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Karlberg AT, Börje A, Lepoittevin JP, Giménez-Arnau E, Bråred Christensson J, Hagvall L. Letter to the Editor Regarding the Article by Natsch et al., 2015. Chem Res Toxicol 2015; 28:2079-81. [DOI: 10.1021/acs.chemrestox.5b00306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ann-Therese Karlberg
- Department of Chemistry and Molecular Biology, Dermatochemistry
and Skin Allergy, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Anna Börje
- Department of Chemistry and Molecular Biology, Dermatochemistry
and Skin Allergy, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Jean-Pierre Lepoittevin
- Laboratoire de Dermatochimie, ILB 4, rue Blaise Pascal - CS 90032, F-67081 Strasbourg cedex, France
| | - Elena Giménez-Arnau
- Laboratoire de Dermatochimie, ILB 4, rue Blaise Pascal - CS 90032, F-67081 Strasbourg cedex, France
| | - Johanna Bråred Christensson
- Department of Chemistry and Molecular Biology, Dermatochemistry
and Skin Allergy, University of Gothenburg, SE-412 96 Gothenburg, Sweden
- Department of Dermatology, Sahlgrenska
Academy, University of Gothenburg, SE-405 03 Gothenburg, Sweden
| | - Lina Hagvall
- Department of Dermatology, Sahlgrenska
Academy, University of Gothenburg, SE-405 03 Gothenburg, Sweden
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Rudbäck J, Islam MN, Börje A, Nilsson U, Karlberg AT. Essential oils can contain allergenic hydroperoxides at eliciting levels, regardless of handling and storage. Contact Dermatitis 2015; 73:253-4. [DOI: 10.1111/cod.12427] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 04/29/2015] [Accepted: 04/29/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Johanna Rudbäck
- Department of Chemistry and Molecular Biology, Dermatochemistry and Skin Allergy; University of Gothenburg; 412 96 Gothenburg Sweden
| | - M. Nurul Islam
- Department of Chemistry and Molecular Biology, Dermatochemistry and Skin Allergy; University of Gothenburg; 412 96 Gothenburg Sweden
| | - Anna Börje
- Department of Chemistry and Molecular Biology, Dermatochemistry and Skin Allergy; University of Gothenburg; 412 96 Gothenburg Sweden
| | - Ulrika Nilsson
- Department of Environmental Science and Analytical Chemistry; Stockholm University; 106 91 Stockholm Sweden
| | - Ann-Therese Karlberg
- Department of Chemistry and Molecular Biology, Dermatochemistry and Skin Allergy; University of Gothenburg; 412 96 Gothenburg Sweden
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Karlsson I, Persson E, Ekebergh A, Mårtensson J, Börje A. Ketoprofen-induced formation of amino acid photoadducts: possible explanation for photocontact allergy to ketoprofen. Chem Res Toxicol 2014; 27:1294-303. [PMID: 24892789 DOI: 10.1021/tx5001656] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Photocontact allergy is a well-known side effect of topical preparations of the nonsteroidal anti-inflammatory drug ketoprofen. Photocontact allergy to ketoprofen appears to induce a large number of photocross allergies to both structurally similar and structurally unrelated compounds. Contact and photocontact allergies are explained by structural modification of skin proteins by the allergen. This complex is recognized by the immune system, which initiates an immune response. We have studied ketoprofen's interaction with amino acids to better understand ketoprofen's photoallergenic ability. Irradiation of ketoprofen and amino acid analogues resulted in four different ketoprofen photodecarboxylation products (6-9) together with a fifth photoproduct (5). Dihydroquinazoline 5 was shown to be a reaction product between the indole moiety of 3-methylindole (Trp analogue) and the primary amine benzylamine (Lys analogue). In presence of air, dihydroquinazoline 5 quickly degrades into stable quinazolinone 12. The corresponding quinazolinone (17) was formed upon irradiation of ketoprofen and the amino acids N-acetyl-l-Trp ethyl ester and l-Lys ethyl ester. The formation of these models of an immunogenic complex starts with the ketoprofen-sensitized formation of singlet oxygen, which reacts with the indole moiety of Trp. The formed intermediate subsequently reacts with the primary amino functionality of Lys, or its analogue, to form a Trp-Lys adduct or a mimic thereof. The formation of a specific immunogenic complex that does not contain the allergen but that can still induce photocontact allergy would explain the large number of photocross allergies with ketoprofen. These allergens do not have to be structurally similar as long as they can generate singlet oxygen. To the best of our knowledge, there is no other suggested explanation for ketoprofen's photoallergenic properties that can account for the observed photocross allergies. The formation of a specific immunogenic complex that does not contain the allergen is a novel hypothesis in the field of contact and photocontact allergy.
