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Chang P, Zuckermann AME, Williams S, Close AJ, Cano-Jaimez M, McEvoy JP, Spencer J, Walker MC, Williams RSB. Seizure control by derivatives of medium chain fatty acids associated with the ketogenic diet show novel branching-point structure for enhanced potency. J Pharmacol Exp Ther 2014; 352:43-52. [PMID: 25326131 DOI: 10.1124/jpet.114.218768] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The medium chain triglyceride (MCT) ketogenic diet is a major treatment of drug-resistant epilepsy but is problematic, particularly in adults, because of poor tolerability. Branched derivatives of octanoic acid (OA), a medium chain fat provided in the diet have been suggested as potential new treatments for drug-resistant epilepsy, but the structural basis of this functionality has not been determined. Here we investigate structural variants of branched medium chain fatty acids as new seizure-control treatments. We initially employ a series of methyl-branched OA derivatives, and using the GABAA receptor antagonist pentylenetetrazol to induce seizure-like activity in rat hippocampal slices, we show a strong, branch-point-specific activity that improves upon the related epilepsy treatment valproic acid. Using low magnesium conditions to induce glutamate excitotoxicity in rat primary hippocampal neuronal cultures for the assessment of neuroprotection, we also show a structural dependence identical to that for seizure control, suggesting a related mechanism of action for these compounds in both seizure control and neuroprotection. In contrast, the effect of these compounds on histone deacetylase (HDAC) inhibition, associated with teratogenicity, shows no correlation with therapeutic efficacy. Furthermore, small structural modifications of the starting compounds provide active compounds without HDAC inhibitory effects. Finally, using multiple in vivo seizure models, we identify potent lead candidates for the treatment of epilepsy. This study therefore identifies a novel family of fatty acids, related to the MCT ketogenic diet, that show promise as new treatments for epilepsy control and possibly other MCT ketogenic diet-responding conditions, such as Alzheimer disease.
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Affiliation(s)
- Pishan Chang
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom (P.C., A.M.E.Z., J.P.M., R.S.B.W.); Department of Chemistry, School of Life Sciences, University of Sussex, Falmer, United Kingdom (A.J.C., J.S.); and Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, United Kingdom (S.W., M.C.-J., M.C.W.)
| | - Alexandra M E Zuckermann
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom (P.C., A.M.E.Z., J.P.M., R.S.B.W.); Department of Chemistry, School of Life Sciences, University of Sussex, Falmer, United Kingdom (A.J.C., J.S.); and Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, United Kingdom (S.W., M.C.-J., M.C.W.)
| | - Sophie Williams
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom (P.C., A.M.E.Z., J.P.M., R.S.B.W.); Department of Chemistry, School of Life Sciences, University of Sussex, Falmer, United Kingdom (A.J.C., J.S.); and Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, United Kingdom (S.W., M.C.-J., M.C.W.)
| | - Adam J Close
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom (P.C., A.M.E.Z., J.P.M., R.S.B.W.); Department of Chemistry, School of Life Sciences, University of Sussex, Falmer, United Kingdom (A.J.C., J.S.); and Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, United Kingdom (S.W., M.C.-J., M.C.W.)
| | - Marife Cano-Jaimez
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom (P.C., A.M.E.Z., J.P.M., R.S.B.W.); Department of Chemistry, School of Life Sciences, University of Sussex, Falmer, United Kingdom (A.J.C., J.S.); and Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, United Kingdom (S.W., M.C.-J., M.C.W.)
| | - James P McEvoy
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom (P.C., A.M.E.Z., J.P.M., R.S.B.W.); Department of Chemistry, School of Life Sciences, University of Sussex, Falmer, United Kingdom (A.J.C., J.S.); and Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, United Kingdom (S.W., M.C.-J., M.C.W.)
| | - John Spencer
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom (P.C., A.M.E.Z., J.P.M., R.S.B.W.); Department of Chemistry, School of Life Sciences, University of Sussex, Falmer, United Kingdom (A.J.C., J.S.); and Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, United Kingdom (S.W., M.C.-J., M.C.W.)
| | - Matthew C Walker
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom (P.C., A.M.E.Z., J.P.M., R.S.B.W.); Department of Chemistry, School of Life Sciences, University of Sussex, Falmer, United Kingdom (A.J.C., J.S.); and Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, United Kingdom (S.W., M.C.-J., M.C.W.)
| | - Robin S B Williams
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom (P.C., A.M.E.Z., J.P.M., R.S.B.W.); Department of Chemistry, School of Life Sciences, University of Sussex, Falmer, United Kingdom (A.J.C., J.S.); and Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, United Kingdom (S.W., M.C.-J., M.C.W.)
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Eddington ND, Cox DS, Roberts RR, Butcher RJ, Edafiogho IO, Stables JP, Cooke N, Goodwin AM, Smith CA, Scott KR. Synthesis and anticonvulsant activity of enaminones. 4. Investigations on isoxazole derivatives. Eur J Med Chem 2002; 37:635-48. [PMID: 12161061 DOI: 10.1016/s0223-5234(02)01377-6] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Due to the exceptional anticonvulsant activity displayed by substituted aniline enaminones, related pyridine derivatives and phenothiazines synthesised in our laboratories, the further investigation of various aromatic heterocycles was undertaken. Condensation of cyclic 1,3-diketo esters with 3-, and 5-aminoisoxazole derivatives led to a series of potent anti-maximal electroshock (MES) analogues, three of which occurred in the 3-amino series: ethyl ester (10), orally (po) active in rats [ED(50) 68.9 mg kg(-1), TD(50) > 500 mg kg(-1), protective index (PI = TD(50)/ED(50)) > 49.6]; methyl ester (9), ED(50) 68.9 mg kg(-1) intraperitoneally (ip) in mice, TD(50) > 500 mg kg(-1), PI > 7.3, and tert-butyl ester (8), ED(50) 28.1 mg kg(-1) po in rats, TD(50) > 500 mg kg(-1), PI > 17.8. Sodium channel binding studies, as well as evaluations against pentylenetetrazol, bicuculline, and picrotoxin on isoxazole 10 were all negative, leading to an unknown mechanism of action. X-ray diffraction patterns of a representative of the 3-amino series (isoxazoles 6-11) unequivocally display the existence of intramolecular hydrogen bonding of the nitrogen to the vinylic proton in the cyclohexene ring, providing a pseudo three ring structure which was also shown previously with the vinylic benzamides. Physicochemical-permeability across the BBB suggested an efflux mechanism for the previously synthesised aniline enaminones, but not with isoxazole 10.
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Affiliation(s)
- Natalie D Eddington
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201-4403, USA
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