Derivatives of the saturated steroid cholestane with methyl groups at C-18 and C-19 and an iso-octyl side chain at C-17.

Archean molecular fossils and the early rise of eukaryotes. (1/103)

Molecular fossils of biological lipids are preserved in 2700-million-year-old shales from the Pilbara Craton, Australia. Sequential extraction of adjacent samples shows that these hydrocarbon biomarkers are indigenous and syngenetic to the Archean shales, greatly extending the known geological range of such molecules. The presence of abundant 2alpha-methylhopanes, which are characteristic of cyanobacteria, indicates that oxygenic photosynthesis evolved well before the atmosphere became oxidizing. The presence of steranes, particularly cholestane and its 28- to 30-carbon analogs, provides persuasive evidence for the existence of eukaryotes 500 million to 1 billion years before the extant fossil record indicates that the lineage arose.  (+info)

Gene transfection activities of amphiphilic steroid-polyamine conjugates. (2/103)

The design and evaluation of a novel potent class of DNA delivery agents based on steroid-polyamine conjugates bearing a flexible linker are reported. The hydrophobic regions are based on steroids, i.e. chlolestane and lithocholic acid motifs. The linker, which couples a hydrophobic steroid and a hydrophilic polyamine, in this study can be regarded as a two-atom extension of the conventional carbamate linker. We found that the gene transfection activity of the steroid-polyamine conjugates is influenced by the polyamine chain length and steroid structure. Molecular modeling of the relevant amphiphilic molecules revealed low-energy structures in which the polyamine chains are folded rather than stretched. This work suggests a significant effect of space-filling, i.e. the shape and orientation of the hydrophilic and hydrophobic regions, upon the efficiency of gene transfection.  (+info)

Biosynthesis of bile acids in man. Hydroxylation of the C27-steroid side chain. (3/103)

The first step in the degradation of the steroid side chain during biosynthesis of bile acids from cholesterol in man was studied in microsomal and mitochondrial fraction of homogenate of livers from 14 patients. The microsomal fraction was found to catalyze an efficient 25-hydroxylation of 5,8-cholestane-3a,7a,12atriol. A small extent of 23-, 24-, and 26-hydroxylation of the same substrate was observed. 53-Cholestane-3a,7adiol was hydroxylated in the 25-position only to a very small extent. The mitochondrial fraction was found to catalyze 26-hydroxylation of cholesterol, 5-cholestene-3P,7a-diol, 5P-cholestane-3a,7a-diol, 7a-hydroxy-4-cholesten-3-one, and 5,0-cholestane-3a,7a,12a-triol. Addition of Mg++ stimulated the 26-hydroxylation of cholesterol but had no effect or an inhibitory effect on 26-hydroxylation of the other substrates, indicating a heterogeneity of the mitochondrial 26-hydroxylating system. The level of 26-hydroxylase activity towards different substrates varied considerably with different mitochondrial preparations. The roles of the microsomal and mitochondrial 26- hydroxylations as well as the microsomal 25-hydroxylation in biosynthesis of bile acids in man are discussed. The results indicate that microsomal 26-hydroxylation is less important than mitochondrial 26-hydroxylation under normal conditions. The possibility that microsomal 25-hydroxylation is important cannot be ruled out.  (+info)

Cholestane glycosides from the bulbs of Galtonia candicans and their cytotoxicity. (4/103)

Further search for cytotoxic compounds contained in the bulbs of Galtonia candicans (Liliaceae) led to the isolation of four potent cytotoxic cholestane glycosides (1-4) based upon 3beta,16beta,17alpha-trihydroxycholest-5-en-22-one, three of which (2-4) have not been reported previously. A new cholestane bisdesmoside (5) and a new rearranged cholestane glycoside (6) were also isolated. The structural assignment of the new constituents was carried out by spectroscopic analysis and a few chemical transformations.  (+info)

The role of a 5alpha-hydroxylated intermediate in the formation of the 5, 6-double bond in cholesterol biosynthesis. (5/103)

