A new bioactive steroidal ketone from the South China Sea sponge Xestospongia testudinaria

A new steroidal ketone (1), with an ergosta-22,25-diene side chain, was obtained from the South China Sea marine sponge Xestospongia testudinaria. The structure of 1 was determined on the basis of detailed spectroscopic analysis and by comparison with literature. Compound 1 exhibited significant inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), a key target for the treatment of type II diabetes and obesity, with an IC50 value of 4.27 ± 0.55 μM, which is comparable with the positive control oleanolic acid (IC50 = 2.63 ± 0.22 μM).

Bufadienolides and polyhydroxycholestane derivatives from Bufo bufo gargarizans

A new polyhydroxycholestane sulfate ester, 3α,12β,25,26-tetrahydroxy-7-oxo-5β-cholestane 26-O-sulfate (1), was isolated from dried skin of Bufo bufo gargarizans Cantor and its structure was elucidated on the basis of extensive 1D and 2D NMR as well as HR-ESI-MS analysis. A comparison of steroidal metabolite profiles, based on HPLC and LC-MS analyses, indicates that the chemical compositions of the various parts of toads, such as venom, skin and stratum corneum, are significantly different.

Microdiplanol and microdiplane: a new m-anisaldehyde and a new 24-methylcholestanol derivative from the endophytic fungus Microdiplodia sp

Phytochemical investigation of the endophytic fungus Microdiplodia sp. afforded a new m-anisaldehyde derivative named microdiplanol (1) and a new 24-methylcholestanol derivative named microdiplane (2). Their structures were confirmed by a comprehensive analysis of 1D and 2D NMR and mass spectrometric data.

A novel varanic acid epimer--(24R,25S)-3α,7α,12α,24-tetrahydroxy-5β-cholestan-27-oic acid--is a major biliary bile acid in two varanid lizards and the Gila monster

A key intermediate in the biosynthetic pathway by which C(24) bile acids are formed from cholesterol has long been considered to be varanic acid, (24ξ,25ξ)-3α,7α,12α-24-tetrahydroxy-5β-cholestan-27-oic acid. The (24R,25R)-epimer of this tetrahydroxy bile acid, in the form of its taurine N-acyl amidate, was thought to be the major biliary bile acid in lizards of the family Varanidae. We report here that a major biliary bile acid of three lizard species - the Komodo dragon (Varanus komodoensis), Gray's monitor (Varanus olivaceus), and the Gila monster (Heloderma suspectum) - is a novel epimer of varanic acid. The epimer was shown to be (24R,25S)-3α,7α,12α,24-tetrahydroxy-5β-cholestan-27-oic acid (present in bile as its taurine conjugate). The structure was established by mass spectroscopy and by (1)H and (13)C nuclear magnetic spectroscopy, as well as by synthesis of the compound.

A novel sterol sulfate and new oligosaccharide polyester from the aerial parts of Polygala sibirica

Polygalasterol A (1), a new sterol sulfate, and a new oligosaccharide ester, polygalasibiricose I (2), have been isolated from the n-butanol soluble fraction of the aerial parts of Polygala sibirica L. Their structures were determined to be (24R)-24-sulfo-5a-cholestane-3a,7a,12a,24-tetrol (1) and 3-O-benzoyl-beta-D-fructofuranosyl-(2-->1 )-[beta-D-glucopyranosyl-( 1 --2)]-4-0- {4-0-[3-O-[3-O-benzoyl-(2-O-acetyl)-alpha-L-rhamnopyranosyl-(1-->3 )]-2-O-acetyl-alpha-L-rhamnopyranosyl]-(Z)-p-coumaroyl}-alpha-D-glucopyranoside (2), respectively, by HRESIMS, and 1D and 2D NMR spectroscopic studies.

Polyhydroxylated steroids from the bamboo coral Isis hippuris

In previous studies on the secondary metabolites of the Taiwanese octocoral Isis hippuris, specimens have always been collected at Green Island. In the course of our studies on bioactive compounds from marine organisms, the acetone-solubles of the Taiwanese octocoral I. hippuris collected at Orchid Island have led to the isolation of five new polyoxygenated steroids: hipposterone M–O (1–3), hipposterol G (4) and hippuristeroketal A (5). The structures of these compounds were determined on the basis of their spectroscopic and physical data. The anti-HCMV (human cytomegalovirus) activity of 1–5 and their cytotoxicity against selected cell lines were evaluated. Compound 2 exhibited inhibitory activity against HCMV, with an EC₅₀ value of 6.0 μg/mL.

