共查询到20条相似文献,搜索用时 15 毫秒
1.
Amalia Slomiany Bronislaw L. Slomiany 《Biochemical and biophysical research communications》1980,93(3):770-775
A fucose-containingceramide octadekahexoside exhibiting blood-group (A+H) activity has been isolated from hog gastric mucosa. Based on the results of partial acid hydrolysis, sequential degradation with specific glycosidases, oxidation with periodate and chromium trioxide, and permethylation analysis, we propose that the carbohydrate chain of this fucolipid contains four branches. Two of the branches are terminated by βGall→4βGlcNAc, one by and one by . 相似文献
2.
The presence of 5β-cholanic acid has been detected in the seeds of jequirity bean ( L.) Its structure was unequivocally established by spectroscopic methods. This report provides proof, for the first time, of the occurrence of 5β-cholanic acid in a plant source. 相似文献
3.
A formal synthesis of -18-hydroxyestrone has been achieved by the preparation of -3-methanesulfonyloxy-13β,17β-dicarboxy-18--norestra-1,3,5(10)-triene anhydride, the dextrorotatory enantiomer of which is an intermediate in Barton's conversion of -estrone to -1β-hydroxyestrone (KC-6A). 相似文献
4.
Occelasterol, a new marine C27 sterol, has been isolated from an annelida, and its structure was confirmed as 22--27-nor-(24S)-24-methylcholesta-5, 22-dien-3β-ol (IIa) from the spectral data and by synthesis. Thissterol, the second member of a class of sterols having 27-norergostane-type side chain, had been formerly regarded as 22--cholesta-5, 22-dien-3β-ol (Va). Gas-liquid Chromatographic studies have shown that occelasterol is distributed in various amounts in most of marine invertebrates. 相似文献
5.
A tetrahydroxylated steroid isolated from a gorgonian, , has been shown by spectral analyses and degradative studies to be 5α-cholestane-3β,5,6β,9-tetrol. 相似文献
6.
From the leaves of R.Br., a new steroidal sapogenin diol has been isolated, to which the trivial name brisbagenin has been given. Mass spectral, infra-red and nuclear magnetic resonance data of brisbagenin and its acetylated derivatives showed. the sapogenin to be 1β, 3β-dihydroxy-5α, 25α-spirostane. Jones oxidation of brisbagenin-1-acetate yielded 5α,25α-spirost-1-en-3-one. A compound, identical to this synthetic material was isolated from the leaves of an undescribed species, but the product was considered to be an artefact produced during its isolation. 相似文献
7.
A new polyhydroxysterol 1β,3β,5,6β-tetrahydroxy-5α-androstan-17-one () was isolated from the soft coral . The structure of was deduced from comparison of the spectral data with those of known 1β,3β,5α,6β-tetrahydroxysterols and confirmed by the synthesis starting from 1β,3β-dihydroxy-5,16-pregnadien-20-one () 相似文献
8.
Akhil G. Jhingran R.C. Gupta Suprabhat Ray A.K. Agarwal M.M. Singh Nitya Anand 《Steroids》1983,42(6):627-634
The syntheses of (±) 2α,6β-diethyl-7α-ethynyl-3α-(-hydroxyphenyl)--bicyclo[4.3.0]nonan-7β-ol (), (±)2β,6β-diethyl-7α-ethynyl-3β-(-methoxyphenyl)--bicyclo[4.3.0]nonan-7β-ol () and (±) 2α,6β-diethyl-7α-ethynyl-3β-(-hydroxyphenyl)--bicyclo[4.3.0]nonan-7β-ol () and their derivatives, which are essentially B-seco-steroids having and geometries have been carried out. A study of their antiimplantation activities (AI) and receptor binding affinities (RBA) show that compounds are biologically most potent, followed by the corresponding and compounds. The most potent compound is active at 1 mg/kg in rats. Introduction of 7α-ethynyl group increases their AI activity; however, no significant effect on their RBA is observed. 相似文献
9.
The conversion of a 5β-pregnan-3-one into a 3-thia-A-nor-pregnane is described. The single epimer, characterized as the 5β-isomer by nmr spectroscopy, was obtained.A previous report [1] from this laboratory described the synthesis of the epimeric 3-oxa-A-norpregnan-20-ones and from A-norprogesterone. Recently, the total synthesis of the related A-nor-3-thiaestra-1,-5(10)-diene derivative has been described [2]. Continuing interest [3] in A-ring-modified steroids as probes of drug-receptor interactions prompts this report of the preparation of the 3-thia-5β-A-norpregnan-20-one . 相似文献
10.
Affinity chromatography has been used to isolate and compare the peanut agglutinin receptors from neuraminidase-treated human, bovine and porcine erythrocyte membranes. Passage of Triton X-100-solubilised membrane material through either Sepharose- or acrylamide-based affinity columns resulted in the reversible binding of receptor molecules to the immobilised lectin. Elution with 0.2M galactose released specifically bound glycoprotein fractions, the composition and molecular weights of which were determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate.Carbohydrate analysis by gas chromatography identified these bound glycoprotein fractions as the major sources of the disaccharide in these membranes. It is suggested that these isolated fractions represent a discrete population of glycoproteins within the membranes studied, which possess both - and carbohydrates. 相似文献
11.
Steroids from starfish 总被引:2,自引:0,他引:2
Starfish and were examined for sterols and sapogenins. All asteroids contained cholestanol in addition to C27 to C30 mono and diunsaturated sterols. A planci contained largest amounts of 5α-cholesta-9(11), 20(22)-diene-3β, 6α-diol-23-one and 5α-pregn-9(11)-ene-3β,6α-diol-20-one whereas contained only small amounts. Neither pregnane nor cholestane genins were detected in and . 相似文献
12.
