Two new cerebrosides leptasteriacerebroside A (1) and B (2) were isolated from the starfish Leptasterias polaris acervata, together with two known ones (2S,3R,4E,9Z)-1-O-(β-D-glucopyranosyl)-2-[(2R)-2-hydroxyhexadecanoylamino]-4,9-docosadien-3-ol (3) and astrocerebroside B (4). The structures of the isolated compounds were characterized using spectroscopic techniques HRESIMS, ESIMS/MS, 1D and 2D NMR as well as by chemical modification and subsequent analysis of derivatives. The antimicrobial, urease inhibitory, cytotoxic, and cytoprotective activities of compounds 1–4 were investigated. Notably, compound 1 exhibited significant protection of H9c2 cardiomyocytes against CoCl2-induced toxicity, while compounds 2 and 4 demonstrated efficacy in mitigating TNF-α-mediated cytotoxicity, likely through inhibition of the NF-κB-dependent inflammatory pathway.

Triple-negative breast cancer (TNBC) represents significant therapeutic challenges due to its aggressive behavior, metabolic plasticity, and lack of targeted treatments, prompting investigation of biologically active triterpene glycosides from the starfish Solaster pacificus. This study evaluated the ability of pacificusoside D (SpD) to synergistically enhance the anticancer efficacy of the glycolytic inhibitor 2-deoxy-D-glucose (2-DG) in TNBC MDA-MB-231 cells by targeting mitochondrial oxidative phosphorylation (OXPHOS). Methods included metabolic profiling via glucose uptake, lactate, and glutamate Glo assays; IC50 determination by MTS and trypan blue assays; colony formation evaluation using a soft agar assay; and molecular mechanism elucidation by Western blot, fluorescence microscopy and spectrometry, and flow cytometry analyses. Results demonstrated that MDA-MB-231 cells predominantly utilized glycolysis under basal conditions, shifting to OXPHOS with 2-DG (0.5 mM). IC50 values were 8.0/8.4 mM for 2-DG and 0.3/0.25 μM for SpD after 24 h of cell treatment. SpD exhibited a significant decrease in the number of colonies in MDA-MB-231 cells and possessed synergistic anticancer effects with 2-DG. Mechanistically, SpD increased tumor suppressor VHL expression level, down-regulated expression level of electron transport chain enzymes, generated reactive oxygen species, induced mitochondrial dysfunction, and triggered Bax/Bak-mediated apoptosis. These findings highlighted the synergistic anticancer potential of SpD in combination with 2-DG in aggressive breast cancer, offering insights into improved clinical outcomes in the future.

Unusual 1,2-cyclic acetal-type glycero-3-phosphoethanolamines, isolated from the EtOH extract of the Arctic starfish Asterias -microdiscus (Chukchi Sea), were analysed as constituents of a RP-HPLC fraction using extensive NMR, MS techniques, and chemical transformations. Four new ethanolamine glycerophospholipids were found to differ from each other in the positions of - CH = CH - CH(OOH/OH)- moieties in linear acetal-linked C20 chains. The mixture of these compounds showed cardioprotective activity against CoCl2-induced damage of H9c2 cardiomyocytes via partial restoration of mitochondrial membrane potential.

