Screening and characterization of an antifreeze peptide from sea cucumber intestinal protein hydrolysates.

Protein deterioration caused by ice crystals is an important factors affecting the frozen storage of fish. In this study, antifreeze peptides extracted from hydrolysates of sea cucumber intestinal protein with inhibition of protein denaturation were screened and characterized. The peptide Leu-Pro-Glu-Phe-Thr-Glu-Glu-Glu-Lys (LPEFTEEEK), derived from neutral protease hydrolysates of sea cucumber intestinal protein, was investigated for its potential to enhance the quality of salmon fillets during three freeze-thaw cycles. The results showed that the application of LPEFTEEEK effectively maintained the texture of fish fillets, as well as the oxidative and conformation stability of myofibrillar protein during the freezing process. Additionally, molecular dynamics simulations verified that LPEFTEEEK could bind to ice crystals and inhibit their recrystallization, thus preventing organisms from being damaged by freezing. This suggests that LPEFTEEEK holds significant promise as a novel cryoprotective agent for marine-derived antifreeze peptides.

Metabolomic analysis reveals the potential of fucosylated chondroitin sulfate from sea cucumber in modulating metabolic homeostasis.

In this study, we prepared four derivatives of fucosylated chondroitin sulfate (FCS): full-length FCS (flFCS) from Holothuria leucospilota, low molecular weight FCS (lmFCS) derived from flFCS, and their de-branched counterparts, de-branched flFCS (d-flFCS) and de-branched lmFCS (d-lmFCS) via controlled acid treatment. Following structural verification using various analytical techniques, we applied targeted metabolomics to examine the impact of FCS on nutritional efficacy and its structure-activity relationship. Analysis of 225 plasma and feces samples from 75 mice revealed a positive correlation between metabolomic shifts and increased weight gain, underscoring FCS's potential to enhance nutrient absorption and promote growth. The observed linear relationship between the levels of short-chain fatty acids in plasma and feces suggests that FCS may facilitate catabolic activities in the gastrointestinal tract. The comparative study of different FCS derivatives on mouse growth and metabolic homeostasis regulation led to the conclusion that FCS exhibits greater biological activity with a higher degree of branching and larger molecular weight.

Identification of Structure-Linked Activity on Bioactive Peptides from Sea Cucumber (Stichopus japonicus): A Compressive In Silico/In Vitro Study.

BACKGROUND: A sea cucumber (Stichopus japonicus) is an invertebrate rich in high-quality protein peptides that inhabits the coastal seas around East Asian countries. Such bioactive peptides can be utilized in targeted disease therapies and practical applications in the nutraceutical industry. METHODS: Bioactive peptides were isolated from Stichopus japonicus through ultrafiltration and Sephadex G-10 size exclusion chromatography. The low-molecular-weight fraction (ACSH-III) showed the highest hydroxyl radical scavenging and angiotensin-converting enzyme (ACE) inhibitory activities. Subsequent purification of ACSH-III resulted in four fractions, of which ACSH-III-F3 and ACSH-III-F4 exhibited significant bioactivity. RESULTS: Peptides identified in these fractions, including Phenylalanine-Proline-Threonine-Tyrosine (FPTY) and Tyrosine-Proline-Serine-Tyrosine-Proline-Serine (YPSYPS), were characterized using high-performance liquid chromatography (HPLC) and quadrupole time-of-flight mass spectrometry (QTOF-MS). FPTY demonstrated the most potent antioxidant and antihypertensive activities among these peptides, with IC50 values of 0.11 ± 0.01 mg/mL for hydroxyl radicals and 0.03 ± 0.01 mg/mL for ACE inhibition. Docking simulations revealed strong binding affinities of these peptides to the active site of the ACE, with FPTY displaying interactions similar to those of the synthetic inhibitor lisinopril. CONCLUSIONS: These findings suggest that the identified peptides, particularly FPTY, have potential applications as natural antioxidants and functional foods.