If the biological conversion of cholest-7-en-3beta-ol (I) into cholesterol (IV) occurred thorugh the intermediacy of cholest-7-ene-3beta,5alpha-diol (II) then the factor(s) adversely affecting the convwesion of the 5alpha-hydroxy sterol (II) into cholesterol must at least equally adversely affect the formation of cholesterol from cholest-7-en-3beta-ol. By using partial denaturation techniquws and dual-labelled precursors it was shown that the enzyme system responsible for the conversion of the 5alpha-hydroxy sterol (II) into cholesterol denatured faster than that for the corresponding conversion from cholest-7-en-3beta-ol (I).  (+info)

Four new 26-aminocholestane-type glycosides from Solanum abutiloides. (6/103)

From the fresh roots of Solanum abutiloides, four new 26-aminocholesteryl glycosides were obtained, and their structures were characterized by analysis of their spectra data, including two-dimensional (2D) NMR spectroscopy. These compounds were regarded as key intermediates in the biogenesis of steroidal alkaloids.  (+info)

Rapid transbilayer movement of spin-labeled steroids in human erythrocytes and in liposomes. (7/103)

The transbilayer movement and distribution of spin-labeled analogs of the steroids androstane (SLA) and cholestane (SLC) were investigated in the human erythrocyte and in liposomes. Membranes were labeled with SLA or SLC, and the analogs in the outer leaflet were selectively reduced at 4C using 6-O-phenylascorbic acid. As shown previously, 6-O-phenylascorbic acid reduces rapidly nitroxides exposed on the outer leaflet, but its permeation of membranes is comparatively slow and thus does not interfere with the assay. From the reduction kinetics, we infer that transbilayer movement of SLA in erythrocytes is rapid at 4C with a half-time of approximately 4.3 min and that the probe distributes almost symmetrically between both halves of the plasma membrane. We have no indication that a protein-mediated transport is involved in the rapid transbilayer movement of SLA because 1) pretreatment of erythrocytes with N-ethyl maleimide affected neither flip-flop nor transbilayer distribution of SLA and 2) flip-flop of SLA was also rapid in pure lipid membranes. The transbilayer dynamics of SLC in erythrocyte membranes could not be resolved by our assay. Thus, the rate of SLC flip-flop must be on the order of, or even faster than, that of probe reduction rate on the exoplasmic leaflet (half-time approximately 0.5 min). The results are discussed with regard to the transbilayer dynamics of cholesterol.  (+info)

Appetite suppression and weight reduction by a centrally active aminosterol. (8/103)

The rise in obesity and its complications has generated enormous interest in the regulation of feeding and body weight. We show that a spermine metabolite of cholesterol (MSI-1436) decreases body weight, specifically fat, by suppressing feeding and preventing the reduction in energy expenditure, hormonal changes, and patterns of neuropeptide expression normally associated with weight loss. MSI-1436 enters the brain after peripheral injection and is more potent when injected into the cerebral ventricle (intracerebroventricular [ICV]). Systemic or ICV MSI-1436 administration induced similar patterns of Fos immunoreactivity in the brain, especially the paraventricular hypothalamic nucleus (PVN). This brain region integrates neural signals from hypothalamic and brain stem nuclei and regulates feeding behavior, autonomic function, and neuroendocrine function. Microinjection of MSI-1436 into the PVN potently suppressed feeding and reduced body weight for several days. Unlike caloric restriction, MSI-1436 decreased mRNA levels of agouti-related peptide and neuropeptide Y in the hypothalamus. These findings indicate that MSI-1436 acts in the brain to regulate food intake and energy expenditure, likely through suppression of orexigenic hypothalamic pathways.  (+info)

Cholestanes are a type of steroid compound that are derived from cholesterol. They are characterized by a fully saturated steroid nucleus, which means that all of the double bonds in the cholesterol molecule have been reduced to single bonds through a process called hydrogenation.

Cholestanes are important intermediates in the biosynthesis of other steroids, such as bile acids and steroid hormones. They can also be found in some natural sources, including certain plants and fungi.

It's worth noting that cholestanes themselves do not have any specific medical significance, but they are important for understanding the biochemistry of steroids and their role in human health and disease.