Marine triterpene glycosides are known to exhibit significant anticancer activity. We investigated pacificusoside C and cucumariosides C1 and C2 isolated from a sea star Solaster pacificus in prostate cancer models with varying drug resistance and in non-cancerous cells in vitro. Cucumarioside C1 showed selectivity comparable to cisplatin, whereas the other compounds were less selective. Cucumarioside C1 induced apoptosis and enhanced cytotoxic effects of cisplatin, carboplatin, docetaxel, and cabazitaxel, making it a potential candidate for combination therapy. All three glycosides were active in docetaxel-resistant cells and were neither inhibitors nor substrates of P-glycoprotein, indicating P-glycoprotein-independent activity. To explore the mechanism of anticancer activity of cucumarioside C1, we performed functional kinome profiling of treated 22Rv1 cells, predicting activation of kinases involved in stress response and survival (IKKα, IKKβ, IKKε), necroptosis (MLKL), metabolism (GCN2, PDK1), cytoskeletal dynamics (RHOK), mitophagy (PINK1), apoptosis and cell cycle regulation (PITSLRE), and immune modulation (COT). Notably, only MAP kinases p38 and ERK1/2 were predicted to be specifically inhibited, that was further validated by Western blotting. These findings may potentially explain previously reported anticancer effects of cucumarioside C1 and related marine glycosides. To our knowledge, this is the first study to report triterpene glycosides’ effects on the kinome of cancer cells.

CYP51 steroid-14α-demethylases are members of a large superfamily of cytochrome P450 enzymes found in all kingdoms of living organisms, and catalyze the 14α-demethylation reaction of a number of natural steroids, including lanosterol, obtusifoliol, and 24,25-dihydrolanosterol. CYP51 are important components of the eukaryotic steroid biosynthetic chain, and thus represent one of the main targets for antifungal therapy. A 14α-demethylase CYP51 homologous gene has also been found in the genome of Mycobacterium tuberculosis. At the same time, M. tuberculosis lacks the de novo pathway for steroid biosynthesis. Conservation of CYP51 among the Mycobacterium genus and colocalization in the genome with 3Fe-4S ferredoxin Rv0763c, which maintains its catalytic activity in vitro, may indirectly indicate the involvement of MTCYP51 in a biochemical process important for mycobacteria. In order to characterize the specificity of the MTCYP51 active site to various compounds of isoprenoid nature, we obtained a highly purified MTCYP51 and, using spectrophotometric titration and surface plasmon resonance methods, studied the interaction of MTCYP51 with steroids from marine organisms obtained in the Pacific Institute of Bioorganic Chemistry of the Far Eastern Branch of the Russian Academy of Sciences. The investigated compounds represent a wide range of evolutionarily ancient isoprenoids. The results showed that MTCYP51 is able to bind structurally diverse steroid derivatives in the active site. The conducted studies suggest the biological role of MTCYP51 for pathogenic mycobacteria, which consists in the binding and possible metabolism of exogenous bioregulatory isoprenoids in vivo.

Three new monosulfated polyhydroxysteroid glycosides, spiculiferosides A (1), B (2), and C (3), along with new related unsulfated monoglycoside, spiculiferoside D (4), were isolated from an ethanolic extract of the starfish Henricia leviuscula spiculifera collected in the Sea of Okhotsk. Compounds 1–3 contain two carbohydrate moieties, one of which is attached to C-3 of the steroid tetracyclic core, whereas another is located at C-24 of the side chain of aglycon. Two glycosides (2, 3) are biosides, and one glycoside (1), unlike them, includes three monosaccharide residues. Such type triosides are a rare group of polar steroids of sea stars. In addition, the 5-substituted 3-OSO3-α-L-Araf unit was found in steroid glycosides from starfish for the first time. Cell viability analysis showed that 1–3 (at concentrations up to 100 μM) had negligible cytotoxicity against human embryonic kidney HEK293, melanoma SK-MEL-28, breast cancer MDA-MB-231, and colorectal carcinoma HCT 116 cells. These compounds significantly inhibited proliferation and colony formation in HCT 116 cells at non-toxic concentrations, with compound 3 having the greatest effect. Compound 3 exerted anti-proliferative effects on HCT 116 cells through the induction of dose-dependent cell cycle arrest at the G2/M phase, regulation of expression of cell cycle proteins CDK2, CDK4, cyclin D1, p21, and inhibition of phosphorylation of protein kinases c-Raf, MEK1/2, ERK1/2 of the MAPK/ERK1/2 pathway.

