Structure-activity relationships in the inhibition of monoamine oxidase B by 1-methyl-3-phenylpyrroles
Date
2008Author
Ogunrombi, Modupe O.
Malan, Sarel F.
Terre'Blanche, Gisella
Bergh, Jacobus J.
Petzer, Jacobus P.
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Show full item recordAbstract
1-Methyl-3-phenyl-3-pyrrolines are structural analogues of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and like MPTP are selective substrates of monoamine oxidase B (MAO-B). As part of an ongoing investigation into the substrate properties of various 1-methyl-3-phenyl-3-pyrrolinyl derivatives, it is shown in the present study that their respective MAO-B catalyzed oxidation products act as reversible competitive inhibitors of the enzyme. The most potent inhibitor among the oxidation products considered was 1-methyl-3-(4-trifluoromethylphenyl)pyrrole with an enzyme-inhibitor dissociation constant (Ki value) of 1.30 μM. The least potent inhibitor was found to be 1-methyl-3-phenylpyrrole with a Ki value of 118 μM. The results of an SAR study established that the potency of MAO-B inhibition by the 1-methyl-3-phenylpyrrolyl derivatives examined here is dependent on the Taft steric parameter (Es) and Swain–Lupton electronic constant (F) of the substituents attached to C-4 of the phenyl ring. Electron-withdrawing substituents with a large degree of steric bulkiness appear to enhance inhibition potency. Potency was also found to vary with the substituents at C-3, again with Es and F being the principal substituent descriptors
URI
http://hdl.handle.net/10394/2700https://www.sciencedirect.com/science/article/pii/S0968089607010280
https://doi.org/10.1016/j.bmc.2007.11.059
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