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Kundu S, Sarkar D. Synthetic Attempts Towards α‐Tocopherol – An Overview. J Heterocycl Chem 2022. [DOI: 10.1002/jhet.4565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Subhradip Kundu
- Organic Synthesis and Molecular Engineering Lab, Department of Chemistry National Institute of Technology Rourkela Odisha India
| | - Debayan Sarkar
- Organic Synthesis and Molecular Engineering Lab, Department of Chemistry National Institute of Technology Rourkela Odisha India
- Department of Chemistry Indian Institute of Technology Indore Madhya Pradesh India
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Drozdov FV, Surin NM, Peregudova SM, Trukhanov VA, Dmitryakov PV, Chvalun SN, Parashchuk DY, Ponomarenko SA. Synthesis and Properties of Alternating Copolymers Based on 4H-Cyclopenta[2,1-b:3,4-b']dithiophene and 4H-Dithieno[3,2-b:2',3'-d]silol. POLYMER SCIENCE SERIES B 2019. [DOI: 10.1134/s1560090419010032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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3
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Harned AM. From determination of enantiopurity to the construction of complex molecules: The Horeau principle and its application in synthesis. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.05.056] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Gamalevich GD, Vlasyuk AL, Serebryakov ÉP. Chiral Analogs of a-tocopherol. Antioxidant Activity of the (R) and (S) Enantiomers of {2-[6-hydroxy-2,5,7,8-tetramethylchroman-2-yl]ethyl}-trimethylammonium-p-toluenesulfonate Depending on Their Configuration. Pharm Chem J 2017. [DOI: 10.1007/s11094-017-1650-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Fu JY, Htar TT, De Silva L, Tan DMY, Chuah LH. Chromatographic Separation of Vitamin E Enantiomers. Molecules 2017; 22:E233. [PMID: 28165404 PMCID: PMC6155869 DOI: 10.3390/molecules22020233] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 12/19/2016] [Accepted: 12/20/2016] [Indexed: 01/27/2023] Open
Abstract
Vitamin E is recognized as an essential vitamin since its discovery in 1922. Most vegetable oils contain a mixture of tocopherols and tocotrienols in the vitamin E composition. Structurally, tocopherols and tocotrienols share a similar chromanol ring and a side chain at the C-2 position. Owing to the three chiral centers in tocopherols, they can appear as eight different stereoisomers. Plant sources of tocopherol are naturally occurring in the form of RRR while synthetic tocopherols are usually in the form of all-racemic mixture. Similarly, with only one chiral center, natural tocotrienols occur as the R-isoform. In this review, we aim to discuss a few chromatographic methods that had been used to separate the stereoisomers of tocopherols and tocotrienols. These methods include high performance liquid chromatography, gas chromatography and combination of both. The review will focus on method development including selection of chiral columns, detection method and choice of elution solvent in the context of separation efficiency, resolution and chiral purity. The applications for separation of enantiomers in vitamin E will also be discussed especially in terms of the distinctive biological potency among the stereoisoforms.
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Affiliation(s)
- Ju-Yen Fu
- Nutrition Unit, Product Development and Advisory Services Division, Malaysian Palm Oil Board, 6 Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia.
| | - Thet-Thet Htar
- School of Pharmacy, Monash University Malaysia, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia.
| | - Leanne De Silva
- School of Pharmacy, Monash University Malaysia, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia.
| | - Doryn Meam-Yee Tan
- Nutrition Unit, Product Development and Advisory Services Division, Malaysian Palm Oil Board, 6 Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia.
| | - Lay-Hong Chuah
- School of Pharmacy, Monash University Malaysia, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia.
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Lankhorst PP, Netscher T, Duchateau ALL. A Simple13C NMR Method for the Discrimination of Complex Mixtures of Stereoisomers: All Eight Stereoisomers of α-Tocopherol Resolved. Chirality 2015; 27:850-5. [DOI: 10.1002/chir.22535] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/13/2015] [Accepted: 08/27/2015] [Indexed: 01/08/2023]
Affiliation(s)
| | - Thomas Netscher
- DSM Nutritional Products; Research and Development; Basel Switzerland
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Wang A, Fraga RPA, Hörmann E, Pfaltz A. Iridium-Catalyzed Asymmetric Hydrogenation of Unfunctionalized, Trialkyl-Substituted Olefins. Chem Asian J 2010; 6:599-606. [DOI: 10.1002/asia.201000595] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Indexed: 11/06/2022]
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Gembus V, Sala-Jung N, Uguen D. A Convenient Access to (All-rac)-α-Tocopherol Acetate from Linalool and Dihydromyrcene. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2009. [DOI: 10.1246/bcsj.82.829] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Odinokov VN, Spivak AI, Knyshenko OV. Racemic and optically active tocopherol analogues with a modified side chain: Synthesis and biological activity (Review). RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2007; 33:387-404. [PMID: 17886430 DOI: 10.1134/s1068162007040012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Information on the synthesis and biological activity of natural and synthetic analogues of alpha-tocopherol with a modified side chain is systematized. These compounds are of interest as vitamin E metabolites, hydrophilic antioxidants, and precursors of drugs with combined pharmacological properties useful in therapy of pathological disorders caused by oxidative stress.
