Unusual Structures and Cytotoxicities of Chitonoidosides A, A1, B, C, D, and E, Six Triterpene Glycosides from the Far Eastern Sea Cucumber Psolus chitonoides.

Six new triterpene tetra-, penta- and hexaosides, chitonoidosides A (1), A1 (2), B (3), C (4), D (5), and E (6), containing one or two sulfate groups, have been isolated from the Far-Eastern sea cucumber Psolus chitonoides, collected near Bering Island (Commander Islands) from the depth of 100-150 m. Three of the isolated compounds (1, 3 and 6) are characterized by the unusual aglycone of new type having 18(20)-ether bond and lacking a lactone in contrast with wide spread holostane derivatives. Another unexpected finding is 3-O-methylxylose residue as a terminal unit in the carbohydrate chains of chitonoidosides B (3), C (4), and E (6), which has never been found before in the glycosides from holothurians belonging to the Psolidae family. Moreover, this monosaccharide is sulfated in the compound 4 into unprecedented 3-O-methylxylose 4-O-sulfate residue. Chitonoidoside C (4) is characterized by tetrasaccharide moiety lacking a part of the bottom semi-chain, but having disaccharide fragment attached to C-4 of Xyl1. Such architecture is not common in sea cucumber glycosides. Cytotoxic activities of the compounds 1-5 against mouse and human erythrocytes and human cancer cell lines: adenocarcinoma HeLa, colorectal adenocarcinoma DLD-1, and leukemia promyeloblast HL-60 cells were studied. The cytotoxic effect of chitonoidoside d (5) was the most significant in this series due to the presence of pentasaccharide disulfated sugar chain in combination with holostane aglycone. Surprisingly, the glycosides 1 and 3, comprising the new aglycone without γ-lactone, demonstrated similar activity to the known compounds with holostane aglycones. Chitonoidoside C (4) was less cytotoxic due to the different architecture of the carbohydrate chain compared to the other glycosides and probably due to the presence of a sulfate group at C-4 in 3-O-MeXyl4.

The Antitumor Antibiotics Complex of Aureolic Acids from the Marine Sediment-associated Strain of Streptomyces sp. KNIM 9048.

A new antibiotic complex of six aureolic acids was isolated from the marine sediment-associated strain Streptomyces sp. KMM 9048. Four of the compounds (3-6) were found to be similar but not identical to the known chromomycins A2, A3, demethyl chromomycin A3 and A4. The two remaining.compounds; A2₋1 (1) and A3₋1 (2), were established as novel chromomycin analogs, which did not contain sugar B. Spectroscopic methods including ID and 2D NMR, and HRMS and MS/MS were applied for structure elucidation. Compounds 1-5 showed strong antimicrobial activity against Gram-positive indicatory bacteria Enterococcusfaecium, Staphylococcus aureus, S. epidernzidis, and Bacillus subtilis. Antitumor assay indicated that all tested compounds, in different manners, inhibited colony formation of RPMI-7951 and SK-Mel-28 cancer cells. This is the first study reporting the inhibitory effects of chromomycin analogs 1-5 on the colony formation of the investigated cancer cell lines. Compound 3, in a concentration of 5 nM, inhibited colony formation of RPMI-7951 and SK-Mel-28 cells by 82 % and 72 %, respectively. Our finding indicated that, of the compounds tested, 3 and 4 are promising anticancer and antimicrobial agents.

Colochiroside E, an Unusual Non-holostane Triterpene Sulfated Trioside from the Sea Cucumber Colochirus robustus and Evidence of the Impossibility of a 7(8)-Double Bond Migration in Lanostane Derivatives having an 18(16)-Lactone.

The unusual non-holostane triterpene glycoside, colochiroside E (1) was isolated from the sea cucumber Colochirus robustus (Cucumariidae, Dendrochirotida). The structure of 1 was established by analysis of 1D, 2D NMR and HRESI MS data. Colochiroside E (1) belongs to a rare group of glycosylated 9ß-H-lanosta-18(16)-lactones and has an unprecedented sulfated trisaccharide carbohydrate chain consisting of two glucose and one xylose units. In contrast with (9ß-H)-7(8)-unsaturated holostane glycosides, the 7(8)-double bond in the having (9ß-H)-configuration aglycone of colochiroside E is not capable of migration into the 8(9)- and then into the 9(11)-position on treatment with HCl. The formation of a chlorine derivative of 1 was observed under these conditions.

