Steroid compounds from the Far East starfish <Emphasis Type="Italic">Pteraster obscurus</Emphasis> and the ophiura <Emphasis Type="Italic">Asteronyx loveni</Emphasis>

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-2β-hydroxycholesta-5,24(28)-diene-3α,21-diyl disulfate, (20R)-5α-cholestane-3β,21-diyl disulfate, (20R)-3β-hydroxy-5α-cholestan-21-yl sulfate, (20R)-cholest-5-ene-3β,21-diyl disulfate, (20R)-2β-hydroxycholest-5-ene-3α,21-diyl disulfate, (20R)-cholest-5-en-3β-yl sulfate, and (20R)-5α-cholestan-3β-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.     

Steroid compounds from the Far Eastern starfish Diplopteraster multipes

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.     

Polyhydroxylated steroid compounds from the Far Eastern starfish Distolasterias nipon

Two new steroid glycosides: distolasteroside D6, (24S)-24-O-(beta-D-xylopyranosyl)-5alpha-cholestane-3beta,6alpha,8,15beta,16beta,24-hexaol, and distolasteroside D7. (22E,24R)-24-O-(beta-D-xylopyranosyl)-5alpha-cholest-22-ene-3beta,6alpha,8,15beta,24-pentaol were isolated along with the previously known distolasterosides D1, D2, and D3, echinasteroside C, and (25S)-5alpha-cholestane-3beta,4beta,6alpha,7alpha,8,15alpha,16beta,26-octaol from the Far Eastern starfish Distolasterias nipon. The structures of new compounds were elucidated by NMR spectroscopy and MALDI TOF mass spectrometry. Like neurotrophins, distolasterosides D1, D2, and D3 were shown to induce neuroblast differentiation in a mouse neuroblastoma C 1300 cell culture.     

Steroid compounds from pacific starfish Mithrodia clavigera and their toxicity to human melanoma cells

A new sulfated polyoxide steroid (20S)-3??,6??,20-trihydroxi-5??-cholest-9(11)-ene 3-sulfate (sodium salt) named mithrotriol was isolated from the Pacific starfish Mithrodia clavigera. Additionally, six previously known compounds were isolated and identified including glycosides echinasteroside B, granulatoside A, linckoside K, and forbeside L, as well as sulfates of thornasterol A and cholesterol. The structure of mithrotriol was elucidated by NMR (¹H, ¹³C, DEPT, COSY-45, NOESY, HSQC, and HMBC) and massspectrometry. Minimal inhibitory concentrations were determined for the isolated compounds that demonstrated cytotoxic activity in human melanoma cells SK-MEL-28, SK-MEL-5, and RPMI-7951.     

Steroid Compounds from the Far Eastern Starfish Diplopteraster multipes

Sodium salt of (20R)-3,4-dihydroxycholest-5-ene-21-yl sulfate and disodium salts of (20R)-4-hydroxycholest-5-ene-3,21-diyl disulfate, (20R)-24-methylcholest-5,24(28)-diene-3,21-diyl disulfate, (20R)-24-methyl-5-cholest-24(28)-ene-3,21-diyl disulfate, (20R)-cholest-5-ene-3,21-diyl disulfate, (20R)-5-cholestane-3,21-diyl disulfate, and (20R)-3-hydroxycholest-5-ene-2,21-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-hydroxy (or 3-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.     

Steroidal monoglycosides from the Far Eastern starfish Hippasteria kurilensis and hypothetic pathways of polyhydroxysteroid biosynthesis in starfish

Five new steroidal monoglycosides, kurilensosides E (1), F (2), G (3), H (4) and 15-O-sulfate of echinasteroside C (5) were isolated along with the previously known echinasteroside C (6) from the alcoholic extract of the Far Eastern starfish Hippasteria kurilensis collected near Kuril Islands. Compounds 1-3 were determined to contain unusual polyhydroxysteroidal aglycons lacking 6-hydroxy group. Aglycon moiety of kurilensoside H (4) was shown to be the first case of marine polar steroids containing 4,5-epoxy functionality. Hypothetic pathways of the biosynthesis of polyhydroxysteroids and related glycosides in starfish and the existence of the late C-6 oxidation pathway in H. kurilensis are discussed.     

