Search

Six new polyhydroxylated steroids conjugated with taurine, microdiscusols A-F, were isolated from the alcoholic extract of the Arctic starfish Asterias microdiscus. Three of them have been found to have additional sulfate groups in tetracyclic cores. The structures of new compounds were established by 1D and 2D NMR and HRESIMS techniques. The found steroid taurine conjugates resemble, by their structures, salts of bile acids and alcohols of lower vertebrates., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Six new polyhydroxysteroidal glycosides, anthenosides S1  - S6 (1 - 6), along with a mixture of two previously known related glycosides, 7 and 8, were isolated from the methanolic extract of the starfish Anthenea sibogae. The structures of 1 - 6 were established by NMR and HR-ESI-MS techniques as well as by chemical transformations. All new compounds have a 5α-cholest-8(14)-ene-3α,6β,7β,16α-tetrahydroxysteroidal nucleus and differ from majority of starfish glycosides in positions of carbohydrate moieties at C(7) and C(16) (1 - 4, 6) or only at C(16) (5). The 4-O-methyl-β-d-glucopyranose residue (2) and Δ 24 -cholestane side chain (3) have not been found earlier in the starfish steroidal glycosides. The mixture of 7 and 8 slightly inhibited the proliferation of human breast cancer T-47D cells and decreased the colony size in the colony formation assay., (© 2018 Wiley-VHCA AG, Zurich, Switzerland.)

In recent years many sterols with unusual structures and promising biological profiles have been identified from marine sources. Here we report the isolation of a series of 24-alkylated-hydroxysteroids from the soft coral Sinularia kavarattiensis, acting as pregnane X receptor (PXR) modulators. Starting from this scaffold a number of derivatives were prepared and evaluated for their ability to activate the PXR by assessing transactivation and quantifying gene expression. Our study reveals that ergost-5-en-3β-ol (4) induces PXR transactivation in HepG2 cells and stimulates the expression of the PXR target gene CYP3A4. To shed light on the molecular basis of the interaction between these ligands and PXR, we investigated, through docking simulations, the binding mechanism of the most potent compound of the series, 4, to the PXR. Our findings provide useful functional and structural information to guide further investigations and drug design.

Three new steroidal compounds with polyhydroxy groups, tupisteroide A-C (1-3), were obtained from the roots of Tupistra chinensis, together with one known compound (4) that was isolated from this plant for the first time. The structures of tupisteroide A-C were determined on the basis of one- and two-dimensional NMR spectroscopy, including (1) H-(1) H Correlation Spectroscopy, Heteronuclear Multiple Bond Correlation, and Heteronuclear Single Quantum Coherence experiments. The isolated compounds were evaluated for their cytotoxic activities against A549, HepG2, and CaSki cancer cell lines in vitro. Among them, compounds 1, 2, and 4 did not show significant inhibitory activity, but compound 3 showed cytotoxicity against A549 cancer cell lines with IC(50) values of 25.0 μM., (Copyright © 2012 John Wiley & Sons, Ltd.)

9alpha-Hydroxy derivatives were prepared from 11 steroids ofandrostane and pregnane series using Rhodococcus erythropolis VKPM Ac-1740 culture with 0.5-20 g/l substrate concentration in the reaction mixture. 9alpha-Monohydroxylation proceeded regardless of the substituent structure at C17. However, the structure of the steroid molecule influenced the time of complete conversion of the substrate and the yield of the transformation product. 9alpha-Hydroxy-androstenedione was obtained in 35 h in a yield of 85% when the maximum concentration of androstenedione (AD) was 10 g/l. 9alpha-Hydroxy-AD was also formed by the actinobacterium cells entrapped in poly(vinyl alcohol) cryogel beads. Nine successive transformation cycles were carried out using immobilized cells at 4.0 g/l concentration of AD in the medium. The yield of 9alpha-hydroxy-AD formed during six cycles (from two to eight with the duration of each cycle for 22-24 h) was 98%.

Thirteen steroidal compounds including three new polyhydroxysteroids, (24R,25S)-24-methyl-5α-cholestane-3β,6α,8,15β,16β,26-hexaol, (22E,24R,25S)-24-methyl-5α-cholest-22-ene-3β,6α,8,15β,16β,26-hexaol and (22E,24R,25S)-24-methyl-5α-cholest-22-ene-3β,4β,6α,8,15β,16β,26-heptaol, have been isolated along with the previously known ten polyhydroxysteroids from the tropical starfish Asteropsis carinifera collected near the coast of Vietnam. The structures of new compounds were elucidated by spectroscopic methods (mainly 2D NMR and ESI-mass-spectrometry).

