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Özçınar Ö, Yusufoglu H, Kivçak B, Bedir E. Biotransformation of Neoruscogenin by the Endophytic Fungus Alternaria eureka. JOURNAL OF NATURAL PRODUCTS 2018; 81:1357-1367. [PMID: 29893560 DOI: 10.1021/acs.jnatprod.7b00898] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Biotransformation of neoruscogenin (NR, 1, spirosta-5,25(27)-diene-1β,3β-diol), the major bioactive sapogenin of Ruscus preparations, was carried out with the endophytic fungus Alternaria eureka. Fourteen new biotransformation products (2-15) were isolated, and their structures were elucidated by NMR and HRESIMS data analyses. A. eureka affected mainly oxygenation, oxidation, and epoxidation reactions on the B and C rings of the sapogenin to afford compounds 8-15. In addition to these, cleavage of the spiroketal system as in compounds 2-7 and subsequent transformations provided unusual metabolites. This is the first study reporting conversion of the spirostanol skeleton to cholestane-type metabolites 2-5. Additionally, the cleavage of the C-22/C-26 oxygen bridge yielding a furostanol-type steroidal framework and subsequent formation of the epoxy bridge between C-18 and C-22 in 7 was encountered for the first time in steroid chemistry.
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Affiliation(s)
- Özge Özçınar
- Department of Pharmacognosy, Faculty of Pharmacy , Ege University , 35100 Bornova - İzmir , Turkey
| | - Hasan Yusufoglu
- Department of Pharmacognosy, College of Pharmacy , Prince Sattam Bin Abdulaziz University , 11942 Al-Kharj , Saudi Arabia
| | - Bijen Kivçak
- Department of Pharmacognosy, Faculty of Pharmacy , Ege University , 35100 Bornova - İzmir , Turkey
| | - Erdal Bedir
- Department of Bioengineering, Faculty of Engineering , Izmir Institute of Technology , 35430 Urla - Izmir , Turkey
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Shen Y, Wen L, Zhang R, Wei Z, Shi N, Xiong Q, Xia Q, Xing Z, Zeng Z, Niu H, Huang W. Dihydrodiosgenin protects against experimental acute pancreatitis and associated lung injury through mitochondrial protection and PI3Kγ/Akt inhibition. Br J Pharmacol 2018; 175:1621-1636. [PMID: 29457828 DOI: 10.1111/bph.14169] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 01/22/2018] [Accepted: 01/25/2018] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND AND PURPOSE Acute pancreatitis (AP) is a painful and distressing disorder of the exocrine pancreas with no specific treatment. Diosgenyl saponins extracted from from Dioscorea zingiberensis C. H. Wright have been reported to protect against experimental models of AP. Diosgenin, or its derivatives are anti-inflammatory in various conditions. However, the effects of diosgenin and its spiroacetal ring opened analogue, dihydrodiosgenin (Dydio), on AP have not been determined. EXPERIMENTAL APPROACH Effects of diosgenin and Dydio on sodium taurocholate hydrate (Tauro)-induced necrosis were tested, using freshly isolated murine pancreatic acinar cells. Effects of Dydio on mitochondrial dysfunction in response to Tauro, cholecystokinin-8 and palmitoleic acid ethyl ester were also assessed. Dydio (5 or 10 mg·kg-1 ) was administered after the induction in vivo of Tauro-induced AP (Wistar rats), caerulein-induced AP and palmitoleic acid plus ethanol-induced AP (Balb/c mice). Pancreatitis was assessed biochemically and histologically. Activation of pancreatic PI3Kγ/Akt was measured by immunoblotting. KEY RESULTS Dydio inhibited Tauro-induced activation of the necrotic cell death pathway and prevented pancreatitis stimuli-induced mitochondrial dysfunction. Therapeutic administration of Dydio ameliorated biochemical and histopathological responses in all three models of AP through pancreatic mitochondrial protection and PI3Kγ/Akt inactivation. Moreover, Dydio improved pancreatitis-associated acute lung injury through preventing excessive inflammatory responses. CONCLUSION AND IMPLICATIONS These data provide in vitro and in vivo mechanistic evidence that the diosgenin analogue, Dydio could be potential treatment for AP. Further medicinal optimization of diosgenin and its analogue might be a useful strategy for identifying lead candidates for inflammatory diseases.
