Effect of Crocus Sativus Extract and Crocin on Oxidative Damage and Inflammation in Streptozotocin-Diabetic Rats

Diabetes is characterized by high glucose concentrations that lead to an increased production of reactive oxygen species. The resulting oxidative stress can play a key role in diabetes pathogenesis and development of late complications of diabetes, including retinopathy, nephropathy, inflamation, cardiovascular diseases and cognitive disorders. The aim of the present study was to investigate the antihyperglycemic effect, protective potential and memory improvement of the diabetic rats. Materials and Methods: Male Wistarrats (300±30 g) were randomly divided into 7 groups, including: control, diabetic (Streptozotocin, 55mg/kg)and diabetics treated intraperitoneally with crocin (at doses of 15, 30 and 60 mg/kg) or saffron extract (at doses of 50 and 100 mg/kg) for 6 weeks. The bloodglucose levels were spectrophotometrically measured in all groups at weeks 0 (before diabetes induction), 3 and 6. The levels of thiobarbituric acid reactive substances (TBARS) and total thiol (SH) groups were measured in 10% liver, kidney and cerebral cortex homogenates at the end of 6 th week. Results: Diabetic rats showed an elevated serum glucose level over those of control rats at weeks 3 and 6 (P<0.001). Under ourexperimental conditions, crocin at dose of 60 mg/kg and saffron at dose of 100 mg/kg was found to significantly reduce the blood glucose level in diabetic animals (respectively, P<0.05, P<0.001) at the end of week 6. In addition, there was a significant increase in TBARSlevels in the liver, kidney and cerebral cortex of diabetic animals (respectively, P<0.001, P<0.01, P<0.005) and decrement in total thiol concentrations in the liver of diabetics (P<0.01) compared to controls. Treatment of diabetic rats with crocin at doses of 30 and 60 mg/kgfor 6 weeks reduced TBARS content in the liver and kidney (respectively, P<0.01, P<0.001), and crocin at doses of 15 and 30 mg/kg decreased TBARS levels in the cerebral cortex (P<0.01) compared to diabetic rats. Treatment of diabetic rats with saffron at doses of 50 and 100 mg/kg did not change the TBARS and total thiol levels in the tissues compared to diabetics. Conclusions: Our findings suggest that crocin has the hypoglycemic, antiinflamtory properties in streptozotocin-induced diabetes and it can be used with some profit in the treatment of diabetic patients.affron extract and crocin in streptozotocin inducedwere