Identification of squalamine in the plasma membrane of white blood cells in the sea lamprey, Petromyzon marinus

It is well established that innate mechanisms play an important role in the immunity of fish. Antimicrobial peptides have been isolated and characterized from several species of teleosts. Here, we report the isolation of an antimicrobial compound from the blood of bacterially challenged sea lamprey, Petromyzon marinus. An acetic acid extract from the blood cells of challenged fish was subjected to solid-phase extraction, cation-exchange chromatography, gel-filtration chromatography, and reverse-phase high-performance liquid chromatography, with the purified fractions assayed for antimicrobial activity. Surprisingly, antimicrobial activity in these fractions originated from squalamine, an aminosterol previously identified in the dogfish shark, Squalus acanthias. Further chromatographic and mass spectrometric analyses confirmed the identity of squalamine, an antimicrobial and antiangiogenic agent, in the active fraction from the sea lamprey blood cells. Immunocytochemical analysis localized squalamine to the plasma membrane of white blood cells. Therefore, we postulate that squalamine has an important role in the innate immunity that defends the lamprey against microbial invasion. The full biochemical and immunological roles of squalamine in the white blood cell membrane remain to be investigated.

[Steroid compounds from the Far East starfish Pteraster obscurus and the ophiura Asteronyx loveni]

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.

[Reversing effect of brassinolide on multidrug resistance of-CCRF-VCR1000 cells and a preliminary investigation on its mechanisms]

AIM

To investigate the effect of brassinolide, a plant growth modulator, on multidrug resistance (MDR) of human T lymphoblastoid cell line CCRF-VCR 1000 which was obtained by progressively addition of vincristine (VCR) to sensitive CCRF-CEM cells, and to explore preliminarily the mechanism of reversing action.

METHODS

MTT method was used to detect the resistant factor of resistant cell line and the reversing fold after addition of brassinolide. The intracellular accumulation of rhodamine 123, a fluorescent dye transported by P-glycoprotein was detected by flow cytometry, the catalytic activity of topoisomerase II was assessed by Sulliven method to find the effect of brassinolide on resistance. The protein expression of p53 was measured using Western blotting in the sensitive cells and resistant cells to explore the effect of brassinolide.

RESULTS

The resistant factors of CCRF-VCR cells on adriamycin, VP-16 and VCR are respectively as 153.1, 55.9 and 8123.1 folds comparing to the sensitive cell line CCRF-CEM. After treatment of brassinolide under the concentration of 0.001 - 10.0 microg x mL(-1), the resistance of CCRF-VCR was reversed partly with the reversing folds respectively as 4.4 - 11.6. The intracellular accumulation of rhodamine 123 was significantly reduced in the resistant cells. After treatment of brassinolide, the accumulation increased, the level of fluorescent dye was situated between resistant cells and sensitive cells. No alteration of the catalytic activity of topoisomerase II was found among three groups. The level of protein expression of p53 in resistant cells was higher than that of sensitive cells. After brassinolide treatment, the expression of p53 in CCRF-VCR cells restored to the level of sensitive cells.

CONCLUSION

Brassinolide could effectively reverse the resistance of CCRF-VCR cells by inhibiting the effusion of drug transported by P-glucoprotein. To down regulate the abnormal expression of p53 maybe one of the mechanisms of reversing MDR for brassinolide.

Physicochemical and physiological properties of 5alpha-cyprinol sulfate, the toxic bile salt of cyprinid fish

5alpha-Cyprinol sulfate was isolated from bile of the Asiatic carp, Cyprinus carpio. 5alpha-Cyprinol sulfate was surface active and formed micelles; its critical micellization concentration (CMC) in 0.15 M Na+ using the maximum bubble pressure device was 1.5 mM; by dye solubilization, its CMC was approximately 4 mM. At concentrations >1 mM, 5alpha-cyprinol sulfate solubilized monooleylglycerol efficiently (2.1 molecules per mol micellar bile salt). When infused intravenously into the anesthetized rat, 5alpha-cyprinol sulfate was hemolytic, cholestatic, and toxic. In the isolated rat liver, it underwent little biotransformation and was poorly transported (Tmax congruent with 0.5 micromol/min/kg) as compared with taurocholate. 5alpha-Cyprinol, its bile alcohol moiety, was oxidized to its corresponding C27 bile acid and to allocholic acid (the latter was then conjugated with taurine); these metabolites were efficiently transported. 5alpha-Cyprinol sulfate inhibited taurocholate uptake in COS-7 cells transfected with rat asbt, the apical bile salt transporter of the ileal enterocyte. 5alpha-Cyprinol had limited aqueous solubility (0.3 mM) and was poorly absorbed from the perfused rat jejunum or ileum. Sampling of carp intestinal content indicated that 5alpha-cyprinol sulfate was present at micellar concentrations, and that it did not undergo hydrolysis during intestinal transit. These studies indicate that 5alpha-cyprinol sulfate is an excellent digestive detergent and suggest that a micellar phase is present during digestion in cyprinid fish.