Colochirosides A1, A2, A3, and D, Four Novel Sulfated Triterpene Glycosides from the Sea Cucumber Colochirus robustus (Cucumariidae, Dendrochirotida).

Four new triterpene glycosides, colochirosides A1 (1), A2 (2), A3 (3) and D (4), have been isolated from the sea cucumber Colochirus robustus (Cucumariidae, Dendrochirotida). Structures of the glycosides have been elucidated by 2D NMR spectroscopy and mass-spectrometry. Colochiroside D (4) has a new type of carbohydrate chain having the only sulfate group attached to C-6 of the third (glucose) monosaccharide residue. Cytotoxic activities of glycosides 1-4 against the ascite form of mouse Ehrlich carcinoma cells and hemolytic activity against mouse erythrocytes have been studied. Hemolytic activity of the glycosides was higher than cytotoxic. Glycosides 1, 3 and 4 demonstrated strong effects, whereas compound 2 showed only moderate activity.

Guaiane Sesquiterpenoids from the Gorgonian Menella woodin.

Two new guaiane derivatives (1 and 2) along with six known sesquiterpenoids (3-8) were isolated from the gorgonian Menella woodin. Their structures -were elucidated by ID and 2D NMR and HRESIMS data as well as by comparison of their spectra with those in the literature. Relative configurations of asymmetric centers in 1 and 2 were suggested on the basis of NOESY and ID NOE correlations, absolute stereochemistry of these compounds was proposed in result of comparison of calculated (for both enatiomers) and experimental ECD. Some suggestions were made regarding a biosynthesis of guaiane sesquiterpenoids in this species. All the compounds were firstly isolated from M woodin.

Fallaxosides C1, C2, D1 and D2, Unusual Oligosulfated Triterpene Glycosides from the Sea Cucumber Cucumariafallax (Cucumariidae, Dendrochirotida, Holothurioidea) and Taxonomic Status of this Animal.

Four hew triterpene glycosides, fallaxosides C, (1), C2 (2), D, (3) and D2 (4) along with the known cucumarioside A3-2 (5) and koreoside A (6) have-been isolated from the sea cucumber Cucumaria fallax (Cucumariidae, Dendrochirotida). Structures of the glycosides have been elucidated by 2D NMR spectroscopy and mass spectrometry. All of the glycosides are rare non-holostane derivatives having shortened side chains and contain pentasaccharide carbohydrate moieties with two or three sulfate groups. Structures of these triterpene glycosides and their comparison with those earlier isolated from Cucuniaria spp. and Pseudocnus dubiosus leoninus allow us to suggest that the present assignment of C. fallax to the genus Pseudocnus is not correct, and this species.should be assigned to the genus Cucumaria. Cytotoxic activity of glycosides 1-5 against the ascite form of mouse Ehrlich carcinoma cells and mouse spleen lymphocytes and hemolytic activity against mouse erythrocytes have been studied. The glycosides were expectedly not active in all the tests due to the absence of an 18(20)-lactone in their aglycones and the presence of several sulfate groups. There was one exception, cucumarioside A3-2 (5), which. demonstrated a weak cytotoxicity against lymphocytes and moderate hemolytic activity.

Regulusosides A, B, and C, Three New Polyhydroxysteroid Glycosides from the Starfish Pentaceraster regulus.

Three new polyhydroxysteroid glycosides, regulusosides A-C (1-3) along with the previously known five steroid compounds (4-8) were isolated from the tropical starfish Pentaceraster regulus. The structures of compounds 1-3 were established by extensive NMR and ESI-MS techniques. New glycosides have the same aglycon, (24S)-5α-cholestane-3ß,5,6ß,8,15α,24-hexol, and various disaccharide moieties: ß-D-xylopyranosyl-(l->2)-3-0-methyl-α-L- arabinofuranosyl (1), ß-D-xylopyranosyl-(l->2)-c-L-arabinofuranosy (2), and 2-0-methyl-ß-D-xylopyranosyl-(->2)-3-0-methyl-α-L-arabinofuranosy (3), attached at C-24 of the side chain. Compounds 1, 2 and 6 exhibit potential immunomodulatory properties, inducing intracellular ROS (reactive oxygen species) formation in the RAW 264.7 murine macrophage cells.