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Affiliation(s)
- Isabella Karlsson
- Dermatochemistry and Skin Allergy, Department of Chemistry and Molecular Biology, University of Gothenburg , SE-412 96 Gothenburg, Sweden
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Rudbäck J, Hagvall L, Börje A, Nilsson U, Karlberg AT. Characterization of skin sensitizers from autoxidized citronellol - impact of the terpene structure on the autoxidation process. Contact Dermatitis 2014; 70:329-39. [DOI: 10.1111/cod.12234] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 02/04/2014] [Accepted: 02/19/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Johanna Rudbäck
- Department of Chemistry and Molecular Biology; Dermatochemistry and Skin Allergy, University of Gothenburg; 412 96 Gothenburg Sweden
| | - Lina Hagvall
- Department of Chemistry and Molecular Biology; Dermatochemistry and Skin Allergy, University of Gothenburg; 412 96 Gothenburg Sweden
- Department of Dermatology; Sahlgrenska Academy, University of Gothenburg; 405 30 Gothenburg Sweden
| | - Anna Börje
- Department of Chemistry and Molecular Biology; Dermatochemistry and Skin Allergy, University of Gothenburg; 412 96 Gothenburg Sweden
| | - Ulrika Nilsson
- Department of Analytical Chemistry; Stockholm University; 106 91 Stockholm Sweden
| | - Ann-Therese Karlberg
- Department of Chemistry and Molecular Biology; Dermatochemistry and Skin Allergy, University of Gothenburg; 412 96 Gothenburg Sweden
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Bråred Christensson J, Hellsén S, Börje A, Karlberg AT. Limonene hydroperoxide analogues show specific patch test reactions. Contact Dermatitis 2014; 70:291-9. [DOI: 10.1111/cod.12195] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 10/17/2013] [Accepted: 12/10/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Johanna Bråred Christensson
- Dermatochemistry and Skin Allergy, Department of Chemistry and Molecular Biology; University of Gothenburg; SE-405 30 Gothenburg Sweden
- Department of Dermatology; Sahlgrenska Academy at University of Gothenburg; 405 30 Gothenburg Sweden
| | - Staffan Hellsén
- Dermatochemistry and Skin Allergy, Department of Chemistry and Molecular Biology; University of Gothenburg; SE-405 30 Gothenburg Sweden
| | - Anna Börje
- Dermatochemistry and Skin Allergy, Department of Chemistry and Molecular Biology; University of Gothenburg; SE-405 30 Gothenburg Sweden
| | - Ann-Therese Karlberg
- Dermatochemistry and Skin Allergy, Department of Chemistry and Molecular Biology; University of Gothenburg; SE-405 30 Gothenburg Sweden
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Albrekt AS, Johansson H, Börje A, Borrebaeck C, Lindstedt M. Skin sensitizers differentially regulate signaling pathways in MUTZ-3 cells in relation to their individual potency. BMC Pharmacol Toxicol 2014; 15:5. [PMID: 24517095 PMCID: PMC3932014 DOI: 10.1186/2050-6511-15-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 01/27/2014] [Indexed: 01/10/2023] Open
Abstract
Background Due to the recent European legislations posing a ban of animal tests for safety assessment within the cosmetic industry, development of in vitro alternatives for assessment of skin sensitization is highly prioritized. To date, proposed in vitro assays are mainly based on single biomarkers, which so far have not been able to classify and stratify chemicals into subgroups, related to risk or potency. Methods Recently, we presented the Genomic Allergen Rapid Detection (GARD) assay for assessment of chemical sensitizers. In this paper, we show how the genome wide readout of GARD can be expanded and used to identify differentially regulated pathways relating to individual chemical sensitizers. In this study, we investigated the mechanisms of action of a range of skin sensitizers through pathway identification, pathway classification and transcription factor analysis and related this to the reactive mechanisms and potency of the sensitizing agents. Results By transcriptional profiling of chemically stimulated MUTZ-3 cells, 33 canonical pathways intimately involved in sensitization to chemical substances were identified. The results showed that metabolic processes, cell cycling and oxidative stress responses are the key events activated during skin sensitization, and that these functions are engaged differently depending on the reactivity mechanisms of the sensitizing agent. Furthermore, the results indicate that the chemical reactivity groups seem to gradually engage more pathways and more molecules in each pathway with increasing sensitizing potency of the chemical used for stimulation. Also, a switch in gene regulation from up to down regulation, with increasing potency, was seen both in genes involved in metabolic functions and cell cycling. These observed pathway patterns were clearly reflected in the regulatory elements identified to drive these processes, where 33 regulatory elements have been proposed for further analysis. Conclusions This study demonstrates that functional analysis of biomarkers identified from our genomics study of human MUTZ-3 cells can be used to assess sensitizing potency of chemicals in vitro, by the identification of key cellular events, such as metabolic and cell cycling pathways.
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Affiliation(s)
- Ann-Sofie Albrekt
- Department of Immunotechnology, Lund University, Medicon Village building 406, 223 81 Lund, Sweden.
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Karlberg AT, Börje A, Duus Johansen J, Lidén C, Rastogi S, Roberts D, Uter W, White IR. Activation of non-sensitizing or low-sensitizing fragrance substances into potent sensitizers - prehaptens and prohaptens. Contact Dermatitis 2013; 69:323-34. [DOI: 10.1111/cod.12127] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 06/25/2013] [Accepted: 06/29/2013] [Indexed: 12/01/2022]
Affiliation(s)
- Ann-Therese Karlberg
- Division of Dermatochemistry and Skin Allergy, Department of Chemistry and Molecular Biology; University of Gothenburg; SE-412 96 Gothenburg Sweden
| | - Anna Börje
- Division of Dermatochemistry and Skin Allergy, Department of Chemistry and Molecular Biology; University of Gothenburg; SE-412 96 Gothenburg Sweden
| | - Jeanne Duus Johansen
- National Allergy Research Centre, Department of Dermato-Allergology; Gentofte Hospital, University of Copenhagen; DK-2900 Hellerup Denmark
| | - Carola Lidén
- Institute of Environmental Medicine; Karolinska Institutet; SE-171 77 Stockholm Sweden
| | | | - David Roberts
- School of Pharmacy and Biomolecular Sciences; Liverpool John Moores University; Liverpool L3 3AF UK
| | - Wolfgang Uter
- Department of Medical Informatics, Biometry and Epidemiology; University Erlangen/Nürnberg; 91054 Erlangen Germany
| | - Ian R. White
- Department of Cutaneous Allergy; St John's Institute of Dermatology, St Thomas' Hospital; London SE1 7EH UK
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Uter W, Johansen JD, Börje A, Karlberg AT, Lidén C, Rastogi S, Roberts D, White IR. Categorization of fragrance contact allergens for prioritization of preventive measures: clinical and experimental data and consideration of structure-activity relationships. Contact Dermatitis 2013; 69:196-230. [DOI: 10.1111/cod.12117] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 05/17/2013] [Accepted: 05/21/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Wolfgang Uter
- Department of Medical Informatics, Biometry and Epidemiology; University of Erlangen/Nürnberg; 91054 Erlangen; Germany
| | - Jeanne D. Johansen
- Department of Dermato-Allergology, National Allergy Research Centre; Gentofte Hospital, University of Copenhagen; 2900 Hellerup; Denmark
| | - Anna Börje
- Department of Chemistry and Molecular Biology; University of Gothenburg; 41137 Gothenburg; Sweden
| | - Ann-Therese Karlberg
- Department of Chemistry and Molecular Biology; University of Gothenburg; 41137 Gothenburg; Sweden
| | - Carola Lidén
- Institute of Environmental Medicine; Karolinska Institutet; 17177 Stockholm; Sweden
| | | | - David Roberts
- Liverpool John Moores University; Liverpool, Merseyside L3 5UZ; UK
| | - Ian R. White
- Department of Cutaneous Allergy, St John's Institute of Dermatology; St Thomas' Hospital; London SE1 7EH; UK
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Abstract
The first total synthesis of the mitotic spindle poison nostodione A is described. The inherent oxidative sensitivity of indoles is utilized for a late introduction of a second carbonyl to the cyclopent[b]indole-2-one system. The tricyclic system is prepared from indole-3-acetic acid and O-silylated 4-ethynylphenol, using a stereoselective intramolecular reductive Heck cyclization as the key transformation.
