Determination of triterpene glycosides in sea cucumber (Stichopus japonicus) and its related products by high-performance liquid chromatography

Diterpenoid glucosides with anti-inflammatory activity from Sigesbeckia glabrescens

Six previously undescribed diterpenoid glucosides, along with four known compounds, were isolated from the aerial parts of Sigesbeckia glabrescens. The structures and absolute configurations of undescribed compounds were elucidated using extensive spectroscopic techniques, ECD calculations and chemical methods. Compounds 1 and 8 exhibited anti-inflammatory activity against LPS-induced NO production in RAW 264.7 macrophages, with compound 8 demonstrating significant inhibitory activity compared to positive control minocycline, boasting an IC50 value at 14.20 μM.

Chemical derivatization strategies for enhancing the HPLC analytical performance of natural active triterpenoids

Triterpenoids widely exist in nature, displaying a variety of pharmacological activities. Determining triterpenoids in different matrices, especially in biological samples holds great significance. High-performance liquid chromatography (HPLC) has become the predominant method for triterpenoids analysis due to its exceptional analytical performance. However, due to the structural similarities among botanical samples, achieving effective separation of each triterpenoid proves challenging, necessitating significant improvements in analytical methods. Additionally, triterpenoids are characterized by a lack of ultraviolet (UV) absorption groups and chromophores, along with low ionization efficiency in mass spectrometry. Consequently, routine HPLC analysis suffers from poor sensitivity. Chemical derivatization emerges as an indispensable technique in HPLC analysis to enhance its performance. Considering the structural characteristics of triterpenoids, various derivatization reagents such as acid chlorides, rhodamines, isocyanates, sulfonic esters, and amines have been employed for the derivatization analysis of triterpenoids. This review comprehensively summarized the research progress made in derivatization strategies for HPLC detection of triterpenoids. Moreover, the limitations and challenges encountered in previous studies are discussed, and future research directions are proposed to develop more effective derivatization methods.

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.

Novel peptides from sea cucumber intestinal hydrolysates promote longitudinal bone growth in adolescent mice through accelerating cell cycle progress by regulating glutamine metabolism

Sea cucumber intestines are recognized as a major by-product in the sea cucumber processing industry and have been shown to exhibit bioactive properties. However, whether the sea cucumber intestine is beneficial for osteogenesis remains unknown. In this study, low molecular weight peptides rich in glutamate/glutamine were obtained from sea cucumber intestines (SCIP) by enzymatic hydrolysis, and orally administered to adolescent mice to investigate the effects on longitudinal bone growth. The results showed that the SCIP supplement significantly increased the femur length and new bone formation rate by 9.6% and 56.3%, and elevated the levels of serum osteogenic markers alkaline phosphatase (ALP), Collagen I and osteocalcin (OCN). Notably, H&E staining showed that SCIP significantly increased the height of the growth plate, in which the height of the proliferation zone was elevated by 95.6%. Glutamine is a major determinant of bone growth. SCIP supplement significantly increased glutamine levels in the growth plate by 44.2% and upregulated the expression of glutamine metabolism-related enzymes glutaminase 1 (Gls1) and glutamate dehydrogenase 1 (GLUD1) in the growth plate. Furthermore, SCIP supplement upregulated growth plate acetyl coenzyme A levels to promote histone acetylation and accelerated cell cycle progression by upregulating Sox9 expression, thereby contributing to rapid chondrocyte proliferation. To the best of our knowledge, this is the first report where SCIP could enhance longitudinal bone growth via promoting growth plate chondrocyte proliferation. The present study will provide new ideas and a theoretical basis for the high-value utilization of sea cucumber intestines.

Comparative study of holothurin A and echinoside A on inhibiting the high bone turnover via downregulating PI3K/AKT/β-catenin and OPG/RANKL/NF-κB signaling in ovariectomized mice

Holothurin A (HA) and Echinoside A (EA) are the most abundant monomers in sea cucumber saponins, exhibiting different structures only in the side chain at position 20. However, although sea cucumber saponins have been proved to have osteogenic activity, the effect and structure-activity relationship of sea cucumber saponins to improve osteoporosis remain unknown. In the current study, mice with ovariectomization-induced osteoporosis were orally administered with HA and EA for 90 days. The result showed that both HA and EA reduced the levels of serum osteogenesis markers ALP, collagen I, and OCN and bone resorption markers MMP-9, Cath-K and TRAP, and thus inhibited the high bone turnover induced by ovariectomy. Furthermore, we found that HA and EA increased the bone mineral density and apposition rate, reversed the loss of trabecular bone and bone marrow stroma, in which EA exhibited more effective effects. CB1 and MKP-1 are the targets of the glucocorticoid-like effect of saponins. PCR and western blot results indicated that HA and EA alleviated overactive osteogenesis via stimulating CB1 and MKP-1, downregulating the PI3K/AKT/β-catenin signal pathway. The OPG/RANKL/NF-κB pathway was identified as a critical regulator of bone resorption. Further investigation revealed that HA and EA significantly downregulate the expression of IKK, NF-κB and phosphorylated NF-κB p65, suppressing the expression of osteoclastogenesis transcription factors c-fos and NFATC1. To the best of our knowledge, this is the first report showing that both HA and EA improved osteoporosis, and these activities depend on the structure of saponins. These findings would provide guidance for the application of saponins in the management of osteoporosis.