Two new steroid 3β,21-disulfates (1, 2) and two new steroid 3β,22- and 3α,22-disulfates (3, 4), along with the previously known monoamine alkaloid tryptamine (5) were found in the ethanolic extract of the Far Eastern slime sea star Pteraster marsippus. Their structures were determined on the basis of detailed analysis of one-dimensional and two-dimensional NMR, HRESIMS, and HRESIMS/MS data. Compounds 1 and 2 have a Δ22-21-sulfoxy-24-norcholestane side chain. Compounds 3 and 4 contain a Δ24(28)-22-sulfoxy-24-methylcholestane side chain, which was first discovered in the polar steroids of starfish and brittle stars. The influence of substances 1–4 on cell viability, colony formation, and growth of human breast cancer T-47D, MCF-7, and MDA-MB-231 cells was investigated. It was shown that compounds 1 and 2 possess significant colony-inhibiting activity against T-47D cells, while compounds 3 and 4 were more effective against MDA-MB-231 cells.

Four new glycosides of polyhydroxysteroids, ceramasterosides A, B, D, and E (1–4), and two previously known compounds, ceramasteroside C1 (5) and attenuatoside B-I (6), were isolated from an extract of a deep-sea sea star species, the orange cookie star Ceramaster patagonicus. The structures of 1–4 were elucidated by the extensive NMR and ESIMS methods. Steroid monoglycosides 1 and 2 had a common 3β,6α,8,15β,16β-pentahydroxysteroid nucleus and a C–29 oxidized stigmastane side chain and differed from each other only in monosaccharide residues. Ceramasteroside A (1) contained 3-O-methyl-4-O-sulfated β-D-xylopyranose, while ceramasteroside B (2) had 3-O-methyl-4-O-sulfated β-D-glucopyranose, recorded from starfish-derived steroid glycosides for the first time. Their biological activity was studied using a model of lipopolysaccharide-induced (LPS) inflammation in a SIM-A9 murine microglial cell line. During the LPS-induced activation of microglial cells, 1, 3, and 5, at a non-toxic concentration of 1 µM, showed the highest efficiency in reducing the production of intracellular NO, while 4 proved to be most efficient in reducing the extracellular nitrite production. All the test compounds reduced the LPS-induced malondialdehyde (MDA) production. The in vitro experiments have demonstrated, for the first time, the antioxidant activity of the compounds under study.

Six previously unknown triterpene glycosides, pacificusosides L–Q (1–6), and two previously known triterpene glycosides, cucumariosides B1 (7) and A5 (8), were isolated from an alcoholic extract of Pacific sun star, Solaster pacificus. The structures of 1–6 were determined using 1D and 2D NMR, ESIMS, and chemical modifications. Compound 1 is a rare type of triterpene glycoside with non-holostane aglycon, having a linear trisaccharide carbohydrate chain. Pacificusosides M–P (2–5) have new structures containing a Δ8(9)-3,16,18-trihydroxy tetracyclic triterpene moiety. This tetracyclic fragment in sea star or sea cucumber triterpene glycosides was described for the first time. All the compounds under study exhibit low or moderate cytotoxic activity against colorectal carcinoma HCT 116 cells, and breast cancer MDA-MB-231 cells were assessed by MTS assay. Compound 2 effectively suppresses the colony formation of cancer cells at a non-toxic concentration, using the soft-agar assay. A scratch assay has shown a significant anti-invasive potential of compound 2 against HCT 116 cells, but not against MDA-MB-231 cells.

The opportunistic fungus Candida krusei is the causative agent of nosocomial infections characterized by high mortality and development of resistance to drugs of the azole class. Therefore, develjoment of non-azole antifungal agents against resistant fungal strains is extremly important. Lanosterol 14-alpha demethylase (CYP51) is a well-known antifungal target. The optical SPR biosensor is a universal tool for screening studies in search of new drug prototypes. This paper presents the methodological aspects of high-hroughput SPR based screening of a library of low molecular weight compounds of natural origin for their interaction with C. krusei CYP51. It has been shown that when performing high-throughput screening, a researcher should pay special attention to the degree of a sensorgram curvature in the association phase. The described approaches to the analysis of high throughput screening data can be useful for researchers working with SPR biosensors from various manufacturers.

