Olive Leaves Extract Alleviate Diabetic Nephropathy in Diabetic Male Rats: Impact on Oxidative Stress and Protein Glycation

Diabetes (DM) is one of the top five causes of death worldwide. Controlling glucose level is vital for protecting the complications and improving the diabetics' health. Olive (Olea europaea L.) leave extract (OLE) contains biologically active antioxidant phenolic compounds. This research was carried out to evaluate the effect of OLE on oxidative status and advanced glycation end products (AGEs) in DM rats. Male Wister rats (n=40, 200 +/- 20 g) were divided into Group (1); Control rats and Groups (2-5); DM rats were intraperitoneal(i.p.) injected with STZ (65 mg/kg), only DM rats (fasting blood glucose >250 mg/dl) were randomly classified into DM , DM+ metformin (MT) (600 mg/kg) as reference drug, DM+OLE (200 mg/kg), and DM+OLE (400 mg/kg) groups. At the end of the experiment (6 weeks), blood and kidney samples were collected for biochemical and histopathological studies. Serum glucose, renal functions (creatinine (Cr), and blood urea nitrogen (BUN)), electrolyte ions (sodium (Na+) and potassium (K+)), as well as renal oxidative statusbiomarkers (nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), and AGEs) were determined. The results revealed that there were significant increases in glucose, Cr, BUN, and K+ with a significant decrease in Na+ levels, as well as significant decrease in renal oxidative stress and elevated AGEs levels compared to the control rats. Although MT treatment was more effective than OLE (400 mg/kg) in reducing glucose level, while OLE treatment was more effective than MT in reducing oxidative stress and AGEs levels. Oral administration of OLE (400 mg/kg) showed significant hypoglycemic and antioxidant effects as well as improved renal functions and inhibited AGEs levels compared to the DM rats. Also overcome most of the renal histopathological changes induced by DM. Therefore, co-administration of MT and OLE is recommended in preventing DM complications.