Hemolytic steroid disulfates from the far eastern starfish Pteraster pulvillus

Six steroidal ophiuroid-type disulfates, namely, disodium salts of (20R)-cholest-5-ene-3alpha,4beta,21-triol 3, 21-disulfate (1), (20R)-5alpha-cholestane-3alpha,4beta,21-triol 3,21-disulfate (2), (20R)-5alpha-cholestane-2beta,3alpha,21-triol 3,21-disulfate (3), and (20R)-5alpha-cholestane-3alpha,21-diol 3,21-disulfate (4), the dityrammonium salt of (20R)-5alpha-cholestane-3alpha,21-diol 3,21-disulfate (5), and a mixture of sodium and tyrammonium salts (1:1) of (20R)-cholest-5-ene-3alpha,21-diol 3,21-disulfate (6), have been isolated from the ethanolic extracts of Far Eastern starfish Pteraster pulvillus. Steroids 2 and 3 are new compounds. Steroids 1, 2, and 4-6 showed hemolytic activity to mouse erythrocytes with HC(50) values of 8.0 x 10(-5), 4.5 x 10(-5), 1.0 x 10(-5), 1.8 x 10(-5), and 3.3 x 10(-5) M, respectively.

Identification of cyprinol and cyprinol sulfate from grass carp bile and their toxic effects in rats

To elucidate the responsible toxic components of grass carp bile, the bile salt 5 alpha-cyprinol sulfate and its desalted form 5 alpha-cyprinol from grass carp bile were purified and identified by analyses of infrared spectrum, (1)H-, (13)C-nuclear magnetic resonance spectra and mass spectrum. The toxicity of grass carp bile powder, butanol extract of grass carp bile powder, 5 alpha-cyprinol and 5 alpha-cyprinol sulfate in rats were further determined. The kidney and liver functions were significantly affected by grass carp bile powder, butanol extract and 5 alpha-cyprinol sulfate. However, 5 alpha-cyprinol also significantly affected the kidney function, but the toxic effect was less.

[Isolation and identification of two steroids from Sinularia inexplicita]

Sinularia inexplicita collected from the South China Sea was studied with chromatography, two steroids were isolated. Based on the spectral data and elemental analysis, they were identified as 24-methylene-cholestane-3 beta,5 alpha,6 beta,19-tetrol and grogosterol respectively.

Steroidal compounds from the Caribbean octocoral Eunicea laciniata

A previously isolated trihydroxy-gorgosterol derivative (2), a new gorgosterol (3), and the known sterol cholestane-3beta,5alpha, 6beta-triol are reported from the Caribbean octocoral Eunicea laciniata collected off northeast Venezuela. Using high-resolution 2D NMR techniques, the total structural assignment and detailed stereochemistry of 2 is presented for the first time and the full structure of 3 advanced.

Two new 26,27-cyclosterols from the marine sponge Strongylophora corticata

Two novel steroids with a cyclopropane ring at C-25 and C-26, 7-oxopetrosterol (1) and 7alpha-hydroxypetrosterol (2), along with two known compounds, petrosterol (3) and 23,24-dihydrocalysterol (4), have been isolated from the Japanese marine sponge Strongylophora corticata. The structures of 1 and 2 were determined as 26, 27-cyclo-24,27-dimethyl-3beta-hydroxycholest-5-en-7-one and 26, 27-cyclo-24,27-dimethylcholest-5-en-3beta,7alpha-diol on the basis of spectroscopic investigations.

Cholesterol and its derivatives, are the principal steroids isolated from the leech species Hirudo medicinalis

Steroids were isolated from the blood-sucking leech species Hirudo medicinalis and their structure was studied with one- and two-dimensional NMR spectroscopy (DQF-COSY and HMQC), GC-MS and ESI-MS spectrometry. Fractionating leech lipid using silicic acid chromatography led to the isolation of cholesterol in an early chloroform-eluted peak. Only minor traces of cholest-4-en-3-one, 4 beta-methylcholesterol, and sitosterol were present. The subsequent acetone-eluted fraction contained steroidtriols that were further purified by preparative TLC; these included cholest-7-ene-3,5,6 triol, cholest-4,7-diene-3,6,15 triol and to a lesser amount, cholestane-3,5,6 triol. A developmental study on cholesterol content in the leech showed that it is also the principal steroid in embryonic and freshly hatched leeches prior to feeding. The abundance of cholesterol, comprising approximately 5% of the total leech lipid, suggests that H. medicinalis, a blood sucking leech, has adapted itself fully to its mammalian host in terms of its steroid content. It remains to be seen whether lipids are directly transferred from the host to the parasite or whether leeches have evolved mechanisms to synthesize their own steroids.

Brassinosteroids from seeds of Arabidopsis thaliana

Extracts of seeds of Arabidopsis thaliana (ecotype 24) were analysed for the presence of free and conjugated brassinosteroids. 24-epi-Brassinolide (ca 220 ng kg-1) and castasterone (ca 360 ng kg-1) could be isolated and unambiguously identified as native brassinosteroids by GC/MS.

