Structural Characterization and Anticoagulant Activities of a Keratan Sulfate-like Polysaccharide from the Sea Cucumber Holothuria fuscopunctata

A sulfated polysaccharide (AG) was extracted and isolated from the sea cucumber H. fuscopunctata, consisting of GlcNAc, GalNAc, Gal, Fuc and lacking any uronic acid residues. Importantly, several chemical depolymerization methods were used to elucidate the structure of the AG through a bottom-up strategy. A highly sulfated galactose (oAG-1) and two disaccharides labeled with 2,5-anhydro-D-mannose (oAG-2, oAG-3) were obtained from the deaminative depolymerized product along with the structures of the disaccharide derivatives (oAG-4~oAG-6) identified from the free radical depolymerized product, suggesting that the repeating building blocks in a natural AG should comprise the disaccharide β-D-GalS-1,4-D-GlcNAc6S. The possible disaccharide side chains (bAG-1) were obtained with mild acid hydrolysis. Thus, a natural AG may consist of a keratan sulfate-like (KS-like) glycosaminoglycan with diverse modifications, including the sulfation types of the Gal residue and the possible disaccharide branches α-D-GalNAc4S6S-1,2-α/β-L-Fuc3S linked to the KS-like chain. Additionally, the anticoagulant activities of the AG and its depolymerized products (dAG1-9) were evaluated in vitro using normal human plasma. The AG could prolong activated partial thromboplastin time (APTT) in a dose-dependent manner, and the activity potency was positively related to the chain length. The AG and dAG1-dAG3 could prolong thrombin time (TT), while they had little effect on prothrombin time (PT). The results indicate that the AG could inhibit the intrinsic and common coagulation pathways.

The Holothuria leucospilota genome elucidates sacrificial organ expulsion and bioadhesive trap enriched with amyloid-patterned proteins

Some tropical sea cucumbers of the family Holothuriidae can efficiently repel or even fatally ensnare predators by sacrificially ejecting a bioadhesive matrix termed the Cuvierian organ (CO), so named by the French zoologist Georges Cuvier who first described it in 1831. Still, the precise mechanisms for how adhesiveness genetically arose in CO and how sea cucumbers perceive and transduce danger signals for CO expulsion during defense have remained unclear. Here, we report the first high-quality, chromosome-level genome assembly of Holothuria leucospilota, an ecologically significant sea cucumber with prototypical CO. The H. leucospilota genome reveals characteristic long-repeat signatures in CO-specific outer-layer proteins, analogous to fibrous proteins of disparate species origins, including spider spidroin and silkworm fibroin. Intriguingly, several CO-specific proteins occur with amyloid-like patterns featuring extensive intramolecular cross-β structures readily stainable by amyloid indicator dyes. Distinct proteins within the CO connective tissue and outer surface cooperate to give the expelled matrix its apparent tenacity and adhesiveness, respectively. Genomic evidence offers further hints that H. leucospilota directly transduces predator-induced mechanical pressure onto the CO surface through mediation by transient receptor potential channels, which culminates in acetylcholine-triggered CO expulsion in part or in entirety. Evolutionarily, innovative events in two distinct regions of the H. leucospilota genome have apparently spurred CO's differentiation from the respiratory tree to a lethal defensive organ against predators.

Sulfated fucan could serve as a species marker of sea cucumber with endo-1,3-fucanase as the essential tool

In the past few decades, sulfated fucan from sea cucumber had attracted considerable interest owing to its abundant physiological activities. Nevertheless, its potential for species discrimination had not been investigated. Herein, particular attention was given to sea cucumber Apostichopus japonicus, Acaudina molpadioides, Holothuria hilla, Holothuria tubulosa, Isostichopus badionotus and Thelenota ananas to examine the feasibility of sulfated fucan as a species marker of sea cucumber. The enzymatic fingerprint suggested that sulfated fucan exhibited significant interspecific discrepancy and intraspecific stability, which revealed that sulfated fucan could serve as the species marker of sea cucumber, by utilizing the overexpressed endo-1,3-fucanase Fun168A and the ultra-performance liquid chromatography-high resolution mass spectrum. Moreover, oligosaccharide profile of sulfated fucan was determined. The oligosaccharide profile combined with hierarchical clustering analysis and principal components analysis further confirmed that sulfated fucan could serve as a marker with a satisfying performance. Besides, load factor analysis showed that the minor structure of sulfated fucan also contributed to the sea cucumber discrimination, besides the major structure. The overexpressed fucanase played an indispensable role in the discrimination, due to its specificity and high activity. The study would lead to a new strategy for species discrimination of sea cucumber based on sulfated fucan.

Saponin and Fatty Acid Profiling of the Sea Cucumber Holothuria atra, α-Glucosidase Inhibitory Activity and the Identification of a Novel Triterpene Glycoside

Saponin-rich sea cucumber extracts have shown antidiabetic effects in a few reports. Although the triterpene glycosides of sea cucumbers are commonly isolated from their Cuvierian tubules, these are absent in Holothuria atra Jaeger. Therefore, this study intended to investigate the saponin profile in the body wall of H. atra, as well as to assess the α-glucosidase inhibitory activity of the H. atra extracts. The chemical profiling of sea cucumber extracts was conducted by UPLC-HRMS analysis. This resulted in the tentative identification of 11 compounds, 7 of which have not been reported in the H. Atra body wall before. Additionally, two triterpene glycosides were purified and their structures were elucidated based on HRMS and NMR data: desholothurin B (1), and a novel epimer, 12-epi-desholothurin B (2). Moreover, the fatty acid profile of the H. atra body wall was investigated by GC-MS. It was found that the Me90 fraction of the H. atra body wall showed the strongest α-glucosidase inhibitory activity (IC₅₀ value 0.158 ± 0.002 mg/mL), thus making it more potent than acarbose (IC₅₀ value 2.340 ± 0.044 mg/mL).

Diterpene glycosides from Holothuria scabra exert the α-synuclein degradation and neuroprotection against α-synuclein-Mediated neurodegeneration in C. elegans model

ETHNOPHARMACOLOGICAL RELEVANCE

Holothuria (Metriatyla) scabra Jaeger (H. scabra), sea cucumber, is the marine organism that has been used as traditional food and medicine to gain the health benefits since ancient time. Although our recent studies have shown that crude extracts from H. scabra exhibited neuroprotective effects against Parkinson's disease (PD), the underlying mechanisms and bioactive compounds are still unknown.

AIM OF THE STUDY

In the present study, we examined the efficacy of purified compounds from H. scabra and their underlying mechanism on α-synuclein degradation and neuroprotection against α-synuclein-mediated neurodegeneration in a transgenic Caenorhabditis elegans PD model.

MATERIAL AND METHODS

The H. scabra compounds (HSEA-P1 and P2) were purified and examined for their toxicity and optimal dose-range by food-clearance and lifespan assays. The α-synuclein degradation and neuroprotection against α-synuclein-mediated neurodegeneration were determined using transgenic C. elegans model, Punc-54::α-syn and Pdat-1:: α-syn; Pdat-1::GFP, respectively, and then further investigated by determining the behavioral assays including locomotion rate, basal slowing rate, ethanol avoidance, and area-restricted searching. The underlying mechanisms related to autophagy were clarified by quantitative PCR and RNAi experiments.

