energy metabolism and thus exert its anti-fatigue effects by activating the AMPK signaling pathway and up-regulating the expression of p-AMPK and PGC-α proteins. Therefore, HFOs-AK can be used as an auxiliary functional dietary molecules to exert its good anti-fatigue activity and be applied to anti-fatigue functional foods.

Enhancement of Calcium Chelating Activity in Peptides from Sea Cucumber Ovum through Phosphorylation Modification

Recently, phosphorylation has been applied to peptides to enhance their physiological activity, taking advantage of its modification benefits and the extensive study of functional peptides. In this study, water-soluble peptides (WSPs) of sea cucumber ovum were phosphorylated in order to improve the latter's calcium binding capacity and calcium absorption. Enzymatic hydrolysis methods were screened via ultraviolet-visible absorption spectroscopy (UV-Vis), the fluorescence spectrum, and calcium chelating ability. Phosphorylated water-soluble peptides (P-WSPs) were characterized via high-performance liquid chromatography, the circular dichroism spectrum, Fourier transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, surface hydrophobicity, and fluorescence spectroscopy. The phosphorus content, calcium chelation rate and absorption rate were investigated. The results demonstrated that phosphorylation enhanced the calcium chelating capacity of WSPs, with the highest capacity reaching 0.96 mmol/L. Phosphate ions caused esterification events, and the carboxyl, amino, and phosphate groups of WSPs and P-WSPs interacted with calcium ions to form these bonds. Calcium-chelated phosphorylated water-soluble peptides (P-WSPs-Ca) demonstrated outstanding stability (calcium retention rates > 80%) in gastrointestinal processes. Our study indicates that these chelates have significant potential to develop into calcium supplements with superior efficacy, bioactivity, and stability.

Novel peptides from sea cucumber intestines hydrolyzed by neutral protease alleviate exercise-induced fatigue via upregulating the glutaminemediated Ca2+ /Calcineurin signaling pathway in mice

Sea cucumber intestines are considered a valuable resource in the sea cucumber processing industry due to their balanced amino acid composition. Studies have reported that peptides rich in glutamate and branched-chain amino acids have anti-fatigue properties. However, the function of the sea cucumber intestine in reducing exercise-induced fatigue remains unclear. In this study, we enzymatically hydrolyzed low molecular weight peptides from sea cucumber intestines (SCIP) and administered SCIP orally to mice to examine its effects on exercise-induced fatigue using swimming and pole-climbing exhaustion experiments. The results revealed that supplementation with SCIP significantly prolonged the exhaustion time of swimming in mice, decreased blood lactate and urea nitrogen levels, and increased liver and muscle glycogen levels following a weight-loaded swimming test. Immunofluorescence analysis indicated a notable increase the proportion of slow-twitch muscle fiber and a significant decrease the proportion of fast-twitch muscle fiber following SCIP supplementation. Furthermore, SCIP upregulated mRNA expression levels of Ca2+ /Calcineurin upstream and downstream regulators, thereby contributing to the promotion of skeletal muscle fiber type conversion. This study presents the initial evidence establishing SCIP as a potential enhancer of skeletal muscle fatigue resistance, consequently providing a theoretical foundation for the valuable utilization of sea cucumber intestines.

Chemical substances and their activities in sea cucumber Apostichopus japonicus: A review

Apostichopus japonicus, also known as Stichopus japonicus, with medicinal and food homologous figures, is a globally recognized precious ingredient with extremely high nutritional value. There is no relevant review available through literature search, so this article selects the research articles through the keywords "sea cucumber" and "Apostichopus japonicus (Stichopus japonicus)" in six professional databases, such as Wiley, PubMed, ScienceDirect, ACS, Springer, and Web of Science, from 2000 to the present, summarizing the extraction, isolation, and purification methods for the four major categories (polysaccharides, proteins and peptides, saponins, and other components) of the A. japonicus chemical substances and 10 effective biological activities of A. japonicus. Included are anticoagulation, anticancer/antitumor activities, hematopoiesis, regulation of gut microbiota, and immune regulatory activities that correspond to traditional efficacy. Literature support is provided for the development of medicines and functional foods and related aspects that play a leading role in future directions.