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Affiliation(s)
- Andreas Ekebergh
- Department of Chemical and Biological Engineering/Organic Chemistry, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
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Karlsson I, Persson E, Mårtensson J, Börje A. Investigation of the Sunscreen Octocrylene’s Interaction with Amino Acid Analogs in the Presence of UV Radiation. Photochem Photobiol 2012; 88:904-12. [DOI: 10.1111/j.1751-1097.2012.01142.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Rudbäck J, Bergström MA, Börje A, Nilsson U, Karlberg AT. α-Terpinene, an Antioxidant in Tea Tree Oil, Autoxidizes Rapidly to Skin Allergens on Air Exposure. Chem Res Toxicol 2012; 25:713-21. [DOI: 10.1021/tx200486f] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Johanna Rudbäck
- Department of Chemistry and
Molecular Biology, Dermatochemistry and Skin Allergy, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Moa Andresen Bergström
- Department of Chemistry and
Molecular Biology, Dermatochemistry and Skin Allergy, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Anna Börje
- Department of Chemistry and
Molecular Biology, Dermatochemistry and Skin Allergy, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Ulrika Nilsson
- Department of Analytical Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ann-Therese Karlberg
- Department of Chemistry and
Molecular Biology, Dermatochemistry and Skin Allergy, University of Gothenburg, SE-412 96 Gothenburg, Sweden
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Hagvall L, Bäcktorp C, Norrby PO, Karlberg AT, Börje A. Experimental and Theoretical Investigations of the Autoxidation of Geranial: A Dioxolane Hydroperoxide Identified as a Skin Sensitizer. Chem Res Toxicol 2011; 24:1507-15. [DOI: 10.1021/tx200120q] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lina Hagvall
- Dermatochemistry and Skin Allergy, Department of Chemistry, University of Gothenburg, SE-412 96 Gothenburg, Sweden
- Department of Dermatology, Sahlgrenska Academy at the University of Gothenburg, SE-413 45 Gothenburg, Sweden
| | - Carina Bäcktorp
- Organic Chemistry, Department of Chemistry, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Per-Ola Norrby
- Organic Chemistry, Department of Chemistry, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Ann-Therese Karlberg
- Dermatochemistry and Skin Allergy, Department of Chemistry, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Anna Börje
- Dermatochemistry and Skin Allergy, Department of Chemistry, University of Gothenburg, SE-412 96 Gothenburg, Sweden
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Abstract
The first total synthesis of the dimeric alkaloid pigment scytonemin is described. The key transformations in its synthesis from 3-indole acetic acid are a Heck carbocyclization and a Suzuki-Miyaura cross-coupling, orchestrated in a stereospecific tandem fashion, followed by a biosynthetically inspired oxidative dimerization. The tandem sequence generates a tetracyclic (E)-3-(arylidene)-3,4-dihydrocyclopenta[b]indol-2(1H)-one that is subsequently dimerized into the unique homodimeric core structure of scytonemin.
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Affiliation(s)
- Andreas Ekebergh
- Department of Chemical and Biological Engineering/Organic Chemistry, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
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Karlsson I, Vanden Broecke K, Mårtensson J, Goossens A, Börje A. Clinical and experimental studies of octocrylene's allergenic potency. Contact Dermatitis 2011; 64:343-52. [DOI: 10.1111/j.1600-0536.2011.01899.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Johansson SGH, Emilsson K, Grøtli M, Börje A. Structural influence on radical formation and sensitizing capacity of alkylic limonene hydroperoxide analogues in allergic contact dermatitis. Chem Res Toxicol 2010; 23:677-88. [PMID: 20163165 DOI: 10.1021/tx900433n] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hydroperoxides are known to be strong contact allergens and a common cause of contact allergy. They are easily formed by the autoxidation of, for example, fragrance terpenes, compounds that are common in perfumes, cosmetics, and household products. A requirement of the immunological mechanisms of contact allergy is the formation of an immunogenic hapten-protein complex. For hydroperoxides, a radical mechanism is postulated for this formation. In our previous investigations of allylic limonene hydroperoxides, we found that the formation of carbon- and oxygen-centered radicals, as well as the sensitizing capacity, is influenced by the structure of the hydroperoxides. The aim of the present work was to further investigate the connection between structure, radical formation, and sensitizing capacity by studying alkylic analogues of the previously investigated allylic limonene hydroperoxides. The radical formation was studied in radical-trapping experiments employing 5,10,15,20-tetraphenyl-21H,23H-porphine iron(III) chloride as an initiator and 1,1,3,3-tetramethylisoindolin-2-yloxyl as a radical trapper. We found that the investigated hydroperoxides initially form carbon- and oxygen-centered radicals that subsequently form alcohols and ketones. Trapped carbon-centered radicals and nonradical products were isolated and identified. Small changes in structure, like the omission of the endocyclic double bond or the addition of a methyl group, resulted in large differences in radical formation. The results indicate that alkoxyl radicals seem to be more important than carbon-centered radicals in the immunogenic complex formation. The sensitizing capacities were studied in the murine local lymph node assay (LLNA), and all hydroperoxides tested were found to be potent sensitizers. For two of the hydroperoxides investigated, the recently suggested thiol-ene reaction is a possible mechanism for the formation of immunogenic complexes. For the third investigated, fully saturated, hydroperoxide, the thiol-ene mechanism is not possible for immunogenic complex formation. This strongly indicates that several radical reaction pathways for immunogenic complex formation of limonene hydroperoxides are active in parallel.
