Discerning the antioxidant mechanism of rapanone: A naturally occurring benzoquinone with iron complexing and radical scavenging activities

• Published in: Journal of inorganic biochemistry 2017-05, Vol.170, p.134-147
• Main Authors: de la Vega-Hernández, Karen, Antuch, Manuel, Cuesta-Rubio, Osmany, Núñez-Figueredo, Yanier, Pardo-Andreu, Gilberto L
• Format: Article
• Language: English
• Subjects: Antioxidant; Benzoquinones - chemistry; Coordination Complexes - chemistry; Free Radical Scavengers - chemistry; Iron; Iron - chemistry; Iron-chelation; Mitochondria; Quinones; Rapanone
• ISSN: 0162-0134; 1873-3344
• DOI: 10.1016/j.jinorgbio.2017.02.019

Oxidative stress resulting from iron and reactive oxygen species (ROS) homeostasis breakdown has been implicated in several diseases. Therefore, molecules capable of binding iron and/or scavenging ROS may be reasonable strategies for protecting cells. Rapanone is a naturally occurring hydroxyl-benzoquinone with a privileged chelating structure. In this work, we addressed the antioxidant properties of rapanone concerning its iron-chelating and scavenging activities, and its protective potential against iron and tert-butyl hydroperoxide-induced damage to mitochondria. Experimental determinations revealed the formation of rapanone-Fe(II)/Fe(III) complexes. Additionally, the electrochemical assays indicated that rapanone oxidized Fe(II) and O2−, thus inhibiting Fenton-Haber-Weiss reactions. Furthermore, rapanone displayed an increased 2,2-diphenyl-1-picrylhydrazyl radical scavenging ability in the presence of Fe(II). The above results explained the capacity of rapanone to provide near-full protection against iron and tert-butyl hydroperoxide induced mitochondrial lipid peroxidation in energized organelles, which fail under non-energized condition. We postulate that rapanone affords protection against iron and reactive oxygen species by means of both iron chelating and iron-stimulated free radical scavenging activity. Rapanone provides near-full protection against iron and tert-butyl hydroperoxide induced mitochondrial lipid peroxidation in energized organelles, which fail under non-energized condition. This natural occurring compound affords protection against iron and reactive oxygen species by means of both iron chelating and iron-stimulated free radical scavenging activity. [Display omitted] •Iron complexation is an important antioxidant mechanism of Rapanone.•Rapanone oxidized Fe(II) and O2−, thus inhibiting Fenton-Haber-Weiss reactions.•Increases its antioxidant ability upon interaction with Fe(II) or mitochondria•Rapanone prevents iron or free radical mitochondrial damage by multiple mechanisms.•Antioxidant roles result from iron-chelation and radical scavenging.