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Affiliation(s)
- Yan Shen
- Laboratory of Ethnopharmacology/Regenerative Medicine Research Center, West China Hospital/West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Li Wen
- Department of Integrated Traditional Chinese and Western Medicine, West China Hospital/West China Medical School, Sichuan University, Chengdu, Sichuan, China.,Department of Pediatric Gastroenterology, Children's Hospital of Pittsburgh of UPMC and School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Rui Zhang
- Laboratory of Ethnopharmacology/Regenerative Medicine Research Center, West China Hospital/West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Zeliang Wei
- Laboratory of Ethnopharmacology/Regenerative Medicine Research Center, West China Hospital/West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Na Shi
- Department of Integrated Traditional Chinese and Western Medicine, West China Hospital/West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Qiuyang Xiong
- Laboratory of Ethnopharmacology/Regenerative Medicine Research Center, West China Hospital/West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Qing Xia
- Department of Integrated Traditional Chinese and Western Medicine, West China Hospital/West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Zhihua Xing
- Laboratory of Ethnopharmacology/Regenerative Medicine Research Center, West China Hospital/West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Zhi Zeng
- Laboratory of Ethnopharmacology/Regenerative Medicine Research Center, West China Hospital/West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Hai Niu
- Laboratory of Ethnopharmacology/Regenerative Medicine Research Center, West China Hospital/West China Medical School, Sichuan University, Chengdu, Sichuan, China.,College of Mathematics, Sichuan University, Chengdu, Sichuan, China
| | - Wen Huang
- Laboratory of Ethnopharmacology/Regenerative Medicine Research Center, West China Hospital/West China Medical School, Sichuan University, Chengdu, Sichuan, China
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Feng SX, Zhang YD. One-pot efficient synthesis of 13(R),14(R)-epoxy-17β-methyl-20(S)-hydroxyl-18-nor-pregna-4-en-3-one via a tandem epoxidation-rearrangement-epoxidation reaction sequence. Steroids 2013; 78:1332-8. [PMID: 24145007 DOI: 10.1016/j.steroids.2013.10.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 09/17/2013] [Accepted: 10/07/2013] [Indexed: 11/20/2022]
Abstract
One-pot synthesis of an 18-norsteroid compound, 13(R),14(R)-epoxy-17β-methyl-20(S)-hydroxyl-18-nor-pregna-4-en-3-one has been achieved with peracetic acid/acetic acid under a mild condition, via a proved tandem epoxidation-rearrangement-epoxidation sequence. Its structure was designated on the basis of NMR and X-ray crystallography data.
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Affiliation(s)
- Shu-Xiao Feng
- School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou 450001, China; College of Chemical Engineering and Pharmaceutical, Henan University of Science and Technology, Luoyang 471023, China
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Martin R, Entchev EV, Kurzchalia TV, Knölker HJ. Steroid hormones controlling the life cycle of the nematode Caenorhabditis elegans: stereoselective synthesis and biology. Org Biomol Chem 2010; 8:739-50. [DOI: 10.1039/b918488k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Martin R, Schmidt AW, Theumer G, Krause T, Entchev EV, Kurzchalia TV, Knölker HJ. Synthesis and biological activity of the (25R)-cholesten-26-oic acids--ligands for the hormonal receptor DAF-12 in Caenorhabditis elegans. Org Biomol Chem 2009; 7:909-20. [PMID: 19225674 DOI: 10.1039/b817358c] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe the stereoselective transformation of diosgenin (4a) to (25R)-Delta(4)-dafachronic acid (1a),(25R)-Delta(7)-dafachronic acid (2a), and (25R)-cholestenoic acid (3a), which represent potential ligands forthe hormonal receptor DAF-12 in Caenorhabditis elegans. Key-steps of our synthetic approach are amodified Clemmensen reduction of diosgenin (4a) and a double bond shift from the 5,6- to the 7,8-position. In the 25R-series, the Delta(7)-dafachronic acid 2a exhibits the highest hormonal activity.
