Protective Effects of Cinnamomum Zeylanicum Extract Against Hepatopancreatic Oxidative Stress in Type 2 Diabetic Rats

Abstract

Background and Objective: Type 2 diabetes mellitus (T2DM) is associated with excessive oxidative stress that contributes to hepatopancreatic damage and diabetic complications. Cinnamomum zeylanicum (Ceylon cinnamon) possesses potent antioxidant and antidiabetic properties. This study investigated the protective effects of C. zeylanicum extract against hepatopancreatic oxidative stress in streptozotocin-nicotinamide (STZ-NA) induced type 2 diabetic rats.

Methods: Male Wistar rats were randomly divided into five groups (n=8): Normal Control (NC), Diabetic Control (DC), Diabetic + C. zeylanicum low dose 200 mg/kg (DCL), Diabetic + C. zeylanicum high dose 400 mg/kg (DCH), and Diabetic + Standard drug metformin 100 mg/kg (DS). Type 2 diabetes was induced by intraperitoneal injection of nicotinamide (230 mg/kg) followed by intravenous streptozotocin (65 mg/kg). After 28 days of treatment, blood glucose, glycated hemoglobin (HbA1c), oxidative stress markers, antioxidant enzyme activities, and histopathological changes in liver and pancreatic tissues were evaluated.

Results: Diabetic control animals showed significant hyperglycemia (356.3 ± 21.8 mg/dL vs 87.6 ± 3.5 mg/dL in NC, p<0.001), elevated HbA1c (8.9 ± 0.4% vs 4.2 ± 0.2%, p<0.001), and marked weight loss. C. zeylanicum treatment dose-dependently improved glycemic control, with the high dose reducing blood glucose to 142.6 ± 8.9 mg/dL and HbA1c to 5.4 ± 0.3% (p<0.001 vs DC). Oxidative stress markers were significantly elevated in diabetic tissues: hepatic malondialdehyde (MDA) increased from 2.14 ± 0.18 to 6.87 ± 0.42 nmol/mg protein (p<0.001), while pancreatic MDA rose from 1.98 ± 0.16 to 5.94 ± 0.38 nmol/mg protein (p<0.001). C. zeylanicum treatment significantly reduced MDA levels in both tissues, with the high dose achieving 3.18 ± 0.24 nmol/mg protein in liver and 2.89 ± 0.21 nmol/mg protein in pancreas (p<0.001 vs DC). Antioxidant enzyme activities were severely depleted in diabetic animals: hepatic superoxide dismutase (SOD) decreased from 8.76 ± 0.54 to 4.12 ± 0.31 U/mg protein, catalase from 42.8 ± 2.9 to 18.9 ± 1.4 μmol H₂O₂/min/mg protein, and glutathione peroxidase from 156.4 ± 9.8 to 78.3 ± 5.6 nmol NADPH/min/mg protein (all p<0.001). C. zeylanicum treatment dose-dependently restored antioxidant enzyme activities, with the high dose achieving near-normal levels. Reduced glutathione levels were depleted in diabetic tissues and significantly restored by treatment. Histopathological examination revealed severe hepatic steatosis, necrosis, and pancreatic islet degeneration in diabetic animals, which were markedly improved by C. zeylanicum treatment.

Conclusion: C. zeylanicum extract provides significant protection against hepatopancreatic oxidative stress in type 2 diabetic rats through improved glycemic control, enhanced antioxidant defense systems, and preservation of tissue architecture. The high dose (400 mg/kg) showed efficacy comparable to metformin, suggesting the therapeutic potential of Ceylon cinnamon as an adjuvant therapy for diabetes management and prevention of oxidative stress-related complications