Cancer is one of the main causes of human mortality worldwide. Despite the advances in the diagnostics, surgery, radiotherapy, and chemotherapy, the search for more effective treatment regimens and drug combinations are relevant. This work aimed to assess the radiomodifying effect and molecular mechanism of action of fucoidan from the brown alga Saccharina cichorioides (ScF) and product of its autohydrolysis (ScF_AH) in combination with pacificusoside D from the starfish Solaster pacificus (SpD) on the model of viability and invasion of three-dimension (3D) human melanoma cells SK-MEL-2. The cytotoxicity of ScF (IC50 JB6 Cl41 > 800 µg/mL; IC50 SK-MEL-2 = 685.7 µg/mL), ScF_AH (IC50 JB6 Cl41/SK-MEL-2 > 800 µg/mL), SpD (IC50 JB6 Cl41 = 22 µM; IC50 SK-MEL-2 = 5.5 µM), and X-ray (ID50 JB6 Cl41 = 11.7 Gy; ID50 SK-MEL-2 = 6.7 Gy) was determined using MTS assay. The efficiency of two-component treatment of 3D SK-MEL-2 cells was revealed for ScF in combination with SpD or X-ray but not for the combination of fucoidan derivative ScF_AH with SpD or X-ray. The pre-treatment of spheroids with ScF, followed by cell irradiation with X-ray and treatment with SpD (three-component treatment) at low non-toxic concentrations, led to significant inhibition of the spheroids’ viability and invasion and appeared to be the most effective therapeutic scheme for SK-MEL-2 cells. The molecular mechanism of radiomodifying effect of ScF with SpD was associated with the activation of the initiator and effector caspases, which in turn caused the DNA degradation in SK-MEL-2 cells as determined by the Western blotting and DNA comet assays. Thus, the combination of fucoidan from brown algae and triterpene glycoside from starfish with radiotherapy might contribute to the development of highly effective method for melanoma therapy.

Sea stars or starfish (class Asteroidea) and holothurians or sea cucumbers (class Holothuroidea), belonging to the phylum Echinodermata (echinoderms), are characterized by different sets of glycosidic metabolites: the steroid type in starfish and the triterpene type in holothurians. However, herein we report the isolation of eight new triterpene glycosides, pacificusosides D–K (1–3, 5–9) along with the known cucumarioside D (4), from the alcoholic extract of the Far Eastern starfish Solaster pacificus. The isolated new compounds are closely related to the metabolites of sea cucumbers, and their structures of 1–3 and 5–9 were determined by extensive NMR and ESIMS techniques. Compounds 2, 5, and 8 have a new type of tetrasaccharide chain with a terminal non-methylated monosaccharide unit. Compounds 3, 6, and 9 contain another new type of tetrasaccharide chain, having 6-O-SO3-Glc as one of the sugar units. The cytotoxic activity of 1–9 against non-cancerous mouse epidermal cells JB6 Cl41 and human melanoma cell lines SK-MEL-2, SK-MEL-28, and RPMI-7951 was determined by MTS assay. Compounds 1, 3, 4, 6, and 9 showed potent cytotoxicity against these cell lines, but the cancer selectivity (SI > 9) was observed only against the SK-MEL-2 cell line. Compounds 1, 3, 4, 6, and 9 at the non-toxic concentration of 0.1 μM significantly inhibited neoplastic cell transformation of JB6 Cl41 cells induced by chemical carcinogens (EGF, TPA) or ionizing radiation (X-rays and UVB). Moreover, compounds 1 and 4 at the non-toxic concentration of 0.1 µM possessed the highest inhibiting activity on colony formation among the investigated compounds and decreased the colonies number of SK-MEL-2 cells by 64% and 70%, respectively. Thus, triterpene glycosides 1 and 4 can be considered as prospective cancer-preventive and anticancer-compound leaders.