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Affiliation(s)
- René Martin
- Department Chemie, Technische Universität Dresden, Bergstrasse 66, 01069 Dresden, Germany
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Antonchick AV, Zhabinskii VN, Khripach VA. Synthesis of sterols oxygenated in the terminal fragment of their side chains. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2008. [DOI: 10.1134/s1068162008040018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Alessandrini L, Ciuffreda P, Santaniello E, Terraneo G. Clemmensen reduction of diosgenin and kryptogenin: synthesis of [16,16,22,22,23,23-(2)H(6)]-(25R)-26-hydroxycholesterol. Steroids 2004; 69:789-94. [PMID: 15582533 DOI: 10.1016/j.steroids.2004.09.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2004] [Revised: 09/09/2004] [Accepted: 09/17/2004] [Indexed: 11/18/2022]
Abstract
A new experimental protocol has been established for the Clemmensen reduction of diosgenin and kryptogenin with the aim to prepare deuterated isotopomers of (25R)-26-hydroxycholesterol. Uncontrolled deuteration has been achieved from diosgenin, whereas [16,16,22,22,23,23-(2)H(6)]-(25R)-26-hydroxycholesterol (1) can be synthesized from kryptogenin.
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Affiliation(s)
- Laura Alessandrini
- Dipartimento di Scienze Precliniche LITA Vialba, University of Milan, Via G.B. Grassi, 74-20157 Milano, Italy
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Ciuffreda P, Casati S, Bollini D, Santaniello E. Synthesis of (20S)-[7,7,21,21-2H4]-3beta-(tert-butyldimethylsilanyloxy)-20-methyl-pregn-5-en-21-ol, a useful intermediate for the preparation of deuterated isotopomers of sterols. Steroids 2003; 68:193-8. [PMID: 12606010 DOI: 10.1016/s0039-128x(02)00172-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
(20S)-[7,7,21,21-2H(4)]-3beta-(tert-Butyldimethylsilanyloxy)-20-methyl-pregn-5-en-21-ol, an intermediate for the preparation of deuterated isotopomers of sterols to be used as standards for biomedical studies, was prepared by reduction with dichloroaluminum deuteride of ethyl (20S)-3beta-(tert-butyldimethylsilanyloxy)-7-oxo-pregn-5-en-20-carboxylate. Using controlled experimental conditions, it has also been shown that the dichloroaluminum hydride reduction of a 7-keto steroid affords the corresponding 7beta-hydroxy derivative in a highly stereoselective manner.
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Affiliation(s)
- Pierangela Ciuffreda
- Dipartimento di Scienze Precliniche LITA Vialba, Via G.B. Grassi, 74-20157 Milano, Italy
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Abstract
We describe the synthesis of (25R)-cholest-5-en-3beta,26-diol ((25R)-26-hydroxycholesterol) from diosgenin in four steps in 58% overall, yield via a modified Clemmensen reduction followed by a Barton deoxygenation reaction.
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Affiliation(s)
- John R Williams
- Department of Chemistry, Temple University, 13th & Norris Streets, Beury Hall (016-00), Philadelphia, PA 19122-2585, USA.
