Preventive effects of Laminaria japonica aqueous extract on the oxidative stress and xanthine oxidase activity in streptozotocin-induced diabetic rat liver

Biol Pharm Bull. 2004 Jul;27(7):1037-40. doi: 10.1248/bpb.27.1037.


Increasing evidence in both experimental and clinical studies suggests that oxidative stress plays a major role in the pathogenesis of diabetes mellitus type 1 and type 2. Xanthine oxidase (XO) has been proposed as one of the sources of free radical formation in diabetes. We therefore investigated the preventive effects of Laminaria japonica aqueous extract (LJE) on alterations in the activity of hepatic XO and oxidative stress in the streptozotocin-induced experimental diabetes. We found that lipid peroxide levels and xanthine oxidase activity were increased, whereas glutathione (GSH), GSH reductase and GSH peroxidase were decreased in the liver of streptozotocin-induced diabetic rats. Pretreatment with LJE of 100 mg/kg orally for 5 d significantly reduced blood glucose levels and hepatic lipid peroxidation in the diabetic rats. In addition, the content of glutathione was restored to the control level by LJE pretreatment. Furthermore, LJE significantly suppressed the increased activity of XO and type conversion of the xanthine dehydrogenase to XO in diabetic rat liver. The results suggest that Laminaria japonica would be of great value in preventing hyperglycemia in diabetes mellitus as a dietary supplement possibly, through its antioxidant activity.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Diabetes Mellitus, Experimental / drug therapy*
  • Diabetes Mellitus, Experimental / metabolism
  • Enzyme Inhibitors / isolation & purification
  • Enzyme Inhibitors / pharmacology
  • Enzyme Inhibitors / therapeutic use
  • Laminaria*
  • Liver / drug effects*
  • Liver / metabolism
  • Male
  • Oxidative Stress / drug effects*
  • Oxidative Stress / physiology
  • Plant Extracts / isolation & purification
  • Plant Extracts / pharmacology
  • Plant Extracts / therapeutic use
  • Rats
  • Rats, Sprague-Dawley
  • Water / pharmacology
  • Xanthine Oxidase / antagonists & inhibitors*
  • Xanthine Oxidase / metabolism


  • Enzyme Inhibitors
  • Plant Extracts
  • Water
  • Xanthine Oxidase