A new 3beta,5alpha,6beta-trihydroxysteroid, bebryceoid A (1), has been isolated from an octocoral Bebryce sp. In addition, an octocoral Carijoa sp. yielded two new 3beta,5alpha,6beta-trihydroxysteroids, carijoids A (2) and B (3). The structures of steroids 1-3 were elucidated by spectroscopic methods and by comparison of the spectral data with those of known steroid analogues.

From the ethanolic extract of Lentinus edodes (Shiitake) eight known sterols were isolated and identified: ergosterol, ergosterol peroxide, (22E)-ergosta-5,7,9(11), 22-tetraen-3beta-ol, (22E)-ergosta-7,9(11),22-trien-3beta-ol, (22E)-ergosta-6,8,22-trien-3beta-ol, (22E)-norergosta-5,7,9,22-tetraen-3beta-ol, 3beta,5alpha-dihydroxy-(22E)-ergosta-7,22-dien-6-one, (22E)-ergosta-4,6,8(14),22-tetraen-3-one and, for the first time in mushrooms, (22E)-ergosta-6,22-diene-3beta,5alpha,8alpha-triol.

Bendigoles A approximately C are the first secondary metabolites to be isolated from a member of the actinomycete genus Gordonia. They were detected in a culture filtrate extract of Gordonia australis Acta 2299 by HPLC-diode array analysis and characterized as new steroids by mass spectrometry and NMR experiments. Bendigole C show binding affinity to the human progesterone and A approximately C to androgen receptor but are inactive at mineralocorticoid and estrogen receptors. In in vitro transactivation studies bendigoles A and C showed moderate and weak androgenic activities.

Seven sulfated polyhydroxysteroids were isolated from the Far East starfish Pteraster obscurus and the ophiura (snake star) Asteronyx loveni (collected in the Sea of Okhotsk) and characterized: disodium and sodium salts of (20R)-24-methyl-2beta-hydroxycholesta-5,24(28)-diene-3alpha,21-diyl disulfate, (20R)-5alpha-cholestane-3beta,21-diyl disulfate, (20R)-3beta-hydroxy-5alpha-cholestan-21-yl sulfate, (20R)-cholest-5-ene-3beta,21-diyl disulfate, (20R)-2beta-hydroxycholest-5-ene-3alpha,21-diyl disulfate, (20R)-cholest-5-en-3beta-yl sulfate, and (20R)-5alpha-cholestan-3beta-yl sulfate. The first four compounds turned out to be new, whereas the others were identical to the known compounds. Structures of the isolated steroids were identified by two-dimensional NMR spectroscopy and other physicochemical methods. The compounds isolated from starfish are structurally similar to typical ophiuroid metabolites, which support the opinion of some taxonomists that starfish and ophiuroids are phylogenetically related classes.

Three new polar steroids identified as trofoside A, (20R,24S)-24-O-(3-O-methyl-beta-D-xylopyranosyl)-3beta,6alpha,8,15beta,24-pentahydroxy-5alpha-cholestane, its 22(23)-dehydro derivative (trofoside B), and 15-sulfoxy-(20R,24S)-5alpha-cholestane-3beta,6beta,8,15alpha,24-pentaol sodium salt, were isolated from Trofodiscus uber starfish extracts collected in the Sea of Okhotsk. Two known compounds, trofoside A aglycone, (20R,24S)-3beta,6alpha,8,15beta,24-pentahydroxy-5alpha-cholestane, and triseramide, (20R,24R,25S,22E)-24-methyl-3beta,6alpha,8,15beta-tetrahydroxy-5alpha-cholest-22-en-27-oic acid (2-sulfoethyl)amide sodium salt, were also found. The structures of the isolated polyoxysteroids were established from their spectra. Minimal concentrations causing degradation of unfertilized egg-cells of the sea-urchin Strongylocentrotus intermedius (C(min)) and terminating the cell division at the stage of the first division (C(min) embr.), as well as the concentrations causing 50% immobilization of sperm cells (ImC50) and inhibiting their ability to fertilize egg-cells by 50% (IC50) were determined for the isolated compounds. Of three compounds highly toxic in embryos and sea-urchin sperm cells, the polyol with a sulfo group in the steroid core was the most active; two glycosides with monosaccharide chains located at C3 and C24 atoms were less toxic. Note that all the compounds with the spermiotoxic activities differently affected the embryo development. The positions of monosaccharide residues in the core considerably influence the compound activity. For example, both mono- and double chained glycosides with the monosaccharide fragment at C3 and C24 atoms are active against sea-urchin sperm cells and embryos, whereas the C24 glycosylated trofoside A does not affect embryos and displays a poor spermiotoxicity.