Mechanisms of Action of Sea Cucumber Triterpene Glycosides Cucumarioside A0-1 and Djakonovioside A Against Human Triple-Negative Breast Cancer.

Breast cancer is the most prevalent form of cancer in women worldwide. Triple-negative breast cancer is the most unfavorable for patients, but it is also the most sensitive to chemotherapy. Triterpene glycosides from sea cucumbers possess a high therapeutic potential as anticancer agents. This study aimed to identify the pathways triggered and regulated in MDA-MB-231 cells (triple-negative breast cancer cell line) by the glycosides cucumarioside A0-1 (Cuc A0-1) and djakonovioside A (Dj A), isolated from the sea cucumber Cucumaria djakonovi. Using flow cytometry, fluorescence microscopy, immunoblotting, and ELISA, the effects of micromolar concentrations of the compounds on cell cycle arrest, induction of apoptosis, the level of reactive oxygen species (ROS), mitochondrial membrane potential (Δψm), and expression of anti- and pro-apoptotic proteins were investigated. The glycosides caused cell cycle arrest, stimulated an increase in ROS production, and decreased Δψm in MDA-MB-231 cells. The depolarization of the mitochondrial membrane caused by cucumarioside A0-1 and djakonovioside A led to an increase in the levels of APAF-1 and cytochrome C. This, in turn, resulted in the activation of caspase-9 and caspase-3 and an increase in the level of their cleaved forms. Glycosides also affected the expression of Bax and Bcl-2 proteins, which are associated with mitochondria-mediated apoptosis in MDA-MB-231 cells. These results indicate that cucumarioside A0-1 and djakonovioside A activate the intrinsic apoptotic pathway in triple-negative breast cancer cells. Additionally, it was found that treatment with Cuc A0-1 resulted in in vivo inhibition of tumor growth and metastasis of murine solid Ehrlich adenocarcinoma.

Extraction and characterization of collagen and gelatin from body wall of sea cucumbers Stichopus horrens and Holothuria arenicola.

Background: Marine invertebrates, including sponges, molluscs, jellyfish, mussels, and sea cucumbers, are abundant sources of high-quality collagen and offer advantages such as availability, ease of processing, lower inflammatory response, and good metabolic compatibility. Approximately 70% of the total protein in the body wall of sea cucumbers is collagen. Gelatin is a water-soluble protein produced from heat-denatured collagen and has various industrial applications. Methods: Pepsin-solubilized collagen was extracted from the body wall of two sea cucumber Stichopus horrens and Holothuria arenicola, species found in the Oman Sea and characterized with SDS-PAGE and amino acid composition. Then gelatin was extracted from pepsin-solubilized collagen of S. horrens and some rheological properties were measured. Results: Amino acid composition and SDS-PAGE analysis showed that the collagen from both species was type I, with one α1 chain and ß chains, with molecular weights of 125 and 250 kDa, respectively. Glycine was the most abundant amino acid in the collagen from both sea cucumber species. The pepsin-soluble collagens from both species had high levels of glycine, proline, alanine, glutamic acid, and hydroxyproline. The gelatin from S. horrens had a melting point of 30 °C and displayed exceptional thermal stability, surpassing that of mammalian gelatin. Its gelling point was 5 °C, like that of cold-water fish gelatin, with a viscosity of 2.065 cp-lower than mammal gelatins. These findings suggested that collagen and gelatin from sea cucumbers could be useful in nutraceutical, pharmaceutical and cosmetic industries.

