Depression is highly prevalent in diabetics and is associated with poor glucose regulation and increased risk of diabetic complications. Identification and effective treatment of comorbid depression are increasingly being considered essential components of clinical care of diabetics. In the present study, the antidepressant activity of quercetin (50 and 100 mg/kg, i.p.), a bioflavonoid, was evaluated using the Porsolt forced swimming-induced behavioral despair test in control and 6-week-streptozotocin-induced diabetic mice. The effect of quercetin was compared with that of the classical antidepressants fluoxetine (5 mg/kg, i.p.) and imipramine (15 mg/kg, i.p.). Streptozotocin-induced diabetic mice exhibited prolonged immobility duration during the test as compared with age-matched control mice. Quercetin dose-dependently reduced the immobility period in diabetic mice, and this effect was comparable to that of fluoxetine (5 mg/kg, i.p.) and imipramine (15 mg/kg, i.p.). Fluoxetine and imipramine significantly lowered the immobility time in naive mice also, but quercetin failed to induce any antidepressant activity in naive mice. The results of our preliminary study indicate that quercetin has the potential to be employed as a therapy for depression associated with diabetes.

The present study was designed to investigate the renoprotective effect of 3,4-methylenedioxyphenol (sesamol) on ferric nitrilotriacetate-induced renal toxicity. Rats were pretreated with sesamol (2, 4 and 8 mg/kg, p.o.) 30 min. prior to administration of ferric nitrilotriacetate (8 mg iron/kg, i.p.) to determine the blood urea nitrogen and serum creatinine levels along with renal oxidative stress. Challenge with ferric nitrilotriacetate markedly increased the blood urea nitrogen and serum creatinine levels, which was coupled with a marked lipid peroxidation, reduced activity of glutathione and decreased total nitric oxide levels in rat kidneys. It also produced significant renal morphological alterations and increased serum tumour necrosis factor-alpha levels. Pretreatment with sesamol significantly reduced the serum creatinine and blood urea nitrogen levels, lipid peroxidation, restored levels of reduced glutathione and increased total renal nitric oxide levels. It also attenuated the increased tumour necrosis factor-alpha levels and restored the normal morphology of the kidneys. Present findings strongly suggest the pivotal role of oxidative stress in the ferric nitrilotriacetate-induced renal dysfunction and points towards the renoprotective potential of sesamol in oxidative renal pathologies.

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