Effects of combined Quercetin and coenzyme Q10 treatment on oxidative stress in normal and diabetic rats

Allan D. Coldiron, Ruth A. Sanders, John B. Watkins

Research output: Contribution to journalArticle

45 Scopus citations


Reactive oxygen species may be actively involved in the genesis of various pathological states such as ischemia-reperfusion injury, cancer, and diabetes. Our objective was to determine if subacute treatment with combined antioxidants quercetin and coenzyme Q10 (10 mg/kg/day ip for 14 days) affects the activities of antioxidant enzymes in normal and 30-day streptozotocin-induced diabetic Sprague-Dawley rats. Quercetin treatment raised blood glucose concentrations in normal and diabetic rats, whereas treatment with coenzyme Q10 did not. Liver, kidney, heart, and brain tissues were excised and the activities of catalase, glutathione reductase, glutathione peroxidase, superoxide dismutase, and concentrations of oxidized and reduced glutathione were determined. In the liver of diabetic rats, superoxide dismutase, glutathione peroxidase, and levels of both oxidized and reduced glutathione were significantly decreased from the non-diabetic control, and these effects were not reversed when antioxidants were administered. In kidney, glutathione peroxidase activity was significantly elevated in the diabetic rats as compared to nondiabetic rats, and antioxidant treatment did not return the enzyme activity to nondiabetic levels. In heart, catalase activity was increased in diabetic animals and restored to normal levels after combined treatment with quercetin and coenzyme Q10. Cardiac superoxide dismutase was lower than normal in quercetin- and quercetin + coenzyme Q10-treated diabetic rats. There were no adverse effects on oxidative stress markers after treatment with quercetin or coenzyme Q10 singly or in combination. In spite of the elevation of glucose, quercetin may be effective in reversing some effects of diabetes, but the combination of quercetin + coenzyme Q10 did not increase effectiveness in reversing effects of diabetes.

Original languageEnglish (US)
Pages (from-to)197-202
Number of pages6
JournalJournal of Biochemical and Molecular Toxicology
Issue number4
StatePublished - Oct 23 2002



  • Catalase
  • Coenzyme Q
  • Diabetes
  • Glutathione peroxidase
  • Glutathione reductase
  • Heart
  • Kidney
  • Liver
  • Oxidative stress
  • Quercetin
  • Streptozotocin
  • Superoxide dismutase

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Toxicology
  • Health, Toxicology and Mutagenesis

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