Aphelasteroside F, a new Asterosaponin from the Far Eastern Starfish Aphelasterias japonica.

A new asterosaponin aphelasteroside F (1) was isolated from the ethanolic extract of the Far Eastern starfish Aphelasterias japonica along with the previously known ophidianoside F (2). The structure of 1 was elucidated by extensive use of NMR and ESI-MS techniques, and chemical transformations. Compound 1 contains a new type of asterosaponin carbohydrate chain linked to C-6 of the steroid aglycone aphelaketotriol. Compounds 1 and 2 at non-toxic concentrations slightly inhibited cell proliferation and colony formation of the cancer melanoma cell lines SK-Mel-28, SK-Mel-5, and RPMI-7951.

Unusual Steroid Constituents from the Tropical Starfish Leiaster sp.

Two polar steroid compounds, taurochenodeoxycholic acid sodium salt (1) and a rare cyclic steroid glycoside luzonicoside A (2), were isolated from the tropical starfish Leiaster sp. and identified by extensive NMR and ESIMS techniques. The isolation of primary bile acid 1 is the first report from a representative of the class Asteroidea and on the whole in invertebrates. Its presence confirms the hypothesis about the digestive role of some polar steroids in starfish and possibly demonstrates the parallel evolution of fat emulsifying agents in vertebrates and some starfish. Compound 2 was also obtained from starfish belonging to this genus for the first time. This finding indicates that cyclic steroid glycosides are more widely distributed in starfish than the two species of the genus Echinaster from which they were isolated earlier.

Colochirosides B1, B2, B3 and C, Novel Sulfated Triterpene Glycosides from the Sea Cucumber Colochirus robustus (Cucumariidae, Dendrochirotida).

Four new triterpene glycosides, colochirosides B1 (1), B2 (2), B3 (3) and C (4) have been isolated from the sea cucumber Colochirus robustus (Cucumariidae, Dendrochirotida). Six known earlier glycosides from representatives of two families of the order Dendrochirotida have also been found in C. robustus. Structures of the glycosides have been elucidated by 2D NMR spectroscopy and mass spectrometry. All the glycosides belong to the holostane series and contain tetrasaccharide linear carbohydrate chains with one or two sulfate groups. Cytotoxic activities of glycosides 1-4 against the ascite form of mouse Ehrlich carcinoma cells and hemolytic activities against mouse erythrocytes have been studied. Hemolytic activity of the glycosides was higher than cytotoxic. Glycosides 3 and 4 demonstrated strong effects, whereas compounds 1 and 2 containing the hydroxy-group in the side chains showed moderate hemolytic activity and were not cytotoxic.

The Assignment of the Absolute Configuration of C-22 Chiral Center in the Aglycones of Triterpene Glycosides from the Sea Cucumber Cladolabes schmeltzi and Chemical Transformations of Cladoloside C.

The absolute R-configuration of the C-22 chiral center in cladoloside C (1) and therefore in all related glycosides isolated from the sea cucumber Cladolabes schmeltzii has been assigned by Mosher's method. Some chemical transformations of the native glycoside 1 were carried out to apply this method. This resulted in the isolation and elucidation of chemical structures of progenin 2 and artefact aglycones 3 and 4, obtained from 1 and assignment of the absolute R-configuration of C-22 in the progenin 2. The coincidence of C-22 configurations in the studied compounds with those of the earlier known lanostane-type aglycone of frondoside C and holostane-type aglycone of cladoloside C (1) confirms the generic biosynthetic pathways to different types of sea cucumber glycoside aglycones. It suggests the same R-configuration of C-22 chiral centers in all the sea cucumber glycosides having C-22 functionalities.

New Metabolites from a Marine Sediment-Derived Fungus, Aspergillus carneus.

A new polyketide 1 and a new decaline derivative 2 were isolated from a sediment-derived fungus Aspergillus carneus Blochwitz, together with one known bisabolane sesquiterpenoid and seven known polyketide metabolites. The structures of the isolated compounds were established by HR-MS, and 1D and 2D NMR spectroscopy. The cytotoxic and antiradical activities of the isolated compounds were evaluated.

Cucumarioside E from the Far Eastern Sea Cucumber Cucumaria japonica (Cucumariidae, Dendrochirotida), New Minor Monosulfated Holostane Triterpene Pentaoside with Glucose as the Second Monosaccharide Residue.

