Protective Effects of Frankincense Supplementation Against Oxidative Stress and Inflammatory Imbalance in Diabetic Rats

Abstract

Background:Persistent oxidative stress and chronic low-grade inflammation are hallmarks of diabetes mellitus, and both are important factors in the onset and course of diabetic complications. Although frankincense (Boswellia sacra) is widely known for its anti-inflammatory and antioxidant properties, its coordinated effects on pro- and anti-inflammatory mediators in the context of diabetes remain poorly understood.Methods:Three groups of adult male Sprague-Dawley rats were randomly assigned: 10 healthy control rats, 15 diabetic control rats, and 15 diabetic rats administered oral frankincense extract (500 mg/kg/day) for 28 days. Type 2 diabetes mellitus was induced in the designated groups by a single intraperitoneal injection of streptozotocin (STZ; 55 mg/kg). On days 14 and 28, serum samples were collected to measure antioxidant indicators, including glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA). Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), transforming growth factor-β (TGF-β), connective tissue growth factor (CTGF), serum amyloid A (SAA), C-reactive protein (CRP), and interleukin-10 (IL-10) were among the inflammatory and regulatory biomarkers evaluated. Histopathological samples were collected from the liver, kidneys, and pancreas on day 28 of the experiment.Results:Diabetic controls exhibited significant reductions in CAT, SOD, and GPx activities compared with healthy controls (p < 0.05), alongside elevated MDA, CRP, SAA, TNF-α, and IL-1β (p < 0.05). Frankincense supplementation for 28 days significantly increased CAT (101.3 ± 19.11 U/L) and GPx (39.39 ± 0.93 mU/mL) compared with diabetic controls (64.14 ± 1.25 U/L and 20.43 ± 0.97 mU/mL; p < 0.05 and 0.001, respectively). MDA levels were reduced from 17.4 ± 0.82 to 9.44 ± 0.29 nmol/mL (p < 0.001). CRP and SAA decreased markedly to 50.4 ± 2.08 U/L and 9.65 ± 0.40 ng/mL, respectively (p < 0.01 vs. diabetic controls). TNF-α was significantly reduced to 14.11 ± 0.98 pg/mL on day 14 (p < 0.001), but returned to levels comparable to untreated diabetic rats by day 28. At the end of the experiment, Frankincense supplementation significantly elevated TGF-β levels (p < 0.01) but did not significantly alter CTGF levels, while IL-10 levels decreased significantly (p < 0.001). Frankincense ameliorated and partially restored the adverse histopathological findings of diabetes in rats, including hepatocyte swelling and fatty degeneration, glomerular hemorrhage and inflammation, and pancreatic injury.Conclusions:Frankincense supplementation at 500 mg/kg for 28 days effectively attenuates diabetes-induced oxidative stress by restoring antioxidant activities and reducing lipid peroxidation, while suppressing key proinflammatory mediators. These findings support the further investigation of frankincense as an adjunctive strategy for managing the oxidative and inflammatory burden associated with diabetes.