Identification and molecular mechanism of the anti-inflammatory effect of sea cucumber peptides: Network pharmacology, molecular docking and animal experiments.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease for which there is currently no efficacious therapeutic drug with fewer side effects. Therefore, the development of approaches for the prevention of UC from natural food sources is urgently needed. In this study, mice were pre-fed with sea cucumber peptides prior to dextran sodium sulfate (DSS) induction. Results showed that sea cucumber peptides decreased pro-inflammatory cytokine (IL-4 and IL-10) levels and remissions of main clinic symptoms in a dose-dependent manner. The composition of peptides was identified, and the anti-inflammatory molecular mechanism was evaluated by silico prediction. The molecular weight of the peptides was 243-1800 Da and composed of 3-18 amino acid residues. Online activity assessment and molecular docking prediction revealed that tripeptides of FGI, FLI, FLL, GFL, GFM, IGF and LDF exhibited strong anti-inflammatory activity. Particularly, LDF showed the highest potency, with a binding energy of -5.37 kJ/mol. Network pharmacology analysis of UC related diseases indicated that active peptides interact with colitis disease targets, primarily proto-oncogene tyrosine-protein kinase Src (SRC), E3 ubiquitin-protein ligase XIAP (XIAP) and angiotensin-converting enzyme (ACE). The results suggest that sea cucumber peptides have potential as a novel nutraceutical option for colitis relief.

Anti-enterovirus 71 activity of native fucosylated chondroitin sulfates and their derivatives.

Enterovirus 71 (EV71) is recognized as a major causative agent of hand, foot, and mouth disease (HFMD), posing a significant global public health concern due to its widespread impact and resulting in a major public health issue worldwide. Despite its prevalence, current clinical therapy lacks effective antiviral agents. Fucosylated chondroitin sulfates (FCS) derived from sea cucumber exhibits a range of biological activities including potent antiviral effects. This study provides compelling evidence of the potent antiviral efficacy of FCS against EV71. To further elucidate the impact of structural variations on the anti-EV71 activity, native FCSs with diverse sulfation patterns and a varity of FCS derivatives were prepared and analyzed. Notably, this study presents the detailed structural characterization of FCSs from the sea cucumbers Holothuria scabra Jaege and Holothuria fuscopunctata. Analysis of the structure-activity relationships revealed that molecular weight, sulfated fucose branches, and sulfation pattern were all crucial factors contributing to the potent inhibitory effects of FCS against EV71. Interestingly, molecular weight emerged as the most significant structural determinant of the antiviral potency. These findings suggest the promising potential of utilizing FCS as an innovative EV71 entry inhibitor for the treatment of HFMD.

Preparation of antibacterial composite film based on arginine-modified chitosan and its application in the preservation of ready-to-eat sea cucumber.

An edible composite film was developed and applied for ready-to-eat sea cucumber storage to improve the product quality. The PAC film base is first prepared by mixing 0.5 % glycerin (GL) with 4 % polyvinyl alcohol (PVA) and 1 % arginine-modified chitosan (Arg-CTS) in the same volume. After the addition of nano-ZnO (ZnO) and thymol (Thy) to the PAC film base, the mechanical properties and functions were tested. Compared to the PAC film, the PAC-ZnO-ThyH composite film showed a 1.34-fold increase in the DPPH scavenging rate and a 2.19-fold increase in the ABTS scavenging rate. Contrary to the PAC film, the inhibition zone diameter of Escherichia coli and Staphylococcus aureus significantly increased by 2.35 and 4.08 folds in the PAC-Zno-ThyH film, respectively. After applying the PAC-ZnO-ThyH film to store ready-to-eat sea cucumber for 10 days, there was a significant reduction in weight loss, total volatile basic nitrogen (TVB-N), and lipid oxidation levels to 1.47 and 1.26 folds to the Ctrl group. After preservation, the hardness and chewiness of ready-to-eat sea cucumber were maintained at 1079.62 ± 138.86 N and 913.73 ± 175.79 N, respectively. The novel PAC-ZnO-ThyH composite film can be used as an active food packaging for promising seafood applications.

Extraction of Omega-3 Fatty Acids from Atlantic Sea Cucumber (Cucumaria frondosa) Viscera Using Supercritical Carbon Dioxide.