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Affiliation(s)
- Staffan G H Johansson
- Dermatochemistry and Skin Allergy and Medicinal Chemistry, Department of Chemistry, University of Gothenburg, SE-412 96 Gothenburg, Sweden
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Johansson S, Redeby T, Altamore TM, Nilsson U, Börje A. Mechanistic proposal for the formation of specific immunogenic complexes via a radical pathway: a key step in allergic contact dermatitis to olefinic hydroperoxides. Chem Res Toxicol 2010; 22:1774-81. [PMID: 19725554 DOI: 10.1021/tx9001435] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The widespread use of scented products causes an increase of allergic contact dermatitis to fragrance compounds in Western countries today. Many fragrance compounds are prone to autoxidation, forming hydroperoxides as their primary oxidation products. Hydroperoxides are known to be strong allergens and to form specific immunogenic complexes. However, the mechanisms for the formation of the immunogenic complexes are largely unknown. We have investigated this mechanism for (5R)-5-isopropenyl-2-methyl-2-cyclohexene-1-hydroperoxide (Lim-2-OOH) by studying the formation of adducts in the reaction between this hydroperoxide and 5,10,15,20-tetraphenyl-21H,23H-porphine iron(III) chloride (Fe(III)TPPCl) in the presence of protected cysteine (NAc-Cys-OMe) or glutathione (GSH). Isolated adducts originate from the addition of the thiol group of NAc-Cys-OMe over the carbon-carbon double bonds of carvone. Furthermore, adducts between NAc-Cys-OMe and carveol as well as between GSH and carvone have been identified. The formation of these adducts most likely proceeds via the radical thiol-ene mechanism. The addition of a terpene moiety to cysteine offers an explanation of the specificity of the immune response to structurally different hydroperoxides. These results also explain the lack of cross-reactivity between carvone and Lim-2-OOH. In conclusion, we propose that immunogenic complexes of olefinic hydroperoxides can be formed via the radical thiol-ene mechanism. These complexes will be specific for the individual olefinic hydroperoxides due to the inclusion of a terpene moiety derived from the hydroperoxide.
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Affiliation(s)
- Staffan Johansson
- Department of Chemistry, Dermatochemistry and Skin Allergy, University of Gothenburg, Gothenburg, Sweden
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Redeby T, Nilsson U, Altamore TM, Ilag L, Ambrosi A, Broo K, Börje A, Karlberg AT. Specific Adducts Formed through a Radical Reaction between Peptides and Contact Allergenic Hydroperoxides. Chem Res Toxicol 2009; 23:203-10. [DOI: 10.1021/tx9003352] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Theres Redeby
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Ulrika Nilsson
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Timothy M. Altamore
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Leopold Ilag
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Annalisa Ambrosi
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Kerstin Broo
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Anna Börje
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Ann-Therese Karlberg
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Department of Analytical Chemistry, Stockholm University, Stockholm, Sweden
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Karlsson I, Hillerström L, Stenfeldt AL, Mårtensson J, Börje A. Photodegradation of Dibenzoylmethanes: Potential Cause of Photocontact Allergy to Sunscreens. Chem Res Toxicol 2009; 22:1881-92. [DOI: 10.1021/tx900284e] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Isabella Karlsson
- Dermatochemistry and Skin Allergy, Department of Chemistry, University of Gothenburg, SE-412 96 Gothenburg, Sweden, and Department of Chemical and Biological Engineering/Organic Chemistry, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Lisa Hillerström
- Dermatochemistry and Skin Allergy, Department of Chemistry, University of Gothenburg, SE-412 96 Gothenburg, Sweden, and Department of Chemical and Biological Engineering/Organic Chemistry, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Anna-Lena Stenfeldt
- Dermatochemistry and Skin Allergy, Department of Chemistry, University of Gothenburg, SE-412 96 Gothenburg, Sweden, and Department of Chemical and Biological Engineering/Organic Chemistry, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Jerker Mårtensson
- Dermatochemistry and Skin Allergy, Department of Chemistry, University of Gothenburg, SE-412 96 Gothenburg, Sweden, and Department of Chemical and Biological Engineering/Organic Chemistry, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Anna Börje
- Dermatochemistry and Skin Allergy, Department of Chemistry, University of Gothenburg, SE-412 96 Gothenburg, Sweden, and Department of Chemical and Biological Engineering/Organic Chemistry, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
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Hagvall L, Sköld M, Bråred-Christensson J, Börje A, Karlberg AT. Lavender oil lacks natural protection against autoxidation, forming strong contact allergens on air exposure. Contact Dermatitis 2008; 59:143-50. [PMID: 18759894 DOI: 10.1111/j.1600-0536.2008.01402.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Lavender oil is an essential oil frequently used as a fragrance ingredient and in traditional herbal medicine. We have previously studied the effect of air oxidation on the skin sensitizing potency of the monoterpenes linalyl acetate, linalool and beta-caryophyllene, the main constituents of lavender oil. OBJECTIVE The aim of this study was to investigate if the autoxidation observed for the single synthetic terpenes, resulting in strong contact allergens, will take place also in lavender oil. METHODS Lavender oil was exposed to air and the autoxidation was followed by chemical analysis. The sensitizing potency before and after air exposure was investigated in mice using the local lymph node assay. Patients with patch test reactions to oxidized linalool were tested to investigate if air-exposed lavender oil could elicit dermatitis in these individuals. RESULTS The terpenes oxidized in air-exposed lavender oil at the same rates as the pure compounds exposed to air, and the same oxidation products were identified. The sensitizing potency of lavender oil increased accordingly on air exposure. Patch testing showed positive reactions to air-exposed lavender oil and also to oxidized linalyl acetate in patients with contact allergy to oxidized linalool. CONCLUSION This study shows that lavender oil lacks natural protection against autoxidation, and that air-exposed lavender oil can be an important source of exposure to allergenic hydroperoxides.