Identification of castasterone, 6-deoxocastasterone, typhasterol and 6-deoxotyphasterol from the shoots of Arabidopsis thaliana

Endogenous brassinosteroids in the shoots of Arabidopsis thaliana were investigated. Castasterone, 6-deoxocastasterone, typhasterol and 6-deoxotyphasterol were identified by GC-MS. The co-occurrence of 6-deoxo-brassinosteroids and 6-oxo-brassinosteroids suggests that there are both early and late C6-oxidation pathways of brassinosteroids in A. thaliana.

Study on the bile salt, sodium scymnol sulfate, from Rhizoprionodon acutus. IV. Structures of chimaerol and sodium chimaerol sulfate in the bile of Lamna ditropis and Rhizoprionodon acutus

Sodium chimaerol sulfate (1) was isolated from the bile of Lamna ditropis and Rhizoprionodon acutus by chromatography on silica gel and Sephadex LH-20, together with sodium scymnol sulfates, (24R,25S)- and (24R,25R)-(+)-3 alpha,7 alpha,12 alpha,24,26-pentahydroxy-5 beta-cholestan-27-yl sodium sulfates (3 and 4) and 3, respectively. On acid hydrolysis, compound 1 afforded chimaerol (2), which was identified as (24R,25R)-(+)-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,26-pentol by direct comparison with an authentic sample, prepared by reduction of (24R,25S)-(+)-24,26-epoxy-5 beta-cholestane-3 alpha,7 alpha,12 alpha,27-tetrol (5) with LiAlH4. The structure of 1 was concluded to be (24R,25R)-(+)-3 alpha,7 alpha,12 alpha,24-tetrahydroxy-5 beta-cholestan-26-yl sodium sulfate, based on the chemical transformation and spectral data.

Study on pharmacological effect of bile salts, sodium scymnol sulfate, from Rhizoprionodon acutus. I. Effect of scymnol, chimaerol and sodium scymnol sulfate on cerebral anoxia

The effects of scymnol, chimaerol and sodium scymnol sulfate, prepared from the bile of Rhizoprionodon acutus, on cerebral anoxia were investigated in experimental models of hypoxia, ischemia and histotoxic anoxia in mice. Scymnol, at a dose of 100 mg/kg, showed a significant protective action against cerebral anoxia in all of the models studied and significantly increased the partial oxygen pressure of the arterial blood. The anti-anoxic activity of scymnol was found to be slightly greater than that of idevenone. A similar protective effect of sodium scymnol sulfate was seen at doses higher than 100 mg/kg. The survival time on hypoxia was significantly prolonged in the animals pretreated with chimaerol.

Bile salts of the toad, Bufo marinus: characterization of a new unsaturated higher bile acid, 3 alpha,7 alpha,12 alpha,26-tetrahydroxy-5 beta-cholest-23-en-27-oic acid

The bile salts present in gallbladder bile of the toad, Bufo marinus, were found to consist of a mixture of bile alcohol sulfates and unconjugated bile acids. The major bile alcohol was 5 beta-bufol; 5 alpha- and 5 beta-cholestane-3 alpha,7 alpha,12 alpha, 26-tetrols occurred as the minor bile alcohols. Bile acids of Bufo marinus were cholic acid, allocholic acid, 3 alpha,7 alpha,12 alpha-trihydroxy-5 alpha- and 5 beta-cholestan-26-oic acids, 3 alpha,7 alpha,12 alpha-trihydroxy-5 alpha- and 5 beta-cholest-23-en-26-oic acids, 3 alpha,7 alpha,12 alpha, 26-tetrahydroxy-5 beta-cholestan-27-oic acid, and a C27 bile acid which has not been previously described. By chromatographic behavior, mass spectral data, and identification of the products of catalytic hydrogenation and ozonolysis, the structure of the new higher bile acid was elucidated as 3 alpha,7 alpha,12 alpha,26-tetrahydroxy-5 beta-cholest-23-en-27-oic acid. The bile salt pattern of Bufo marinus closely resembles that of Bufo vulgaris formosus, except for the absence of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholest-22-ene-24-carboxylic acid, the major bile acid of the latter toad.

Structure of the novel steroidal antibiotic squalamine determined by two-dimensional NMR spectroscopy

Squalamine is a novel aminosterol recently isolated from the dogfish shark, Squalus acanthias. This water-soluble steroid exhibits potent antibacterial activity against both gram-negative and gram-positive bacteria. In addition, squalamine is fungicidal and induces osmotic lysis of protozoa. We report here the structural determination of squalamine, 3 beta-N-1-[N(3-[4-aminobutyl])-1,3 diaminopropane]-7 alpha,24 zeta-dihydroxy-5 alpha-cholestane 24-sulfate, which was deduced from the analysis of fast atom bombardment spectra and a series of two-dimensional nuclear magnetic resonance (NMR) spectra. Squalamine is a cationic steroid characterized by a condensation of an anionic bile salt intermediate with the polyamine, spermidine. This molecule is a potential host-defense agent in the shark, and provides insight into a new class of vertebrate antimicrobial molecules.