New minor triterpene glycoside, cucumarioside E (1) has been isolated from the Far Eastern sea cucumber Cucumaria japonica. The structure of the glycoside was elucidated by 2D-NMR specroscopy and mass-spectrometry. The glycoside has glucose instead of quinovose as the second monosaccharide residue and xylose as third monosaccharide residue that is unique structural feature for triterpene glycosides carbohydrate chains from sea cucumbers belonging to the genus Cucumaria.

The Influence on LPS-Induced ROS Formation in Macrophages of Capelloside A, a New Steroid Glycoside from the Starfish Ogmaster capella.

A new steroid glycoside, capelloside A (1), was isolated from the ethanolic extract of the startish Ugmaster capella along with the previously known coscinasteroside B (2). The structures of 1 was elucidated by extensive NMR and ESI-MS techniques as (24S)-24-O-(3-O-methyl-ß-D-xylopyranosyl)-5a- cholestane-3ß,6ß,8,15α,24-pentoI 15-O-sulfate (1). Compounds 1 and 2 decreased intracellular ROS (reactive oxygen species) levels in murine macrophages of the RAW 264.7 cell line at induction by endotoxic lipopolysaccharide (LPS) from E. coli by 60% and 41%, correspondingly.

Triterpene glycosides from the sea cucumber Cladolabes schmeltzii. II. Structure and biological action of cladolosides A1-A6 .

Six new triterpene glycosides, cladolosides Al-A6 (1-6), have been isolated from the Vietnamese sea cucumber Cladolabes schmeltzii (Cladolabinae, Sclerodactylidae, Dendrochirotida). Structures of the glycosides were elucidated by 2D NMR spectroscopy and MS. All the glycosides have nonsulfated tetrasaccharide linear carbohydrate moieties. Glycoside 6 has a glucose residue as the third monosaccharide unit, while the rest of the compounds comprise a xylose in this postion of the carbohydrate chain. Glycosides 1-6 differ from each other in the structures of their holostane aglycones. Cytotoxic activities of glycosides 1-6 were studied against mouse spleenocytes, along with hemolytic activities against mouse erythrocytes. All the compounds, except cladoloside A5 (5) posessing a hydroxy-group in the aglycone side chain, demonstrated rather strong cytotoxic and hemolytic effects. The most active glycosides were cladolosides A1 (1) and A2 (2) having two O-acetic groups and the xylose residue in the third position of the sugar chain.

Structures of violaceusosides C, D, E and G, sulfated triterpene glycosides from the sea cucumber Pseudocolochirus violaceus (Cucumariidae, Dendrochirotida).

Four new triterpene glycosides, violaceusosides C (1), D (2), E (3) and G (4) have been isolated from the sea cucumber Pseudocolochirus violaceus (Cucumariidae, Dendrochirotida). Eight known glycosides, DS-holothurin A and holothurinoside A, isolated earlier from Holothuria forskalii (order Aspidochirotida); and violaceuside A, lefevreoside C, philinopside E, intercedenside B, violaceuside II and liovilloside A isolated earlier from representatives of the family Cucumariidae, order Dendrochirotida have also been found in P. violaceus. The chemical structures of the glycosides were elucidated by 2D NMR spectroscopy and mass spectrometry. Violaceusosides C (1), D (2), E (3) and G (4) have holostane-type aglycones and tetrasaccharide linear carbohydrate chains differing in the sugar composition and the number and position of sulfate groups. Violaceusosides E (3) and G (4) are characterized by the presence of a sulfate group at C-3 of the quinovose residue that is very rare among sea cucumber glycosides. Cytotoxic activities of the glycosides 1-4 against cells of the ascite form of mouse Ehrlich carcinoma and hemolytic activities against mouse erythrocytes have been studied. Violaceusosides C (1) and D (2) demonstrated moderate cytotoxic and hemolytic effects, while violaceusosides E (3) and G (4) have more powerful activities.

Kolgaosides A and B, two new triterpene glycosides from the Arctic deep water sea cucumber Kolga hyalina (Elasipodida: Elpidiidae).

