Protective Effects of Adansonia digitata Fruit Fiber on Oxidative Stress and Histopathology in Streptozotocin-Induced Diabetic Rats

Abstract

Background: Oxidative stress plays a critical role in the pathogenesis of diabetes mellitus and contributes to progressive damage of vital organs, including the liver, kidney, and pancreas. Adansonia digitata (baobab) fruit fiber is rich in dietary fiber and antioxidant phytochemicals that may mitigate diabetes-associated oxidative injury. Objective: This study evaluated the proximate composition of Adansonia digitata fruit red fiber and investigated the effects of BFRF-supplemented diets on antioxidant status and histopathological alterations in the liver, kidney, and pancreas of streptozotocin (STZ)-induced diabetic rats. Methods: The proximate composition of BFRF was determined using standard AOAC methods. Thirty (30) adult male Wistar rats were randomly assigned into five groups of six rats each: normal control, diabetic untreated, metformin-treated diabetic rats (250 mg/kg), diabetic rats that were fed 10% BFRF-supplemented diet, and diabetic rats that were fed 20% BFRF-supplemented diet for eight weeks. Diabetes was induced by a single intraperitoneal injection of streptozotocin (50 mg/kg). Serum malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were assessed or determined, while histopathological examinations of the liver, kidney, and pancreatic tissues was also carried out. Data were analyzed using one-way ANOVA followed by Tukey's post hoc test, with level of the significance set at p < .05. Results: Proximate analysis revealed that BFRF contained high crude fiber (39.58 ± 0.59%) and carbohydrate (39.67 ± 0.06%) contents, with moderate protein and low fat and moisture contents. Significant treatment effects were observed for all antioxidant parameters evaluated (p < .001). Diabetic control rats exhibited marked oxidative stress, characterized by elevated MDA levels (2.45 ± 0.50 nmol/mg) and significantly reduced SOD (1.55 ± 0.49 U/mg), CAT (35.75 ± 3.30 U/mg), and GPx (32.00 ± 4.32 U/mg) activities compared with normal controls. Supplementation with BFRF improved antioxidant status in a dose-dependent manner. The 20% BFRF group significantly increased CAT (48.25 ± 4.35 U/mg) and GPx (46.50 ± 3.87 U/mg) activities, with values comparable to the metformin-treated group (51.75 ± 2.50 and 46.75 ± 1.26 U/mg, respectively). Histopathological examination revealed severe renal, hepatic, and pancreatic lesions in untreated diabetic rats, including tubular degeneration, glomerular congestion, hepatocellular necrosis, sinusoidal congestion, acinar degeneration, and distortion of pancreatic islets. BFRF supplementation attenuated these pathological changes, with the 20% BFRF group exhibiting near-normal tissue architecture, minimal inflammatory infiltration, and marked restoration of renal, hepatic, and pancreatic structures. Conclusion: Thus, the findings suggest that Adansonia digitata fruit red fiber has considerable potential as a functional dietary intervention for diabetes mellitus and its associated complications. However, evidence from human clinical studies remains limited, highlighting the need for further research to establish its safety, efficacy, optimal dosage, and underlying mechanisms before clinical application.