Squalamine: an aminosterol antibiotic from the shark

In recent years, a variety of low molecular weight antibiotics have been isolated from diverse animal species. These agents, which include peptides, lipids, and alkaloids, exhibit antibiotic activity against environmental microbes and are thought to play a role in innate immunity. We report here the discovery of a broad-spectrum steroidal antibiotic isolated from tissues of the dogfish shark Squalus acanthias. This water-soluble antibiotic, which we have named squalamine, exhibits potent bactericidal activity against both Gram-negative and Gram-positive bacteria. In addition, squalamine is fungicidal and induces osmotic lysis of protozoa. The chemical structure of the antibiotic 3 beta-N-1-(N-[3-(4-aminobutyl)]- 1,3-diaminopropane)-7 alpha,24 zeta-dihydroxy-5 alpha-cholestane 24-sulfate has been determined by fast atom bombardment mass spectroscopy and NMR. Squalamine is a cationic steroid characterized by a condensation of an anionic bile salt intermediate with spermidine. The discovery of squalamine in the shark implicates a steroid as a potential host-defense agent in vertebrates and provides insights into the chemical design of a family of broad-spectrum antibiotics.

Capillary gas-liquid chromatographic separation of bile alcohols

Gas-liquid chromatographic separation of C23, C24, C25, C26, and C27 bile alcohols with either 3 alpha, 7 alpha-dihydroxylated or 3 alpha, 7 alpha, 12 alpha-trihydroxylated ring system on two capillary columns, CP-Sil-19 CB and CP-Sil-5 CB, is described. Bile alcohols with two ring hydroxyl groups at 3 alpha- and 7 alpha-positions consistently showed larger retention times on CP-Sil-19 CB columns and smaller retention times on CP-Sil-5 CB columns than the corresponding bile alcohols with three ring hydroxyl groups at 3 alpha-, 7 alpha-, and 12 alpha-positions. Resolutions of all bile alcohols were better on CP-Sil-19 CB columns; however, we hope that the gas-liquid chromatographic characteristics on the two columns will be useful for better identification of bile alcohols in biological fluids.

Synthesis of 3 alpha, 7 alpha-dihydroxy-5 beta-cholestan-26-oic acid from 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oic acid: configuration in the bile of Alligator mississippiensis

Synthesis of 25R- and 25S-diastereoisomers of 3 alpha,7 alpha-dihydroxy-5 beta-cholestan-26-oic acid from 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oic acid is described. The 25S-diastereoisomer of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan- 26-oic acid was obtained by vigorous hydrolysis of the bile of Alligator mississippiensis followed by repeated crystallization of the hydrolysate, and the 25R-diastereoisomer was isolated by hydrolysis of the bile salts in bile of A mississippiensis with rat feces. Acetylation of the 25R- or 25S-diastereoisomer of methyl 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oic acid under controlled conditions yielded the corresponding 3 alpha,7 alpha-diacetate in approximately 70% yield. The diacetate was quantitatively oxidized to methyl 3 alpha,7 alpha-diacetoxy-12-oxo-5 beta-cholestan-26-oate, which was converted into the 12-tosylhydrazone in approximately 58% yield. Reduction of the tosylhydrazone with sodium borohydride in acetic acid yielded the 25R- or the 25S-diastereoisomer of 3 alpha,7 alpha-dihydroxy-5 beta-cholestan-26-oic acid as the major product. Purification via column chromatography yielded the pure diastereoisomers in approximately 25% overall yield. The two diastereoisomers were resolved on thin-layer chromatography and high-performance liquid chromatography. When the bile of A mississippiensis was hydrolyzed with rat fecal bacteria, the 3 alpha,7 alpha-dihydroxy-5 beta-cholestan-26-oic acid isolated via chromatographic purification was shown to be the 25R-diastereoisomer.

Two polyhydroxylated steroids from the Chinese soft coral Sinularia microclavata

Two polyhydroxylated steroids have been isolated from the South China Sea soft coral Sinularia microclavata, and their structures were established as 24-methylenecholestane-1 alpha,3 beta,5 alpha,6 beta-tetrol and 1 alpha,3 beta,5 alpha-trihydroxy-24-methylenecholestan-6-one from spectral evidence and from comparison with two reference compounds, numersterol A and 24-methylenecholestane-1 alpha,3 beta,5 alpha,6 beta, 25-pentol, which were isolated from the soft corals, Simularia numerosa and Sarcophyton glaucum, respectively.