(1) 4,6-O-Ethylidene-d-glucose is a good inhibitor of adipocyte sugar transport from the external surface. Using radioactively labelled 4,6-O-methylidene-d-glucose we have shown that this compound is not taken up into cells by the hexose transporter but through a route which is insulin insensitive, d-glucose insensitive, temperature sensitive and which is slightly inhibited by phloretin. When efflux of 3-O-methyl-d-glucose is studied with 4,6-O-methylidene-d-glucose only present inside the cells then no detectable inhibition is observed indicating that this compound is a good side-specific analogue with a high affinity for only the external site of the hexose transporter. (2) Radioactively labelled alkyl-β-d-glucosides have been prepared. These also penetrate the adipocyte membrane by an insulin and d-glucose insensitive route. The half-times for equilibration with methyl-, n-propyl-, and are 255, 9.45 and 3.3 min, respectively, indicating that the uptake rates are dependent upon the size of the alkyl group. (3) The glucosides show poor inhibition of 3-O-methyl-d-glucose transport when added to the external solution only. When cells are preincubated with and an increase in the amount of inhibition of 3-O-methyl-d-glucosez uptake is observed. This increase in inhibition correlates well with the glucoside uptake rates and indicates that availability of the glucosides at the internal surface of the transporter is required for inhibition. This has been confirmed by measuring 3-O-methyl-d-glucose exit in the presence of at the internal surface only. Thus, is a good side-specific analogue with high affinity only for the internal site of the hexose transporter. (4) inhibition of d-allose transport is fully reversible. If cells are washed after a preincubation with the analogue then the inhibition is lost. The inhibition of d-allose transport is reduced competitively by 3-O-methyl-d-glucose. (5) 6-O-Propyl-d-galactose has low affinity for both internal and external sites. 相似文献
13.
The novel cyclopropyl sterol, 24ξ, 25ξ-24, 26-cyclocholest-5-en-3β-ol (24, 26-cyclocholesterol), has been isolated from the sponge . ( Ridley) and its structure established by spectral analysis and by correlation with papakusterol. 相似文献
14.
Neurobiology of tetrahydro-beta-carbolines 总被引:1,自引:0,他引:1
N S Buckholtz 《Life sciences》1980,27(11):893-903
Tetrahydro-β-carbolines (THβC's) are tricyclic compounds structurally related to the indoleamines. Recent studies have reported the and formation of these compounds in brain and other tissues. This information and other data indicating that THβC's interact relatively specifically with various aspects of the serotonergic neurotransmitter system has suggested that THβC's may serve as endogenous neuromodulators of neurotransmitters. Evidence for the formation of these compounds as well as their neurochemical, neuroendocrinological, and behavioral effects is described in this review. 相似文献
15.
This paper describes the synthesis of a series of new 10β-substituted 4-estrene-3,17-dione analogs (). These compounds, together with a number of known analogs (), have been evaluated as reversible or irreversible inhibitors of human placental microsomal aromatase. The best reversible inhibitor is the 10β-vinyl compound (). The only compounds causing irreversible inhibition of aromatase are the 10β-propargyl compound () and the 10β-difluoromethyl compound (). 相似文献
16.
Gerald A. Schwarting Peter G. Carroll William C. DeWolf 《Biochemical and biophysical research communications》1983,112(3):935-940
Several novel glycosphingolipids have been isolated from the human teratocarcinoma cell line HT-E (833K). These cells contain two neutral glycolipids which metabolically incorporate radio-labelled fucose. In addition, there are three new gangliosides present, which are all members of the globoside series of glycolipids. One of the fucose containing glycolipids forms globoside when treated with α-fucosidase, and one of the gangliosides forms globoside when treated with neuraminidase. On the basis of chromatographic behavior, exoglycosidase treatment and antibody reactivity, the tentative structures of these new glycolipids are: 相似文献
17.
18.
Repetition of an investigation of the petrol extracts of Rhodomyrtus tomentosa has led to the isolation of two new triterpenoids, R4 from the leaves and R5 from the stems besides R1, R2, R3 and the other known compounds already reported. R1 and R4 were proved to be 21α-hop-22(29)en-3β,30-diol and 3β-hydroxy-21α-hop-22(29)-en-30-al respectively, and R2, R3 and R5 are 3β-acetoxy-11α,12α-epoxyoleanan-28,13β-olide, 3β-acetoxy-12α-hydroxyoleanan-28, 13β-olide and 3β-acetoxy-12-oxo-oleanan-28,13β- olide respectively. The ethanol extract of the leaves contained betulinic, ursolic and aliphitolic acids and that of the stems betulonic, betulinic and oleanolic acids. 相似文献
19.
20.
Almost an of the solvent-extractable sterols and their nuclearsaturated analogues in a sample of Walvis Bay surface sediment have been analysed by capillary GLC and GC-MS, and by coinjection with a variety of standards. The presence in sediments of 22--24-nor-5α-cholest-22-en-3β-ol, 24-methylene-5α-cholestan-3β-ol, and components tentatively assigned as 23,24-dimethylcholesta-5,22-dien-3β-ol and 23,24-dimethyl-5α-cholest-22-en-3β-ol has been demonstrated for the first time. A novel sterol and its saturated analogue have also been found. The sterol distribution cannot be related solely to the reported major input of phytoplankton; the presence of 22,23-methylene-23,24-dimethylcholest-5-en-3β-ol and its saturated analogue indicates a coelenterate contribution. The analysis emphasises the necessity of glass capillary columns and coinjection of standards. 相似文献