« Back to Farmacia Journal 5/2026

OLIVE LEAF EXTRACT AMELIORATES HYPERGLYCAEMIA, OXIDATIVE STRESS AND PANCREATIC AND HEPATIC INJURY IN STREPTOZOTOCIN-INDUCED DIABETIC RATS: A DOSE-DEPENDENT COMPARISON WITH METFORMIN

ALAA TALAL QUMSANI ¹*, MOHAMED EZZAT ELBEEH ¹,²

Download Full Article PDF

We evaluated whether a standardised olive leaf extract (OLE; Olea europaea L., 94.7 mg/g oleuropein) lowers fasting blood glucose in a dose-dependent manner and restores pancreatic and hepatic antioxidant capacity, using metformin as a reference. Fifty-eight male Wistar rats were used; forty-eight of them were allocated to six groups (n = 8): Normal, Normal + OLE 400, Diabetic, Diabetic + OLE 200 or 400 mg/kg, and Diabetic + metformin 200 mg/kg; streptozotocin (55 mg/kg, i.p.) induced diabetes. After four weeks, we assessed glycaemic indices, oral glucose tolerance, and pancreatic and hepatic oxidative markers (malondialdehyde, MDA; reduced glutathione, GSH; superoxide dismutase, SOD; catalase, CAT) with blinded histopathology. Streptozotocin produced marked hyperglycaemia, elevated HbA1c, hypoinsulinaemia and tripled MDA with antioxidant depletion. OLE produced a dose-dependent recovery; at 400 mg/kg, it lowered fasting glucose by 59% (Cohen's d = 4.85, 95% CI 2.81-6.90). It restored antioxidant enzymes to values not significantly different from metformin. Histopathology showed attenuation of pancreatic and hepatic lesions, with no overt adverse change in non-diabetic animals. Standardised OLE exerts dose-dependent anti-hyperglycaemic and antioxidant effects and protects pancreatic and hepatic tissue.