High-performance liquid chromatographic separation of bile acids and bile alcohols diastereoisomeric at C-25

The high-performance liquid chromatographic separation of the 25R and 25S diastereoisomers of the bile alcohols 5 beta-cholestane-3 alpha,7 alpha,26-triol and 5 beta-cholestane-3 alpha,7 alpha, 12 alpha, 26-tetrol and the bile acids, 3 alpha,7 alpha-dihydroxy-5 beta-cholestane-26-oic acid and 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestane-26-oic acid is described. A Radial-Pak microBondapak C18 reversed-phase cartridge was used for the separations and elutions were carried out with acetonitrile-water-methanol-acetic acid mixtures. All eight diastereoisomeric compounds showed baseline separation when up to 200 micrograms of the isomeric mixtures were injected into the column and the method can be used for isolation of pure diastereoisomers of these bile acids and bile alcohols.

Minor and trace sterols in marine invertebrates. 61. Isolation and structure elucidation of new A-nor sterols from the marine sponge Phakellia aruensis

An examination of the Australian sponge Phakellia aruensis led to the isolation and identification of sterols with six different nuclei. Eight new sterols were isolated which included three delta 15-A-nor sterols, three delta 7-A-nor sterols, and two saturated A-nor sterols. Their structures were established through mass spectrometry and 1H-NMR spectral studies.

Biosynthesis of cholesterol in the yeast mutant erg6

A mutant (erg6) of Saccharomyces cerevisiae defective in S-adenosylmethionine: delta 24-sterol-C-methyl transferase (EC2.1.1.41) which normally produces cholesta-5,7,24-trienol and cholesta-5,7,22,24-tetraenol as the major sterols (total 4,4-desmethyl sterol content-8.3 fg/cell) was shown to synthesize trace levels of cholesterol (0.08 fg/cell). The identity of cholesterol was established by co-chromatography in TLC, GLC and HPLC with an authentic sample, mass spectroscopy and after an incubation with [1-14C]acetate by isotopic dilution and recrystallization of the radiochemically purified material to constant specific activity.

Identification of bile alcohols in serum from healthy humans

Bile alcohol glucuronides present in human serum were isolated by ion exchange chromatography on piperidino-hydroxypropyl Sephadex LH-20. Following hydrolysis with beta-glucuronidase, the bile alcohols were analyzed by a combination of gas-liquid chromatography and mass spectrometry. Bile alcohols identified were 27-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentol, 27-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25,26-hexol, 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentol, 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,26-pentol, 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25,26-pentol, and 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25,26-hexol. The bile alcohol composition in serum was similar to that in urine but not to that in bile. The concentration of total bile alcohols in serum was 59.5 +/- 24.6 micrograms/L.

Identification of new bile alcohols, 5 beta-cholestane-3 alpha,7 alpha,24,26-tetrol, 5 beta-cholestane-3 alpha,7 alpha,25,26-tetrol, and 5 beta-cholestane-3 alpha,7 alpha,26,27-tetrol in human gallbladder bile

The nature of cholestanetetrols present as the glucurono-conjugates in human gallbladder bile was studied. Glucurono-conjugated bile alcohols were isolated by ion exchange chromatography and, after enzymatic hydrolysis, were fractionated by reversed phase partition chromatography to give a fraction containing tetrahydroxy bile alcohols which was analyzed by gas-liquid chromatography and mass spectrometry. Along with the three previously identified bile alcohols, 5 alpha- and 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha,24-tetrols, and 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha,26-tetrol, three new cholestanetetrols, possessing two hydroxyl groups in the ring system and two in the side chain, were detected in the tetrahydroxy bile alcohol fraction. These new bile alcohols were identified as 5 beta-cholestane-3 alpha, 7 alpha,24,26-tetrol, 5 beta-cholestane-3 alpha, 7 alpha,25,26-tetrol, and 5 beta-cholestane-3 alpha, 7 alpha,26,27-tetrol by direct comparison of their gas-liquid chromatographic behaviors and mass spectral data with those of authentic standards prepared from chenodeoxycholic acid by partial synthesis.

24xi-Methyl 5 alpha-cholestane-3 alpha,6 beta,9 alpha,25-tetrol 24-monoacetate, a novel polyhydroxylated steroid from the soft coral Sarcophyton tortuosum

A novel polyhydroxylated steroid, named sartortuosterol A, with rare 3 alpha- and 6-hydroxyl groups, was isolated from the South China Sea soft coral Sarcophyton tortuosum Tixier-Durivault, and its structure was established as 24xi-methyl 5 alpha-cholestane-3 alpha, 6 beta, 9 alpha,25-tetrol 25-monoacetate from spectroscopic data and chemical conversions.

Bile acids. LXXVII. Large-scale preparation of 5 alpha-anhydrocyprinol from carp bile

An improved method of preparation of 5 alpha-anhydrocyprinol from large quantities of carp bile is reported. The following materials were obtained by this method: 5 alpha-anhydrocyprinol, 5 alpha-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol, 5 alpha-cholestane 3 alpha,7 alpha,12 alpha,26-tetrol, an unidentified sterol from the neutral lipid fraction, allocholic acid and allochenodeoxycholic acid from the bile acid fraction. Yields of 5 alpha-anhydrocyprinol and bile acids vary in different batches. The identity and purity of these materials were verified by thin-layer chromatography, gas liquid chromatography and gas chromatography-mass spectrometry.

