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Query: CAS:22373-09-7 (cholestane)
 779 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An extensive phytochemical analysis of the saponin content has been undertaken on leek, Allium porrum L., sown and collected at different seasons. As a result of this investigation, eight saponins (1-8) have been isolated, four of them (5-8) being novel compounds. Compounds 5 and 6, possessing the same tetrasaccharide moiety of compounds 1 and 3, display very unusual spirostane aglycones, 12-ketoporrigenin and 2,12-diketoporrigenin (named porrigenin C), respectively, recently isolated for the first time as free sapogenin in the same plant. Compounds 7 and 8 are rare cholestane bidesmosides possessing a di- and trisaccharide residues linked to a polyhydroxycholesterol aglycone, respectively. The structures of the isolated compounds have been determined by nondegradative spectroscopic analysis, mainly based on NMR. All the eight saponins isolated from leek were tested for their cytotoxic activity against two different cell lines in vitro, and compounds 1, 2, and 6 resulted particularly active.
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PMID:Cytotoxic saponins from bulbs of Allium porrum L. 1095 33

A chemical investigation of the aerial parts of Polianthes tuberosa resulted in the isolation of a new bisdesmosidic cholestane glycoside (1) and three new spirostanol saponins (2-4), along with a known cholestane glycoside. The structures of new glycosides were determined by spectroscopic analysis, including 2D NMR spectroscopic data, and the results of hydrolytic cleavage. The isolated compounds were evaluated for their cytotoxic activity on HL-60 human promyelocytic leukemia cells.
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PMID:Steroidal glycosides from the aerial parts of Polianthes tuberosa. 1108 96

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.
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PMID:Steroidal compounds from the Caribbean octocoral Eunicea laciniata. 1114 Nov 11

Further phytochemical analysis of the bulbs of Ornithogalum saundersiae has yielded two new cytotoxic cholestane triglycosides (1 and 2). The structures of these compounds were determined by spectroscopic analysis, including 2D NMR spectroscopic data, and the results of hydrolytic cleavage. Compounds 1 and 2 and several analogues were evaluated for their cytotoxicity against HL-60 cells.
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PMID:Cytotoxic cholestane glycosides from the bulbs of Ornithogalum saundersiae. 1117 Jun 74

Phytochemical analysis of the bulbs of Camassia leichtlinii (Liliaceae) resulted in the isolation of six new spirostanol saponins, a new furostanol saponin, a cholestane glucoside, and four known steroidal saponins. The structures of the new saponins were determined by detailed analysis of their spectral data, including two-dimensional NMR spectroscopy, and by the results of hydrolytic cleavage. Cytotoxic activities of the isolated compounds against human oral squamous cell carcinoma (HSC-2) cells and normal human gingival fibroblasts (HGF) are also reported.
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PMID:Steroidal glycosides from the bulbs of Camassia leichtlinii and their cytotoxic activities. 1141 25

Five new steroid sulfates, sodium 2beta,3alpha-dihydroxy-5alpha-cholestane 3-sulfate (6), sodium 2beta,3alpha-dihydroxy-5alpha-cholestane 2-sulfate (7), disodium 2beta,3alpha-dihydroxy-5alpha-cholestane disulfate (8), sodium 3alpha-acetoxy-2beta-hydroxy-5alpha-cholestane 2-sulfate (12), and sodium 2beta-acetoxy-3alpha-hydroxy-5alpha-cholestane 3-sulfate (13), have been synthesized starting from 3beta-hydroxy-5alpha-cholestane (1). The synthetic steroids were completely characterized by one-dimensional and two-dimensional NMR and FABMS spectra. Sulfation was performed using triethylamine-sulfur trioxide complex in dimethylformamide as the sulfating agent. The sulfated steroids were comparatively evaluated for their inhibitory effect on the replication of herpes simplex virus type 2 (HSV-2). Compounds 7 and 8 were the most effective in their inhibitory action against HSV-2. The disulfated steroid 8 also proved to be active against DEN-2 and JV.
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PMID:Synthesis and antiviral activity of sulfated and acetylated derivatives of 2beta,3alpha-dihydroxy-5alpha-cholestane. 1260 2