Cholestane is not exclusively derived from diagenesis of animal-derived steroid molecules; cholestane may also be associated ... For cholestane specifically, diagenesis of cholesterol to cholestane produces a molecule that is fully saturated compared to ... Additional diagenetic processes can further alter the cholestane molecule. For instance, cholestane is susceptible to ... but cholestane can be found in the fossil record with many stereochemical configurations. Cholestane in the fossil record is ...
Categories: Cholestanes Image Types: Photo, Illustrations, Video, Color, Black&White, PublicDomain, CopyrightRestricted 4 ...
All MeSH CategoriesChemicals and Drugs CategoryPolycyclic CompoundsFused-Ring CompoundsSteroidsCholestanesSterolsPhytosterols ...
Temraz, A.; Hozaien, H.E.; El-Tantawy, W.H.; El-Gindi, O.D.; Taha, K.F. Cholestane and spirostane-type glycosides from the ...
Cholestane, 3,5-dichloro-6-nitro-, (3á,5à,6á)-. 28.32. C29H56N2O10Si3. 676. 0.65. D-Glucopyranosiduronic acid,3-(5- ...
Brassinosteroids are plant-derived polyhydroxylated derivatives of 5a-cholestane, structurally similar to cholesterol-derived ... Brassinosteroids are plant-derived polyhydroxylated derivatives of 5a-cholestane, structurally similar to cholesterol-derived ...
An internal standard (1 mL of 1 mg/mL 5-cholestane) was added and saponified at room temperature for 20 h and was then mixed ...
1a) 5β-cholestane-3α,7α,12α-triol + 2 reduced adrenodoxin + 2 H+ + O2 = (25R)-5β-cholestane-3α,7α,12α,26-tetraol + 2 oxidized ... Masui, T., Herman, R. and Staple, E. The oxidation of 5β-cholestane-3α,7α,12α,26-tetraol to 5β-cholestane-3α,7α,12α-triol-26- ... 5β-cholestane-3α,7α,12α-triol 26-hydroxylase; 5β-cholestane-3α,7α,12α-triol hydroxylase; cholestanetriol 26-hydroxylase; sterol ... 5β-cholestane-3α,7α,12α-triol + 6 reduced adrenodoxin + 6 H+ + 3 O2 = (25R)-3α,
Cholestane, C27H48, is a true, highly-reduced hydrocarbon, but is not to be confused with the oxidized, biotic, molecule ... Cholestane and cholesterol have similar geometric structures, and share similar carbon skeletons; there the similarity ends. ... Cholestane is a constituent of natural petroleum; cholesterol is not. Significantly, the Fischer-Tropsch synthesis produces ... cholestane, terpines, and clorins. Closer investigations have proven such claims to be groundless. Pristane and phytane are ...
Preparation and reactions of some 2-oxygenated 3α,5-cyclo-5α-cholestane derivatives. 1970, Vol. 35, Issue 4, pp. 1235-1254 [ ... Reactions and stereochemistry of some 2-oxygenated A-homo-5α-cholestane derivatives. 1973, Vol. 38, Issue 2, pp. 565-574 [ ... The configuration of some 3-dimethylamino derivatives of cholestane. 1954, Vol. 19, Issue 6, pp. 1249-1257 [Abstract] ...
5α-cyprinol = 5α-cholestane-3α,7α,12α,26,27-pentol. ...
3a,12b,25,26-Tetrahydroxy-7-oxo-5b-cholestane-26-O-sulfate. 530.71 C27H46O8S. ...
As a member of the wwPDB, the RCSB PDB curates and annotates PDB data according to agreed upon standards. The RCSB PDB also provides a variety of tools and resources. Users can perform simple and advanced searches based on annotations relating to sequence, structure and function. These molecules are visualized, downloaded, and analyzed by users who range from students to specialized scientists.
Powered by Pure, Scopus & Elsevier Fingerprint Engine™ All content on this site: Copyright © 2024 Elsevier B.V. or its licensors and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies. For all open access content, the Creative Commons licensing terms apply We use cookies to help provide and enhance our service and tailor content. By continuing you agree to the use of cookies. ...
Cholestanes [D04.210.500.247]. *Cholestenes [D04.210.500.247.222]. *Ergosterol [D04.210.500.247.222.537]. Below are MeSH ...