Evolution of pelagic direct development in the starfish Pteraster tesselatus (Asteroidea: Velatida)

Despite a diversity of larval forms, remarkably conservative features of asteroid development define a larval body plan that occurs throughout the class. However, recent work on the starfish Pteraster tesselatus has documented a highly derived pattern of development. Several features, including radial symmetry, parallel embryonic and adult axes of symmetry, absence of a preoral lobe, and formation of coeloms in the adult orientation from seven separate enterocoels, have not been reported in asteroids before. The complete absence of the larval body plan features that are found in other asteroids, indicates that P. tesselatus develops directly from the embryo to the juvenile and has a pelagic, nonfeeding (lecithotrophic), but nonlarval mode of development. I postulate that direct development evolved over an extended period in a lineage of brooding, deep-sea velatid (probably pterastcrid) ancestors of P. tesselatus. Selection for increased developmental efficiency (loss of nonfunctional larval features) in the brooded offspring, could explain the lack of larval settlement structures, the nonlarval arrangement of coeloms, the lack of a preoral lobe, the transverse orientation of the juvenile disc, and the lack of bilateral symmetry. The pattern of coclomogenesis could have been derived from that of other velatids (e.g. solasterids) by relatively simple changes in timing and orientation of entcroeoel formation. Rotation and posterior translation of the coelomic fate map of the archenteron prior to enlerocoel formation would produce the coelomic compartments in the adult orientation that characterizes direct development in P. tesselatus. These unusual developmental features lead to a radically different interpretation for the evolution of the pelagic ‘larva’ of P. tesselatus: (1) evolution of benthie brooding, (2) extreme simplification of development involving the loss of all larval features from the life cycle, and (3) subsequent re-evolution of pelagic development. In the case of P. tesselatus, where all larval structures were lost, there do not seem to be functional constraints preventing the re-evolution of pelagic development. Analysis of pelagic and benthie larvae, in other asteroids, suggests that major ecological transitions in life histories need not be associated with substantia] changes in morphology. The loss of pelagic development should have occurred repeatedly and should be readily reversible. These findings have interesting implications for the loss and evolution of pelagic dispersal in the life histories of marine benthie invertebrates.     

Steroidal polyols from Far Eastern starfish Henricia sanguinolenta and H. leviuscula leviuscula

Two new asterosaponins, (20R)-3-O-beta-D-(2-O-methylxylopyranosyl)-24-propylcholest-4-ene-3 beta,6 beta, 8, 15 alpha, 16 beta, 29-hexaol (sanguinoside A) and (20R,24S)-3-O-beta-D-(2,3,4-tri-O-methylxylopyranosyl)-5 alpha-cholestane-3 beta, 4 beta, 6 beta, 8, 15 alpha, 24-hexaol (sanguinoside B), were isolated from two species of Pacific Far Eastern Starfish Henricia sanguinolenta and H. leviuscula leviuscula, collected in the Sea of Okhotsk. Both glycosides contain aglycones with pentahy-droxysteroid nuclei of similar structures, which are substituted at the 3-hydroxy group with differently methylated beta-D-xylosyl residues. Sanguinoside A has an unusual structure of its aglycone side chain, whereas sanguinoside B has a unique permethylated carbohydrate chain. In addition, laevisculoside G, a known glycoside, was identified in the H. leviuscula starfish. The structures of the isolated glycosides were established by interpreting their spectral data and by comparing their spectral characteristics with those of known compounds. The English version of the paper. Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 2; see also http://www.maik.ru.     

Polyhydroxylated steroid compounds from the Far Eastern starfish <Emphasis Type="Italic">Distolasterias nipon</Emphasis>

Two new steroid glycosides: distolasteroside D₆, (24S)-24-O-(β-D-xylopyranosyl)-5α-cholestane-3β,6α,8,15β,16β,24-hexaol, and distolasteroside D₇, (22E,24R)-24-O-(β-D-xylopyranosyl)-5α-cholest-22-ene-3β,6α,8,15β,24-pentaol were isolated along with the previously known distolasterosides D₁, D₂, and D₃, echinasteroside C, and (25S)-5α-cholestane-3β4β,6α,7α,8,15α,16β,26-octaol from the Far Eastern starfish Distolasterias nipon. The structures of new compounds were elucidated by NMR spectroscopy and MALDI TOF mass spectrometry. Like neurotrophins, distolasterosides D₁, D₂, and D₃ were shown to induce neuroblast differentiation in a mouse neuroblastoma C1300 cell culture.     