New steroidal 3β,21-disulfates (2–4), steroidal 3β,22-disulfate (5), and the previously known related steroidal 3β,21-disulfate (1) were isolated from the ethanolic extract of the Far Eastern starfish Pteraster marsippus, collected off Urup Island in the Sea of Okhotsk. The structures of these compounds were determined by intensive NMR and HRESIMS techniques as well as by chemical transformations. Steroids 2 and 3 have an oxo-group in the tetracyclic nucleus at position C-7 and differ from each other by the presence of the 5(6)-double bond. The Δ24-22-sulfoxycholestane side chain of the steroid 5 has not been found previously in the starfish or ophiuroid steroids. The cytotoxic activities of 1, 4, 5, and the mixture of 2 and 3 were determined on the models of 2D and 3D cultures of human epithelial kidney cells (HEK293), melanoma cells (SK-MEL-28), small intestine carcinoma cells (HuTu80), and breast carcinoma cells (ZR-75-1). The mixture of 2 and 3 revealed a significant inhibitory effect on the cell viability of human breast carcinoma ZR-75-1 cells, but other tested compounds were less effective.

Three new ceramides (1–3) and three new cerebrosides (4, 8, and 9), along with three previously known cerebrosides (ophidiocerebrosides C (5), D (6), and CE-3-2 (7)), were isolated from a deep-sea starfish species, the orange cookie starfish Ceramaster patagonicus. The structures of 1−4, 8, and 9 were determined by the NMR and ESIMS techniques and also through chemical transformations. Ceramides 1–3 contain iso-C21 or C23 Δ9-phytosphingosine as a long-chain base and have C16 or C17 (2R)-2-hydroxy-fatty acids of the normal type. Cerebroside 4 contains C22 Δ9-sphingosine anteiso-type as a long-chain base and (2R)-2-hydroxyheptadecanoic acid of the normal type, while compounds 8 and 9 contain saturated C-17 phytosphingosine anteiso-type as a long-chain base and differ from each other in the length of the polymethylene chain of (2R)-2-hydroxy-fatty acids of the normal type: C23 in 8 and C24 in 9. All the new cerebrosides (4, 8, and 9) have β-D-glucopyranose as a monosaccharide residue. The composition of neutral sphingolipids from C. patagonicus was described for the first time. The investigated compounds 1–3, 5–7, and 9 exhibit slight to moderate cytotoxic activity against human cancer cells (HT-29, SK-MEL-28, and MDA-MB-231) and normal embryonic kidney cells HEK293. Compounds 2, 5, and 6 at a concentration of 20 µM inhibit colony formation of MDA-MB-231 cells by 68%, 54%, and 68%, respectively. The colony-inhibiting activity of compounds 2, 5, and 6 is comparable to the effect of doxorubicin, which reduces the number of colonies by 70% at the same concentration.

Colorectal cancer is one of the most frequent types of malignancy in the world. The search for new approaches of increasing the efficacy of cancer therapy is relevant. This work was aimed to study individual, combined anticancer effects, and molecular mechanism of action of sulfated laminaran AaLs of the brown alga Alaria angusta and protolinckiosides A (PL1), B (PL2), and linckoside L1 (L1) of the starfish Protoreaster lincki using a 3D cell culture model. The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS), soft agar, 3D spheroids invasion, and Western blotting assays were performed to determine the effect and mechanism of the action of investigated compounds or their combinations on proliferation, colony formation, and the invasion of 3D HCT 116 spheroids. AaLs, PL1, PL2, and L1 individually inhibited viability, colony growth, and the invasion of 3D HCT 116 spheroids in a variable degree with greater activity of linckoside L1. AaLs in combination with L1 exerted synergism of a combined anticancer effect through the inactivation of protein kinase B (AKT) kinase and, consequently, the induction of apoptosis via the regulation of proapoptotic/antiapoptotic proteins balance. The obtained data about the efficacy of the combined anticancer effect of a laminaran derivative of brown algae and polyhydroxysteroid glycosides of starfish open up prospects for the development of new therapeutic approaches for colorectal cancer treatment.

