Anti-hyperglycemic effects of saffron and its active constituents, crocin and safranal, in alloxan-induced diabetic rats

Background: Saffron is the dried stigmata of the flowers of saffron (Crocus sativus L., Iridaceae). Saffron and its major active constituents, crocin (crocetin glycoside), crocetin and safranal, have a variety of pharmacological effects including high antioxidant properties and crocetin has insulin sensitizing effect possibly due to its antioxidant activity. Oral crocin is not absorbed and is hydrolyzed and absorbed as the active metabolite crocetin in the rat intestines. Objective: Study of the saffron, crocin and safranal effects on the blood levels of fasting glucose, HbA1c (glycosylated hemoglobin) and liver/kidney function tests in alloxan-diabetic rats. Methods: The effects of 6 weekschr('39') daily oral administration of saffron methanolic extract, crocin and safranal on the fasting blood glucose, HbA1c, insulin, creatinine and SGOT and SGPT levels after single alloxan intraperitoneal injection at a dose of 125 mg/kg in rats were evaluated. Results: Alloxan injection resulted in significant increase of fasting blood glucose and HbA1c levels but decreased blood insulin levels significantly. Saffron methanolic extract (80 and 240 mg/kg), crocin (50 and 150 mg/kg) and safranal (0.25 and 0.5 ml/kg) significantly reduced the fasting blood glucose and HbA1c levels but significantly increased the blood insulin levels without any significant effects on the blood SGOT, SGPT and creatinine levels in the diabetic rats compared with the control diabetic rats. Conclusion: The results suggest that saffron may have anti-hyperglycemic and blood insulin level elevating effects without hepatic and renal toxicities in the alloxan - diabetic rats. Further, crocin, crocetin and safranal may be involved in these effects of saffron.