Absolute configuration at carbon 23 of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,23,25-pentol excreted by patients with cerebrotendinous xanthomatosis

Absolute configuration at C-23 of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,23,25-pentol, one of the bile alcohols isolated from the patients with cerebrotendinous xanthomatosis, was unequivocally determined as 23S by conversion of a key intermediate, (23S)-5 beta-cholest-25-ene-3 alpha,7 alpha,12 alpha,23-tetrol to either the bile alcohol of known absolute configuration, (23R)-5 beta-cholestane-3 alpha,7 alpha,12 alpha,23-tetrol, or the naturally occurring 23,25-pentol.

Synthesis of four diastereoisomers at carbons 24 and 25 of 3 alpha,7 alpha,12 alpha,24-tetrahydroxy-5 beta-cholestan-26-oic acid, intermediates of bile acid biosynthesis

The synthesis of four stereoisomers at C-24 and C-25 of 3 alpha,7 alpha,12 alpha,24-tetrahydroxy-5 beta-cholestan-26-oic acid is described. Pyridium chlorochromate oxidation of 3 alpha,7 alpha,12 alpha-triacetoxy-5 beta-cholan-24-ol (II) prepared from cholic acid (I) afforded 3 alpha,7 alpha,12 alpha-triacetoxy-5 beta-cholan-24-al (III) which was converted to a mixture of the four stereoisomers (IV-VII) by a Reformatsky reaction with ethyl DL-alpha-bromopropionate followed by alkaline hydrolysis. Separation of these isomers (IV-VII) was achieved by silica gel column chromatography, and subsequent reversed-phase partition column chromatography. The configurations at C-24 were elucidated by conversion of each isomer into (24R)- or (24S)-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24-tetrol (XII or XI) by Kolbe electric coupling, the C-24 configurations of which were determined by modified Horeau's method and 13C-nuclear magnetic resonance spectroscopy. The stereochemistries at C-25 were deduced by comparison of IV-VII with the products of the hydroboration followed by oxidation with alkaline hydrogen peroxide of (24E)-3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholest-24-en-26-oic acid (XIII).

Dinoflagellate sterols IV: Isolation and structure of 4 alpha, 23xi, 24xi-trimethylcholestanol from the dinoflagellate Glenodinium hallii

The dinoflagellate Glenodinium hallii was investigated for its sterol composition. Five of the six sterols were isolated and identified as cholest-5en-3beta-ol, (24xi)-24-methylcholest-5-en-3beta-ol, stigmasta-5,22-dien-3beta-ol, (22E,24R)-4 alpha, 23, 24-trimethyl-5 alpha-cholest-22-en-3 beta-ol, and 4 alpha, 23 xi, 24 xi-trimethyl-5 alpha-cholestan-3 beta-ol.

Occurrence of bile alcohol glucuronides in bile of patients with cerebrotendinous xanthomatosis

Using thin-layer chromatography, bile alcohol glucuronides were found with taurine- and glycine-conjugated bile acids in the bile of four patients with cerebrotendinous xanthomatosis. The concentration of the bile alcohol glucuronides was 1.7-5.2 times higher than that of the conjugated bile acids. Detectable amounts of unconjugated bile alcohols were not found in the bile of these patients. The bile alcohol glucuronides were isolated from the bile of one of the patients by means of preparative thin-layer chromatography. Treatment with beta-glucuronidase of the bile alcohol glucuronides liberated glucuronic acid and a mixture of bile alcohols. More than 90% of the liberated bile alcohols was 5 beta-cholestane-3 alpha, 7 alpha, 25-tetrol, and lesser amounts of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 23-tetrol, 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 24-tetrol, 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 23, 25-pentol, and 5 beta-cholestane-3 alpha,-7 alpha, 12 alpha, 24 alpha, 25-pentol were also obtained. The bile alcohol glucuronides were not oxidized by the treatment with 3 alpha-hydroxysteroid dehydrogenase, indicating that the glucuronide moiety was at 3 alpha-hydroxyl position of the bile alcohols. Comparison of the mass spectra of the acetylated and methylated derivatives of the natural glucuronides and the synthetic 7 alpha, 12 alpha, 25-triacetoxy-5 beta-cholestan-3 alpha-O-(methyl 2,3,4-tri-O-acetyl-beta-D-glucopyranosyluronate) also indicated that the bile alcohol glucuronides consisted of mainly 5 beta - cholestane - 3 alpha, 7 alpha, 12 alpha, 25 - tetrol - glucuronide.