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Lahmann M, Gybäck H, Garegg PJ, Oscarson S, Suhr R, Thiem J. A facile approach to diosgenin and furostan type saponins bearing a 3beta-chacotriose moiety. Carbohydr Res 2002; 337:2153-9. [PMID: 12433478 DOI: 10.1016/s0008-6215(02)00275-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Combination of a one-pot coupling technique and the use of benzyl ethers as permanent protecting groups offered a short and simple route to dioscin-type saponins. This strategy in combination with a mild reductive opening procedure of the spiroketal function in diosgenin also offered a convenient approach to bidesmosidic furostan type saponins. Me(3)N.BH(3)/AlCl(3) promoted acetal opening of 3-O-TBDMS-protected diosgenin gave the 26-OH acceptor 9 into which a benzylated beta-glucose moiety was introduced by a S(N)2-type imidate coupling. After cleavage of the silyl ether, the 3beta-O-glucose and the 4-O-linked rhamnose of the chacotriose unit were introduced by a NIS/AgOTf-promoted one-pot coupling sequence utilising thioglycoside donors and their different reactivity in different solvents. After removal of a benzoyl group, the same coupling conditions were also used for the coupling of the second 2-O-linked rhamnose unit. The target substance was obtained after cleavage of the protecting benzyl ethers under Birch-type conditions, which did not affect the double bond in the steroid skeleton.
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Affiliation(s)
- Martina Lahmann
- Department of Organic Chemistry, Stockholm University, S-10691 Stockholm, Sweden
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11
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Gardner RG, Shan H, Matsuda SP, Hampton RY. An oxysterol-derived positive signal for 3-hydroxy- 3-methylglutaryl-CoA reductase degradation in yeast. J Biol Chem 2001; 276:8681-94. [PMID: 11134013 DOI: 10.1074/jbc.m007888200] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sterol synthesis by the mevalonate pathway is modulated, in part, through feedback-regulated degradation of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR). In mammals, both a non-sterol isoprenoid signal derived from farnesyl diphosphate (FPP) and a sterol-derived signal appear to act together to positively regulate the rate of HMGR degradation. Although the nature and number of sterol-derived signals are not clear, there is growing evidence that oxysterols can serve in this capacity. In yeast, a similar non-sterol isoprenoid signal generated from FPP acts to positively regulate HMGR degradation, but the existence of any sterol-derived signal has thus far not been revealed. We now demonstrate, through the use of genetic and pharmacological manipulation of oxidosqualene-lanosterol cyclase, that an oxysterol-derived signal positively regulated HMGR degradation in yeast. The oxysterol-derived signal acted by specifically modulating HMGR stability, not endoplasmic reticulum-associated degradation in general. Direct biochemical labeling of mevalonate pathway products confirmed that oxysterols were produced endogenously in yeast and that their levels varied appropriately in response to genetic or pharmacological manipulations that altered HMGR stability. Genetic manipulation of oxidosqualene-lanosterol cyclase did result in the buildup of detectable levels of 24,25-oxidolanosterol by gas chromatography, gas chromatography-mass spectroscopy, and NMR analyses, whereas no detectable amounts were observed in wild-type cells or cells with squalene epoxidase down-regulated. In contrast to mammalian cells, the yeast oxysterol-derived signal was not required for HMGR degradation in yeast. Rather, the function of this second signal was to enhance the ability of the FPP-derived signal to promote HMGR degradation. Thus, although differences do exist, both yeast and mammalian cells employ a similar strategy of multi-input regulation of HMGR degradation.