Three new triterpene glycosides, pacificusosides A–C (1–3), and three previously known triterpene glycosides, cucumariosides C1 (4), C2 (5), and A10 (6), were isolated from the alcoholic extract of the Far Eastern starfish Solaster pacificus. The structures of 1–3 were elucidated by extensive NMR and ESIMS techniques and chemical transformations. Compound 1 has a novel, unique structure, containing an aldehyde group of side chains in its triterpene aglycon. This structural fragment has not previously been found in the sea cucumber triterpene glycosides or starfish steroidal glycosides. Probably, pacificusoside A (1) is a product of the metabolism of the glycoside obtained through dietary means from a sea cucumber in the starfish. Another two new triterpene glycosides (2, 3) have closely related characteristics to sea cucumber glycosides. The cytotoxicity of compounds 1–6 was tested against human embryonic kidney HEK 293 cells, colorectal carcinoma HT-29 cells, melanoma RPMI-7951 cells, and breast cancer MDA-MB-231 cells using MTS assay. Compounds 4–6 revealed the highest cytotoxic activity against the tested cell lines, while the other investigated compounds had moderate or slight cytotoxicity. The cytotoxic effects of 2–6 were reduced by cholesterol like the similar effects of the previously investigated individual triterpene glycosides. Compounds 3, 4, and 5 almost completely suppressed the colony formation of the HT-29, RPMI-7951, and MDA-MB-231 cells at a nontoxic concentration of 0.5 µM.

Sphingolipids are complex lipids widespread in nature as structural components of biomembranes. Commonly, the sphingolipids of marine organisms differ from those of terrestrial animals and plants. The gangliosides are the most complex sphingolipids characteristic of vertebrates that have been found in only the Echinodermata (echinoderms) phylum of invertebrates. Sphingolipids of the representatives of the Asteroidea and Holothuroidea classes are the most studied among all echinoderms. In this review, we have summarized the data on sphingolipids of these two classes of marine invertebrates over the past two decades. Recently established structures, properties, and peculiarities of biogenesis of ceramides, cerebrosides, and gangliosides from starfishes and holothurians are discussed. The purpose of this review is to provide the most complete information on the chemical structures, structural features, and biological activities of sphingolipids of the Asteroidea and Holothuroidea classes.

This study was aimed to determine the efficacy of combination of fucoidan from the brown algae Fucus evanescens (FeF) or its derivatives with thornasteroside A (ThA) or asteropsiside A (AsA) from the starfish Asteropsis carinifera in combating human melanoma cells. In vitro MTS and soft agar methods were performed to determine effect of FeF, its derivatives, ThA, AsA or their combination on proliferation and colony formation of SK-MEL-28 cells in 2D and 3D culture. Desulfation of FeF, but not deacetylation, led decreasing of its Mw and anti-proliferative activity. The combinatorial effect of FeF with ThA and AsA depended on the sequences of treatment by compounds. There was additive anticancer effect of FeF with ThA or AsA during simultaneous treatment of cells. ThA and AsA were not active against SK-MEL-28 cells after their pre-treatment with FeF. Potential synergism of action was identified only when SK-MEL-28 cells were pre-treated with ThA and AsA and then by FeF. This process going through the regulation of MEK1/2/ERK1/2/MSK1 pathway and expression of the cell cycle proteins as determined by Western Blot. Thus, the combination of fucoidan with the asterosaponins opens up the prospects for the development of effective combined chemotherapeutic methods for melanoma treatment.