RESULTS

Our results showed that HSEA-P1 and HSEA-P2 significantly diminished α-synuclein accumulation, improved motility deficits, and recovered the shortened lifespan. Moreover, HSEA-P1 and HSEA-P2 significantly protected dopaminergic neurons from α-synuclein toxicity and alleviated dopamine-associated behavioral deficits, i.e., basal slowing, ethanol avoidance, and area-restricted searching. HSEA-P1 and HSEA-P2 also up-regulated autophagy-related genes, including beclin-1/bec-1, lc-3/lgg-1, and atg-7/atg-7. RNA interference (RNAi) of these genes in transgenic α-synuclein worms confirmed that lc-3/lgg-1 and atg-7/atg-7 were required for α-synuclein degradation and DAergic neuroprotection activities of HSEA-P1 and HSEA-P2. NMR and mass spectrometry analysis revealed that the HSEA-P1 and HSEA-P2 contained diterpene glycosides.

CONCLUSION

These findings indicate that diterpene glycosides extracted from H. scabra decreases α-synuclein accumulation and protects α-synuclein-mediated DAergic neuronal loss and its toxicities via lgg-1 and atg-7.

Beneficial Effects of Cyclic Ether 2-Butoxytetrahydrofuran from Sea Cucumber Holothuria scabra against Aβ Aggregate Toxicity in Transgenic Caenorhabditis elegans and Potential Chemical Interaction

The pathological finding of amyloid-β (Aβ) aggregates is thought to be a leading cause of untreated Alzheimer’s disease (AD). In this study, we isolated 2-butoxytetrahydrofuran (2-BTHF), a small cyclic ether, from Holothuria scabra and demonstrated its therapeutic potential against AD through the attenuation of Aβ aggregation in a transgenic Caenorhabditis elegans model. Our results revealed that amongst the five H. scabra isolated compounds, 2-BTHF was shown to be the most effective in suppressing worm paralysis caused by Aβ toxicity and in expressing strong neuroprotection in CL4176 and CL2355 strains, respectively. An immunoblot analysis showed that CL4176 and CL2006 treated with 2-BTHF showed no effect on the level of Aβ monomers but significantly reduced the toxic oligomeric form and the amount of 1,4-bis(3-carboxy-hydroxy-phenylethenyl)-benzene (X-34)-positive fibril deposits. This concurrently occurred with a reduction of reactive oxygen species (ROS) in the treated CL4176 worms. Mechanistically, heat shock factor 1 (HSF-1) (at residues histidine 63 (HIS63) and glutamine 72 (GLN72)) was shown to be 2-BTHF’s potential target that might contribute to an increased expression of autophagy-related genes required for the breakdown of the Aβ aggregate, thus attenuating its toxicity. In conclusion, 2-BTHF from H. scabra could protect C. elegans from Aβ toxicity by suppressing its aggregation via an HSF-1-regulated autophagic pathway and has been implicated as a potential drug for AD.

Holospiniferoside: A New Antitumor Cerebroside from The Red Sea Cucumber Holothuria spinifera: In Vitro and In Silico Studies

Chemical investigation of the methanolic extract of the Red Sea cucumber Holothuria spinifera led to the isolation of a new cerebroside, holospiniferoside (1), together with thymidine (2), methyl-α-d-glucopyranoside (3), a new triacylglycerol (4), and cholesterol (5). Their chemical structures were established by NMR and mass spectrometric analysis, including gas chromatography-mass spectrometry (GC-MS) and high-resolution mass spectrometry (HRMS). All the isolated compounds are reported in this species for the first time. Moreover, compound 1 exhibited promising in vitro antiproliferative effect on the human breast cancer cell line (MCF-7) with IC50 of 20.6 µM compared to the IC50 of 15.3 µM for the drug cisplatin. To predict the possible mechanism underlying the cytotoxicity of compound 1, a docking study was performed to elucidate its binding interactions with the active site of the protein Mdm2-p53. Compound 1 displayed an apoptotic activity via strong interaction with the active site of the target protein. This study highlights the importance of marine natural products in the design of new anticancer agents.

Chemical Defense Mechanisms and Ecological Implications of Indo-Pacific Holothurians

Sea cucumbers are slow-moving organisms that use morphological, but also a diverse combination of chemical defenses to improve their overall fitness and chances of survival. Since chemical defense compounds are also of great pharmaceutical interest, we pinpoint the importance of biological screenings that are a relatively fast, informative and inexpensive way to identify the most bioactive organisms prior to further costly and elaborate pharmacological screenings. In this study, we investigated the presence and absence of chemical defenses of 14 different sea cucumber species from three families (Holothuriidae, Stichopodidae and Synaptidae) against ecological factors such as predation and pathogenic attacks. We used the different sea cucumber crude extracts as well as purified fractions and pure saponin compounds in a portfolio of ecological activity tests including fish feeding assays, cytotoxicity tests and antimicrobial assays against environmental pathogenic and non-pathogenic bacteria. Furthermore, we quantified and correlated the concentrations of sea cucumber characteristic saponin compounds as effective chemical defensive compounds in all 14 crude extracts by using the vanillin-sulfuric acid test. The initial results revealed that among all tested sea cucumber species that were defended against at least one ecological threat (predation and/or bacterial attack), Bohadschiaargus, Stichopuscholoronotus and Holothuria fuscopunctata were the three most promising bioactive sea cucumber species. Therefore, following further fractionation and purification attempts, we also tested saponin-containing butanol fractions of the latter, as well as two purified saponin species from B. argus. We could demonstrate that both, the amount of saponin compounds and their structure likely play a significant role in the chemical defense strategy of the sea cucumbers. Our study concludes that the chemical and morphological defense mechanisms (and combinations thereof) differ among the ecological strategies of the investigated holothurian species in order to increase their general fitness and level of survival. Finally, our observations and experiments on the chemical ecology of marine organisms can not only lead to a better understanding of their ecology and environmental roles but also can help in the better selection of bioactive organisms/compounds for the discovery of novel, pharmacologically active secondary metabolites in the near future.

The nervous system component of the mesentery of the sea cucumber Holothuria glaberrima in normal and regenerating animals

The mesenterial tissues play important roles in the interactions between the viscera and the rest of the organism. Among these roles, they serve as the physical substrate for nerves connecting the visceral nervous components to the central nervous system. Although the mesenterial nervous system component has been described in vertebrates, particularly in mammals, a description in other deuterostomes is lacking. Using immunohistochemistry in tissue sections and whole mounts, we describe here the nervous component of the intestinal mesentery in the sea cucumber Holothuria glaberrima. This echinoderm has the ability to regenerate its internal organs in a process that depends on the mesentery. Therefore, we have also explored changes in the mesenterial nervous component during intestinal regeneration. Extensive fiber bundles with associated neurons are found in the mesothelial layer, extending from the body wall to the intestine. Neuron-like cells are also found within a plexus in the connective tissue layer. We also show that most of the cells and nerve fibers within the mesentery remain during the regenerative process, with only minor changes: a general disorganization of the fiber bundles and a retraction of nerve fibers near the tip of the mesentery during the first days of regeneration. Our results provide a basic description of mesenterial nervous component that can be of importance for comparative studies as well as for the analyses of visceral regeneration.