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Affiliation(s)
- R G Gardner
- Section of Cell and Developmental Biology, Division of Biology, University of California at San Diego, La Jolla, California 92093 , USA
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12
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Abstract
Oxygenated derivatives of cholesterol (oxysterols) present a remarkably diverse profile of biological activities, including effects on sphingolipid metabolism, platelet aggregation, apoptosis, and protein prenylation. The most notable oxysterol activities center around the regulation of cholesterol homeostasis, which appears to be controlled in part by a complex series of interactions of oxysterol ligands with various receptors, such as the oxysterol binding protein, the cellular nucleic acid binding protein, the sterol regulatory element binding protein, the LXR nuclear orphan receptors, and the low-density lipoprotein receptor. Identification of the endogenous oxysterol ligands and elucidation of their enzymatic origins are topics of active investigation. Except for 24, 25-epoxysterols, most oxysterols arise from cholesterol by autoxidation or by specific microsomal or mitochondrial oxidations, usually involving cytochrome P-450 species. Oxysterols are variously metabolized to esters, bile acids, steroid hormones, cholesterol, or other sterols through pathways that may differ according to the type of cell and mode of experimentation (in vitro, in vivo, cell culture). Reliable measurements of oxysterol levels and activities are hampered by low physiological concentrations (approximately 0.01-0.1 microM plasma) relative to cholesterol (approximately 5,000 microM) and by the susceptibility of cholesterol to autoxidation, which produces artifactual oxysterols that may also have potent activities. Reports describing the occurrence and levels of oxysterols in plasma, low-density lipoproteins, various tissues, and food products include many unrealistic data resulting from inattention to autoxidation and to limitations of the analytical methodology. Because of the widespread lack of appreciation for the technical difficulties involved in oxysterol research, a rigorous evaluation of the chromatographic and spectroscopic methods used in the isolation, characterization, and quantitation of oxysterols has been included. This review comprises a detailed and critical assessment of current knowledge regarding the formation, occurrence, metabolism, regulatory properties, and other activities of oxysterols in mammalian systems.
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Affiliation(s)
- G J Schroepfer
- Departments of Biochemistry, Rice University, Houston, Texas, USA.
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Tercel M, Gieseg MA, Denny WA, Wilson WR. Synthesis and Cytotoxicity of Amino-seco-DSA: An Amino Analogue of the DNA Alkylating Agent Duocarmycin SA. J Org Chem 1999. [DOI: 10.1021/jo990464j] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Moana Tercel
- Auckland Cancer Society Research Centre, Faculty of Medicine and Health Science, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Michael A. Gieseg
- Auckland Cancer Society Research Centre, Faculty of Medicine and Health Science, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - William A. Denny
- Auckland Cancer Society Research Centre, Faculty of Medicine and Health Science, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - William R. Wilson
- Auckland Cancer Society Research Centre, Faculty of Medicine and Health Science, The University of Auckland, Private Bag 92019, Auckland, New Zealand
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Li S, Pang J, Wilson WK, Schroepfer GJ. Sterol synthesis. Preparation and characterization of fluorinated and deuterated analogs of oxygenated derivatives of cholesterol. Chem Phys Lipids 1999; 99:33-71. [PMID: 10377963 DOI: 10.1016/s0009-3084(99)00005-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Oxygenated sterols, including both autoxidation products and sterol metabolites, have many important biological activities. Identification and quantitation of oxysterols by chromatographic and spectroscopic methods is greatly facilitated by the availability of authentic standards, and deuterated and fluorinated analogs are valuable as internal standards for quantitation. We describe the preparation, purification and characterization of 43 oxygenated sterols, including the 4 beta-hydroxy, 7 alpha-hydroxy, 7 beta-hydroxy, 7-keto, and 19-hydroxy derivatives of cholesterol and their analogs with 25,26,26,26,27,27,27-heptafluoro (F7) and 26,26,26,27,27,27-hexadeuterio (d6) substitution. The 7 alpha-hydroxy, 7 beta-hydroxy, and 7-keto derivatives of (25R)-cholest-5-ene-3 beta, 26-diol (1d) and their 16,16-dideuterio analogs were also prepared. These d2-26-hydroxysterols and [16,16-2H2]-(25R)-cholest-5-ene-3 beta, 26-diol (1e) were synthesized from [16,16-2H2]-(25R)-cholest-5-ene-3 beta, 26-diol diacetate (2e), which can be prepared from diosgenin. The highly specific deuterium incorporation at C-16 in 1e and 2e should be useful in mass spectral analysis of 26-hydroxycholesterol samples by isotope dilution methods. The delta 5-3 beta, 7 alpha, 26- and delta 5-3 beta, 7 beta, 26-triols were regioselectively oxidized/isomerized to the corresponding delta 4-3-ketosteroids with cholesterol oxidase. Also described are 5,6 alpha-epoxy-5 alpha-cholestan-3 beta-ol, its 5 beta,6 beta-isomer, cholestane-3 beta, 5 alpha,6 beta-triol, their F7 and d6 derivatives, and d3-25-hydroxycholesterol, which was prepared from 3 beta-acetoxy-27-norcholest-5-en-25-one (30). The 43 oxysterols and most synthetic intermediates were isolated in high purity and characterized by chromatographic and spectroscopic methods, including mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy. Detailed mass spectral assignments are presented, and 1H NMR stereochemical assignments are derived for the C-19 protons of 19-hydroxysterols and for the side-chain protons of 30.