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Affiliation(s)
- Lina Hagvall
- Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, Gothenburg, Sweden
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Christensson JB, Johansson S, Hagvall L, Jonsson C, Börje A, Karlberg AT. Limonene hydroperoxide analogues differ in allergenic activity. Contact Dermatitis 2008; 59:344-52. [DOI: 10.1111/j.1600-0536.2008.01442.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Bäcktorp C, Börje A, Nilsson J, Karlberg AT, Norrby PO, Nyman G. Mechanisms of Air Oxidation of Ethoxylated Surfactants-Computational Estimations of Energies and Reaction Behaviors. Chemistry 2008; 14:9549-54. [DOI: 10.1002/chem.200800545] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Johansson S, Giménez-Arnau E, Grøtli M, Karlberg AT, Börje A. Carbon- and Oxygen-Centered Radicals Are Equally Important Haptens of Allylic Hydroperoxides in Allergic Contact Dermatitis. Chem Res Toxicol 2008; 21:1536-47. [DOI: 10.1021/tx800104c] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Staffan Johansson
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Institut de Chimie de Strasbourg (CNRS-ULP), Laboratoire de Dermatochimie, Clinique Dermatologique CHU, Strasbourg, France
| | - Elena Giménez-Arnau
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Institut de Chimie de Strasbourg (CNRS-ULP), Laboratoire de Dermatochimie, Clinique Dermatologique CHU, Strasbourg, France
| | - Morten Grøtli
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Institut de Chimie de Strasbourg (CNRS-ULP), Laboratoire de Dermatochimie, Clinique Dermatologique CHU, Strasbourg, France
| | - Ann-Therese Karlberg
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Institut de Chimie de Strasbourg (CNRS-ULP), Laboratoire de Dermatochimie, Clinique Dermatologique CHU, Strasbourg, France
| | - Anna Börje
- Department of Chemistry, Dermatochemistry and Skin Allergy, Medicinal Chemistry, University of Gothenburg, Gothenburg, Sweden, and Institut de Chimie de Strasbourg (CNRS-ULP), Laboratoire de Dermatochimie, Clinique Dermatologique CHU, Strasbourg, France
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Sköld M, Börje A, Harambasic E, Matura M, Karlberg AT. FS06.2
Autoxidation of linalool and impact on the sensitizing capacity and allergenicity. Contact Dermatitis 2008. [DOI: 10.1111/j.0105-1873.2004.0309bk.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Matura M, Sköld M, Börje A, Frosch P, Goossens A, White I, Bruze M, Menné T, Andersen K, Karlberg AT. FS06.1
Contact allergy to oxidized fragrance terpenes. Contact Dermatitis 2008. [DOI: 10.1111/j.0105-1873.2004.0309bj.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Karlberg AT, Bergström MA, Börje A, Luthman K, Nilsson JLG. Allergic contact dermatitis--formation, structural requirements, and reactivity of skin sensitizers. Chem Res Toxicol 2007; 21:53-69. [PMID: 18052130 DOI: 10.1021/tx7002239] [Citation(s) in RCA: 196] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Contact allergy is caused by a wide range of chemicals after skin contact. Its clinical manifestation, allergic contact dermatitis (ACD), is developed upon repeated contact with the allergen. This perspective focuses on two areas that have yielded new useful information during the last 20 years: (i) structure-activity relationship (SAR) studies of contact allergy based on the concept of hapten-protein binding and (ii) mechanistic investigations regarding activation of nonsensitizing compounds to contact allergens by air oxidation or skin metabolism. The second area is more thoroughly reviewed since the full picture has previously not been published. Prediction of the sensitizing capacity of a chemical is important to avoid outbreaks of ACD in the population. Much research has been devoted to the development of in vitro and in silico predictive testing methods. Today, no method exists that is sensitive enough to detect weak allergens and that is robust enough to be used for routine screening. To cause sensitization, a chemical must bind to macromolecules (proteins) in the skin. Expert systems containing information about the relationship between the chemical structure and the ability of chemicals to haptenate proteins are available. However, few designed SAR studies based on mechanistic investigations of prohaptens have been published. Many compounds are not allergenic themselves but are activated in the skin (e.g., metabolically) or before skin contact (e.g., via air oxidation) to form skin sensitizers. Thus, more basic research is needed on the chemical reactions involved in the antigen formation and the immunological mechanisms. The clinical importance of air oxidation to activate nonallergenic compounds has been demonstrated. Oxidized fragrance terpenes, in contrast to the pure terpenes, gave positive patch test reactions in consecutive dermatitis patients as frequently as the most common standard allergens. This shows the importance of using compounds to which people are exposed when screening for ACD in dermatology clinics.
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Affiliation(s)
- Ann-Therese Karlberg
- Dermatochemistry and Skin Allergy and Medical Chemistry, Department of Chemistry, Götegorg University, Göteborg, Sweden.
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Bäcktorp C, Hagvall L, Börje A, Karlberg AT, Norrby PO, Nyman G. Mechanism of Air Oxidation of the Fragrance Terpene Geraniol. J Chem Theory Comput 2007; 4:101-6. [DOI: 10.1021/ct7001495] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Carina Bäcktorp
- Department of Chemistry, Physical Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden, Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden, and Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
| | - Lina Hagvall
- Department of Chemistry, Physical Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden, Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden, and Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
| | - Anna Börje
- Department of Chemistry, Physical Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden, Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden, and Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
| | - Ann-Therese Karlberg
- Department of Chemistry, Physical Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden, Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden, and Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
| | - Per-Ola Norrby
- Department of Chemistry, Physical Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden, Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden, and Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
| | - Gunnar Nyman
- Department of Chemistry, Physical Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden, Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden, and Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
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Karlberg AT, Bråred-Christensson J, Börje A, Harambasic E, Matura M. Methyl esterification of 15-hydroperoxyabietic acid does not affect the patch-test result in colophonium allergic patients. Contact Dermatitis 2007; 56:355-6. [PMID: 17577378 DOI: 10.1111/j.1600-0536.2006.01037.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Colophonium (gum rosin) consists of numerous compounds. We have previously shown that abietic acid (Fig. 1), the major compound in gum rosin, is oxidized to strong contact allergens at air exposure (1). The most potent allergen identified is 15-hydroperoxyabietic acid (15-HPA, Fig. 1), which was isolated as its methyl ester (Fig. 1) and used for patch testing (2, 3). The aim of this study was to confirm the previous postulate that methyl esterification of the carboxyl group in 15-HPA does not affect the allergenic activity.
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Affiliation(s)
- Ann-Therese Karlberg
- Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, Göteborg, Sweden.
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Hagvall L, Bäcktorp C, Svensson S, Nyman G, Börje A, Karlberg AT. Fragrance compound geraniol forms contact allergens on air exposure. Identification and quantification of oxidation products and effect on skin sensitization. Chem Res Toxicol 2007; 20:807-14. [PMID: 17428070 DOI: 10.1021/tx700017v] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fragrances are common causes of contact allergy. Geraniol (trans-3,7-dimethyl-2,6-octadiene-1-ol) is an important fragrance terpene. It is considered a weak contact allergen and is used for fragrance allergy screening among consecutive dermatitis patients. Analogous to other monoterpenes studied, such as limonene and linalool, geraniol has the potential to autoxidize on air exposure and form highly allergenic compounds. The aim of the present study was to investigate and propose a mechanism for the autoxidation of geraniol at room temperature. To investigate whether allergenic compounds are formed, the sensitizing potency of geraniol itself, air-exposed geraniol, and its oxidation products was determined using the local lymph node assay in mice. The results obtained show that the allylic alcohol geraniol follows an oxidation pattern different from those of linalool and limonene, which autoxidize forming hydroperoxides as the only primary oxidation products. The autoxidation of geraniol follows two paths, originating from allylic hydrogen abstraction near the two double bonds. From geraniol, hydrogen peroxide is primarily formed together with aldehydes geranial and neral from a hydroxyhydroperoxide. In addition, small amounts of a hydroperoxide are formed, analogous to the formation of the major linalool hydroperoxide. The autoxidation of geraniol greatly influenced the sensitizing effect of geraniol. The oxidized samples had moderate sensitizing capacity, quite different from that of pure geraniol. The hydroperoxide formed is believed to be the major contributor to allergenic activity, together with the aldehydes geranial and neral. On the basis of the present study and previous experience, we recommend that the possibility of autoxidation and the subsequent formation of contact allergenic oxidation products are considered in risk assessments performed on fragrance terpenes.
