1. Antioxidant properties and free radical-scavenging reactivity of a family of hydroxynaphthalenones and dihydroxyanthracenones
- Author
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Claudio Olea-Azar, Ester Norambuena, Cristina Cavieres, Jorge Rodríguez, Ramiro Araya-Maturana, Tomás Delgado-Castro, and Jorge Soto-Delgado
- Subjects
Antioxidant ,DPPH ,Radical ,medicine.medical_treatment ,Clinical Biochemistry ,Pharmaceutical Science ,Naphthalenes ,Photochemistry ,Sensitivity and Specificity ,Biochemistry ,Antioxidants ,law.invention ,Mice ,chemistry.chemical_compound ,Galvinoxyl ,law ,Cell Line, Tumor ,Drug Discovery ,medicine ,Animals ,Organic chemistry ,Reactivity (chemistry) ,Electron paramagnetic resonance ,Molecular Biology ,Anthracenes ,Molecular Structure ,Hydroquinone ,Spin trapping ,Organic Chemistry ,Electron Spin Resonance Spectroscopy ,Reproducibility of Results ,Hydrogen Bonding ,Free Radical Scavengers ,Oxygen ,Kinetics ,chemistry ,Molecular Medicine ,Reactive Oxygen Species - Abstract
This study was undertaken to investigate the free radical-scavenging and antioxidant activities of various structurally related hydroquinones including hydroxynaphthalenones and dihydroxyanthracenones. Electron spin resonance spectroscopy and spin trapping techniques were used to evaluate the ability of hydroquinones to scavenge hydroxyl, diphenylpicrylhydrazyl, and galvinoxyl radicals. In addition, the oxygen radical absorbing capacity assay using fluorescein (ORAC-FL) was used to obtain the relative antioxidant capacity of these radicals. The rate constants of the first H atom abstraction by 2,2-diphenyl-2-picrylhydrazyl ( k 2 ), were obtained under pseudo-first-order conditions. The free radical-scavenging activities and k 2 values discriminate well between hydroxynaphthalenones and dihydroxyanthracenones, showing that the latter have better antioxidant properties. The aforementioned experimental data agree with quantum-chemical results demonstrating the relevance of intramolecular H bonding to radical-scavenging activities.
- Published
- 2007