This study explores the potential of Cucumaria frondosa (C. frondosa) viscera as a natural source of omega-3 FAs using supercritical carbon dioxide (scCO2) extraction. The extraction conditions were optimized using a response surface design, and the optimal parameters were identified as 75 °C and 45 MPa, with a 20 min static and a 30 min dynamic extraction, and a 2:1 ethanol to feedstock mass ratio. Under these conditions, the scCO2 extraction yielded higher FAs than the solvent-based Bligh and Dyer method. The comparative analysis demonstrated that scCO2 extraction (16.30 g of FAs/100 g of dried samples) yielded more fatty acids than the conventional Bligh and Dyer method (9.02 g, or 13.59 g of FAs/100 g of dried samples with ultrasonic assistance), indicating that scCO2 extraction is a viable, green alternative to traditional solvent-based techniques for recovering fatty acids. The pre-treatment effects, including drying methods and ethanol-soaking, were investigated. Freeze-drying significantly enhanced FA yields to almost 100% recovery, while ethanol-soaked viscera tripled the FA yields compared to fresh samples, achieving similar EPA and DHA levels to hot-air-dried samples. These findings highlight the potential of sea cucumber viscera as an efficient source of omega-3 FA extraction and offer an alternative to traditional extraction procedures.

Microplastics occurrence in sea cucumbers and impacts on sea cucumbers & human health: A systematic review.

Microplastics (MPs) are a developing concern in marine environments, with scientists concentrating more on their effects on various creatures. Sea cucumbers (SCs), as suspension and deposit feeders, are expected to be exposed to and consume MPs in their habitat. The purpose of this methodical review is to gather and integrate accessible research on the presence and effects of MPs on SCs. A systematic search of relevant databases yielded relevant papers exploring the occurrence of MPs in SC habitats as well as the possible effects of MP intake on SCs. Bibliometric analysis was also conducted to collect and analyze a large volume of data. Then the papers were sorted (a total of 249) related to the occurrence and effects of MPs in SCs. Finally, targeted data were collected from the articles for the study. The review emphasizes the ubiquity of MPs in SC ecosystems, citing studies that found high quantities in coastal areas and sediment. MPs have a variety of effects on SCs, with some studies indicating that they lower eating efficiency, affect behavior, and cause tissue damage. However, there is still no unanimity on the overall effects of MP exposure on SCs. This review gives a complete summary of the present state of information about the incidence and impact of MPs on SCs, highlighting the need for additional study in this area. Understanding the possible dangers of MPs on SCs is critical for the survival of these ecologically significant creatures.

Combined UPLC-QqQ-MS/MS and AP-MALDI Mass Spectrometry Imaging Method for Phospholipidomics in Obese Mouse Kidneys: Alleviation by Feeding Sea Cucumber Phospholipids.

Sea cucumber phospholipids have ameliorative effects on various diseases related to lipid metabolism. However, it is unclear whether it can ameliorate obesity-associated glomerulopathy (ORG) induced by a high-fat diet (HFD). The present study applied UPLC-QqQ-MS/MS and atmospheric pressure matrix-assisted laser desorption ionization mass spectrometry imaging (AP-MALDI MSI) to investigate the effects of sea cucumber phospholipids, including plasmalogen PlsEtn and plasmanylcholine PakCho, on phospholipid profiles in the HFD-induced ORG mouse kidney. Quantitative analysis of 135 phospholipids revealed that PlsEtn and PakCho significantly modulated phospholipid levels. Notably, PlsEtn modulated kidney overall phospholipids better than PakCho. Imaging the "space-content" of 9 phospholipids indicated that HFD significantly increased phospholipid content within the renal cortex. Furthermore, PlsEtn and PakCho significantly decreased the expression of transport-related proteins CD36, while elevating the expression of fatty acid ß-oxidation-related protein PPAR-α in the renal cortex. In conclusion, sea cucumber phospholipids reduced renal lipid accumulation, ameliorated renal damage, effectively regulated the content and distribution of renal phospholipids, and improved phospholipid homeostasis, exerting an anti-OGR effect.