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Affiliation(s)
- Lina Hagvall
- Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden
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Matura M, Sköld M, Börje A, Andersen KE, Bruze M, Frosch P, Goossens A, Johansen JD, Svedman C, White IR, Karlberg AT. Not only oxidized R-(+)- but also S-(?)-limonene is a common cause of contact allergy in dermatitis patients in Europe. Contact Dermatitis 2006; 55:274-9. [PMID: 17026692 DOI: 10.1111/j.1600-0536.2006.00939.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Limonene, one of the most often used fragrance terpenes in any kind of scented products, is prone to air-oxidation. The oxidation products formed have a considerable sensitizing potential. In previous patch test studies on consecutively tested dermatitis patients, oxidized R-limonene has been proven to be a good and frequent indicator of fragrance-related contact allergy. The current study extends these investigations to 6 European clinics of dermatology, where the oxidation mixture of both enantiomers of limonene (R and S) have been tested in 2411 dermatitis patients. Altogether, 63 out of 2411 patients tested (2.6%) reacted to 1 or both the oxidized limonene preparations. Only 2.3% reacted to the oxidized R-limonene and 2.0% to the oxidized S-limonene. In 57% of the cases, simultaneous reactions were observed to both oxidation mixtures. Concomitant reactions to the fragrance mix, colophonium, Myroxylon pereirae, and fragrance-related contact allergy were common in patients reacting to 1 or both the oxidized limonene enantiomers. Our study provides clinical evidence for the importance of oxidation products of limonene in contact allergy. It seems advisable to screen consecutive dermatitis patients with oxidized limonene 3% petrolatum, although this patch test material is not yet commercially available.
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Affiliation(s)
- Mihaly Matura
- Dermatochemistry and Skin Allergy, Department of Chemistry, Göteborg University, Gothenburg, Sweden.
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Abstract
This study concerns the autoxidation of one of the most used fragrances in daily life, linalool (3,7-dimethyl-1,6-octadien-3-ol). It reacts with O2 to form hydroperoxides, which are known to be important contact allergens. Pathways for hydroperoxide formation are investigated by means of quantum mechanical electronic structure calculations. Optimized molecular geometries and harmonic vibrational frequencies are determined using density functional theory (DFT). Insight into how the addition of O2 to linalool occurs is obtained by establishing a theoretical framework and systematically investigating three smaller systems: propene, 2-methyl-2-butene, and 2-methyl-2-pentene. 2-Methyl-2-pentene was chosen as a model system and used to compare with linalool. This theoretical study characterizes the linalool-O2 biradical intermediate state, which constitutes a branching point for the further oxidation reactions pathways. Thus, the observed linalool oxidation product spectrum is discussed in terms of a direct reaction path, the ene-type mechanism, and the radical mechanism. The major hydroperoxide found in experiments is 7-hydroperoxy-3,7-dimethyl-octa-1,5-diene-3-ol, and the calculated results support this finding.
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Affiliation(s)
- Carina Bäcktorp
- Department of Chemistry, Physical Chemistry, Electrochemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden.
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Abstract
Concomitant positive reactions to colophonium, oxidized limonene, and/or oxidized linalool are recorded in patch test studies. The main allergens in these patch test mixtures are hydroperoxides, which form antigens by a radical pathway. Theoretically, concomitant reactions can be explained not only by concomitant sensitization or by true cross-reactions but also by the hydroperoxides acting as oxidizing agents on skin proteins to form non-specific antigens without hapten-protein binding. The aim of this study was to explore concomitant reactions and cross-reactivity patterns among hydroperoxide haptens. We investigated whether individuals allergic to the main allergen in colophonium, 15-hydroperoxyabietic acid, would also react to limonene hydroperoxide or linalool hydroperoxide. Only 1 of 29 individuals reacted to more than 1 hydroperoxide. The cross-reactivity pattern among cumene hydroperoxide, limonene hydroperoxide, 1-(1-hydroperoxy-1-methylethyl) cyclohexene (cyclohexene hydroperoxide), and 15-hydroperoxydehydroabietic acid was investigated in guinea-pigs. No general cross-reactivity was observed. Cross-reactions between cumene hydroperoxide and cyclohexene hydroperoxide show that similarity in the overall structure and the way of antigen formation are needed. Quantum calculations were used to determine the formation energies of the intermediary radicals. We concluded that hydroperoxides form specific antigens and that formation of non-specific antigens is unlikely. The concomitant patch test reactions described in the literature are best explained as a result of multiple sensitizations.
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Sköld M, Karlberg AT, Matura M, Börje A. The fragrance chemical beta-caryophyllene-air oxidation and skin sensitization. Food Chem Toxicol 2005; 44:538-45. [PMID: 16226832 DOI: 10.1016/j.fct.2005.08.028] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Revised: 08/08/2005] [Accepted: 08/31/2005] [Indexed: 11/24/2022]
Abstract
Fragrances are common causes of allergic contact dermatitis. beta-Caryophyllene is a sesquiterpene that is used as a fragrance chemical. Analogous to the monoterpenes R-limonene and linalool, it can be expected to autoxidize when air exposed. The aim of the present study was to investigate the autoxidation of beta-caryophyllene and to evaluate the effect on the contact allergenic activity. beta-Caryophyllene started to oxidize immediately when air exposed and after 5 weeks almost 50% of the original compound was consumed. Caryophyllene oxide was found to be the major oxidation product. Hydroperoxides of beta-caryophyllene could not be detected in the oxidation mixture. Caryophyllene oxide was shown to be an allergen of moderate strength and beta-caryophyllene air exposed for 10 weeks showed a weak sensitizing capacity in the local lymph node assay. The study reveals that the allergenic activity of beta-caryophyllene is affected by autoxidation, but to a lesser extent when compared to R-limonene and linalool. The present findings support our results in clinical studies showing oxidized beta-caryophyllene to be a rather rare sensitizer compared to oxidized R-limonene and linalool.