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Netscher T, Mazzini F, Jestin R. Tocopherols by Hydride Reduction of Dialkylamino Derivatives. European J Org Chem 2007. [DOI: 10.1002/ejoc.200600874] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Cohen N, Banner BL, Neukom C. Improvements in the Synthesis of a Key α-tocopherol, Intermediate[sbnd] (s)-(−)-3,4-Dihydro-6-Hydroxy-2,5,7,8-Tetramethyll-2H-1-Benzopyran-2-Acetic Acid. SYNTHETIC COMMUN 2007. [DOI: 10.1080/00397918208080067] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
Vitamin E compounds are biologically essential fat-soluble antioxidants derived from 6-chromanol. This chapter covers the representative literature on the preparation of various stereoisomeric forms and homologues of tocopherols and tocotrienols, and of respective starting materials and intermediates. The industrially most relevant (all-rac)-alpha-tocopherol is generally built up by coupling of arenes with aliphatic precursors. For the synthesis of optically active vitamin E components, various strategies are compiled. In approaches to chiral chroman and side chain building blocks, a broad variety of methods from the repertoire of asymmetric synthesis were applied, that is optical resolution and use of chiral pool starting materials and chiral auxiliaries in stoichiometric as well as catalytic amounts, including catalysis by metal complexes, microorganisms, and enzymes. Most efforts were directed to (2R,4'R,8'R)-alpha-tocopherol due to its prominent biological activity. Syntheses of different stereoisomers (and mixtures thereof) and (beta-, gamma-, delta-) homologues of tocopherols and tocotrienols, as well as methods for their interconversion, are also described.
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Affiliation(s)
- Thomas Netscher
- Research and Development, DSM Nutritional Products CH-4002 Basel, Switzerland
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Abstract
Vitamin E comprises a group of compounds possessing vitamin E activity. alpha-Tocopherol is the compound demonstrating the highest vitamin E activity, which is available both in its natural form as RRR-alpha-tocopherol isolated from plant sources, but more common as synthetically manufactured all-rac-alpha-tocopherol. Synthetic all-rac-alpha-tocopherol consists of a racemic mixture of all eight possible stereoisomers. Assessing the correct biological activity in form of bioavailability and biopotency has been a great challenge during many years as it is difficult to measure clinical endpoints in larger animals than rats and poultry. Thus, the biological effects in focus are resorption of fetuses, testicular degeneration, muscle dystrophy, anemia, encephalomalacia, and in recent years the influence of vitamin E on the immune system are the most important clinical markers of interest. For humans and animals, only different biomarkers or surrogate markers of bioactivity have been measured. In studies with rats, a good consistency between the classical resorption-gestation test and the bioavailability of the individual stereoisomers in fluids and tissues has been shown. For humans and other animals, only different biomarkers or surrogate markers of bioactivity have been measured, and due to the lack of good biological markers for bioactivities, bioavailability is often used as one of the surrogate markers for bioactivities with those limitations this must give. Therefore, a relatively simple analytical method, which allows analysis of the individual stereoisomers of alpha-tocopherol, is an important tool in order to quantify relative bioavailability of the individual stereoisomers. The analytical method presented here allows the quantification of total tocopherol content and composition by normal phase HPLC and subsequent separation of the stereoisomers of alpha-tocopherol as methyl ethers by chiral HPLC. Using this method, the alpha-tocopherol stereoisomers are separated into five peaks. The first peak consists of the four 2S isomers (SSS-, SSR-, SRR-, SRS-), the second peak consists of RSS-, the third peak consists of RRS-, the fourth peak consists of RRR-, and the fifth peak consists of RSR-alpha-tocopherol. The discussion on the bioavailability of RRR- and all-rac-alpha-tocopheryl acetate has primarily been based on human and animal studies using deuterium-labeled forms, whereby a higher biopotency of 2:1 (of RRR: all-rac) has been demonstrated, differing from the accepted biopotency ratio of 1.36:1. In agreement with previous studies, the 2S-forms exert very little importance for the vitamin E activity due to their limited bioavailability. We find notable differences between animal species with regard to the biodiscrimination between the 2R-forms. Especially, cows preferentially transfer RRR- alpha-tocopherol into the milk and blood system. The distribution of the stereoisomer forms varies from tissue to tissue, and in some cases, higher levels of the synthetic 2R-forms than of the RRR-form are obtained, for example, for rats. However, the biodiscrimination of the stereoisomers forms is influenced by other factors such as age, dietary levels, and time after dosage. More focus should be given on the bioactivity of the individual 2R-forms rather than just the comparison between RRR- and all-rac-alpha-tocopheryl acetate.