Holothuria Leucospilota Polysaccharides Ameliorate Hyperlipidemia in High-Fat Diet-Induced Rats via Short-Chain Fatty Acids Production and Lipid Metabolism Regulation

Holothuria leucospilota polysaccharides (HLP) are expected to become potential resources for the treatment of hyperlipidemia because of their various bioactivities. In the study, the treatment of HLP on improving hyperlipidemia in rats was explored. Oral administration of HLP at 100 or 200 mg/kg body weight effectively alleviated serum lipid levels and liver histological abnormalities in high-fat-diet rats. HLP regulated abnormal mRNA, lipogenesis-related hormones and inflammatory cytokines (tumor necrosis factor-α, interleukin-6 and interleukin-12) levels. HLP improved the ability of gut microbiota to produce short-chain fatty acids (SCFAs). SCFAs have been found to ameliorate liver lesions. Therefore, HLP alleviated hyperlipidemia by improving the levels of SCFAs to regulate lipid metabolism. These results indicated that HLP could be used as beneficial polysaccharides to alleviate hyperlipidemia.

Saponin-enriched extracts from body wall and Cuvierian tubule of Holothuria leucospilota reduce fat accumulation and suppress lipogenesis in Caenorhabditis elegans

BACKGROUND

Saponins have been shown to possess many pharmacological properties, including altered fat metabolism. The black sea cucumber, Holothuria leucospilota, is a marine animal that contains a specialized organ called a Cuvierian tubule that produces and secrete the bioactive saponins into the tubules and body wall. Therefore, the aims of this study are to investigate the anti-obesity effect of saponins extracted from body wall and Cuvierian tubules of H. leucospilota.

RESULTS

The butanol extracts of H. leucospilota body wall and Cuvierian tubules containing high amounts of saponins significantly reduced fat deposition and triglyceride levels in Caenorhabditis elegans fed with 50 mmol L^-1 glucose. Moreover, the saponin-enriched extracts of H. leucospilota significantly restored the lifespan of 2% glucose-fed worms (18.71%). Green fluorescence protein-labeled sbp-1 gene expression and nuclear translocation of daf-16 were also significantly decreased in H. leucospilota treatment. The saponin-enriched extracts downregulated the messenger RNA expressions of genes involved in fat storage and metabolism, including sbp-1, cebp, and daf-16 but upregulated the expression of nhr-49 gene.

CONCLUSION

Our results suggest that H. leucospilota-derived saponins may mediate the reduction of glucose-induced fat accumulation through sbp-1, cebp, daf-16 and nhr-9 pathways. Therefore, the H. leucospilota extracts could be used as nutraceuticals for anti-obesity prevention. © 2019 Society of Chemical Industry.

Molecular Networking-Based Analysis of Cytotoxic Saponins from Sea Cucumber Holothuria atra

The saponin composition of a specimen of black sea cucumber, Holothuria atra collected in the Persian Gulf was studied by a combined approach including LC-MS/MS, Molecular Networking, pure compound isolation, and NMR spectroscopy. The saponin composition of Holothuria atra turned out to be more complex than previously reported. The most abundant saponins in the extract (1⁻4) were isolated and characterized by 1D- and 2D-NMR experiments. Compound 1 was identified as a new triterpene glycoside saponin, holothurin A5. The side chain of the new saponin 1, unprecedented among triterpene glycosides, is characterized by an electrophilic enone function, which can undergo slow water or methanol addition under neutral conditions. The cytotoxic activity of compounds 1⁻4, evaluated on the human cervix carcinoma HeLa cell line, was remarkable, with IC50 values ranging from 1.2 to 2.5 µg/mL.

(3, 2)D 1H, 13C BIRDr,X-HSQC-TOCSY for NMR structure elucidation of mixtures: application to complex carbohydrates

Overlap of NMR signals is the major cause of difficulties associated with NMR structure elucidation of molecules contained in complex mixtures. A 2D homonuclear correlation spectroscopy in particular suffers from low dispersion of ¹H chemical shifts; larger dispersion of ¹³C chemical shifts is often used to reduce this overlap, while still providing the proton-proton correlation information e.g. in the form of a 2D ¹H, ¹³C HSQC-TOCSY experiment. For this methodology to work, ¹³C chemical shift must be resolved. In case of ¹³C chemical shifts overlap, ¹H chemical shifts can be used to achieve the desired resolution. The proposed (3, 2)D ¹H, ¹³C BIRD^r,X-HSQC-TOCSY experiment achieves this while preserving singlet character of cross peaks in the F₁ dimension. The required high-resolution in the ¹³C dimension is thus retained, while the cross peak overlap occurring in a regular HSQC-TOCSY experiment is eliminated. The method is illustrated on the analysis of a complex carbohydrate mixture obtained by depolymerisation of a fucosylated chondroitin sulfate isolated from the body wall of the sea cucumber Holothuria forskali.

Proximate composition and mineral contents in the body wall of two species of sea cucumber from Oman Sea

The proximate composition and mineral contents of Stichopus horrens and Holothuria arenicola from Chabahar Bay were analyzed and investigated. During the present study, we aimed to demonstrate the nutritive value. The approximate percent composition of moisture, protein, fat, and ash were 92.8, 3.47, 0.4, and 3.33% in S. horrens and 93, 4.4, 0.6, and 2% in H. arenicola, respectively. Atomic absorption spectrophotometry of the ashes indicated the body wall of two species of sea cucumbers contained higher amounts of both macro minerals (92.5 mg/100 g Mg in S. horrens and 115 mg/100 g Mg in H. arenicola; 106.25 mg/100 g Ca in S. horrens and 83.25 mg/100 g Ca in H. arenicola) and trace elements (521.781 mg/100 g Fe in S. horrens; 60.354 mg/100 g Fe in H. arenicola, and 0.096 mg/100 g Zn in S. horrens; 0.04 mg/100 g Zn in H. arenicola). For both species, there were high content of protein and essential mineral. Also, they have low content of fat in the body wall of two species in the experiment.

Selective toxicity of persian gulf sea cucumber holothuria parva on human chronic lymphocytic leukemia b lymphocytes by direct mitochondrial targeting

Natural products isolated from marine environment are well known for their pharmacodynamic potential in diversity of disease treatments such as cancer or inflammatory conditions. Sea cucumbers are one of the marine animals of the phylum Echinoderm. Many studies have shown that the sea cucumber contains antioxidants and anti-cancer compounds. Chronic lymphocytic leukemia (CLL) is a disease characterized by the relentless accumulation of CD5⁺ B lymphocytes. CLL is the most common leukemia in adults, about 25-30% of all leukemias. In this study B lymphocytes and their mitochondria (cancerous and non-cancerous) were obtained from peripheral blood of human subjects and B lymphocyte cytotoxicity assay, and caspase 3 activation along with mitochondrial upstream events of apoptosis signaling including reactive oxygen species (ROS) production, collapse of mitochondrial membrane potential (MMP) and mitochondrial swelling were determined following the addition of Holothuria parva extract to both cancerous and non-cancerous B lymphocytes and their mitochondria. Our in vitro finding showed that mitochondrial ROS formation, MMP collapse, and mitochondrial swelling and cytochrome c release were significantly (P < 0.05) increased after addition of different concentrations of H. parva only in cancerous BUT NOT normal non-cancerous mitochondria. Consistently, different concentrations of H. parva significantly (P < 0.05) increased cytotoxicity and caspase 3 activation only in cancerous BUT NOT normal non-cancerous B lymphocytes. These results showed that H. parva methanolic extract has a selective mitochondria mediated apoptotic effect on chronic lymphocytic leukemia B lymphocytes hence may be promising in the future anticancer drug development for treatment of CLL. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1158-1169, 2017.