Steroid compounds from two pacific starfish of the genus <Emphasis Type="Italic">Evasterias</Emphasis>

Three new steroid glycosides (evasteriosides C, D, and E) along with six known compounds were isolated from two Pacific starfish of the genus Evasterias. Evasterioside C from E. retiferacollected from the Sea of Japan was identified as (20R, 22E)-3-O-(β-D-xylopyranosyl)-24-nor-5α-cholest-22-ene-3β,6β,15α,26-pentaol 26-sulfate sodium salt. The structures of evasteriosides D and E from E. echinosoma (collected from the Gulf of Shelichov, the Sea of Okhotsk) were established as (20R, 24S)-24-O-(β-D-glucopyranosyl)-5α-cholestane-3β,6α,8,15β,24-pentaol and (20R,24S)-3,24-di-O-(β-D-xylopyranosyl)-cholest-4-ene-3β,6β,8,15α,24-pentaol, respectively. In addition, the known compounds pycnopodiosides A and C, luridoside A, 5α-cholestane-3β,6α,8,15β,16β,26-hexaol. 5α-Cholestane-3β,6α,8,15β,24-pentaol 24-sulfate sodium saltand marthasterone sulfate sodium salt were identified in E. echinosoma. The structures of the isolated compounds were established on the basis of spectroscopic analyses, using 1D and 2D NMR techniques, mass spectrometry, and some chemical transformations.     

Two new steroid glycosides from the Far East starfish <Emphasis Type="Italic">Hippasteria kurilensis</Emphasis>

Two new steroid glycosides were isolated from the Far East starfish Hippasteria kurilensis collected in the Sea of Okhotsk. They were characterized as (22E,24R)-3-O-(2-O-methyl-β-D-xylopyranosyl)-24-O-[2-O-methyl-β-D-xylopyranosyl-(1→5)-α-L-arabinofuranosyl]-5α-cholest-22-ene-3β,4β,6α,7α,8,15β,24-heptaol (kurilensoside I) and (24S)-3-O-(2-O-methyl-β-D-xylopyranosyl)-24-O-(α-L-arabinofuranosyl)-5α-cholestane-3β,4β,6β,15α,24-pentaol (kurilensoside J). In addition, the earlier known glycosides linkosides F and L1, leviusculoside G, forbeside L, desulfated echinasteroside, and granulatoside A were isolated and identified. The structures of the new compounds were established with the help of two-dimentional NMR spectroscopy and mass- spectrometry.     

Steroid Polyols from the Far Eastern Starfish Henricia sanguinolenta and H. leviuscula leviuscula

Two new asterosaponins, (20R)-3-O--D-(2-O-methylxylopyranosyl)-24-propylcholest-4-ene-3,6,8,15,16,29-hexaol (sanguinoside A) and (20R,24S)-3-O--D-(2,3,4-tri-O-methylxylopyranosyl)-5-cholestane-3,4,6,8,15,24-hexaol (sanguinoside B), were isolated from two species of Pacific Far Eastern Starfish Henricia sanguinolenta and H. leviuscula leviuscula, collected in the Sea of Okhotsk. Both glycosides contain aglycones with pentahydroxysteroid nuclei of similar structures, which are substituted at the 3-hydroxy group with differently methylated -D-xylosyl residues. Sanguinoside A has an unusual structure of its aglycone side chain, whereas sanguinoside B has a unique permethylated carbohydrate chain. In addition, laevisculoside G, a known glycoside, was identified in the H. leviuscula starfish. The structures of the isolated glycosides were established by interpreting their spectral data and by comparing their spectral characteristics with those of known compounds.     

Two onygenalean fungi from Russian Far East soil

Two onygenalean fungi isolated from forest soil in the Sikhote-Alin reserve, Russian Far East (east Siberia), are described and illustrated:Gymnostellatospora parvula as a new species andAphanoascus canadensis as a new record.Gymnostellatospora parvula is characterized by psychrophilic growth, pale yellow to pale cinnamon ascomata with a hyphal peridium, small, hyaline discoid ascospores with an equatorial rim and more or less longitudinally ridged wall.