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Affiliation(s)
- Søren Krogh Jensen
- Department of Animal Health, Welfare and Nutrition, Faculty of Agricultural Sciences, University of Aarhus, DK-8830 Tjele, Denmark
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Thirumamagal BTS, Zhao XB, Bandyopadhyaya AK, Naranyanasamy S, Johnsamuel J, Tiwari R, Golightly DW, Patel V, Jehning BT, Backer MV, Barth RF, Lee RJ, Backer JM, Tjarks W. Receptor-Targeted Liposomal Delivery of Boron-Containing Cholesterol Mimics for Boron Neutron Capture Therapy (BNCT). Bioconjug Chem 2006; 17:1141-50. [PMID: 16984121 DOI: 10.1021/bc060075d] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Liposomes have been a main focus of tumor-selective boron delivery strategies in boron neutron capture therapy (BNCT), a binary method for the treatment of cancer that is based on the nuclear reaction between boron atoms and low-energy thermal neutrons. Three novel carboranyl cholesterol derivatives were prepared as lipid bilayer components for the construction of nontargeted and receptor-targeted boronated liposomes for BNCT. A major structural feature of these novel boronated cholesterol mimics is the replacement of the B and the C ring of cholesterol with a carborane cluster. Computational analyses indicated that all three boronated compounds have structural features and physicochemical properties that are very similar to those of cholesterol. One of the synthesized boronated cholesterol mimics was stably incorporated into non-, folate receptor (FR)-, and vascular endothelial growth factor receptor-2 (VEGFR-2)-targeted liposomes. No major differences were found in appearance, size distribution, and lamellarity between conventional dipalmitoylphosphatidylcholine (DPPC)/cholesterol liposomes, nontargeted, and FR-targeted liposomal formulations of this carboranyl cholesterol derivative. FR-targeted boronated liposomes were taken up extensively in FR overexpressing KB cells in vitro, and the uptake was effectively blocked in the presence of free folate. In contrast, a boronated cholesterol mimic incorporated into nontargeted liposomes showed significantly lower cellular uptake. There was no apparent in vitro cytotoxicity in FR overexpressing KB cells and VEGFR-2 overexpressing 293/KDR cells when these were incubated with boronated FR- and (VEGFR-2)-targeted liposomes, respectively, although the former accumulated extensively in KB cells and the latter effectively interacted with VEGFR-2 by causing autophosphorylation and protecting 293/KDR cells from SLT (Shiga-like toxin)-VEGF cytotoxicity.
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Affiliation(s)
- B T S Thirumamagal
- Division of Medicinal Chemistry & Pharmacognosy, The Ohio State University, Columbus, 43210, USA
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Bell S, Wüstenberg B, Kaiser S, Menges F, Netscher T, Pfaltz A. Asymmetric Hydrogenation of Unfunctionalized, Purely Alkyl-Substituted Olefins. Science 2006; 311:642-4. [PMID: 16339409 DOI: 10.1126/science.1121977] [Citation(s) in RCA: 249] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Asymmetric hydrogenation of olefins is one of the most useful reactions for the synthesis of optically active compounds, especially in industry. However, the application range of the catalysts developed so far is limited to alkenes with a coordinating functional group or an aryl substituent next to the double bond. We have found a class of chiral iridium catalysts that give high enantioselectivity in the hydrogenation of unfunctionalized, trialkyl-substituted olefins. Because these catalysts do not require the presence of any particular functional group or aryl substituent in the substrate, they considerably broaden the scope of asymmetric hydrogenation.