Baseline of polycyclic aromatic hydrocarbons in the surface sediment and sea cucumbers (Holothuria leucospilota and Stichopus hermanni) in the northern parts of Persian Gulf

Polycyclic aromatic hydrocarbons (PAHs) were determined in the surface sediments and in the sea cucumbers (Holothuria leucospilota and Stichopus hermanni) from around six Islands in the northern parts of Persian Gulf. The ranges of the average concentrations of PAHs in surface sediments, H. leucospilota and S. hermanni were 10.33-186.16ngg(-1) dw, 12.49-505.44ngg(-1) dw and 8.08-389.39ngg(-1) dw, respectively. The spatial distribution of PAHs reveals that pollutant concentration is relatively higher at the western parts of Persian Gulf. International sedimentary quality guidelines (TEL-PEL) indicated a low probability of harmful effects to benthic organisms. PAH source identification showed that the PAHs in the sediments come from pyrogenic and mixed origin.

Assessment of trace metal contamination in the sea cucumber (Holothuria tubulosa) and sediments from the Dardanelles Strait (Turkey)

This study was performed to determine the concentrations of some trace metals (Cd, Cu, Pb, Ni, Zn, and Fe) in Holothuria tubuosa (Gmelin, 1788) belonging to Echinoderm species and in sediments that they live at three different stations (Gelibolu, Umur Bey/Lapseki, and Dardanos) on Dardanelles Strait between April 2013 and March 2014. The mean trace metal concentrations determined in H. tubulosa and sediment were as follows: Cd 0.18 mg/kg, Cu 2.43 mg/kg, Pb 2.09 mg/kg, Ni 14.58 mg/kg, Zn 16.86 mg/kg, and Fe 73.46 mg/kg and Cd 0.70 mg/kg, Cu 5.03 mg/kg, Pb 14.57 mg/kg, Ni 27.15 mg/kg, Zn 54.52 mg/kg, and Fe 3779.9 mg/kg, respectively. It was detected that the statistical difference between trace metals determined seasonally in muscle tissue of H. tubulosa was significant (p > 0.05). As a result of the study, it was detected that H. tubulosa is a bioindicator species in determining Ni trace metal in sediment. The results were compared to the limit values of National and International Food Safety, and it was detected that Cd and Ni concentrations measured in sediment were above LEL of Ni and Cd concentrations according to Sediment Quality Guidelines.

Heavy metal accumulation in tissues of two sea cucumbers, Holothuria leucospilota and Holothuria scabra in the northern part of Qeshm Island, Persian Gulf

The concentrations of some heavy metals (Cd, Cu, Zn andPb) were investigated in the sediments and the two species of sea cucumber (Holothuria leucospilota and Holothuria scabra) from northern part of Qeshm Island, Persian Gulf. The levels of Cu, Zn and Pb in sediment varied significantly among sampling sites (p<0.05). The highest levels of Zn and Pb in H. leucospilota were recorded in body wall whereas the highest contents of Zn and Pb in H. scabra were measured in respiratory tree organ, respectively. Cu and Cd were the most abundant elements in gonads of H. leucospilota while highest levels of Cd and Cu in H. scabra were measured in the gonad and derm, respectively. Cu and Zn concentrations were below permissible limits for human consumption while Cd and Pb were above permissible limits for human consumption.

Cytotoxic and anti-colorectal tumor effects of sulfated saponins from sea cucumber Holothuria moebii

BACKGROUND

Whether sulfated saponins from Holothuria moebii inhibit the proliferation of colorectal cancer cells and have anti-colorectal tumor effects in animal model has not been investigated.

PURPOSE

To evaluate the cytotoxic and anti-colorectal tumor effects of sulfated saponins from sea cucumber Holothuria moebii.

METHOD

(1) Column chromatography was used to prepare the total and individual saponins and HPLC was applied to define the components of the total saponins; (2) the activity of the total and individual saponins inhibiting the proliferation of human colorectal cancer cells was determined by SRB assay and the apoptosis induced by the saponins was qualified using cytometric analysis with Annexin V-FITC/PI double staining; and (3) the antitumor effects of the sulfated saponins on colorectal CT-26 tumor-bearing Balb/c mice were tested.

RESULTS

The total and individual sulfated saponins significantly inhibited the proliferation of four different human colorectal cancer cells with IC50 values ranging from 1.04 to 4.08 μM (or 1.46 to 3.24 μg/ml for total saponins) and induced late apoptosis at an early treatment time in cancer cells. The total saponins (120 mg/kg) had antitumor activity in colorectal CT-26 tumor-bearing Balb/c mice.

CONCLUSION

The sulfated saponins from H. moebii remarkably inhibited the proliferation of different human colorectal cancer cells and had significant anti-colorectal tumor activity in animal model.

Cytoprotective Effects of Lysophospholipids from Sea Cucumber Holothuria atra

Lysophospholipids are important signaling molecules in animals and metazoan cells. They are widely distributed among marine invertebrates, where their physiological roles are unknown. Sea cucumbers produce unique lysophospholipids. In this study, two lysophospholipids were detected in Holothuria atra for the first time, lyso-platelet activating factor and lysophosphatidylcholine, with nuclear magnetic resonance and liquid chromatography-time-of-flight mass spectrometric analyses. The lipid fraction of H. atra contained lyso-platelet activating factor and lysophosphatidylcholine, and inhibited H2O2-induced apoptosis in the macrophage cell line J774A.1. The antioxidant activity of the lysophospholipid-containing lipid fraction of H. atra was confirmed with the oxygen radical absorbance capacity method. Our results suggest that the lysophospholipids from H. atra are potential therapeutic agents for the inflammation induced by oxidative stress.

Anti-fibrotic effect of Holothuria arenicola extract against bile duct ligation in rats

BACKGROUND

Holothuria arenicola is the most important and abundant sea cucumber species in the Mediterranean Sea on the Egyptian coast. The present study aims to assess the anti-oxidative and anticholestatic effects of the sea cucumber Holothuria arenicola extract (HaE) in a model of bile duct ligation in male albino rats.