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Affiliation(s)
- S Li
- Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77005-1892, USA
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Morzycki JW, Kalinowski S, Łotowski Z, Rabiczko J. Synthesis of dimeric steroids as components of lipid membranes. Tetrahedron 1997. [DOI: 10.1016/s0040-4020(97)00669-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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16
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D'Ambra TE, Javitt NB, Nakanishi K, Warchol T. Synthesis of (25R)-cholest-5-ene-3β, 26-diol and its radiolabeled analog. Tetrahedron Lett 1997. [DOI: 10.1016/s0040-4039(97)00750-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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17
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Kim HS, Kim IC, Lee SO. Synthesis of two marine natural products: the aglycones of pavoninin-1 and 2. Tetrahedron 1997. [DOI: 10.1016/s0040-4020(97)00497-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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18
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Abstract
Material dealing with the chemistry, biochemistry, and biological activities of oxysterols is reviewed for the period 1987-1995. Particular attention is paid to the presence of oxysterols in tissues and foods and to their physiological relevance.
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Affiliation(s)
- L L Smith
- University of Texas Medical Branch, Galveston 77555-0653, USA
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19
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Wilson WK, Sumpter RM, Warren JJ, Rogers PS, Ruan B, Schroepfer GJ. Analysis of unsaturated C27 sterols by nuclear magnetic resonance spectroscopy. J Lipid Res 1996. [DOI: 10.1016/s0022-2275(20)39137-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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20
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Siddiqui AU, Wilson WK, Schroepfer GJ. Inhibitors of sterol synthesis. An improved chemical synthesis of 26-oxygenated delta 8(14)-15-ketosterols having the 25R configuration. Chem Phys Lipids 1994; 71:205-18. [PMID: 8076403 DOI: 10.1016/0009-3084(94)90072-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
(25R)-3 beta,26-Dihydroxy-5 alpha-cholest-8(14)-en-15-one (I) was synthesized in four steps from (25R)-3 beta,26-diacetoxycholesta-5,7-diene (III) in 30% overall yield. Isomerization of III with HCl in chloroform-dichloromethane at -60 degrees C gave (25R)-3 beta,26-diacetoxy-5 alpha-cholesta-7,14-diene together with the 5 alpha-delta 8,14 and 5 beta-delta 8,14 isomers in a 5:1:1 ratio. Epoxidation of the crude diene mixture with m-chloroperbenzoic acid, followed by hydrolysis in acetone containing concentrated HClO4 (0.1%) gave (25R)-3 beta,26-diacetoxy-5 alpha-cholest-8(14)-en-15-one (VIII), accompanied by numerous minor byproducts, including the 5 alpha,14 beta-delta 7, 5 alpha, 14 beta-delta 8 and 5 beta,14 beta-delta 8 isomers of VIII. All four 15-ketosterol esters were isolated by chromatography and fully characterized by mass spectrometry and 1H and 13C nuclear magnetic resonance. Treatment of VIII with potassium carbonate in degassed methanol gave I.
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Affiliation(s)
- A U Siddiqui
- Department of Biochemistry, Rice University, Houston, Texas 77251-1892
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