Structural Elucidation and Biological Activity of a Highly Regular Fucosylated Glycosaminoglycan from the Edible Sea Cucumber Stichopus herrmanni

Edible sea cucumbers are widely used as a health food and medicine. A fucosylated glycosaminoglycan (FG) was purified from the high-value sea cucumber Stichopus herrmanni. Its physicochemical properties and structure were analyzed and characterized by chemical and instrumental methods. Chemical analysis indicated that this FG with a molecular weight of ∼64 kDa is composed of N-acetyl-d-galactosamine, d-glucuronic acid (GlcA), and l-fucose. Structural analysis clarified that the FG contains the chondroitin sulfate E-like backbone, with mostly 2,4-di-O-sulfated (85%) and some 3,4-di-O-sulfated (10%) and 4-O-sulfated (5%) fucose side chains that link to the C3 position of GlcA. This FG is structurally highly regular and homogeneous, differing from the FGs of other sea cucumbers, for its sulfation patterns are simpler. Biological activity assays indicated that it is a strong anticoagulant, inhibiting thrombin and intrinsic factor Xase. Our results expand the knowledge on structural types of FG and illustrate its biological activity as a functional food material.

Sea Cucumber Glycosides: Chemical Structures, Producing Species and Important Biological Properties

Sea cucumbers belonging to echinoderm are traditionally used as tonic food in China and other Asian countries. They produce abundant biologically active triterpene glycosides. More than 300 triterpene glycosides have been isolated and characterized from various species of sea cucumbers, which are classified as holostane and nonholostane depending on the presence or absence of a specific structural unit γ(18,20)-lactone in the aglycone. Triterpene glycosides contain a carbohydrate chain up to six monosaccharide units mainly consisting of d-xylose, 3-O-methy-d-xylose, d-glucose, 3-O-methyl-d-glucose, and d-quinovose. Cytotoxicity is the common biological property of triterpene glycosides isolated from sea cucumbers. Besides cytotoxicity, triterpene glycosides also exhibit antifungal, antiviral and hemolytic activities. This review updates and summarizes our understanding on diverse chemical structures of triterpene glycosides from various species of sea cucumbers and their important biological activities. Mechanisms of action and structural-activity relationships (SARs) of sea cucumber glycosides are also discussed briefly.

Effect and potential mechanism of action of sea cucumber saponins on postprandial blood glucose in mice

Postprandial blood glucose control is the major goal in the treatment of diabetes. Here, we investigated the effect of sea cucumber saponins (SCSs) on postprandial blood glucose levels. SCS inhibited yeast as well as rat intestinal α-glucosidase activity in a dose-dependent manner and showed better inhibition of yeast α-glucosidases compared to the positive control. Further studies were performed using ICR mice treated with SCS and starch or SCS alone by oral gavage. Unexpectedly, SCS increased postprandial blood glucose levels a short time (1 h) after oral gavage. The serum corticosterone (CORT) level showed a consistent correlation with glucose levels. In vitro experiments confirmed that SCS treatment increased the secretion of CORT in the Y1 adrenal cell line. Overall, these studies demonstrated that SCS gavage could inhibit α-glucosidase activity but cannot attenuate postprandial blood glucose level within short time periods. The underlying mechanisms are probably related to increased serum CORT levels.

Determination of the triterpene glycosides in sea cucumbers by liquid chromatography with evaporative light scattering and mass spectrometry detection

Holothurian triterpene glycosides possess various kinds of biological activities, including antifungal, cytotoxic, hemolytic, cytostatic, and immunomodulatory effects. In this study, a rapid extraction method of triterpene glycosides from sea cucumbers using a small column of C18 solid phase was first developed. Furthermore, a novel high-performance liquid chromatography method coupled with evaporative light scattering detection and electrospray ionization mass spectrometry was established for the determination of each triterpene glycosides from different sea cucumbers. Simultaneous separation of all kind of triterpene glycoside were achieved on a C18 column. A gradient of aqueous acetonitrile was applied, and the method was validated. The liquid chromatography method was applied to the online mass detection to identify the triterpene glycosides in the purified extraction of eight kinds of pulverized sea cucumber from the market of Qingdao, China. The negative mode of [M-H](-)/[M-Na](-) exclusively shown signals corresponding to the triterpene glycosides previously reported and the MS(2) product ions of those ions indicate the specific structure of each triterpene glycoside.