Research progress on the chemical components and biological activities of sea cucumber polypeptides

Owing to their unique physical and chemical properties and remarkable biological activities, marine biological resources are emerging as important sources of raw materials for producing health products, food, and cosmetics. Collagen accounts for approximately 70% of the sea cucumber body wall, and its hydrolysis produces small-molecule collagen polypeptides with diverse biological functions, such as anticancer, antihypertensive, immune-enhancing, memory-enhancing, and cartilage tissue repairing effects. Notably, the potential of sea cucumber polypeptides in combination with anticancer therapy has garnered considerable attention. Determining the composition and structure of sea cucumber polypeptides and exploring their structure-activity relationships will aid in obtaining an in-depth understanding of their diverse biological activities and provide scientific insights for the development and utilization of these polypeptides. Therefore, this review focuses on the amino acid structures and activities of sea cucumber polypeptides of varying molecular weights. This study also provides an overview of the biological activities of various sea cucumber polypeptides and aims to establish a scientific basis for their development.

Antidiabetic Effect of Collagen Peptides from Harpadon nehereus Bones in Streptozotocin-Induced Diabetes Mice by Regulating Oxidative Stress and Glucose Metabolism

Oxidative stress and abnormal glucose metabolism are the important physiological mechanisms in the occurrence and development of diabetes. Antioxidant peptides have been reported to attenuate diabetes complications by regulating levels of oxidative stress, but few studies have focused on peptides from marine bone collagen. In this study, we prepared the peptides with a molecular weight of less than 1 kD (HNCP) by enzymolysis and ultrafiltration derived from Harpadon nehereus bone collagen. Furthermore, the effects of HNCP on blood glucose, blood lipid, liver structure and function, oxidative stress, and glucose metabolism were studied using HE staining, kit detection, and Western blotting experiment in streptozocin-induced type 1 diabetes mice. After the 240 mg/kg HNCP treatment, the levels of blood glucose, triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) in streptozotocin-induced diabetes mice decreased by 32.8%, 42.2%, and 43.2%, respectively, while the levels of serum insulin and hepatic glycogen increased by 142.0% and 96.4%, respectively. The antioxidant enzymes levels and liver function in the diabetic mice were markedly improved after HNCP intervention. In addition, the levels of nuclear factor E2-related factor 2 (Nrf2), glucokinase (GK), and phosphorylation of glycogen synthase kinase-3 (p-GSK3β) in the liver were markedly up-regulated after HNCP treatment, but the glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase1 (PEPCK1) were down-regulated. In conclusion, HNCP could attenuate oxidative stress, reduce blood glucose, and improve glycolipid metabolism in streptozocin-induced type 1 diabetes mice.

The Research Progress of Bioactive Peptides Derived from Traditional Natural Products in China

Traditional natural products in China have a long history and a vast pharmacological repertoire that has garnered significant attention due to their safety and efficacy in disease prevention and treatment. Among the bioactive components of traditional natural products in China, bioactive peptides (BPs) are specific protein fragments that have beneficial effects on human health. Despite many of the traditional natural products in China ingredients being rich in protein, BPs have not received sufficient attention as a critical factor influencing overall therapeutic efficacy. Therefore, the purpose of this review is to provide a comprehensive summary of the current methodologies for the preparation, isolation, and identification of BPs from traditional natural products in China and to classify the functions of discovered BPs. Insights from this review are expected to facilitate the development of targeted drugs and functional foods derived from traditional natural products in China in the future.

Screening anti-fatigue components of American ginseng saponin by analyzing spectrum-effect relationship coupled with UPLC-Q-TOF-MS

Background

American ginseng has an obvious anti-fatigue effect, but the effective material basis is still unclear. The spectrum-effect relationship is a scientific method that studies the correlations between chemical spectra and pharmacological effect.

Objective

To reveal the real bioactive compounds in American ginseng saponin (AGS) based on a study of the underlying correlations between these compounds' occurrence in rat serum after their intake of AGS and the anti-fatigue effect of AGS.