The Composition of Triterpene Glycosides in the Sea Cucumber Psolus peronii: Anticancer Activity of the Glycosides against Three Human Breast Cancer Cell Lines and Quantitative Structure-Activity Relationships (QSAR).

Eight sulfated triterpene glycosides, peronioside A (1) and psolusosides A (2), B (3), G (4), I (5), L (6), N (7) and P (8), were isolated from the sea cucumber Psolus peronii. Peronioside A (1) is a new glycoside, while compounds 2-8 were found previously in Psolus fabricii, indicating the phylogenetic and systematic closeness of these species of sea cucumbers. The activity of 1-8 against human erythrocytes and their cytotoxicity against the breast cancer cell lines MCF-7, T-47D and triple-negative MDA-MB-231 were tested. The most active against cancer cell compounds, psolusosides A (2) and L (6), which were not cytotoxic to the non-transformed cells of the mammary gland, were chosen to study the inhibition of the migration, formation and growth of colonies of the cancer cell lines. Glycoside 2 effectively inhibited the growth of colonies and the migration of the MDA-MB-231 cell line. Compound 6 blocked the growth of colonies of T-47D cells and showed a pronounced antimigration effect on MDA-MB-231 cells. The quantitative structure-activity relationships (QSAR) indicated the strong impact on the activity of the form and size of the molecules, which is connected to the length and architecture of the carbohydrate chain, the distribution of charge on the molecules' surface and various aspects of hydrogen bond formation, depending on the quantity and positions of the sulfate groups. The QSAR calculations were in good accordance with the observed SAR tendencies.

Proteomics Analysis of the Protective Effect of Polydeoxyribonucleotide Extracted from Sea Cucumber (Apostichopus japonicus) Sperm in a Hydrogen Peroxide-Induced RAW264.7 Cell Injury Model.

Sea cucumber viscera contain various naturally occurring active substances, but they are often underutilized during sea cucumber processing. Polydeoxyribonucleotide (PDRN) is an adenosine A2A receptor agonist that activates the A2A receptor to produce various biological effects. Currently, most studies on the activity of PDRN have focused on its anti-inflammatory, anti-apoptotic, and tissue repair properties, yet relatively few studies have investigated its antioxidant activity. In this study, we reported for the first time that PDRN was extracted from the sperm of Apostichopus japonicus (AJS-PDRN), and we evaluated its antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), and hydroxyl radical scavenging assays. An in vitro injury model was established using H2O2-induced oxidative damage in RAW264.7 cells, and we investigated the protective effect of AJS-PDRN on these cells. Additionally, we explored the potential mechanism by which AJS-PDRN protects RAW264.7 cells from damage using iTRAQ proteomics analysis. The results showed that AJS-PDRN possessed excellent antioxidant activity and could significantly scavenge DPPH, ABTS, and hydroxyl radicals. In vitro antioxidant assays demonstrated that AJS-PDRN was cytoprotective and significantly enhanced the antioxidant capacity of RAW264.7 cells. The results of GO enrichment and KEGG pathway analysis indicate that the protective effects of AJS-PDRN pretreatment on RAW264.7 cells are primarily achieved through the regulation of immune and inflammatory responses, modulation of the extracellular matrix and signal transduction pathways, promotion of membrane repair, and enhancement of cellular antioxidant capacity. The results of a protein-protein interaction (PPI) network analysis indicate that AJS-PDRN reduces cellular oxidative damage by upregulating the expression of intracellular selenoprotein family members. In summary, our findings reveal that AJS-PDRN mitigates H2O2-induced oxidative damage through multiple pathways, underscoring its significant potential in the prevention and treatment of diseases caused by oxidative stress.

Dynamic water migration and flavor analysis of sea cucumber in the process of Sichuan pepper seasoning soak.