Effects of two sulfated triterpene saponins echinoside A and holothurin A on the inhibition of dietary fat absorption and obesity reduction

Two similarly sulfated triterpene saponins from Pearsonothuria graeffei were prepared to investigate the anti-obesity effects of echinoside A (EA) and holothurin A (HA). The in vitro inhibitory activities of EA and HA toward pancreatic lipase were investigated, and two in vivo studies were performed: (i) Male Wistar rats were orally administered the lipid emulsion with or without a saponin (HA or EA). The serum’s total triglyceride concentration was measured at various times. (ii) C57BL/6 mice were assigned to four groups, high fat (HF), EA (0.03%), HA (0.04%), and orlistat (0.01%), and the weight of adipose tissue and level of fatty acids excreted in the feces were determined. Both EA and HA repressed the pancreatic lipase activity and increased fatty acid excretion in the feces. Treatment with EA and HA significantly decreased the adipose tissue accumulation in mice. EA and HA manifested different inhibitory activities in vitro, but each of them dramatically inhibited lipid absorption in vivo and showed strong anti-obesity activity.

Ds-echinoside A, a new triterpene glycoside derived from sea cucumber, exhibits antimetastatic activity via the inhibition of NF-κB-dependent MMP-9 and VEGF expressions

Ds-echinoside A (DSEA), a non-sulfated triterpene glycoside, was isolated from the sea cucumber Pearsonothuria graeffei. In vitro and in vivo investigations were conducted on the effects of DSEA on tumor cell adhesion, migration, invasion, and angiogenesis. In this study, we found that DSEA inhibited the proliferation of human hepatocellular liver carcinoma cells Hep G2, with a half-maximal inhibitory concentration (IC₅₀) of 2.65 μmol/L, and suppressed Hep G2 cell adhesion, migration, and invasion in a dose-dependent manner. DSEA also reduced tube formation of human endothelial cells ECV-304 on matrigel in vitro and attenuated neovascularization in the chick embryo chorioallantoic membrane (CAM) assay in vivo. Immunocytochemical analysis revealed that DSEA significantly decreased the expression of matrix metalloproteinase-9 (MMP-9), which plays an important role in the degradation of basement membrane in tumor metastasis and angiogenesis. DSEA also increased the protein expression level of tissue inhibitor of metalloproteinase-1 (TIMP-1), an important regulator of MMP-9 activation. From the results of Western blotting, the expressions of nuclear factor-kappa B (NF-κB) and vascular endothelial growth factor (VEGF) were found to be remarkably reduced by DSEA. These findings suggest that DSEA exhibits a significant anti-metastatic activity through the specific inhibition of NF-κB-dependent MMP-9 and VEGF expressions.

Simultaneous determination of four 5-hydroxy polymethoxyflavones by reversed-phase high performance liquid chromatography with electrochemical detection

Accumulating evidence has suggested the potential health-promoting effects of 5-hydroxy polymethoxyflavones (5-OH-PMFs) naturally existing in citrus genus. However, research efforts are hampered by the lack of reliable and sensitive methods for their determination in plant materials and biological samples. Using reversed-phase high performance liquid chromatography (HPLC) equipped with electrochemical (EC) detection, we have developed a fast and highly sensitive method for quantification of four 5-OH-PMFs, namely 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone, 5-hydroxy-3,6,7,8,3',4'-hexamethoxyflavone, 5-hydroxy-6,7,4'-trimethoxyflavone, and 5-hydroxy-6,7,8,4'-tetramethoxyflavone. The method was fully validated in terms of linearity, accuracy and precision. The limit of detection (LOD) was determined as being between 0.65 and 1.8ng/mL (ppb), demonstrating an over 160 times higher sensitivity in comparison with the previously reported method using UV detection. The recovery rate of the method was between 96.17% and 110.82%, and the precision for the retention times and peak areas was all below 13%. The method was successfully used to quantify 5-OH-PMFs with a wide range of abundance in the citrus products and preparations, such as orange juice, citrus peel, and dried tangerine peel. The quantification method for 5-OH-PMFs developed herein could be useful for the nutritional and pharmacological studies of these compounds in future.