Minor and trace sterols in marine invertebrates XVI. 3 epsilon-hydroxymethyl-A-nor-5 alpha-gorgostane, a novel sponge sterol

The free sterol mixture of the sponge Stylotella agminata contained a series of 3-hydroxymethyl-A-nor sterols of 5 alpha-cholestane, 5 alpha-cholest-22-ene, 24-methyl-5 alpha-cholestane, 24-ethyl-5 alpha-cholestane, and 24-ethyl-5 alpha-cholest-22-ene. A new cyclopropane-containing sterol was isolated and shown to be 3 epsilon-hydroxymethyl-A-nor-5 alpha-gorgostane. Sterols with conventional nuclei were also present as minor constituents;

Bile acids and bile alcohols of bullfrog

Gallbladder bile of the bullfrog, Rana cetesbeiana was found to contain a number of minor bile acids and bile alcohols in unconjugated forms. The following bile acids and bile alcohols were identified by combined gas-liquid chromatography-mass spectrometry: cholic acid, allocholic acid, 3 alpha,7 alpha,12 alpha-trihydroxy-5 alpha-cholestan-26-oic acid, 3 alpha,7 alpha,12 alpha-trihydroxy-24-methyl-5 beta-cholestan-26-oic acid, 3 alpha,7 alpha,12 alpha,24-tetrahydroxy-5 alpha-cholestan-26-oic acid, 3 alpha,7 alpha,12 alpha,24-tetrahydroxy-5 beta-cholestan-26-oic acid, 3 alpha,7 alpha,12 alpha,26-tetrahydroxy-5 alpha-cholestan-27-oic acid, 3 alpha,7 alpha,12 alpha,26-tetrahydroxy-5 beta-cholestan-27-oic acid, 3 alpha,7 alpha,12 alpha-trihydroxy-27-nor-5 alpha-cholestan-24-one, and 3 alpha,7 alpha,12 alpha-trihydroxy-27-nor-5 beta-cholestan-24-one. These minor constituents of the bile may represent intermediates in the biosynthetic pathway of bile acids and bile alcohols in the bullfrog.

Configuration at C-25 in 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholestan-26-oic acid by X-ray crystallography

The two diastereoisomers at carbon-25 of 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholestan-26-oic acid, a key intermediate in the biosynthetic pathway of cholic acid, were obtained in pure form by a combination of fractional crystallization and thin-layer chromatography. The configuration at C-25 of these two isomers was established by X-ray crystallography as 25S for one diastereoisomer (mp 199-201 degrees C) and 25R for the other (mp 180-182 degrees C). These findings permit us to determine, unequivocally, the configuration of this naturally occurring C27-bile acid in man and other animals and to establish the stereospecificity of the microsomal and mitochondrial omega-hydroxylation pathway for the side-chain oxidation of cholesterol to bile acids.

Bile acids. LIX. Purification of 5 alpha-anhydrocyprinol by preparative high-performance liquid chromatography

26,27-Oxido-5 alpha-cholestane-3 alpha,7 alpha,12 alpha-triol can be obtained in a homogeneous state in gram quantities by passing it through one PrepPak-500/Silica cartridge mounted in a Waters Assoc. preparative liquid chromatograph. The elution solvent was methanol-chloroform (1:14). The isolated material was analyzed for purity by several chromatographic means and by elemental analysis, and was finally characterized by the usual spectroscopic means. Gas-liquid chromatography of its trimethylsilyl ether indicated the formation of a tetrakis-trimethylsilyl-26-chloro derivative, in addition to the expected tris-trimethylsilylated substance. The structure of the former compound is deduced from the fragmentation and isotope abundance in its mass spectrum and from chemical principles.

Marine sterols. IX. Occurrence of 24 xi-methylcholestane-1 beta, 3 beta, 5 alpha, 6 beta, 25-pentol 25-monoacetate in the soft coral, Sarcophyton glaucum

The southern Japan's soft coral, Sarcophyton glaucum, was found to contain several polyhydroxylates steroids. One of the minor components was isolated and its structure was established as 24 xi-methylcholestane-1 beta, 3 beta, 5 alpha, 6 beta, 25-pentol 25-monoacetate from spectral evidence and from comparison with a reference compound, 5 alpha-spirostan-1 beta, 3 beta, 5 alpha, 6 beta-tetrol, which was synthesized from ruscogenin. A mixture of 1 beta, 3 beta, 5 alpha, 6 beta-tetra hydroxy C27- and C28-sterols was also isolated.

Preparation and characterization of (24R and 24S)-5beta-cholestane-3alpha,7alpha,24,25-tetrols and (24R and 24S)-5beta-cholestane-3alpha,24,25-triols

(24R and 24S)-5beta-cholestane-3alpha,7alpha,24,25-tetrols were prepared by osmium tetroxide oxidation of 5beta-cholest-24-ene-3alpha,7alpha-diol. The resulting diastereomeric tetrols were separated by thin-layer chromatography, their purity ascertained by melting point, gas-liquid chromatography and mass spectra and their structural configurations were assigned by molecular rotation measurement and circular dichroism studies. In a similar fashion, the (24R and 24S)-5beta-cholestane-3alpha,24,25-triols were prepared and their structures identified.