Anti-diabetic effect of <i>Eucalyptus camaldulensis</i> (Red gum) leaf-supplemented diet in streptozotocin-induced diabetic rats

Abstract

Purpose: To investigate the potential anti-diabetic effect of supplementing a diet with Eucalyptus camaldulensis leaves in streptozotocin (STZ) induced Wistar rats. Methods: Methanolic extract of E. camaldulensis was screened using gas chromatography-mass spectrometric analysis. After that, eighteen animals were separated into three groups: Group A served as control group. Group B, the diabetic control group, was induced with STZ, and Group C was induced with STZ and fed a 10 % E. camaldulensis leaf-supplemented diet for 14 days. Thereafter, rats were sacrificed, and fasting blood was collected for serum glucose, enzyme and protein activity tests. Organs were excised for biochemical and histological analysis. Results: The GC-MS fingerprint identified 17 constituents, with 2-hydroxy carbazole being the most abundant. Rats on the E. camaldulensis leaf-based diet for 14 days exhibited a significant decrease (p < 0.05) in serum glucose, alanine aminotransferase (ALT), aspartate aminotransferase (AST), amylase, albumin, total bilirubin, urea, and creatinine concentrations compared to diabetic controls. Insulin levels significantly increased (p < 0.05). Additionally, the E. camaldulensis diet led to a significant decrease in serum lipid profile levels but increased high-density lipoprotein cholesterol (HDL-C). Superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities increased significantly, while malondialdehyde levels decreased significantly (p < 0.05). Histopathology revealed positive effects on hepatocytes, acini, pancreatic duodenal lymphoid activation, islets of Langerhans resurgence, and normal kidneys. Conclusion: Eucalyptus camaldulensis leaf-supplemented diet demonstrates anti-diabetic, hypolipidemic and antioxidant enzyme activities. Carbazole identified by GC-MS may be the potential anti-diabetic and hypolipidemic agent in E. camaldulensis leaf-based diet.