METHODS

Fifty four male Wistar albino rats were assigned into two main groups, the Sham-operated control and bile duct ligated (BDL) group. After 14 days of surgery, the animals of the group I (Sham control) received distilled water only for 7, 14 and 28 days. Second group (BDL group) was divided into 2 subgroups, animals of these subgroups treated for 7, 14 and 28 consecutive days as follow: subgroup I (BDL), rats of this subgroup administered distilled water orally. Subgroup II (HaE), animals of this subgroup treated orally with HaE (200 mg/kg body weight).

RESULTS

The HaE revealed significant antifibrotic effect as evident by decreasing the levels of total conjugated and unconjugated bilirubin and the activities of serum aminotransferases (ASAT and ALAT) and alkaline phosphatase (ALP) as well as malondialdehyde (MDA) level, and increasing the serum albumin, glutathione reduced (GSH) levels. Treatment with HaE normalized the antioxidant enzyme, glutathione-S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT) activities activities.

CONCLUSION

The present prospective study correlated the antifibrotic effect of HaE to its direct antioxidant effect that can be related to its contents of phenolic compounds specially chlorogenic acid, pyrogallol, rutin and coumaric acid.

New cytotoxic triterpene glycoside from the East China Sea cucumber Holothuria nobilis

A new cytotoxic triterpene glycoside named nobiliside E (1) has been obtained from the East China Sea cucumber Holothuria nobilis Selenka. Its structure was determined on the basis of NMR spectroscopic and MS analyses, together with chemical evidence. The new compound showed significant cytotoxicity to eight human tumor cell lines with IC50 values in the range of 0.53-4.06 μg/mL.

Bioactive sulfated saponins from sea cucumber Holothuria moebii

The bioactive ingredients of sea cucumber Holothuria moebii were investigated, and four sulfated saponins (1-4) and one desulfated saponin (3B) with an unusual 3,4-epoxy xylose were obtained from this study. Compound 2 is a new triterpenoid saponin and 3B is a new artificial compound. On the basis of the extensive NMR and HRESIMS data, their structures were assigned as 3-O-[β-D-quinovopyranosyl-(1 → 2)-4-sodium sulfato-β-D-xylopyranosyl]-25-acetoxy-22-oxo-9(11)-holostene-3β,12α,17α-triol (2) and 3-O-[β-D-quinovopyranosyl-(1 → 2)-3,4-epoxy-β-xylopyranosyl]-22,25-epoxy-9(11)-holostene-3β,12α,17α-triol (3B). Compounds 1-4 showed activity suppressing the proliferation of four different glioma cells with IC50 values ranging from 0.99 to 8.64 µM. New saponin 2 significantly induced apoptosis in human glioblastoma U87-MG cells and reduced the expression levels of several glioma metabolic enzymes of glycolysis and glutaminolysis. This study reveals for the first time that selectively targeting multiple glioma metabolic regulators of glycolysis and glutaminolysis might be one of the anti-glioma mechanisms of saponin 2.

Identification of proteins associated with adhesive prints from Holothuria dofleinii Cuvierian tubules

Cuvierian tubules are expelled as a defence mechanism against predators by various species within the family Holothuridae. When the tubules are expelled, they become sticky almost immediately and ensnare the predator. The mechanism of this rapid adhesion is not clear, but proteins on the surface of the expelled tubules are widely believed to be involved. This study has examined such proteins from Holothuria dofleinii, sourced from adhesive prints left on glass after the removal of adhered tubules. Gel electrophoresis showed that seven strongly staining protein bands were consistently present in all samples, with molecular masses ranging from 89 to 17 kDa. N-terminal sequence data was obtained from two bands, while others seemed blocked. Tandem mass spectrometry-based sequencing of tryptic peptides derived from individual protein bands indicated that the proteins were unlikely to be homopolymers. PCR primers designed using the peptide sequences enabled us to amplify, clone and sequence cDNA segments relating to four gel bands; for each, the predicted translation product contained other peptide sequences observed for that band that had not been used in primer design. Database searches using the peptide and cDNA-encoded sequences suggest that two of the seven proteins are novel and one is a C-type lectin, while-surprisingly-at least three of the other four are closely related to enzymes associated with the pentose phosphate cycle and glycolysis. We discuss precedents in which lectins and metabolic enzymes are involved in attachment and adhesion phenomena.

Structure elucidation of five novel isomeric saponins from the viscera of the sea cucumber Holothuria lessoni

Sea cucumbers are prolific producers of a wide range of bioactive compounds. This study aimed to purify and characterize one class of compound, the saponins, from the viscera of the Australian sea cucumber Holothuria lessoni. The saponins were obtained by ethanolic extraction of the viscera and enriched by a liquid-liquid partition process and adsorption column chromatography. A high performance centrifugal partition chromatography (HPCPC) was applied to the saponin-enriched mixture to obtain saponins with high purity. The resultant purified saponins were profiled using MALDI-MS/MS and ESI-MS/MS which revealed the structure of isomeric saponins to contain multiple aglycones and/or sugar residues. We have elucidated the structure of five novel saponins, Holothurins D/E and Holothurinosides X/Y/Z, along with seven reported triterpene glycosides, including sulfated and non-sulfated saponins containing a range of aglycones and sugar moieties, from the viscera of H. lessoni. The abundance of novel compounds from this species holds promise for biotechnological applications.

Cytotoxic and apoptosis-inducing activity of triterpene glycosides from Holothuria scabra and Cucumaria frondosa against HepG2 cells

The cytotoxic effects of thirteen triterpene glycosides from Holothuria scabra Jaeger and Cucumaria frondosa Gunnerus (Holothuroidea) against four human cell lines were detected and their cytotoxicity-structure relationships were established. The apoptosis-inducing activity of a more potent glycoside echinoside A (1) in HepG2 cells was further investigated by determining its effect on the morphology, mitochondrial transmembrane potential (Δψ_m) and mRNA expression levels of the apoptosis-related genes. The results showed that the number of glycosyl residues in sugar chains and the side chain of aglycone could affect their cytotoxicity towards tumor cells and selective cytotoxicity. 1 significantly inhibited cell viability and induced apoptosis in HepG2 cells. 1 also markedly decreased the Δψ_m and Bcl-2/Bax mRNA express ratio, and up-regulated the mRNA expression levels of Caspase-3, Caspase-8 and Caspase-9 in HepG2 cells. Therefore, 1 induced apoptosis in HepG2 cells through both intrinsic and extrinsic pathway. These findings could potentially promote the usage of these glycosides as leading compounds for developing new antitumor drugs.

Polyhydroxy cyclohexanols from a Dendrodochium sp. fungus associated with the sea cucumber Holothuria nobilis Selenka

Four cyclohexanol analogues, dendrodochols A-D (1-4), were isolated from a Dendrodochium sp. fungus associated with the sea cucumber Holothuria nobilis Selenka collected from the South China Sea. The structures were elucidated by means of detailed spectroscopic analysis. The absolute configurations were assigned using a solution TDDFT/ECD calculation approach and the modified Mosher's method. In an in vitro bioassay, these compounds exhibited no growth inhibition activity against the A549 and MG63 cell lines. Dendrodochols 1 and 3 exhibited modest antifungal activity against Candida strains, Cryptococcus neoformans, and Trichophyton rubrum, whereas 2 and 4 showed no activity against the tested strains.