Methods

We utilized ultra-performance liquid chromatography (UPLC) with quadrupole and time-of-flight mass spectrometry (Q-TOF-MS) to analyze the extract of AGS and its constituents in serum after oral administration in rats. The anti-fatigue effect of AGS in rats was measured using the time weight-bearing swimming technique, the content of blood urea nitrogen, hepatic glycogen, and blood lactic acid. The relationship between the peak area values in fingerprints from rat serum and pharmacodynamic parameters of AGS was established using correlation analysis with partial least square regression (PLSR) method and gray correlation method.

Results

We detected and identified 22 compounds from extract, and 8 prototype components from serum. Through PLSR and gray correlation method, it was found that the ginsenosides Re, Rb1, and Rb2 were significantly positively related to the pharmacodynamic data.

Conclusions

Based on the spectrum-effect relationship, PLSR and gray correlation method can be used to screen for the anti-fatigue components available in AGS. Such an approach is of practical significance as it provides an effective means for exploring the material basis for the efficacy of American ginseng, particularly as an anti-fatigue agent.

Protein oxidation affected the digestibility and modification sites of myofibrillar proteins from bighead carp fillets treated with hydroxyl radicals and endogenous oxidizing system

This study aimed to investigate the effect of hydroxyl radical oxidizing system (HROS) and endogenous oxidizing system (EOS, i.e., frozen storage at -20 °C) on protein oxidation, digestive properties, and peptide modification of myofibrillar proteins (MPs) in bighead carp (Hypophthalmichthys nobilis) fillets. The oxidation degree increased with the frozen time and H₂O₂ concentration as evidenced by carbonyl group generation and sulfhydryl group loss in MPs. The digestibility of protein declined gradually during frozen storage, while it increased after treatment with 5 mM H₂O₂ compared with no H₂O₂ intervention. More modification numbers and types were observed in the EOS group than HROS in digested MPs peptides, which might be due to the complexity of the frozen fillet system such as the presence of lipid. The potential conversion of α-aminoadipic semialdehyde (AAS) to α-aminoadipic acids (AAA) was observed in HROS. Additionally, the myosin heavy chain was more susceptible to oxidation among all MPs by EOS oxidation.

8 weeks of 2S-hesperidin prevents a decrease in pO2 at submaximal intensity in amateur cyclists in off-season: randomized controlled trial

Although chronic supplementation with 2S-hesperidin has been shown to improve performance, to date, the possible mechanisms underlying this effect have not been explored. Therefore, the aim of this study was to assess whether changes in gasometry may be associated with improved performance after the intake of 2S-hesperidin (500 mg d^-1, 8 weeks). Forty amateur cyclists (n = 20 2S-hesperidin, n = 20 placebo) performed a rectangular test, during which capillary blood samples were taken at the baseline, FatMax1, ventilatory threshold 1 and 2 (VT1 and VT2), power maximum (P_MAX), FatMax2 and excess post-exercise O₂ consumption (EPOC) to measure gasometry parameters. Significantly increased CO₂ and tCO₂ was found at FatMax1, VT1, FatMax2 and EPOC (p = <0.05) after 8 weeks of 2S-hesperidin ingestion. Conversely, the placebo group had a significant decrease in pO₂ at VT2 (p = 0.04) during the rectangular test, with no changes in the 2S-hesperidin group. Therefore, chronic supplementation with 2S-hesperidin prevents decreases in pO₂ at submaximal intensities in amateur cyclists in an off-season period.

The evaluation of sea cucumber (Acaudina leucoprocta) peptide on sex hormone regulation in normal and premature ovarian failure female mice

Sea cucumber peptides (SCPs) have various functional activities. However, studies to evaluate the efficacy and safety of SCPs from the perspective of sex hormones are still lacking. In this study, normal and premature ovarian failure (POF) female mice were used to assess the effect of SCPs on the sex hormones. The ovarian and uterine indices were not influenced by SCP both in normal and POF mice. In normal mice, SCP showed no significant impact on the estrous cycle, ovarian, uterine morphology, sex hormone levels, and sex hormone synthesis-related genes of the ovary. However, 0.6 mg per g bw dosage of SCP (SCPH) statistically increased mapk1 expression on normal mice hypothalamus. In POF mice, SCPH played a more positive role than a low dosage of SCP (0.2 mg per g bw). SCP ameliorated POF-induced estrous cycle disturbances and significantly increased serum estradiol, testosterone, and AMH levels. Moreover, SCP increased the synthesis of the sex hormone by upregulating the expression of StAR, Fshr, and Cyp19a1 in the ovary, which might be due to the activation of the cAMP-related signaling pathways. The upregulation of mapk1, Esr1, and Gnrh was also observed in the hypothalamus. Together, SCP is safe for normal female mice and seems to have positive effects on POF mice from sex hormone regulation. However, the risk of excessive supplementation of sex hormones induced by the SCP intake in POF mice needs to be further explored.