Soaking in seasoning solution is the main process of sea cucumber seasoning. This study analyzed the dynamic changes in water migration and flavor substances in sea cucumbers during soaking in a Sichuan pepper solution. It was found that the sea cucumber experienced a process of water absorption followed by water loss during the 0-48 h soaking process. During this period, the flavor compounds in sea cucumbers showed different dynamic trends. A total of 46 volatiles were identified, of which 29 were key flavor compounds. Its flavor profiles tended to stabilize as soaking time increased. m-Xylene, d-Limonene, Eucalyptol, p-Xylene, Sabinene, Beta-Myrcene, and Beta-Phellandrene were the main characteristic substances contributing to the differences in sea cucumber flavor. Correlation analysis predicted the relationship between water migration and the dynamic shifts in flavor compounds. This study provides a crucial reference for future studies on the processing and flavor modulation of sea cucumber products.

Crosslinking ability of hydrolyzed distarch phosphate and its stabilizing effect on rehydrated sea cucumber.

Effective crosslinking among food constituents has the potential to enhance their overall quality. Distarch phosphate (DSP), a common food additive employed as a thickening agent, bears a pre-crosslinked oligosaccharide (PCO) moiety within its molecular structure. Once this moiety is released, its double reducing end has the potential to undergo crosslinking with amino-rich macromolecules through Maillard reaction. In this study, hydrolyzed distarch phosphate (HDSP) was synthesized, and spectroscopic analysis verified the presence of PCO within HDSP. Preliminary validation experiment showed that HDSP could crosslink chitosan to form a hydrogel and significant browning was also observed during the process. Furthermore, rehydrated sea cucumber (RSC) crosslinked with HDSP exhibited a more intact appearance, higher mechanical strength, better color profile, and increased water-holding capacity. This series of results have confirmed that HDSP is capable to crosslink amino-rich macromolecules and form more stable three-dimensional network.

Study on the adsorption and migration rule of Sichuan pepper characteristic volatile compounds during the cooking process in the sea cucumber body wall.

The natural flavor of sea cucumber is generally not easily accepted by consumers. In this study, the effect of different cooking conditions on the adsorption of the characteristic flavor of Sichuan pepper by sea cucumber was investigated by response surface methodology, and the optimal cooking conditions were identified. A total of 45 volatiles were identified based on gas chromatography-mass spectrometry, of which 27 were key flavor actives. Low-field nuclear magnetic resonance and textural analysis showed that the addition of Sichuan pepper during the cooking process affected the water migration and the textural properties of sea cucumbers. It was shown that the addition of Sichuan pepper could significantly improve the flavor and other quality characteristics of sea cucumber. This study has important practical guiding significance for the flavor improvement and product innovation of sea cucumber food.

Determination of key volatile fishy substances of sea cucumber powder during the processing and their removal by supercritical fluid extraction.

More than 40 volatile compounds were detected in sea cucumber powder during the processing (through freeze-dried, desalination, supercritical fluid extraction and ultra-micro grinding) by multiple methods including e-nose, GC-IMS and GC-MS. It has been determined that aldehydes are the predominant volatile substances in the original freeze-dried sample, accounting for about 30 % of the total volatile substances. In addition, we established a supercritical fluid extraction strategy that could efficiently remove the aldehydes from the sea cucumber powder. GC-IMS and GC-MS showed that the relative content of aldehydes significantly decreased by 14 % and 28 %, respectively. Quantification of aldehydes using GC-MS showed a significant decrease in octanal from 927 µg/kg to 159 µg/kg. Further investigation combined with OAV analysis showed that 17 volatile substances in the freeze-dried sea cucumber powder were considered to be the predominant volatile compounds (OAV > 1).The primary fishy compounds found in sea cucumber powder were identified as hexanal, octanal, and an unidentified compound using GC-O, which can be effectively removed (OAV can't been estimated) by the supercritical fluid extraction strategy we established.

A comprehensive review of sulfated fucan from sea cucumber: Antecedent and prospect.