Antiviral activity of Holothuria sp. a sea cucumber against herpes simplex virus type 1 (HSV-1)

BACKGROUND

Finding the new bioactive compounds with antiviral activity from the natural resources are in interest of many drug discovery scientists. Sea cucumber is among the marine organisms a traditional food item in Asia with different applications in traditional medicine.

METHODS

In current study, a cold water extract of the Holothuria sp, one type Persian Gulf's sea cucumber was evaluated for its antiviral effects against KOS strain of Herpes Simplex Virus tyoe 1 (HSV-1) in cell culture. The half maximal inhibitory concentration (IC50) values were calculated for anti-adsorption activity and intracellular antiviral activity of the crude extract separately.

RESULTS

The extract exhibited antiviral activity not only against the virus adsorption to the cells, but also on virus intracellular replication. The CC50 for sea cucumber extract was 32.57 mg/ml. The IC50 values for the inhibition of the virus adsorption to the cells and virus intracellular replication were 120.2 and 189.9 µg/ml respectively. Selectivity index (SI) value for anti-adsorption activity was 189 while that value for the extract's intracellular antiviral activity was 172.

CONCLUSIONS

The results showed that Holothuria sp, water extract has remarkable antiviral effect against HSV-1 in cell culture and it is crucial to investigate the mechanism(s) of action of extract. Moreover, identification of the effective compound(s) within the extract would be necessary for future studies towards developing the new natural antiviral agent against HSV-1.

Kinetics and thermodynamics of glycans and glycoproteins binding to Holothuria scabra lectin: a fluorescence and surface plasmon resonance spectroscopic study

Holothuria scabra produces a monomeric lectin (HSL) of 182 kDa. HSL showed strong antibacterial activity and induced bacterial agglutination under in vitro conditions, indicating its role in animals' innate immune responses. Very few lectins have been reported from echinoderms and none of these lectins have been explored in detail for their sugar-binding kinetics. Affinity, kinetics and thermodynamic analysis of glycans and glycoproteins binding to HSL were studied by fluorescence and surface plasmon resonance spectroscopy. Lectin binds with higher affinity to O-linked than N-linked asialo glycans, and the affinities were relatively higher than that for sialated glycans and glycoproteins. T-antigen α-methyl glycoside was the most potent ligand having the highest affinity (Ka 8.32 ×10(7) M(-1)). Thermodynamic and kinetic analysis indicated that the binding of galactosyl Tn-antigen and asialo glycans is accompanied by an enthalpic contribution in addition to higher association rate coupled by low activation energy for the association process. Presence of sialic acid or protein matrix inhibits binding. Higher affinity of HSL for O-glycans than N-glycans had biological implications; since HSL specifically recognizes bacteria, which have mucin or O-glycan cognate on their cell surfaces and play a major role in animal innate immunity. Since, HSL had higher affinity to T-antigen, makes it a useful tool for cancer diagnostic purpose.

Antioxidant and cytotoxic properties of two sea cucumbers, Holothuria edulis lesson and Stichopus horrens Selenka

Sea cucumbers are marine invertebrates of the phylum of Echinodermata that have been used in Asian traditional medicine since ancient times. This study was conducted to investigate the antioxidant and cytotoxic properties of aqueous and organic extracts from two sea cucumber species, Holothuria edulis Lesson (Holothuriidae) and Stichopus horrens Selenka (Stichopodidae). Antioxidant activities of the extracts were evaluated by DPPH· and β-carotene bleaching assays, while MTT and trypan blue exclusion assays were used to demonstrate the cytotoxic effects of the extracts against two human cancer cell lines, non-small cell lung cancer cells (A549) and esophageal cancer cells (TE1). The results showed that both aqueous and organic extracts of H. edulis were able to scavenge DPH radical (IC50 at 2.04 mg/ml and 8.73 mg/ml, respectively). Aqueous and organic extracts of S. horrens inhibited 79.62% and 46.66% of β-carotene oxidation by linoleate free radical. On the other hand, the organic extract of S. horrens exhibited the highest cytotoxic effects against A549 and TE1 cancer cells giving IC50 at 15.5 and 4.0 μg/ml, respectively. In conclusion, the present study revealed that H. edulis and S. horrens contain promising levels of antioxidant and cytotoxic natural products that might be used for cancer prevention and treatment.

Antischistosomal effect of holothurin extracted from some Egyptian sea cucumbers

CONTEXT

Holothuria polii (H. polii) Linnaeus (Holothuriidae), Actinopyga mauritiana (A. mauritiana) Quoy & Gaimard (Holothuriidae) and Bohadschia vitiensis (B. vitiensis) Semper (Holothuriidae) are sea cucumbers inhabiting the coasts of Egypt. Their tegument and the cuvierian gland contained a substance called holothurin that was used in traditional medicine. These three species are abundant in the Egyptian coast, however there are no reports about their efficacy as antiparasitic agent.

OBJECTIVE

The antischistosomal effect of the holothurin extracted from the three species of sea cucumber is investigated.

MATERIALS AND METHODS

The ethanol extract was made from the tegument of both H. polii and A. mauritiana while it was made from the cuvierian gland of B. vitiensis. The body wall (or cuvierian gland) of the sea cucumber was blended with 95% ethanol in a volume = 4 × tissue weight. Extraction was done at room temperature for one day then filtered. The ethanol was removed by evaporation using Rotavapour (BÜCHI 461 water bath REIII) at 40°C. Later the aqueous residue was placed in a vacuum oven at 20°C for about 48 h to remove water. The resulting dried mass was then stored at -4°C until use. The percentage yield and the LD₅₀ were calculated for each extract. Each extract was administered orally to Shistosoma mansoni infected mice in acute and chronic phases of infection. The dose of one-tenth of LD₅₀ of each extract was administrated to mice (5.4, 62.2, and 10 mg/kg body weight/mouse for H. polii extract (HPE), A. mauritiana extract (AME), and cuvierian gland of B. vitiensis, respectively) for 24 h. The effects of each extract on the worm burden and total egg count was studied. The effects of each extract on the worm tegument using scanning electron microscope (SEM) were investigated in vivo and in vitro.

RESULTS

The percentage yield of cuvierian gland extract (CGE) was higher (70%) than the tegument AME (33.4%) and HPE (9.3%). The 24 h LD₅₀ of investigated sea cucumber ethanol extracts were 54.46, 627, and 100 mg/kg body weight/mouse for HPE, AME, and CGE. Oral administration of HPE caused decrease in male and female worm burden of 30-day infected mice to reach 60 and 90%, respectively. HPE decreased the egg count significantly in those mice with 30-day (1.75 egg counts/g tissue, p < 0.05) and 45-day (3.25 egg counts/g tissue, p < 0.05) infections. SEM studies of recovered worms from treated mice with all extracts showed different tegumental changes like formation of blebs, wrinkling, formation of numerous pores, and rupturing of some tubercles. These effects were more pronounced in those worms treated in vitro represented by severe shrinkage of the tegument, deformation of spines, rupturing, and collapsing of tubercles.

DISCUSSION AND CONCLUSION

Results support the hypothesis that holothurin is a promising antischistosomal agent.