Structure characterization and anti-fatigue activity of an acidic polysaccharide from Panax ginseng C. A. Meyer

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng C. A. Meyer is a traditional Chinese herbal medicine, which has been used in China for more than 2000 years. Its traditional effect of "invigorating vitality" is mainly reflected in anti-fatigue. However, due to the difficulty of identification of polysaccharide structure, there are few reports on homogeneous ginseng polysaccharide, and the molecular mechanism of its anti-fatigue effect remains to be further explored.

AIM OF THE STUDY

In order to find the homogenous ginseng polysaccharide with the most anti-fatigue effect, this study is for the first time extracted, isolated and structurally identified polysaccharide monomer from Mountain Cultivated Ginseng (MCG). Then the anti-fatigue activity and molecular mechanism were studied.

MATERIALS AND METHODS

The structure of ginseng acidic polysaccharide APS-1 prepared by high performance gel permeation chromatography (HPGPC) was determined by acid hydrolysis/HPLC, methylation/GC-MS and NMR analysis. Anti-fatigue effect was evaluated by exhaustive swimming model, and AMPK axis-related proteins were detected by Western blot.

RESULTS

APS-1 significantly prolonged fatigue tolerance time, alleviated accumulation of BLA, LDH and BUN, increased activities of SOD and CAT, alleviated oxidative damage caused by MDA, increased activity of CK, regulated glycolysis, and alleviated muscle fiber contraction. The expressions of LKB1, p-AMPK, PGC-1α and Glut4 in muscle were significantly up-regulated.

CONCLUSIONS

The anti-fatigue effect of APS-1 was significantly, and the molecular mechanism may be related to the activation of AMPK axis signaling pathway to improve glucose uptake and mitochondrial function.

Anti-Inflammatory Effects of Compounds from Echinoderms

Chronic inflammation can extensively burden a healthcare system. Several synthetic anti-inflammatory drugs are currently available in clinical practice, but each has its own side effect profile. The planet is gifted with vast and diverse oceans, which provide a treasure of bioactive compounds, the chemical structures of which may provide valuable pharmaceutical agents. Marine organisms contain a variety of bioactive compounds, some of which have anti-inflammatory activity and have received considerable attention from the scientific community for the development of anti-inflammatory drugs. This review describes such bioactive compounds, as well as crude extracts (published during 2010-2022) from echinoderms: namely, sea cucumbers, sea urchins, and starfish. Moreover, we also include their chemical structures, evaluation models, and anti-inflammatory activities, including the molecular mechanism(s) of these compounds. This paper also highlights the potential applications of those marine-derived compounds in the pharmaceutical industry to develop leads for the clinical pipeline. In conclusion, this review can serve as a well-documented reference for the research progress on the development of potential anti-inflammatory drugs from echinoderms against various chronic inflammatory conditions.

Semen raphani weakened the action of ginseng under chronic fatigue condition

ETHNOPHARMACOLOGICAL RELEVANCE

Fatigue is a kind of subhealth status and people paid much more attention on it. Ginseng is used to treating fatigue as a kind of qi -tonifying drug in Chinese medicine. In the traditional applications, there is a viewpoint that ginseng could not be used with semen raphani and supposed that semen raphani is a kind of qi regulating drug, which will reduce the qi invigorating effect of ginseng. However, the underlying combination mechanism of the two drugs remained unclear.

AIM OF THE STUDY

The aim of this study is to explore whether ginseng can be used with semen raphani or not to remedy acute and chronic fatigue conditions.

METHODS

We used normal and weight-bearing swimming method combined with appetite control animals. The biochemical indexes in energy metabolism, antioxidant, regulating endocrine system and immunity capacities were performed to explore the antagonism effect of semen raphani on ginseng under acute and chronic fatigue conditions. The serum and urine metabolomics were investigated using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF/MS). Fecal flora was analyzed via 16S rRNA amplicon sequencing.