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Affiliation(s)
- Maria Sköld
- Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden
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Matura M, Sköld M, Börje A, Andersen KE, Bruze M, Frosch P, Goossens A, Johansen JD, Svedman C, White IR, Karlberg AT. Selected oxidized fragrance terpenes are common contact allergens. Contact Dermatitis 2005; 52:320-8. [PMID: 15932583 DOI: 10.1111/j.0105-1873.2005.00605.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Terpenes are widely used fragrance compounds in fine fragrances, but also in domestic and occupational products. Terpenes oxidize easily due to autoxidation on air exposure. Previous studies have shown that limonene, linalool and caryophyllene are not allergenic themselves but readily form allergenic products on air-exposure. This study aimed to determine the frequency and characteristics of allergic reactions to selected oxidized fragrance terpenes other than limonene. In total 1511 consecutive dermatitis patients in 6 European dermatology centres were patch tested with oxidized fragrance terpenes and some oxidation fractions and compounds. Oxidized linalool and its hydroperoxide fraction were found to be common contact allergens. Of the patients tested, 1.3% showed a positive reaction to oxidized linalool and 1.1% to the hydroperoxide fraction. About 0.5% of the patients reacted to oxidized caryophyllene whereas 1 patient reacted to oxidized myrcene. Of the patients reacting to the oxidized terpenes, 58% had fragrance-related contact allergy and/or a positive history for adverse reaction to fragrances. Autoxidation of fragrance terpenes contributes greatly to fragrance allergy, which emphasizes the need of testing with compounds that patients are actually exposed to and not only with the ingredients originally applied in commercial formulations.
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Affiliation(s)
- Mihaly Matura
- Dermatochemistry and Skin Allergy, Department of Chemistry, Göteborg University, Gothenburg, Sweden.
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Sköld M, Börje A, Harambasic E, Karlberg AT. Contact Allergens Formed on Air Exposure of Linalool. Identification and Quantification of Primary and Secondary Oxidation Products and the Effect on Skin Sensitization. Chem Res Toxicol 2004; 17:1697-705. [PMID: 15606147 DOI: 10.1021/tx049831z] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Linalool (3,7-dimethyl-1,6-octadien-3-ol) is an important fragrance chemical, frequently used in scented products because of its fresh, flowery odor. Linalool is an unsaturated hydrocarbon and is therefore susceptible to oxidation in the presence of air. The primary oxidation products, that is, hydroperoxides, formed in the autoxidation process, are reactive compounds that can be suspected to act as sensitizers. In the present investigation, we studied the autoxidation of linalool with emphasis on the formation of hydroperoxides. The oxidation products were isolated using flash chromatography and preparative HPLC and were identified with NMR and GC/MS, using synthesized reference compounds. Two hydroperoxides and several different secondary oxidation products were identified, among which some contain structural features that make them potential allergens. The amounts of linalool and the major oxidation products were quantified over time, using GC and an HPLC-method, suitable for the analysis of thermolabile primary oxidation products. The hydroperoxide 7-hydroperoxy-3,7-dimethylocta-1,5-diene-3-ol was found to be present in 15% in an oxidized sample. The local lymph node assay (LLNA) was used to investigate the sensitizing potential of pure linalool, two samples of air-exposed linalool, and oxidation products of linalool (an alpha,beta-unsaturated aldehyde, a mixture of two hydroperoxides, and an alcohol). Pure linalool showed no sensitizing potential. The air-exposed samples of linalool produced clearly positive responses, and the hydroperoxides were the strongest allergens of the tested oxidation products. The study demonstrates the importance of autoxidation on the sensitizing potential of linalool. We also conclude that the sensitizing potential differs with the composition of the oxidation mixture and thus with the air exposure time.
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Affiliation(s)
- Maria Sköld
- Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden
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Akermark B, Bjernemose J, Börje A, Chmielewski PJ, Paulsen H, Simonsen O, Stein PC, Toftlund H, Wolny JA. Strain-induced substitutional lability in a Ru(ii) complex of a hypodentate polypyridine ligand. Dalton Trans 2004:1215-20. [PMID: 15252663 DOI: 10.1039/b316093a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ruthenium(II) complex of heptadentate N,N,N',N'-tetrakis(2-pyridylmethyl)-2,6-bis(aminomethyl)pyridine (tpap) was isolated as the hexafluorophosphate complex Ru(tpap)(PF6)2. The crystal structure has been determined for the triflate salt Ru(tpap)(CF3SO3)2.2H2O, which crystallizes in the monoclinic space group P2(1)/n. The structure was refined to a final R value of 0.0549 for 5894 observed reflections. The heptadentate ligand coordinates with six nitrogens, i.e. with two tertiary nitrogens and four pyridine nitrogens, one of the pyridines remaining un-coordinated. The resulting structure is significantly distorted from octahedral geometry with an equatorial Nsp3-Ru-Npyridine angle of 120 degrees. The consequence of the above steric strain is a labilization of the system and fluxional behaviour involving exchange between equatorially coordinated and non-coordinated pyridines has been observed by 1H NMR for Ru(tpap)(PF6)2 in d6-acetone solution. The activation parameters of DeltaG(not equal to 298) = 53 kJ mol(-1), DeltaH(not equal) = 56 +/- 1 kJ mol(-1) and DeltaS(not equal) = -10 +/- 3 J mol(-1) K(-1) were determined on the basis of NMR experiments. In addition electronic structure calculations applying density functional theory (DFT) have been performed in order to identify a transition state and to estimate the activation barrier. On the basis of NMR and DFT results the mechanism of isoexchange involving a hepta-coordinated intermediate has been proposed.
