Beneficial effect of myricetin on renal functions in streptozotocin-induced diabetes.

Myricetin is a naturally occurring flavonoid that is known to decrease plasma glucose levels in diabetes; however, its influence on renal functions has not yet been determined. This study investigated the effect of myricetin on structural and functional changes occurring in diabetic nephropathy. Male Albino Wistar rats were divided into three groups: normoglycemic, diabetic and myricetin-treated diabetic. Diabetes was induced by intraperitoneal (ip) injection of streptozotocin (50 mg/kg), and rats having fasting blood glucose (FBG) levels greater than 200 mg/dl were included in the study. Treatment of myricetin (6 mg/day ip) was initiated 16 weeks after diabetes was confirmed. Light microscopy was performed on hematoxylin-eosin- and Masson's trichrome-stained sections to evaluate the effect of myricetin on structural changes in the kidney, while creatinine clearance, blood urea nitrogen (BUN), kidney weight, urine volume and protein were measured to assess kidney functions. Activities of glutathione peroxidase (GPx) and xanthine oxidase (XO) were also measured in renal tissues obtained from all experimental groups. Myricetin treatment significantly decreased glomerulosclerosis and reduced BUN, urinary volume and protein excretion, which was profoundly increased in diabetic rats. Decreased creatinine clearance measured in diabetic rats was significantly increased following myricetin treatment. Myricetin also restored altered renal activities of GPx and XO, which were decreased and increased in diabetic rats, respectively. In conclusion, myricetin improved altered renal functions and restored renal activities of GPx and XO in diabetic rats. Obtained data suggest that myricetin could be of therapeutic potential in diabetic nephropathy.