Four new trihydroxysteroids, sinugrandisterols A-D (1-4), have been isolated from the CH(2)Cl(2)-soluble fraction of the EtOH extract of Sinularia grandilobata. The structures of these metabolites were determined on the basis of spectroscopic (IR, MS, and 1D and 2D NMR) analysis. The cytotoxicity of 1-4 toward a limited panel of cancer cell lines is also reported.

Besides beta-sitosterol and stigmasterol, the major steroids of sugarcane, the following minor steroids have been isolated and identified from sugarcane wax: 3,6-diketosteroids, Delta(4)-3-keto steroids, and Delta(4)-6-hydroxy-3-keto steroids. Their structures were established by spectroscopic techniques and chemical correlations.

Five new polar steroids, polyhydroxysterols 2-5 and the glycoside leviusculoside J (7), were isolated, along with the previously known compounds 1, 6, 8, and 9, from the alcoholic extract of the Far Eastern starfish Henricia leviuscula. The structures of novel compounds were elucidated by interpretation of spectral data (mainly 2D-NMR), and the stereochemistry of chiral centers in the side chain of sterols 2 and 3 was determined by using J-based configuration analysis and the modified Mosher's method. Steroids 1, 3, 6, 7, and 9 showed moderate hemolytic activity in the mouse erythrocytes assay.

Chemical investigation of the dichloromethane extract of the Red Sea marine sponge Lamellodysidea herbacea led to the isolation of four novel polyhydroxysteroids: cholesta-8-en-3beta,5alpha,6alpha,25-tetrol (1), cholesta-8(14)-en-3beta,5alpha,6alpha,25-tetrol (2), cholesta-8,24-dien-3beta,5alpha,6alpha-triol (3), and cholesta-8(14),24-dien-3beta,5alpha,6alpha-triol (4). Their structures were identified through 1D and 2D NMR studies. Relative stereochemistries were established by analysis of chemical shifts, coupling constants, and NOESY correlations. Compounds 3-4 showed antifungal activity against Candida tropicalis, with an inhibition diameter of 13 and 11 mm at 10 microg/disc, respectively.

Seasonal variations in the concentrations of individual polyhydroxysteroids and related low molecular weight glycosides in pyloric caeca and stomach of the starfish Patiria (=Asterina) pectinifera collected at one location near Vladivostok have been studied. HPLC analysis on the fractions containing these substances showed a fairly constant composition of steroids in digestive tissues of P. pectinifera in spite of small seasonal variations in the relative concentrations of individual compounds.

Seasonal variations in the levels of polar steroids including polyhydroxylated steroids and related glycosides in digestive organs of the starfish Patiria (=Asterina) pectinifera have been studied. The concentration of polar steroids is related to the annual reproductive cycle of the starfish and periods of active feeding. Two peaks in concentrations of polar steroids in pyloric caeca and stomach were found, the first in winter during reorganization and the second in summer during intensive gametogenesis before spawning. Probable biological functions of polyhydroxysteroids and related glycosides are discussed. The data support the hypothesis these compounds are involved in digestion in the starfish.

Recently, we have shown that two biologically active, disulfated polyhydroxysteroids from the Pacific brittle star Ophiopholis aculeata stimulate Ca(2+) influx into different cell types. In the present study, 45Ca(2+) and two fluorescent calcium probes, quin-2/AM and fura-2/AM, were employed to investigate the course and amplitude of calcium signals induced in different mouse cells using an radio-isotope, spectrofluorimetry, and microcytofluorimetry techniques. The cytotoxic and hemolytic effects were not observed for both steroids at the wide range of concentrations. Steroids did not influence [3H]-uridine incorporation in a variety of cells. The investigated steroids stimulated a rapid increase in cytosolic Ca(2+) content in Ehrlich mouse carcinoma cells, mouse spleen lymphocytes, and mouse peritoneal macrophages in the concentration range 1-100 microg/ml on a dose-dependent basis. Blockers of L-type calcium channels, such as verapamil, diltiazem, nifedipine (1 x 10(-7)M), and 1mM EGTA, inhibited this process and reduced the response of cells to steroid application. The stimulatory effect of steroids on human fibroblast proliferation and mouse macrophage lysosome activity was observed also. It is suggested that the investigated compounds may act as Ca(2+)-agonists and increase Ca(2+)-transport across cell membranes.

