Reductive activation of terpenylnaphthoquinones

Four terpenylnaphthoquinones were found to enhance the rate of superoxide production in the presence of ascorbate as detected from the superoxide dismutase (SOD)-inhibitable initial oxygen consumption rates. Initial rates of oxygen consumption in the presence of ascorbate plus quinone increase with...

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Bibliographic Details
Published in:Toxicology (Amsterdam) 2002-06, Vol.175 (1), p.167-175
Main Authors: Alegria, Antonio E., Cordones, Emelyn, Santiago, Glysette, Marcano, Yanira, Sanchez, Sheila, Gordaliza, Marina, Martı́n-Martı́n, Maria Luz
Format: Article
Language:English
Subjects:
Animals
Antineoplastic agents
Ascorbate
Ascorbic Acid - chemistry
Biological and medical sciences
Cytochrome c Group - chemistry
Electron Spin Resonance Spectroscopy
General aspects
Horses
Kinetics
Medical sciences
Naphthoquinone
Naphthoquinones - chemistry
Oxidation-Reduction
Pharmacology. Drug treatments
Redox cycling
Semiquinone
Superoxide Dismutase - chemistry
Superoxides - chemistry
Terpenes - chemistry
Terpenylnaphthoquinone
Xanthine - chemistry
Xanthine oxidase
Xanthine Oxidase - chemistry
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Summary:Four terpenylnaphthoquinones were found to enhance the rate of superoxide production in the presence of ascorbate as detected from the superoxide dismutase (SOD)-inhibitable initial oxygen consumption rates. Initial rates of oxygen consumption in the presence of ascorbate plus quinone increase with an increase in the half-wave reduction potentials of the quinones. These quinones also enhance the rate of Cyt(III) c reduction by xanthine/xanthine oxidase (X/XO) in both air- and nitrogen-saturated aqueous solutions at pH 7.4. Maximum rates of Cyt(III) c reduction in nitrogen and oxygen-saturated solutions ( V max), in the presence of X/XO, increase with an increase in the half-wave reduction potentials of the quinones. SOD inhibits Cyt(III) c reduction rates in the presence of these quinones and X/XO in a manner which is also dependent on the quinone half-wave redox potential. The relative antineoplastic activity of two of these quinones follows the order in rates of oxygen consumption or Cyt(III) c reduction. This is consistent with an antineoplastic action of these quinones through the mechanism of redox cycling or possible interference or inhibition of mitochondrial respiration.
ISSN:0300-483X
1879-3185
DOI:10.1016/S0300-483X(02)00076-8