Antidepressant‐like effects of quercetin in diabetic rats are independent of hypothalamic–pituitary–adrenal axis

Objective Quercetin, one of the most potent flavonol in the family of flavonoids, has been shown to have benefits against diabetes and its complications. In the present study, we investigated effects of quercetin on depression-like behaviours and hypothalamic-pituitary-adrenal (HPA) axis in diabetic rats. Methods Experimental diabetes was induced by using streptozotocin, and either 50 or 100 mg/kg quercetin was intraperitoneally administered for 21 days. Following the last treatment, animals were subjected to the forced swim test, and subsequently, the blood was obtained by cardiac puncture to measure plasma adrenocorticotropic hormone (ACTH) and corticosterone (CORT) levels. Results A significant increase of the total immobile time, accompanied by a decrease in the immobility latency, which suggests a depressive status, was observed in diabetic animals that was reversed by the treatment of 50 mg/kg quercetin. However, the higher dose of quercetin (100 mg/kg) was ineffective in alleviating depression-like behaviours. The plasma concentrations of ACTH, and total- and free-CORT were not affected by both doses of quercetin. Conclusion Therefore, we concluded that the antidepressant-like effects of quercetin in diabetes are independent of the HPA axis.