Background
There is increasing evidence that complications related to diabetes are associated with increased oxidative stress. Curcumin, an active principle of turmeric, has several biological properties, including antioxidant activity. The protective effect of curcumin and turmeric on streptozotocin (STZ)-induced oxidative stress in various tissues of rats was studied.
Material and Method
Three-month-old Wistar-NIN rats were made diabetic by injecting STZ (35 mg/kg body weight) intraperitoneally and fed either only the AIN-93 diet or the AIN-93 diet containing 0.002% or 0.01% curcumin or 0.5% turmeric for a period of eight weeks. After eight weeks the levels of oxidative stress parameters and activity of antioxidant enzymes were determined in various tissues.
Results
STZ-induced hyperglycemia resulted in increased lipid peroxidation and protein carbonyls in red blood cells and other tissues and altered antioxidant enzyme activities. Interestingly, feeding curcumin and turmeric to the diabetic rats controlled oxidative stress by inhibiting the increase in TBARS and protein carbonyls and reversing altered antioxidant enzyme activities without altering the hyperglycemic state in most of the tissues.
Conclusions
Turmeric and curcumin appear to be beneficial in preventing diabetes-induced oxidative stress in rats despite unaltered hyperglycemic status.

Keywords: Streptozocin, Plant Preparations - therapeutic use, Oxidative Stress - drug effects, Diabetes Mellitus, Experimental - metabolism, Insulin - blood, Curcumin - pharmacology, Curcuma, Blood Proteins - metabolism, Blood Glucose - metabolism, Antioxidants - pharmacology