RESULTS

The combination of ginseng with semen raphani have no influence on acute fatigue effect compared with ginseng alone. Both can improve the exhausted swimming time, the activity of GSH-Px, LDH and Na⁺-K⁺-ATPase. Furthermore, the combination of ginseng with semen raphani can increase the urine volume of rats and down-regulate the content of AQP-3, which can alleviate the "fireness" side-effect of ginseng. But the abundance and diversity of bacterial are decreased under acute fatigue experiment. Both the combination of ginseng with semen raphani and ginseng alone can remedy chronic-fatigue. They can also regulate the endocrine system, immune system, citric acid cycle metabolism, tryptophan metabolism, fatty acid metabolism, glycolysis/gluconeogenesis, etc. Furthermore, they can promote substance metabolism and energy metabolism in qi deficiency rats, and increase the abundance and diversities of the flora. While with the increased content of semen raphani, the combination of ginseng and semen raphani weaken the capacity of antioxidant, lactic acid metabolism, energy metabolism, flora diversity and regulation of endocrine system.

CONCLUSION

Compared with ginseng alone, the combination of ginseng with semen raphani can weaken the qi invigorating ability under chronic fatigue condition. The more ratios of semen raphani is in the combination of the two drugs, the less the power of treating chronic fatigue is. Compared with ginseng alone, the combination of ginseng with semen raphani have no influence on the qi invigorating ability under actue fatigue experiment. But the combination of ginseng with semen raphani will benefit for the "fireness" side-effect of ginseng.

Production of Bioactive Peptides from Sea Cucumber and Its Potential Health Benefits: A Comprehensive Review

Bioactive peptides from food have been widely studied due to their potential applications as functional foods and pharmaceuticals. Sea cucumber, a traditional tonic food, is characterized by high protein and low fat, thereby substrates are being studied to release sea cucumber peptides (SCPs). Although recent studies have shown that SCPs have various bioactive functions, there is no literature reviewing the development status of SCPs. In this review, we summarized the production of SCPs, including their purification and identification, then mainly focused on the comprehensive potential health benefits of SCP in vivo and in vitro, and finally discussed the challenge facing the development of SCPs. We found that SCPs have well-documented health benefits due to their antioxidation, anti-diabetes, ACE inhibitory, immunomodulatory, anti-cancer, anti-fatigue, anti-aging, neuroprotection, micromineral-chelating, etc. However, the structure-activity relationships of SCPs and the functional molecular mechanisms underlying their regulation in vivo need further investigation. Research on the safety of SCP and its potential regulation mechanism will contribute to transferring these findings into commercial applications. Hopefully, this review could promote the development and application of SCPs in further investigation and commercialization.

Chronic Supplementation of 2S-Hesperidin Improves Acid-Base Status and Decreases Lactate at FatMax, at Ventilatory Threshold 1 and 2 and after an Incremental Test in Amateur Cyclists

Simple Summary

Currently, hesperidin is a molecule found mainly in citrus fruits and is being widely researched in the area of chronic disease, but also in the field of sports nutrition. Some studies have shown its antioxidant, anti-inflammatory, lipid and carbohydrate metabolism modulating effects, including the enhancement of nitric oxide synthesis. However, few human studies have demonstrated a positive effect of hesperidin intake, in particular 2S-hesperidin, on sports performance, particularly in anaerobic and aerobic tests. However, the biochemical mechanisms that may be responsible for this enhanced performance have not yet been described. Therefore, one of the aims of this study was to assess whether an eight-week intake of 2S-hesperidin can improve acid-base status and metabolic status (lactate and glucose) in an incremental test in amateur cyclists. The results showed that amateur cyclists chronically supplemented with 2S-hesperidin improved acid-base status and lactate at FatMax, ventilatory thresholds 1 and 2, and in the acute phase of recovery after maximal effort.