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Affiliation(s)
- Sharon Bell
- Department of Chemistry, University of Basel, St. JohannsRing 19, CH-4056 Basel, Switzerland
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Spivak AY, Knyshenko OV, Mallyabaeva MI, Odinokov VN. Synthesis of α-tocopherol and naphthotocopherol analogs with a carboxyl group in the side chain. Russ Chem Bull 2006. [DOI: 10.1007/s11172-006-0253-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Tietze LF, Sommer KM, Zinngrebe J, Stecker F. Palladium-katalysierte enantioselektive Dominoreaktion zur effizienten Synthese von Vitamin E. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200461629] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Tietze LF, Sommer KM, Zinngrebe J, Stecker F. Palladium-Catalyzed Enantioselective Domino Reaction for the Efficient Synthesis of Vitamin E. Angew Chem Int Ed Engl 2005; 44:257-9. [PMID: 15565667 DOI: 10.1002/anie.200461629] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Lutz F Tietze
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany.
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Schmida R, Antoulas S, Rüttimann A, Schmid M, Vecchi M, Weiserb H. Synthesis of All Four Stereoisomers of (E)-Vitamin KT (Phylloquinone), Analysis of Their Diastereoisomeric and Enantiomeric Purities and Determination of Their Biopotencies. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19900730517] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Hübscher J, Barrier R. Totalsynthese von natülichem α-Tocopherol. 5. Mitteilung. Asymmetrische Alkylierung und asymmetrische Epoxidierung als Methoden zur Einführung der (R)-Konfiguration an C(2) des Chroman-Systems. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19900730431] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Knierzinger A, Walther W, Weber B, Müller RK, Netscher T. Eine neue Methode zur stereochemischen Analyse offenkettiger terpenoider Carbonyl-Verbindungen,. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19900730432] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Vitamin E biopotency: Comparison of various ‘natural-derived’ and chemically synthesized α-tocopherols. Anim Feed Sci Technol 1996. [DOI: 10.1016/0377-8401(95)00892-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Riss G, Kormann AW, Glinz E, Walther W, Ranalder UB. Separation of the eight stereoisomers of all-rac-alpha-tocopherol from tissues and plasma: chiral phase high-performance liquid chromatography and capillary gas chromatography. Methods Enzymol 1994; 234:302-10. [PMID: 7808298 DOI: 10.1016/0076-6879(94)34097-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- G Riss
- F. Hoffmann-La Roche Ltd., Basel, Switzerland
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Götz ME, Künig G, Riederer P, Youdim MB. Oxidative stress: free radical production in neural degeneration. Pharmacol Ther 1994; 63:37-122. [PMID: 7972344 DOI: 10.1016/0163-7258(94)90055-8] [Citation(s) in RCA: 349] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
It is not yet established whether oxidative stress is a major cause of cell death or simply a consequence of an unknown pathogenetic factor. Concerning chronic diseases, as Parkinson's and Alzheimer's disease are assumed to be, it is possible that a gradual impairment of cellular defense mechanisms leads to cell damage because of toxic substances being increasingly formed during normal cellular metabolism. This point of view brings into consideration the possibility that, besides exogenous factors, the pathogenetic process of neurodegeration is triggered by endogenous mechanisms, either by an endogenous toxin or by inherited metabolic disorders, which become progressively more evident with aging. In the following review, we focus on the oxidative stress theory of neurodegeneration, on excitotoxin-induced cell damage and on impairment of mitochondrial function as three major noxae being the most likely causes of cell death either independently or in connection with each other. First, having discussed clinical, pathophysiological, pathological and biochemical features of movement and cognitive disorders, we discuss the common features of these biochemical theories of neurodegeneration separately. Second, we attempt to evaluate possible biochemical links between them and third, we discuss experimental findings that confirm or rule out the involvement of any of these theories in neurodegeneration. Finally, we report some therapeutic strategies evolved from each of these theories.
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Affiliation(s)
- M E Götz
- Department of Psychiatry, University of Würzburg, Germany
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Takabe K, Sawada H, Satani T, Yamada T, Katagiri T, Yoda H. Chemoenzymatic synthesis of optically active α-tocopherol side chain. Bioorg Med Chem Lett 1993. [DOI: 10.1016/s0960-894x(01)80867-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Odinokov VN, Ishmuratov GY, Kharisov RY, Serebryakov EP, Tolstikov GA. Synthesis ofS-(+)-hydroprene. Russ Chem Bull 1993. [DOI: 10.1007/bf00699985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Vecchi M, Walther W, Glinz E, Netscher T, Schmid R, Lalonde M, Vetter W. Chromatographische Trennung und quantitative Bestimmung aller acht Stereoisomeren von ?-Tocopherol. Helv Chim Acta 1990. [DOI: 10.1002/hlca.19900730403] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Dutton PJ, Hughes LA, Foster DO, Burton GW, Ingold KU. Simon metabolites of alpha-tocopherol are not formed via a rate-controlling scission of the 3'C-H bond. Free Radic Biol Med 1990; 9:435-9. [PMID: 2292437 DOI: 10.1016/0891-5849(90)90021-a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The major in vivo oxidation products of alpha-tocopherol, alpha-T, are the Simon metabolites, 1 and 2. For these compounds to be formed from alpha-T the polyisoprenoid tail of alpha-T must be oxidatively cleaved at the 3' carbon atom. Comparison of the levels of 2R,4'R,8'R-alpha-(3',3'-2H2)-T and 2R,4'R,8'R-alpha-[5,7-(C2H3)2]-T remaining in various tissues of rats which had been preloaded with equal quantities of these two forms of vitamin E following a change to a vitamin E-free diet has shown that there is no statistically significant difference in the rates of loss of these two deuterium-labeled alpha-T's. This demonstrates that the Simon metabolites are not formed by a rate-controlling scission of the 3'C-H bond of alpha-T.
