LAUSR

Background: Since many diabetic patients require combination therapy, the use of herbal remedies with anti‐diabetic activity represents a vital option in diabetes mellitus (DM) management. It has been reported that quercetin has hypoglycemic alongside anti‐inflammatory and antioxidant activities. Aim: The present study aimed to investigate the effectiveness of combining quercetin with sitagliptin; a selective dipeptidyl peptidase‐IV (DPP‐IV) inhibitor, in the management of streptozotocin (STZ)‐induced diabetic rats. Methods: DM was induced by a single injection of STZ (45 mg/kg, i.p.) in male adult albino Wistar rats. Diabetic rats were orally treated with sitagliptin (70 mg/kg), quercetin (50 mg/kg) or their combination daily for three consecutive weeks. Serum levels of glucose, C‐peptide, total cholesterol, triglycerides, malondialdehyde (MDA), superoxide dismutase, (SOD), reduced glutathione (GSH), tumor necrosis factor alpha, (TNF‐&agr;), nuclear factor kappa‐B, (NF‐&kgr;B) and adiponectin were estimated. In addition, histopathological, morphometrical and immunohistochemical examinations of pancreatic tissues were conducted. Results: The combined administration of quercetin and sitagliptin normalized serum C‐peptide, MDA, and significantly increased SOD, GSH and decreased NF‐&kgr;B more than sitagliptin alone. Moreover, this combination normalized Islet number, &bgr;‐cells' number, area and perimeter alongside restoring the immunostaining intensity of &bgr;‐cells. Conclusion: Our results suggest the use of quercetin/sitagliptin combination for treating DM based on the observed improvements in glycemic control, metabolic profile, oxidative and inflammatory status, islet structure as well as &bgr;‐cells function compared with either treatment alone.