Sulfated fucan from sea cucumber is mainly consists of L-fucose and sulfate groups. Recent studies have confirmed that the structure of sulfated fucan mainly consists of repeating units, typically tetrasaccharides. However, there is growing evidence indicating the presence of irregular domains with heterogeneous units that have not been extensively explored. Moreover, as a key contributor to the nutritional benefits of sea cucumbers, sulfated fucan demonstrates a range of biological activities, such as anti-inflammatory, anticancer, hypolipidemic, anti-hyperglycemic, antioxidant, and anticoagulant properties. These biological activities are profoundly influenced by the structural features of sulfated fucan including molecular weight and distribution patterns of sulfate groups. The latest research indicates that sulfated fucan is dispersed in the extracellular matrix of the body wall of sea cucumbers. This article aimed to review the research progress on the in-situ distribution, structures, structural elucidation strategies, functions, and structure-activity relationships of sulfated fucan, especially in the last decade. It also provided insights into the major challenges and potential solutions in the research and development of sulfated fucan. Moreover, the fucanase and carbohydrate binding modules are anticipated to play pivotal roles in advancing this field.

Sea cucumber significance: Drying techniques and India's comprehensive status.

Sea cucumbers, members of the echinoderm class Holothuroidea, are marine invertebrates with ecological significance and substantial commercial value. With approximately 1700 species, these organisms contribute to marine ecosystems through nutrient cycling and face various threats, including overfishing and habitat loss. Despite their importance, they are extensively exploited for diverse applications, from seafood to pharmaceuticals. This study investigates sea cucumbers' nutritional profile and bioactive elements, emphasizing their role as sources of essential compounds with potential health benefits. The demand for sea cucumbers, especially in dried form, is significant, prompting exploration into various drying techniques. Examining the global trade in sea cucumbers highlights their economic importance and the conservation challenges they face. Conservation efforts, such as awareness campaigns and international collaboration, are evaluated as essential steps in combating illicit trade and promoting the sustainable stewardship of sea cucumber populations. PRACTICAL APPLICATION: Around 1700 species of sea cucumbers were identified as vital ecological scavengers in the Holothuroidea class. High commercial value due to their health benefits, particularly their demonstrated inhibitory effect against various types of cancer. "Beche-de-mer" holds a 90% market share and is regarded as a luxury food item in Southeast Asian countries. Due to overexploitation, the species is classified as Schedule I under the Wildlife Protection Act (WPA) in India, prompting the implementation of a blanket ban on their harvesting to ensure its conservation.

Purification and Structural Analyses of Sulfated Polysaccharides from Low-Value Sea Cucumber Stichopus naso and Anticoagulant Activities of Its Oligosaccharides.

Three polysaccharides (SnNG, SnFS and SnFG) were purified from the body wall of Stichopus naso. The physicochemical properties, including monosaccharide composition, molecular weight, sulfate content, and optical rotation, were analyzed, confirming that SnFS and SnFG are sulfated polysaccharides commonly found in sea cucumbers. The highly regular structure {3)-L-Fuc2S-(α1,}n of SnFS was determined via a detailed NMR analysis of its oxidative degradation product. By employing ß-elimination depolymerization of SnFG, tri-, penta-, octa-, hendeca-, tetradeca-, and heptadeca-saccharides were obtained from the low-molecular-weight product. Their well-defined structures confirmed that SnFG possessed the backbone of {D-GalNAc4S6S-ß(1,4)-D-GlcA}, and each GlcA residue was branched with Fuc2S4S. SnFS and SnFG are both structurally the simplest version of natural fucan sulfate and fucosylated glycosaminoglycan, facilitating the application of low-value sea cucumbers S. naso. Bioactivity assays showed that SnFG and its derived oligosaccharides exhibited potent anticoagulation and intrinsic factor Xase (iXase) inhibition. Moreover, a comparative analysis with the series of oligosaccharides solely branched with Fuc3S4S showed that in oligosaccharides with lower degrees of polymerization, such as octasaccharides, Fuc2S4S led to a greater increase in APTT prolongation and iXase inhibition. As the degree of polymerization increases, the influence from the sulfation pattern diminishes, until it is overshadowed by the effects of molecular weight.