Abstract

Chronic supplementation with 2S-hesperidin improves performance; however, the mechanisms underlying this effect have not yet been explored. Therefore, the aim of this study was to assess whether changes in acid-base status may be associated with improved performance after 2S-hesperidin supplementation compared to microcellulose (placebo). Forty amateur cyclists (n = 20 per group) underwent a rectangular test where capillary blood samples were taken at baseline, FatMax1, VT1, VT2, P_MAX, FatMax2 and EPOC to measure acid-base parameters. After eight weeks of 2S-hesperidin supplementation (500 mg/d) increased HCO₃⁻, SBC, ABE (p ≤ 0.05) and decreased Lac were found at FatMax1, VT1, FatMax2 and EPOC (p ≤ 0.05), while decreased Lac at VT2 was found with a large effect size (ES = 1.15) compared to placebo. Significant group differences in the area under the curve were observed when comparing pre-post-intervention pH changes (p = 0.02) between groups. Chronic supplementation with 2S-hesperidin improved acid-base status and Lac, both at low-moderate and submaximal intensities, improving recovery after exercise-to-exhaustion in amateur cyclists.

Marine Products As a Promising Resource of Bioactive Peptides: Update of Extraction Strategies and Their Physiological Regulatory Effects

Marine products are a rich source of nutritional components and play important roles in promoting human health. Fish, mollusks, shellfish, as well as seaweeds are the major components of marine products with high-quality proteins. During the last several decades, bioactive peptides from marine products have gained much attention due to their diverse biological properties including antioxidant, antihypertensive, antimicrobial, antidiabetic, immunoregulation, and antifatigue. The structural characteristics of marine bioactive peptides largely determine the differences in signaling pathways that can be involved, which is also an internal mechanism to exert various physiological regulatory activities. In addition, the marine bioactive peptides may be used as ingredients in food or nutritional supplements with the function of treating or alleviating chronic diseases. This review presents an update of marine bioactive peptides with the highlights on the novel producing technologies, the physiological effects, as well as their regulation mechanisms. Challenges and problems are also discussed in this review to provide some potential directions for future research.

Establishment and identification of an animal model of long-term exercise-induced fatigue

In competitive sports, the training load is close to the human physiological limit, which will inevitably lead to exercise-induced fatigue. If fatigue cannot be recovered in time, it will eventually lead to excessive training and affect sport performance. Therefore, fatigue has become an important part of the physical function assessment for athletes. This paper will review animal models of long-term exercise-induced fatigue, modeling schemes of mice under treadmill and swimming training, phenotypes of long-term exercise-induced fatigue (e.g., nervous system damage, myocardial cell damage, bone mineral density changes, and skeletal muscle damage), and fatigue indicators. The relationship between physiological indicators and biomarkers and long-term exercise-induced fatigue is analyzed to promote exercise-induced fatigue monitoring. This paper attempts to provide a reference for the selection of animal models of long-term exercise-induced fatigue and provide a new theoretical basis for medical supervision and recovery of exercise-induced fatigue.

Anti-Fatigue Peptides from the Enzymatic Hydrolysates of Cervus elaphus Blood

Red deer (Cervus elaphus) blood is widely used as a health product. Mixed culture fermentation improves the flavor and bioavailability of deer blood (DB), and both DB and its enzymatic hydrolysates exhibit anti-fatigue activities in vivo. To elucidate the bioactive ingredients, enzymatic hydrolysates were fractioned into different peptide groups using reversed phase resin chromatography, and then evaluated using an exhaustive swimming mice model to assess swimming time and biochemical parameters. The structures of the bioactive peptides were elucidated by high performance liquid chromatography with tandem mass detection. Thirty-one compounds were identified as glutamine or branched-chain amino acids containing short peptides, of which Val-Ala-Asn, Val-Val-Ser-Ala, Leu(Ile)-Leu(Ile)-Val-Thr, Pro-His-Pro-Thr-Thr, Glu-Val-Ala-Phe and Val-Leu(Ile)-Asp-Ala-Phe are new peptides. The fractions containing glutamine or valine short peptides, Ala-Gln, Val-Gln, Val-Val-Ser-Ala, Val-Leu(Ile)-Ser improved exercise endurance by increasing hepatic glycogen (HG) storage. The peptides group containing Leu(Ile)-Leu(Ile), Asp-Gln, Phe- Leu(Ile), Val-Val-Tyr-Pro contributed to decreased muscle lactic acid (MLA)accumulation and to an increase in HG. The anti-fatigue activities of DB hydrolysates were attributed to the synergistic effects of different types of peptides.