Two novel triterpene holostane nonsulfated pentaosides, kolgaosides A (1) and B (2), and one known, holothurinoside B (3), were isolated from the Arctic sea cucumber Kolga hyalina, the second representative of the family Elpidiidae, order Elasipodida, from which triterpene glycosides have been obtained. The structures of 1 and 2 were elucidated using 1H and 13C NMR and 2D NMR procedures (HSQC, HMBC, COSY, ROESY, TOCSY) and HRESI mass-spectrometry. Kolgaosides A (1) and B (2) demonstrate low cytotoxic activity against the cells of the ascite form of mouse Ehrlich carcinoma and moderate hemolytic activity against mouse erythrocytes, despite the presence of hydroxy groups in the side chains of the aglycones. The glycosides of K. hyalina are similar to those of the Antarctic sea cucumber Rhipidothuria racowitzai Hèrouard, 1901 (=Achlionice violaescupidata) (Elasipodida: Elpidiidae); this may have chemotaxonomic significance.

Three new steroid biglycosides, plancisides A, B, and C, from the starfish Acanthaster planci.

Three new steroid biglycosides, plancisides A-C (1-3), were isolated from the ethanolic extract of the starfish Acanthaster planci. The structures of 1-3 were determined by extensive NMR and ESI-MS techniques, as (24S)-28-O-[ß-D-galactofuranosyl-(1-->5)-α-L-arabinofuranosyl]-24-methyl-5α-cholestane-3ß, 4ß, 6α, 8, 15α,16α, 28-heptol (1), (24S)-28-O-[α-L-fucopyranosyl-(1 --> 2)-3-O-methy-ß-D-xylopyranosy]-24-methy-5α-cholestane-3ß, 4ß,6α,8,15ß,16ß,28- heptol (2) and (24S)-28-O-[2,4-di-O-methyl-ß-D-xylopyranosyl-(1 --> 2)-α-L-arabinofuranosyl]-24-methyl-5α-cholestane-3ß,4ß,6α,8,15ß,16ß,28-heptol 6-O-sulfate (3), respectively. Compound 2 is the first steroid glycoside containing an α-fucopyranose unit found from starfish. Compound 1 slightly inhibits cell proliferation of HCT-116, T-47D, and RPMI-7951 cancer cell lines, but has no effect on colony formation of these cells in a soft agar clonogenic assay.

Determination of C-23 configuration in (20R)-23-hydroxycholestane side chain of steroid compounds by 1H and 13C NMR spectroscopy.

Epimeric (20R,23R)- and (20R,23S)-23-hydroxycholestane steroids were synthesized. Their structures were elucidated by extensive 1H and 13C NMR spectroscopy and application of the Mosher's method. All proton and carbon signals of the side chains were assigned. Based on these assignments spectral data allow the determination of the C-23 stereochemistry of (20R)-23-hydroxycholestane side chains of the new natural steroids by comparison with spectra of the obtained model compounds. As a result, the C-23 configuration of two steroid compounds from the starfishes Lethasterias nanimensis chelifera and Lethasterias fusca was established.

Triterpene glycosides from the sea cucumber Eupentacta fraudatrix. Structure and biological action of cucumariosides I1, I3, I4, three new minor disulfated pentaosides.

Three new minor triterpene glycosides, cucumariosides I1 (1), I3 (2) and I4 (3) have been isolated from the Far Eastern sea cucumber Eupentacta fraudatrix. Structures of the glycosides were elucidated by 2D NMR spectroscopy and MS. Glycosides 1-3 belong to the group of cucumariosides I, havingbranched pentasaccharide carbohydrate moieties with two sulfate groups and possessing 3-O-methyl-D-xylose as a terminal monosaccharide unit that is a characteristic feature of all the glycosides isolated from E. fraudatrix. Glycosides 1 and 2 differ from each other by the side chain structures in the holostane aglycone moieties, while cucumarioside I4 (3) has a 23, 24, 25, 26, 27-pentanorlanostane aglycone with an 18 (16)-lactone. Cytotoxic activities of glycosides 1-3 against mouse spleen lymphocytes and ascite form of mouse Ehrlich carcinoma cells, along with hemolytic activity against mouse erythrocytes and antifungal activity were studied. Glycoside 1, having an aglycone side chain with a 24 (25)-double bond, possesses moderate activity in all the tests, while glycoside 2, having 23 (24)-double bond and 25-hydroxy group in the side chain, and glycoside 3 with an aglycone with an 18 (16)-lactone and shortened side chain have either low activity or are non-active.