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Affiliation(s)
- Björn Akermark
- Stockholms Universitet, Organisk Kemi, Arrheniuslaboratoriet, 106 91 Stockholm, Sweden
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Sköld M, Börje A, Matura M, Karlberg AT. Studies on the autoxidation and sensitizing capacity of the fragrance chemical linalool, identifying a linalool hydroperoxide. Contact Dermatitis 2002; 46:267-72. [PMID: 12084079 DOI: 10.1034/j.1600-0536.2002.460504.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Fragrances are among the most common causes of allergic contact dermatitis. The two monoterpenes linalool and d-limonene are the most frequently incorporated fragrance chemicals in scented products. Previous studies on d-limonene show that this monoterpene oxidizes on air exposure (autoxidation) and that allergenic oxidation products are formed. Due to structural similarities, linalool might also form allergenic oxidation products on air exposure. The aim of the present study was to study the autoxidation of linalool and to investigate the sensitizing potential of linalool before and after air exposure. Linalool was oxidized for 10 weeks and gas chromatographic analyses showed that the content of linalool decreased to about 80%. The chromatograms revealed the formation of other compounds during oxidation. One of the major oxidation products was isolated and identified as 7-hydroperoxy-3,7-dimethyl-octa-1,5-diene-3-ol. This substance is, to the best of our knowledge, described for the first time. In sensitization studies in guinea pigs, linalool of high purity gave no reactions, while linalool that had been oxidized for 10 weeks sensitized the animals. It is concluded that autoxidation of linalool is essential for its sensitizing potential.
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Affiliation(s)
- Maria Sköld
- Occupational Dermatology, National Institute for Working Life, Stockholm, Sweden
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Börje A, Köthe O, Juris A. New luminescent and redox-active mono- and polynuclear ruthenium(ii) and osmium(ii) polypyridine complexes. ACTA ACUST UNITED AC 2002. [DOI: 10.1039/b108915c] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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39
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Éll AH, Jonsson SY, Börje A, Adolfsson H, Bäckvall JE. Vanadyl acetylacetonate as peroxide activator in osmium-catalyzed dihydroxylation of olefins by hydrogen peroxide. Tetrahedron Lett 2001. [DOI: 10.1016/s0040-4039(01)00192-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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40
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Börje A, Köthe O, Juris A. A new bridging ligand for the synthesis of luminescent polynuclear Ru(II) and Os(II) polypyridine complexes. NEW J CHEM 2001. [DOI: 10.1039/b008927n] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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41
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Norrby T, Börje A, Zhang L, Åkermark B, Wagenknecht JH, Francis GW, Szúnyog J, Långström B. Regioselective Functionalization of 2,2'-Bipyridine and Transformations into Unsymmetric Ligands for Coordination Chemistry. ACTA ACUST UNITED AC 1998. [DOI: 10.3891/acta.chem.scand.52-0077] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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42
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Norrby T, Börje A, Åkermark B, Hammarström L, Alsins J, Lashgari K, Norrestam R, Mårtensson J, Stenhagen G. Synthesis, Structure, and Photophysical Properties of Novel Ruthenium(II) Carboxypyridine Type Complexes. Inorg Chem 1997; 36:5850-5858. [PMID: 11670208 DOI: 10.1021/ic9705812] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A series of Ru(II) compounds and salts have been synthesized: [Ru(6-carboxylato-bpy)(2)] (5), [Ru(6-carboxylato-bpy)(tpy)]PF(6) (9), [Ru(tpy)(2)](PF(6))(2) (8), and [Ru(bpy)(2)(Pic)]PF(6) (11), where 6-carboxy-bpy (1) = 6-carboxy-2,2'-bipyridine, tpy (2) = 2,2':6',2"-terpyridine, and Pic = 2-carboxylatopyridine. The compounds have been characterized by NMR, electrospray mass spectrometry (ESI-MS), cyclic voltammetry, absorption and emission spectroscopy (at 100, 140, and 298 K), and single-crystal X-ray diffraction (complex 5). Complex 5 crystallizes in the monoclinic system, space group P2(1)/n, formula RuC(22)H(14)N(4)O(4).C(2)H(5)OH, with a = 11.088(3) Å, b = 11.226(3) Å, c = 35.283(9) Å, beta = 91.41(2) degrees, and Z = 8. A linear dependence on the number of coordinated carboxylato groups and the electrochemical redox potentials was found, ca. 0.4 V lower reduction potential for the oxidation step (Ru(II/III)) per carboxylate group. Also, to the best of our knowledge, these are the first examples (9, 11) of mononuclear Ru(II) complexes containing a carboxypyridine-ruthenium moiety displaying any luminescence emission.
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Affiliation(s)
- Thomas Norrby
- Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
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Sun L, Berglund H, Davydov R, Norrby T, Hammarström L, Korall P, Börje A, Philouze C, Berg K, Tran A, Andersson M, Stenhagen G, Mårtensson J, Almgren M, Styring S, Åkermark B. Binuclear Ruthenium−Manganese Complexes as Simple Artificial Models for Photosystem II in Green Plants. J Am Chem Soc 1997. [DOI: 10.1021/ja962511k] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Licheng Sun
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Helena Berglund
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Roman Davydov
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Thomas Norrby
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Leif Hammarström
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Peter Korall
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Anna Börje
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Christian Philouze
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Katja Berg
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Anh Tran
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Michael Andersson
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Gunnar Stenhagen
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Jerker Mårtensson
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Mats Almgren
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Stenbjörn Styring
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
| | - Björn Åkermark
- Contribution from the Department of Chemistry, Organic Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Department of Physical Chemistry, Uppsala University, P.O. Box 532, S-751 21 Uppsala, Sweden, Department of Biochemistry, Center for Chemistry and Chemical Engineering, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden, and Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden
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Korall P, Börje A, Norrby PO, Åkermark B, Robinson WT, Wood BR, Robinson WT, Roos BO, Vallance C, Wood BR. High Yield Preparation of 4'-(4-Bromophenyl)-2,2':6',2"-terpyridine by a Condensation Reaction. Determination of the Stereochemistry of Two Complex By-products by a Combination of Molecular Mechanics and NMR Spectroscopy. ACTA ACUST UNITED AC 1997. [DOI: 10.3891/acta.chem.scand.51-0760] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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45
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Sun L, Hammarström L, Norrby T, Berglund H, Davydov R, Andersson M, Börje A, Korall P, Philouze C, Almgren M, Styring S, Åkermark B. Intramolecular electron transfer from coordinated manganese(ii) to photogenerated ruthenium(iii). Chem Commun (Camb) 1997. [DOI: 10.1039/a700100b] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Noréus D, Törnroos K, Börje A, Szabò T, Bronger W, Spittank H, Auffermann G, Müller P. Na2PdH2, a hydride with a novel linear [PdH2] complex. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/0022-5088(88)90004-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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