Construction and Evaluation of a Rat Model of Postpartum Fatigue

OBJECTIVES

The aim of the study was to construct and evaluate a rat model of postpartum fatigue.

DESIGN

This is an article about animal model building.

METHODS

Sprague-Dawley rats on the 1st day after delivery were randomized into control group and fatigue group. The deep sleep of rats was interfered with by forcing them to stand in water, to make the rats experience mental and physical fatigue. To maintain galactosis and lactation, rats and pups were caged for 90 min after every 3 h of separation. The control group was separated routinely without any stimulus. The model was evaluated from mental and physical fatigue on the 8th day and 15th day. The mental fatigue was evaluated by a water maze test and the rat's 5-hydroxytryptamine (5-HT) level in hippocampus, while the physical fatigue was evaluated using lactic acid level in serum and duration of weight-loaded forced swimming.

RESULTS

Among the 7-day and 14-day modeling groups, compared with the control group, the success rate of water maze landing was significantly decreased, the time for water maze landing was significantly prolonged and 5-HT level in hippocampus significantly decreased in the fatigue group. With respect to physical fatigue, among the 7-day and 14-day modeling groups, the lactic acid level in serum in the fatigue group was significantly increased, and the duration of exhaustive swimming of rats was significantly shortened.

LIMITATIONS

A small sample size was the main limitation of this study.

CONCLUSIONS

We have successfully constructed a rat model of postpartum fatigue by forcing postpartum rats to stand in water, which was similar to a level of stress that contributes to the development of postpartum fatigue. Our model opens the door for future studies evaluating the effectiveness of pharmacological and behavioral therapies.

Amino Acid Profiling with Chemometric Analysis as a Feasible Tool for the Discrimination of Marine-Derived Peptide Powders

Marine-derived peptide powders have suffered from adulteration via the substitution of lower-price peptides or the addition of adulterants in the market. This study aims to establish an effective approach for the discrimination and detection of adulterants for four representative categories of marine-derived peptide powders, namely, oyster peptides, sea cucumber peptides, Antarctic krill peptides, and fish skin peptides, based on amino acid profiling alongside chemometric analysis. The principal component analysis and orthogonal partial least squares discriminant analysis results indicate that four categories of marine-derived peptides could be distinctly classified into four clusters and aggregated with the respective raw materials. Taurine, glycine, lysine, and protein contents were the major discriminants. A reliable classification model was constructed and validated by the prediction dataset, mixture sample dataset, and unclassified sample dataset with accuracy values of 100%, 100%, and 100%, respectively.

Functional foods and bioactive ingredients harnessed from the ocean: current status and future perspectives

With an increase in life expectancy and decrease of quality-of-life couple with the high prevalence of diseases, diet is expected to play a key function in sustaining human health. Nutritionists, food technologists and medical experts are working in synergy to cater for the increasing demand of food with associated therapeutic benefits, commonly known as functional food, that may improve well-being and reduce the risk of diseases. Interestingly, the marine ecosystem, due to its abundant and phenomenal biodiversity of marine organisms, constitutes a vital source of a panoply of healthy foods supply for the thriving functional food industry. Marine organisms such as seaweeds, sea cucumbers, sponges, and mollusks amongst others are sources of thousands of biologically active metabolites with antioxidant, anti-parasitic, antiviral, anti-inflammatory and anticancer properties. Given the growing number of research and interest to probe into the therapeutic roles of marine products, this review was designed to provide a comprehensive summary of the therapeutic properties of marine organisms (macroalgae, sea cucumbers and fish among others) which are consumed worldwide, in addition to their potentials and as sources of functional ingredients for developing novel food and fostering wellness. The gap between research development and actual commercialization, and future prospects of marine-based products also summarized to some extent.

Supplementation with embryo chicken egg extract improves exercise performance and exerts anti-fatigue effects via AMPK/mTOR signalling pathway in mice

BACKGROUND

Embryo chicken egg is a nutritional supplement that has been used to enhance physical fitness and promote wound healing according to traditional Chinese medicine for many years. In this study, we evaluated the effects of embryo chicken egg extract (ECE) on the exercise performance and fatigue in mice and the underlying mechanisms.