Cholestanes [D04.210.500.247] * Sterols [D04.210.500.247.808] * Adosterol [D04.210.500.247.808.050] * Cholecalciferol [D04.210. ... Cholestanes (1968-1972). Sterols (1968-1972). Public MeSH Note. 73. History Note. 73. Date Established. 1973/01/01. Date of ...
Cholesterol, a pharmaceutical secondary standard & certified reference material for use in pharma release testing and pharmaceutical research.
Cholestane and chromic oxide were used as inert digestibility markers. Juvenile halibut (109.5 ±27.6 g) were held in tanks ... lipids; lipid; fatty acids; fatty acid; Atlantic halibut; apparent digestibility; cholestane; Hippoglossus hippoglossus L.. ...
Powered by Pure, Scopus & Elsevier Fingerprint Engine™ All content on this site: Copyright © 2024 Elsevier B.V. or its licensors and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies. For all open access content, the Creative Commons licensing terms apply We use cookies to help provide and enhance our service and tailor content. By continuing you agree to the use of cookies. ...
Estrane, androstane, norandrostane (etiano), cholane, cholestane,. Le spectacle con Esteroides, 2015). Notes: (a) Unsaturation ...
IUPAC recommended ring lettering (left) and atom numbering (right) of cholestane, a prototypical steroid skeleton.[1] The… … ...
Steroid acids and salts. The primary bile acids are derived from cholesterol in the liver and usually conjugated with glycine or taurine. The secondary bile acids are further modified by bacteria in the intestine. They play an important role in the digestion and absorption of fat. They have also been used pharmacologically, especially in the treatment of gallstones ...
Boenzi S, Deodato F, Taurisano R, Goffredo BM, Rizzo C, Dionisi-Vici C. Evaluation of plasma cholestane-3β,5α,6β-triol and 7- ... Kannenberg F, Nofer JR, Schulte E, Reunert J, Marquardt T, Fobker M. Determination of serum cholestane-3β,5α,6β-triol by gas ... Cholestane-3β,5α,6β-triol: high levels in Niemann-Pick type C, cerebrotendinous xanthomatosis, and lysosomal acid lipase ... Cooper JA, Church HJ, Wu HY. Cholestane-3β,5α,6β-triol: further insights into the performance of this oxysterol in diagnosis of ...
Reactions of compounds related to dimethyl octane P methane and cholestane  Chaudhari, P. N. (CSIR-National Chemical ...
1017 - C27-20R5a(H),14ß(H),17ß(H)-cholestane , also noted as c27rch. 0.0000336 0.0000065 GC-MS, gas chromatography-mass ... 1019 - C27-20R5a(H),14a(H),17a(H)-cholestane , also noted as c27rac. 0.0000386 0.0000072 GC-MS, gas chromatography-mass ...
... the one natural way to get ripped is by consuming cholestane-based extract. Cholestane is an extract from male coca leaves that ... Its considered one of the most powerful of all natural steroids. Cholestane has two primary purposes: firstly, it plays a role ... Cholestane-based Extract For some men who want to get rid of excess body fat in order to build muscle, ... There are only three ingredients in Cholestane-based extracts that make up the testosterone-boosting action: L-theanine (or ...
The steroids with eleven pregnane steroids and nine cholestane steroids are only found in the species. In Commiphora species, ... The steroids with eleven pregnane steroids and nine cholestane steroids are only found in the species. In Commiphora species, ... The steroids with eleven pregnane steroids and nine cholestane steroids are only found in the species. In Commiphora species, ...
Cholestane-3ß, 5α, 6ß-triol (abbreviated as triol) is one of the most abundant and active oxysterols. Here, we report that ... Cholestane-3ß, 5α, 6ß-triol suppresses proliferation, migration, and invasion of human prostate cancer cells. ...
Cholestane derivatives containing a fused lactone ring at the 16,17-position and a spiroglycosidic linkage at C-22. Members ...

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