Radical Scavenging Reactivity of Catecholamine Neurotransmitters and the Inhibition Effect for DNA Cleavage
- 25 November 2009
- journal article
- Published by American Chemical Society (ACS) in The Journal of Physical Chemistry B
- Vol. 114 (1), 675-680
- https://doi.org/10.1021/jp909314t
Abstract
Neurotransmitters such as catecholamines (dopamine, l-dopa, epinephrine, norepinephrine) have phenol structure and scavenge reactive oxygen species (ROS) by hydrogen atom transfer (HAT) to ROS. Radical scavenging reactivity of neurotransmitters with galvinoxyl radical (GO•) and cumyloxyl radical (RO•) in acetonitrile at 298 K was determined by the UV−vis spectral change. The UV−vis spectral change for HAT from catecholamine neurotransmitters to GO• was measured by a photodiode array spectrophotometer, whereas HAT to much more reactive cumylperoxyl radical, which was produced by photoirradiation of dicumyl peroxide, was measured by laser flash photolysis. The second-order rate constants (kGO) were determined from the slopes of linear plots of the pseudo-first-order rate constants vs concentrations of neurotransmitters. The kGO value of hydrogen transfer from dopamine to GO• was determined to be 23 M−1 s−1, which is the largest among examined catecholamine neurotransmitters. This value is comparable to the value of a well-known antioxidant: (+)-catechine (27 M−1 s−1). The kGO value of hydrogen transfer from dopamine to GO• increased in the presence of Mg2+ with increasing concentration of Mg2+. Such enhancement of the radical scavenging reactivity may result from the metal ion-promoted electron transfer from dopamine to the galvinoxyl radical. Inhibition of DNA cleavage with neurotransmitters was also examined using agarose gel electrophoresis of an aqueous solution containing pBR322 DNA, NADH, and catecholamine neurotransmitters under photoirradiation. DNA cleavage was significantly inhibited by the presence of catecholamine neurotransmitters that can scavenge hydroperoxyl radicals produced under photoirradiation of an aerated aqueous solution of NADH. The inhibition effect of dopamine on DNA cleavage was enhanced by the presence of Mg2+ because of the enhancement of the radical scavenging reactivity.Keywords
This publication has 60 references indexed in Scilit:
- Role of reactive nitrogen and reactive oxygen species against MPTP neurotoxicity in miceJournal of Neural Transmission, 2008
- Reactivity of adrenaline toward alkoxyl radicals and carbonyl triplet statesOrganic & Biomolecular Chemistry, 2008
- DNA Cleavage by UVA Irradiation of NADH with Dioxygen via Radical Chain ProcessesThe Journal of Physical Chemistry A, 2006
- Hydrogen abstraction from neurotransmitters by active oxygen species facilitated by intramolecular hydrogen bonding in the radical intermediatesOrganic & Biomolecular Chemistry, 2006
- Inhibition of rat brain mitochondrial electron transport chain activity by dopamine oxidation products during extended in vitro incubation: Implications for Parkinson's diseaseBiochimica et Biophysica Acta (BBA) - Molecular Basis of Disease, 2005
- Mechanisms of Hydrogen-, Oxygen-, and Electron-Transfer Reactions of Cumylperoxyl RadicalJournal of the American Chemical Society, 2003
- Chemical behavior of oxygen-radical: quenching process of cumyloxyl radical by nicotinamide derivativesJournal of Photochemistry and Photobiology A: Chemistry, 2001
- Quantitative Evaluation of Lewis Acidity of Metal Ions Derived from theg Values of ESR Spectra of Superoxide: Metal Ion Complexes in Relation to the Promoting Effects in Electron Transfer ReactionsChemistry – A European Journal, 2000
- Effect of magnesium ion distinguishing between one-step hydrogen- and electron-transfer mechanisms for the reduction of stable neutral radicals by NADH analoguesJournal of the Chemical Society, Chemical Communications, 1993
- Antioxidant activities of probucol against lipid peroxidationsBiochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism, 1992