RESULTS

The results indicated that ECE can prolong the exhaustive swimming time, decrease lactic acid, blood urea nitrogen, creatine kinase, and malondialdehyde levels, and increase superoxide dismutase, glutathione peroxidase, and glycogen levels. Additionally, ECE can also regulate the balance of oxidative stress via the adenosine monophosphate activated protein kinase/mammalian target of rapamycin signalling pathway.

CONCLUSION

Taken together, these results showed that ECE can improve exercise performance and reduce physical fatigue in mice, which indicates that ECE can be used as a potential supplement to reduce physical fatigue. © 2020 Society of Chemical Industry.

In Vivo Antifatigue Activity of Spirulina Peptides Achieved by Their Antioxidant Activity and by Acting on Fat Metabolism Pathway in Mice

Spirulina are multicellular and filamentous cyanobacteria that have achieved considerable popularity in the health sector, food industry, and aquaculture. In the present study, we aimed to evaluate the antifatigue effects of Spirulina-derived peptides on Institute for Cancer Research mice and explore the association between antifatigue activity and fat metabolism involving the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. We extracted the peptides from Spirulina by enzymatic hydrolysis and ultrafiltration. The mice were orally administered with Spirulina peptides (0.125, 0.5, and 2 mg/g bw/day) daily for 4 weeks. We found that Spirulina peptides, especially the high-dose group, significantly prolonged the swimming time by 126.1%, increased the activities of antioxidant enzymes, and decreased the content of malondialdehyde by 60.2% compared with the glutathione (GSH) group. The levels of some indicators of exercise fatigue, including lactic dehydrogenase, blood lactic acid, and creatine phosphokinase, were reduced. In the high-dose group, these indicators were reduced by 40.7%, 22.3%, and 11.3% compared with the GSH group. Spirulina peptides did not excessively consume blood sugar or glycogen in the liver and muscle to produce energy. However, the triglyceride level was reduced, and the level of free fatty acids was increased. Besides, the proteins in the AMPK signaling pathway were activated. Taken together, these findings indicated that Spirulina peptides could effectively alleviate physical fatigue by reducing the production of lactic acid and improving antioxidant capacity. Spirulina peptides also helped increase the energy resources by activating the AMPK signaling pathway to utilize fat metabolism.

Sea Cucumber Peptides Improved the Mitochondrial Capacity of Mice: A Potential Mechanism to Enhance Gluconeogenesis and Fat Catabolism during Exercise for Improved Antifatigue Property

Sea cucumber promotes multifaceted health benefits. However, the mechanisms of sea cucumber peptides (Scp) regulating the antifatigue capacity is still unknown. The present study is aimed at further elucidating the effects and mechanisms of Scp on the antifatigue capacity of mice. At first, C57BL/6J mice were assigned into four groups named Con, L-Scp, M-Scp, and H-Scp and received diets containing Scp (0%, 0.15%, 0.3%, and 0.5%, respectively) for continuous 30 days. On the 21th day, a fore grip test was conducted on mice. On the 25th day, a rotating rod test was conducted on mice. On the 30th day, the quantities of glycogen and mitochondrial DNA (mtDNA) were determined in 8 random mice and another 8 mice were forced to swim for 1 hour before slaughter for detecting biochemical indicators. It was observed that the Scp groups significantly prolonged the running time in rotarod, increased forelimb grip strength, improved lactic acid (LD) and urea nitrogen (BUN) levels in the serum, decreased lactic dehydrogenase (LDH) and glutamic oxalacetic transaminase (GOT) activities in the serum, increased blood glucose (BG) and glycogen (GN) levels in the liver and skeletal muscle after swimming, increased the activity of Na⁺-K⁺-ATPase and Ca²⁺-Mg²⁺-ATPase in the skeletal muscle and heart, and improved antioxidant capacity. Furthermore, Scp treatment significantly elevated the mRNA and protein relative levels of power-sensitive factors, lipid catabolism, and mitochondrial biogenesis and significantly upregulated mRNA levels of gluconeogenesis. Besides, mtDNA before the swimming test was increased in the three Scp groups. These results show that Scp treatment has antifatigue capacity. Furthermore, these results suggest that improved energy regulation and antioxidant capacity may be the result of improved mitochondrial function.