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Affiliation(s)
- P J Dutton
- Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario
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[12] Enzymatic production of optically active compounds in biphasic aqueous-organic systems. Methods Enzymol 1987. [DOI: 10.1016/s0076-6879(87)36014-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Rietjens IM, Poelen MC, Hempenius RA, Gijbels MJ, Alink GM. Toxicity of ozone and nitrogen dioxide to alveolar macrophages: comparative study revealing differences in their mechanism of toxic action. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH 1986; 19:555-68. [PMID: 3783771 DOI: 10.1080/15287398609530952] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The toxicity of ozone and nitrogen dioxide is generally ascribed to their oxidative potential. In this study their toxic mechanism of action was compared using an intact cell model. Rat alveolar macrophages were exposed by means of gas diffusion through a Teflon film. In this in vitro system, ozone appeared to be 10 times more toxic than nitrogen dioxide. alpha-Tocopherol protected equally well against ozone and nitrogen dioxide. It was demonstrated that alpha-tocopherol provided its protection by its action as a radical scavenger and not by its stabilizing structural membrane effect, as (1) concentrations of alpha-tocopherol that already provided optimal protection against ozone and nitrogen dioxide did not influence the membrane fluidity of alveolar macrophages and (2) neither one of the structural alpha-tocopherol analogs tested (phytol and the methyl ether of alpha-tocopherol) could provide a protection against ozone or nitrogen dioxide comparable to the one provided by alpha-tocopherol. It was concluded that reactive intermediates scavenged by alpha-tocopherol are important in the toxic mechanism of both ozone and nitrogen dioxide induced cell damage. However, further results presented strongly confirmed that the kind of radicals and/or reactive intermediates, and thus the toxic reaction mechanism involved, must be different in ozone- and nitrogen dioxide-induced cell damage. This was concluded from the observations that showed that (1) vitamin C provided significantly better protection against nitrogen dioxide than against an equally toxic dose of ozone, (2) glutathione depletion affected the cellular sensitivity toward ozone to a significantly greater extent than the sensitivity towards nitrogen dioxide, and (3) the scavenging action of alpha-tocopherol was accompanied by a significantly greater reduction in its cellular level during nitrogen dioxide exposure than during exposure to ozone. One of the possibilities compatible with the results presented in this study might be that lipid (peroxyl) free radicals formed in a radical-mediated peroxidative pathway, resulting in a substantial breakdown of cellular alpha-tocopherol, are involved in nitrogen dioxide-induced cell damage, and that lipid ozonides, scavenged by alpha-tocopherol as well, are involved in ozone-induced cell damage.
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Hoye TR, Suhadolnik JC. Stereocontrolled synthesis of 2,5-linked bistetrahydrofurans via the triepoxide cascade reaction. Tetrahedron 1986. [DOI: 10.1016/s0040-4020(01)90574-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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A total synthesis of enentiomerically pure vitamin e side chain using a chiral propionate synthon. Tetrahedron Lett 1983. [DOI: 10.1016/s0040-4039(00)81623-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
40
|
|
41
|
Gas chromatographic assay of the diastereomeric composition ofall-rac-α-tocopheryl acetate. Lipids 1982. [DOI: 10.1007/bf02535182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
42
|
Acyclic stereoselection. 15. Sequential aldol-claisen as a method for 1,5-stereoselection. Total synthesis of the vitamin-E side chain. Tetrahedron Lett 1982. [DOI: 10.1016/s0040-4039(00)88423-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
43
|
|
44
|
Vecchi M, Schmid M, Walther W, Gerber F. Determination of the diastereomers of vitamin K1. ACTA ACUST UNITED AC 1981. [DOI: 10.1002/jhrc.1240040602] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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