High-value components and bioactives from sea cucumbers for functional foods--a review

Sea cucumbers, belonging to the class Holothuroidea, are marine invertebrates, habitually found in the benthic areas and deep seas across the world. They have high commercial value coupled with increasing global production and trade. Sea cucumbers, informally named as bêche-de-mer, or gamat, have long been used for food and folk medicine in the communities of Asia and Middle East. Nutritionally, sea cucumbers have an impressive profile of valuable nutrients such as Vitamin A, Vitamin B1 (thiamine), Vitamin B2 (riboflavin), Vitamin B3 (niacin), and minerals, especially calcium, magnesium, iron and zinc. A number of unique biological and pharmacological activities including anti-angiogenic, anticancer, anticoagulant, anti-hypertension, anti-inflammatory, antimicrobial, antioxidant, antithrombotic, antitumor and wound healing have been ascribed to various species of sea cucumbers. Therapeutic properties and medicinal benefits of sea cucumbers can be linked to the presence of a wide array of bioactives especially triterpene glycosides (saponins), chondroitin sulfates, glycosaminoglycan (GAGs), sulfated polysaccharides, sterols (glycosides and sulfates), phenolics, cerberosides, lectins, peptides, glycoprotein, glycosphingolipids and essential fatty acids. This review is mainly designed to cover the high-value components and bioactives as well as the multiple biological and therapeutic properties of sea cucumbers with regard to exploring their potential uses for functional foods and nutraceuticals.

Two new cytotoxic triterpene glycosides from the sea cucumber Holothuria scabra

Two new triterpene glycosides, scabraside A (1) and B (2), and a structurally known compound (3), were isolated from the sea cucumber Holothuria scabra (Holothuriidae) collected from the South China Sea. Structure of these compounds was elucidated by spectroscopic and chemical methods. The glycosides 1 and 2 exhibit the same common structural features, i. e., the presence of 12- and 17-hydroxy groups in the holostane-type triterpene aglycone with a 9(11)-ene bond, but are different in the side chains of the triterpene aglycone. The glycosides 1 and 2 had significant in vitro cytotoxicity against four human tumor cell lines in comparison to 10-hydroxycamptothecin.

Antifungal active triterpene glycosides from sea cucumber Holothuria scabra

To study the new antifungal active triterpene glycosides of sea cucumber Holothuria scabra. Triterpene glycosides from Holothuria scabra were separated and purified by silica gel chromatography, reversed-phase silica gel chromatography and RP-HPLC. Their structures were elucidated on the basis of spectral data and chemical evidence. Three triterpene glycosides were identified as scabraside A (1), echinoidea A (2) and holothurin A1 (3). Scabraside A (1) is a new triterpene glycoside, and compounds 2 and 3 were isolated from Holothuria scabra for the first time. They showed antifungal activities (1 < or = MIC80 < or = 16 microg mL(-1)).

Antifungal triterpene glycosides from the sea cucumber Holothuria (Microthele) axiloga

Three new holostan-type triterpene glycosides, arguside F (1), impatienside B (2), and pervicoside D (3), together with a known saponin, holothurin B ( 4) were isolated from the sea cucumber Holothuria (Microthele) axiloga H. L. Clark. On the basis of spectroscopic data and chemical reactions, the structures of the new compounds were elucidated. Compound 2 showed significant antifungal activities against six strains (1 < or = MIC(80) < or = 4 microg/mL). The stereochemistry of holothurin B (4) isolated from the title sea cucumber was also solved through X-ray diffraction analysis.

[Complexation between triterpene glycosides of holothurians and cholesterol is the basis of lipid-saponin carriers of subunit protein antigens]

The ability of some triterpene glycosides of holothurians: cucumarioside A2-2 from Cucumaria japonica, cucumarioside G1 from Cucumaria fraudatrix, frondoside A from Cucumaria frondosa, and holotoxin A1 from A postichopus japonicus to form lipid-saponin supramolecular complexes was studied. The formation of supramolecular cholesterol-glycosides complexes between cholesterol and these glycosides in water medium was observed by transmission electron microscopy. These complexes were considered as nanoparticles with different structure. Complexes formed by cholesterol with cucumarioside A2-2, holotoxin A1, and frondoside A are tubular nanoparticles. In contrast, complexes between cholesterol and cucumarioside G1 have different structured. The structure of nanoparticles formed in the presence of cucumarioside A2-2, holotoxin A1, and cucumarioside G1 was dependent on the ratio of cholesterol in the lipid-saponin system. On the other hand, frondoside A did not shown this tendency. In lipid-saponin systems with a similar molar ratio cholesterol-glycoside, the ordering of the supramolecular structure decreases in the following order: cucumarioside A2-2, holotoxin A1, frondoside A. A comparative analysis of the morphology of the supramolecular complexes and the peculiarities of the molecular structure of triterpene glycosides studied, demonstrated that the structure of supramolecular complexes formed depends on the branching and length of the glycoside carbohydrate chain. On the other hand, the formation of monomeric cholesterol-glycosides complexes depends on the peculiarities of the structure of aglycone. Thus, the possibility of the formation of a new type of antigen carries on the basis of marine triterpene glycosides was proved.

[Screening of bioactive constituents from sea cucumber Holothuria nobilis using conidia of Pyricularia oryzae]

OBJECTIVE

To study the bioactive triterpene glycosides from sea cucumber Holothuria nobilis.

METHODS

Guided by Pyricularia oryzae bioassay method, the glycosides compounds were separated by multi-chromatography, and their structures were elucidated by chemical and spectral analysis.

RESULTS

Twelve triterpene glycosides were obtained and their structures were identified, including seven novel saponins. All saponins showed activities on P. oryzae, and most of them exhibited cytotoxicity on P388 and A549 significantly.

CONCLUSION

Our researches provided valuable leads for pursuing new anticancer drugs, and established a homebase for further development of H. nobilis which is widely distributed in South China Sea.

[Chemical constituents from sea cucumber Holothuria nobilis]

OBJECTIVE

To study the chemical constituents of sea cucumber Holothuria hilla L..

METHODS

Compounds were isolated from the sea cucumber by multi-chromatography on Si gel, ODS Rp C-18 gel, DA101 resin, Sephadex LH-20 and HPLC. The structures were elucidated according to their spectral data and chemical character.

RESULTS

Four compounds were isolated from the sea cucumber, and were identified as: holothuria A (I), thymine (II), uracil (III), cholesterol (IV).

CONCLUSION

Compounds I IV are obtained from this kind of sea cucumber for the first time.

Purification and characterization of a T-antigen specific lectin from the coelomic fluid of a marine invertebrate, sea cucumber (Holothuria scabra)

A novel lectin was purified from the coelomic fluid of the sea cucumber Holothuria scabra (HSL), subjected to bacterial challenge. HSL is a monomeric glycoprotein of molecular mass 182 kDa. The lectin is highly thermostable as it retains full activity for 1 h at 80 degrees C. Further, the hemagglutination activity of HSL is unaffected by pH in the range 2-11. Unlike other lectins purified from marine invertebrates, the hemagglutination activity of HSL does not require any divalent metal ions. The affinity profile of HSL was studied by a combination of hemagglutination inhibition and fluorescence spectroscopy. HSL binds to desialylated glycoproteins, MealphaGal, T-antigen and T (alpha-ser)-antigen with a distinction between beta1-4 and beta1-3 linkages. Mealpha-T-antigen was a potent ligand having highest affinity (Ka 8.32 x 10(7)M(-1)). Monosaccharide binding is enthalphically driven while disaccharide binding involves both entropic and enthalpic contributions.