Sodium salt of (20R)-3 alpha,4 beta-dihydroxycholest-5-ene-21-yl sulfate and disodium salts of (20R)-4 beta-hydoxycholest-5-ene-3 alpha,21-diyl disulfate, (20R)-24-methylcholest-5,24(28)-diene-3 alpha,21-diyl disulfate, (20R)-24-methyl-5 alpha-cholest-24(28)-ene-3 alpha,21-diyl disulfate, (20R)-cholest-5-ene-3 alpha, 21-diyl disulfate, (20R)-5 alpha-cholestane-3 alpha,21-diyl disulfate, and (20R)-3 alpha-hydroxycholest-5-ene-2 beta,21-diyl disulfate were isolated from the far eastern starfish Diplopteraster multipes and characterized. These compounds differ structurally from sulfated polyhydroxysteroids in other starfish species. At the same time, they are typical secondary metabolites of Ophiuroidea and have some structural features characteristic of the ophiuroid-isolated steroids, namely the 3 alpha-hydroxy (or 3 alpha-sulfoxy) and 21-sulfoxy groups. These data support the opinion of some taxonomists that starfishes and ophiuroids are phylogeneteically related classes and are closer to each other than to other classes of the Echinodermata phylum.

The distribution of free sterols, polyhydroxysteroids and steroid glycosides in different body components of the Far-eastern starfish Patiria (=Asterina) pectinifera has been studied. It was shown that free sterol fractions from aboral and oral body walls, gonads, stomach and pyloric ceca contained Delta(7) sterols with a preponderance of 5alpha-cholest-7-en-3beta-ol. All these body components had also toxic steroid oligoglycosides. However, polyhydroxysteroids and related low molecular weight steroid glycosides were found in stomach and pyloric ceca only. In pyloric ceca, the sulfated monoside 'asterosaponin' P(1) was identified as a main polar steroid, whereas 6-sodium sulfate of cholestane-3beta,4beta,6alpha,7alpha,8,15beta,16beta,26-octaol predominated in the stomach. Probable biological functions of polar steroids and free sterols in this starfish were discussed. It was suggested that some polyhydroxysteroids and related monoglycosides play the same biological role as bile alcohols and bile acids do in vertebrates.

The sterol composition of the Caribbean sponge Neofibularia nolitangere has been investigated. In addition to usual sterols this sponge elaborates comparable amounts of 24-methylene-4 alpha-methyl-5 alpha-cholest-8-en-3 beta-ol (1), which is very unusual among sponge sterols, and lesser quantities of two new polyoxygenated sterols, (24S)-24-ethyl-5 alpha-cholest-8-ene-5,6 beta,7 alpha-triol (2) and (24S)-24-ethyl-5 alpha-cholest-8(14)-ene-5,6 beta,7 alpha-triol (3).

Ten new [1-10] and three known [11-13] polyhydroxysteroids were isolated, along with four known asterosaponins [14-17], from the starfish Luidia clathrata, collected from the offshore waters of the northern Gulf of Mexico. The EtOH extracts of this starfish showed feeding-deterrent properties against marine fish, and inhibited the settlement of larvae of barnacles and bryozoans, as well as the growth of several bacteria. The structures of the new compounds were determined by interpretation of their nmr spectral data and by comparison with the spectral data of known compounds. The assignment of the configurations of the side-chain stereogenic centers of compounds 1 and 3-10 were based on the comparison of their nmr data with those of the stereoisomeric model compounds after derivatization with the chiral auxiliary MTPA reagent. Larval settlement assays conducted on ten isolated compounds revealed they are all potent inhibitors of settlement. Two of these isolated compounds inhibited the growth of several bacteria.

A reinvestigation of the starfish Oreaster reticulatus has led to the isolation of sixteen steroidal oligoglycosides and six polyhydroxysteroids. One steroidal monoglycoside has been identified as asterosaponin-1 [5], previously isolated from the same organism, and one pentaglycoside steroidal sulfate has been identified with the known ophidianoside F [1], previously isolated from starfish species of the family Ophidiasteridae. The novel pentaglycoside steroidal sulfates reticulatosides A [3] and B [4] represent the second examples of asterosaponins containing the 5 alpha-cholesta-9(11)-en-3 beta,6 alpha,20,22-tetraol aglycone. Of the remaining new steroidal oligoglycosides, the majority are characterized by the common (24S)-5 alpha-cholesta-3 beta,6 alpha,8,15 alpha,24-pentaol aglycone, with some having a sulfate group at C-6, and differing in the sugar moiety. Compounds 11, 12, 15, and 16 represent major departures from the more common structural features encountered in steroidal glycosides from starfish with the presence in 11 and 12 of a rare 5-O-methylgalactofuranosyl unit and in 15 and 16 of a 3-O-methyl-2-O-sulfate-xylopyranosyl unit. The latter was shown by nmr data combined with molecular dynamics calculations to exist in an 8:2 equilibrium mixture of the 1C4 and 4C1 conformations.

