Beneficial influence of fungal metabolite nigerloxin on diabetes-induced oxidative stress in experimental rats.

Oxidative stress plays a key role in the progression of diabetes and its complications. In this study, the beneficial influence of the fungal metabolite nigerloxin, a new aldose reductase inhibitor and a free-radical scavenger, was investigated on oxidative stress in streptozotocin-induced diabetic rats. Groups of diabetic rats were orally administered nigerloxin for 30 days at a dose of 25 and 100 mg·(kg body mass)(-1)·day(-1). Diabetic rats showed significantly increased lipid peroxide levels in blood and liver, which was accompanied by lowered concentrations of antioxidant molecules and activities of antioxidant enzymes in blood and liver. Administration of nigerloxin for 30 days at a daily dose of 100 mg∙(kg body mass)(-1) to diabetic rats significantly decreased plasma and liver lipid peroxides, elevated the nonenzymatic antioxidants ascorbic acid, reduced glutathione, and total thiols, and elevated the activities of antioxidant enzymes in blood and liver. Nigerloxin showed a tendency to counter lipid abnormalities in diabetic animals, while fasting glucose and body mass were unaffected by nigerloxin treatment. Thus, this animal study has indicated the beneficial influence of nigerloxin on oxidative stress associated with diabetes that may have an implication in delaying or ameliorating the secondary complications.