Nobilisides A - C, three new triterpene glycosides from the sea cucumber Holothuria nobilis

Three new triterpene glycosides, named nobilisides A ( 1), B ( 2) and C ( 3), were isolated from the sea cucumber Holothuria nobilis Selenka. Their structures were deduced by extensive spectral analysis and chemical evidence. Compounds 1 and 3 are non-sulfated monoglycosides while 2 is a sulfated diglycoside. The presence of two conjugated double bonds [22 E,24-diene and 7,9(11)-diene] in the aglycone of 1 is a rare structural feature among sea cucumber glycosides, while 2 and 3 possess the same 22,25-epoxy moiety as their side chains. All three glycosides exhibited significant cytotoxicity against human tumor cell lines.

Constituents of Holothuroidea, 17. Isolation and Structure of Biologically Active Monosialo-Gangliosides from the Sea Cucumber Cucumaria echinata

Three new monosialo-gangliosides, CEG-3 (3), CEG-4 (4), and CEG-5 (5), were obtained, together with two known gangliosides, SJG-1 (1) and CG-1 (2), from the lipid fraction of the chloroform/methanol extract of the sea cucumber Cucumaria echinata. The structures of the new gangliosides were determined on the basis of chemical and spectroscopic evidence to be 1-O-[4-O-acetyl-alpha-L-fucopyranosyl-(1-->11)-(N-glycolyl-alpha-D-neuraminosyl)-(2-->6)-beta-D-glucopyranosyl]-ceramide (3) and 1-O-[alpha-L-fucopyranosyl-(1-->11)-(N-glycolyl-alpha-D-neuraminosyl)-(2-->6)-beta-D-glucopyranosyl]-ceramide (4, 5). The ceramide moieties of each compound were composed of heterogeneous sphingosine or phytosphingosine bases, and 2-hydroxy or nonhydroxylated fatty acid units. These gangliosides showed neuritogenic activity toward the rat pheochromocytoma cell line PC-12 in the presence of nerve growth factor.

Constituents of Holothuroidea, 18. Isolation and Structure of Biologically Active Disialo- and Trisialo-Gangliosides from the Sea Cucumber Cucumaria echinata

Three new disialo- and trisialo-gangliosides, CEG-6 (6), CEG-8 (8), and CEG-9 (9), were obtained, together with one known ganglioside, HLG-3 (7), from the lipid fraction of the chloroform/methanol extract of the sea cucumber Cucumaria echinata. The structures of the new gangliosides were determined on the basis of chemical and spectroscopic evidence to be 1-O-[alpha-L-fucopyranosyl-(1-->11)-(N-glycolyl-alpha-D-neuraminosyl)-(2-->4)-(N-acetyl-alpha-D-neuraminosyl)-(2-->6)-beta-D-glucopyranosyl]-ceramide (6) and 1-O-[(N-glycolyl-D-neuraminosyl)-(2-->11)-(N-glycolyl-D-neuraminosyl)-(2-->4)-(N-acetyl-D-neuraminosyl)-(2-->6)-D-glucopyranosyl]-ceramide (8, 9). The ceramide moieties of each compound were composed of an homogeneous sphingosine or phytosphingosine base and heterogeneous 2-hydroxy or nonhydroxylated fatty acid units. These gangliosides showed neuritogenic activity toward the rat pheochromocytoma cell line PC-12 in the presence of nerve growth factor.

Constituents of Holothuroidea, 15. Isolation of ante-iso type regio-isomer on long chain base moiety of glucocerebroside from the sea cucumber Holothuria leucospilota

An ante-iso type regio-isomer on the long chain base moiety of a glucocerebroside, HLC-2-A, has been isolated from its parent glucocerebroside molecular species HLC-2 composed of iso and ante-iso isomers, from the less polar lipid fraction of a chloroform/methanol extract of the sea cucumber Holothuria leucospilota. Reverse-phase HPLC that included a recycling system was effective in separating the regio-isomer from its counterpart, revealing a very close resemblance in structure. Other typical glucocerebroside molecular species HLC-1 and HLC-3 were obtained together with HLC-2. The structures of these glucocerebrosides were determined on the basis of chemical and spectroscopic evidence.

Determination of steryl sulphates in invertebrate tissue by liquid chromatography–tandem mass spectrometry

A method for the identification and quantification of underivatised steryl sulphates in invertebrates by liquid chromatography (LC) coupled with tandem mass spectrometry (MS) involving a single cleanup step has been developed. Negative electrospray ionisation and positive and negative atmospheric-pressure chemical ionisation (APCI) spectra of steryl sulphate showed pseudomolecular ions ([M+H-H2SO4]+ or [M-H]-). Collision-induced dissociation (CID) was efficient only in positive APCI. LC-MS in negative APCI was least susceptible to interference and possible differences in response factors. The detection limits (signal-to-noise ratio of 3) based on cholest-5-enyl-3-sulphate in positive and negative APCI modes are 3.66 and 0.73 pmol microL(-1), respectively. Calibration plots and response factors for cholest-5-enyl-3-sulphate relative to the internal standard, cholecalciferyl-3-sulphate, in both positive and negative polarities, were linear in the concentration range from 1.22 to 16.4 pmol microL(-1) with good coefficients of determination (R2 > 0.98). It is suggested that the structure elucidation of steryl sulphates is best achieved in CID positive APCI mode, whereas their quantification should be carried out using negative APCI.

Constituents of Holothuroidea, 16. Determination of Absolute Configuration of the Branched Methyl Group in Ante-iso Type Side Chain Moiety on Long Chain Base of Glucocerebroside from the Sea Cucumber Holothuria leucospilota

The absolute configuration of the branched methyl group in ante-iso type side chain moiety on the long chain base of glucocerebroside, HLC-2-A, which was isolated from the sea cucumber Holothuria leucospilota was determined. Oxidation of the glucocerebroside with ozone afforded C13-fragment including the ante-iso moiety. The optically active C13-fragment was synthesized asymmetrically by using the Wittig reaction from chiral synton for comparison with the natural fragment.

[Clinical study on the antithrombotic effects of Holothuria ldeucospilota acidic mucopolysaccharide]

OBJECTIVE

To study the antithrombotic effects of Holothuria Ldeucospilota Acidic Mucopolysaccharide (HLAM).

METHODS

A series of variables were observed before and after treatment with HLAM in normal middle-aged subjects and patients recovering from cerebral embolism or suffering from ischemic heart disease, each of which were divided into two groups according to the dosage administered (60 mg/d and 120 mg/d).

RESULTS

The fat metabolism was enhanced in addition to the anticoagulant and the blood viscosity reducing effects. No side-effect was found.

CONCLUSION

HLAM is a promising drug for antithrombotic therapy.