This paper reports a complete steroid glycoside and polyhydroxysteroid analysis of the starfish Solaster borealis, collected at Mutsu Bay, Japan. The glycosides include a new pentaglycoside steroid sulfate ("asterosaponin"), designated solasteroside A [1], two new sulfated 24-O-diglycosides, both with the common 5 alpha-cholesta-3 beta,6 alpha,8,15 alpha, 24-pentaol aglycone, borealosides A [2] and B [3], two new 24-O-(3-O-methyl)xylosides, borealosides C [4] and D [5], having the same aglycone with an additional hydroxy group at 4 beta-position in 5, and the known amurensoside B, previously isolated from Asterias amurensis. Among the polyhydroxysteroid constituents, four (7-10) are new, and five (11-15) have previously been isolated from starfishes.

Five novel sterols isolated from the marine sponge Oscarella lobularis have been identified on the basis of spectral arguments: cholest-7-ene-3beta,5alpha-diol-6-one (1), cholesta-7,22E-diene-3beta, 5alpha-diol-6-one (2), 24-methylcholesta-7,22E-diene-3beta,5alpha-diol-6-one (3), 24-methylcholesta-7,24(28)-diene-3beta,5alpha-diol-6-one (4), and 24-ethylcholest-7-ene-3beta,5alpha-diol-6-one (5).

In an earlier communication, we conclusively proved that estrone-3-sulfate could be hydroxylated in the 16alpha position by guinea pig liver slices. Disulfates of 16alpha-hydroxyestrone and estriol were identified. Suggestive evidence for 6-hydroxylated metabolites was also mentioned. A careful reinvestigation has now shown that the steroid disulfate fraction is composed of 16alpha- and 16beta-hydroxylated steroids. 16beta-Hydroxyestrone in particular is an important quantitative metabolite of estradiol-17 beta. It is concluded that no firm evidence is available for the formation of 6-hydroxysteroids in the tissue system under consideration.

The 17-keto function of phenolic steroids is reduced by the following intestinal bacteria: Eubacterium lentum, Clostridium paraputrificum, Clostridium J-1 and Clostridium innocuum. The 17-keto group of androstenedione is reduced solely by Bacteroides fragilis.

An improved method for the separation of epimeric C19O2 steroids and their related allylic alcohols is described. In this method, the steroids are first separated by over-run thin-layer chromatography, and the unresolved groups are further analysed as free or as trimethylsilyl ether derivatives by gas-liquid chromatography. The behaviour of twenty-one C19O2 steroids was investigated by thin-layer chromatography in four systems and by gas-liquid chromatography in four liquid phases. All steroid pairs of similar polarity were resolved by the combination of these two fractionation procedures.

From the rhizome D. deltoidea a new trisaccharide of diosgenine has been isolated. This compound is diosgenine-3 (alpha-L-rhamnopyranosyl (1-->2gl)-beta-D-glucopyranosyl-(1-->4 gl)-beta-D-glucopyranoside. This trisaccharide has been termed deltonine. The rhizome D. deltoidea has also displayed furostanolic tetrasaccharide which is a mixture of delta5-furostene-3beta, 22, 26-triol-3beta-deltotrioside-26beta-D-glucopyranoside and its alkoxyderivative. This tetrasaccharide has been termed deltoside. The rhizome has also small quantities of diosgenine-3-beta-D-glucopyranosyl (1-->4)-beta-D-glucopyranoside.

Patients with low-renin essential hypertension have certain features consistent with excessive mineralocorticoid activity. Because known mineralocorticoids are normal in the majority of low-renin essential hypertension patients, an unknown mineralocorticoid was sought in the urine of such patients. Urine extracts from patients with low-renin essential hypertension were assayed for mineralocorticoid activity in adrenalectomized rats and found to contain more such activity than could be accounted for by the known mineralocorticoids in the extracts. The factor responsible for the unexplained mineralocorticoid activity was purfied and then identified by mass spectral analysis as 16beta-hydroxydehydroepiandrosterone (16beta-OH-DHEA). Synthetic 16beta-OH-DHEA was found to have a mineralocorticoid potency one-fortieth that of aldosterone in the rat bioassay. The mineralocorticoid effects of both the urine extracts and the synthetic steroid were blocked in the rat by spironolactone, a mineralocorticoid antagonist. A specific assay for 16beta-OH-DHEA was developed, and its level in the urine was found to be elevated in patients with low-renin essential hypertension.