Our lab is developing a spin-labeled EPR spectroscopic technique complementary to solid-state NMR studies to study the structure, orientation, and dynamics of uniaxially aligned integral membrane proteins inserted into magnetically aligned discotic phospholipid bilayers, or bicelles. The focus of this study is to optimize and understand the mechanisms involved in the magnetic alignment process of bicelle disks in weak magnetic fields. Developing experimental conditions for optimized magnetic alignment of bicelles in low magnetic fields may prove useful to study the dynamics of membrane proteins and its interactions with lipids, drugs, steroids, signaling events, other proteins, etc. In weak magnetic fields, the magnetic alignment of Tm(3+)-doped bicelle disks was thermodynamically and kinetically very sensitive to experimental conditions. Tm(3+)-doped bicelles were magnetically aligned using the following optimized procedure: the temperature was slowly raised at a rate of 1.9K/min from an initial temperature being between 298 and 307K to a final temperature of 318K in the presence of a static magnetic field of 6300G. The spin probe 3beta-doxyl-5alpha-cholestane (cholestane) was inserted into the bicelle disks and utilized to monitor bicelle alignment by analyzing the anisotropic hyperfine splitting for the corresponding EPR spectra. The phases of the bicelles were determined using solid-state 2H NMR spectroscopy and compared with the corresponding EPR spectra. Macroscopic alignment commenced in the liquid crystalline nematic phase (307K), continued to increase upon slowly raising the temperature, and was well-aligned in the liquid crystalline lamellar smectic phase (318K).
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PMID:Magnetically aligned phospholipid bilayers in weak magnetic fields: optimization, mechanism, and advantages for X-band EPR studies. 1266 Jan 14

This paper presents the first time that both solid-state NMR spectroscopy and EPR spectroscopy are used to study the effects of cholesterol on magnetically aligned phospholipid bilayers (bicelles). Solid-state deuterium NMR spectroscopy was carried out using both chain perdeuterated 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC-d(54)) and a partially deuterated beta-[2,2,3,4,4,6-(2)H(6)]cholesterol (cholesterol-d(6)). Also, EPR spectroscopy was carried out utilizing a 3 beta-doxyl-5 alpha-cholestane (cholestane) spin probe incorporated into magnetically aligned bilayers to provide a more complete picture about the ordering and dynamics of the phospholipid and cholesterol molecules in the bicelle membrane system. The results demonstrate that cholesterol was successfully incorporated into the phospholipid bilayers. The molecular order parameters extracted directly from the (2)H NMR spectra of both DMPC-d(54) and cholesterol-d(6) were compared to that from the EPR study of cholestane. The order parameters indicate that the sterol was motionally restricted, and that the DMPC had high order and low motion for the hydrocarbon segments close to the head groups of the phospholipids and less order and more rapid motion toward the terminal methyl groups. Both methods clearly indicate an overall increase in the degree of ordering of the molecules in the presence of cholesterol and a decrease in the degree of ordering at higher temperatures. However, EPR spectroscopy and (2)H NMR spectroscopy exhibit different degrees of sensitivity in detecting the phospholipid molecular motions in the membrane. Finally, cholesterol increases the minimum alignment temperature necessary to magnetically align the phospholipid bilayers.
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PMID:The effects of cholesterol on magnetically aligned phospholipid bilayers: a solid-state NMR and EPR spectroscopy study. 1508 45

Three new steroidal saponins, named agamenosides H-J (1-3), and a new cholestane steroid agavegenin D (4) were isolated from the waste residue of fibre separation from Agave americana leaves, together with six known steroids. Structures of the new compounds 1-4 were deduced to be (22S,23S,24R,25S)-24-[(beta-D-glucopyranosyl)oxy]-5alpha-spirostane-3beta,6alpha,23-triol 6-O-beta-D-glucopyranoside (1), (22S,23S,24R,25S)-5alpha-spirostane-3beta,23,24-triol 24-O-beta-D-glucopyranoside (2), (22S,23S,25R,26S)-23,26-epoxy-5alpha-furostane-3beta,22,26-triol 26-O-beta-D-glucopyranoside (3), and (22S,25S)-5alpha-cholestane-3beta,16beta,22,26-tetrol (4), respectively, by means of spectroscopic analysis, including extensive 1D and 2D NMR data, and the results of hydrolytic cleavage.
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PMID:Four new steroid constituents from the waste residue of fibre separation from Agave americana leaves. 1518 83

Phytochemical analyses have been carried out on the fresh bulbs of Ornithogalum thyrsoides with particular attention to the steroidal glycoside constituents, resulting in the isolation of four new spirostanol saponins and seven new cholestane glycosides, together with three known steroidal compounds. The structures of the new glycosides were determined on the basis of their spectroscopic data, including 2D NMR spectroscopy, and the results of hydrolytic cleavage. The isolated compounds were evaluated for their cytotoxic activities against HL-60 human promyelocytic leukemia cells and HSC-2 human oral squamous cell carcinoma cells.
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PMID:Steroidal glycosides from the bulbs of Ornithogalum thyrsoides. 1549 41


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