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Scavenging of hydroxyl radical by catecholamines
Author(s) -
Kładna Aleksandra,
Berczyński Paweł,
Kruk Irena,
Michalska Teresa,
AboulEnein Hassan Y.
Publication year - 2012
Publication title -
luminescence
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.428
H-Index - 45
eISSN - 1522-7243
pISSN - 1522-7235
DOI - 10.1002/bio.1377
Subject(s) - chemistry , radical , cats , hydroxyl radical , dpph , reactivity (psychology) , dopamine , reaction rate constant , polyphenol , medicinal chemistry , kinetics , nuclear chemistry , antioxidant , organic chemistry , medicine , alternative medicine , pathology , physics , quantum mechanics
ABSTRACT The direct effects of the four catecholamines (CATs), adrenaline (A), noradrenaline (NA), dopamine (D) and isoproterenol (I), on free radicals were investigated using the free radical 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH • ) and hydroxyl radial (HO • ). The CATs examined were found to inhibit the ESR signal intensity of DPPH • in a dose‐dependent manner over the range 0.1–2.5 mmol/L in the following order: NA > A > I > D, with IC 50 = 0.30 ± 0.03 for noradrenaline and IC 50 = 0.86 ± 0.02 for dopamine. Hydroxyl radicals were produced using a Fenton reaction in the presence of the spin trap 5,5‐dimethyl‐1‐pyrroline N ‐oxide (DMPO), and ESR technique was applied to detect the CATs reactivity toward the radicals. The reaction rates constant ( k r ) of CATs with HO • were found to be in the order of 10 9 L/mol/s, and the k r value for noradrenaline was the highest ( k r = 8.4 × 10 9 L/mol/s). The CATs examined exhibited also a strong decrease in the light emission (62–73% at 1 mmol/L concentration and 79–89% at 2 mmol/L concentration) from a Fenton‐like reaction. These reactions may be relevant to the biological action of these important polyphenolic compounds. Copyright © 2012 John Wiley & Sons, Ltd.