Increased blood glucose in diabetes mellitus stimulates nonenzymatic glycosylation of several proteins, including haemoglobin. Although iron is tightly bound to haemoglobin, it is liberated under specific circumstances yielding free reactive iron. Studies with purified haemoglobin from nomlal individuals and diabetic patients revealed that concentration of free iron was significantly higher in the latter cases and increased progressively with extent of the disease. In vitro glycosylation of haemoglobin also led to increase in release of iron from protein. This increase in free iron, acting as a Fenton reagent, might produce free radicals, which, in tum might be causing ox idative stress in diabetes.

Diabetes mellitus is a syndrome characterised by chronic hyperglycemia and disturbance of carbohydrate, fat and protein metabolism associated with absolute or relative deficiencies in insulin secretion and/or insulin action. Free radicals and associated stress have been implicated in eliciting pathological changes of diabetes I. However, the possible source of free radicals under such clinical disorder is yet to be understood.