Context Syzygium densiflorum Wall. ex Wight & Arn (Myrtaceae) has been traditionally used by local tribes of the Nilgiris, Tamil Nadu, India, for the treatment of diabetes, however, no definitive experimental studies are available. Objective This study investigates the antidiabetic, antihyperlipidaemic and antioxidant activities of ethanol extract of S. densiflorum (EFSD) fruits in streptozotocin (STZ) and nicotinamide (NA)-induced diabetic rats. Materials and methods Acute oral toxicity and oral glucose tolerance were assessed in normal rats. The antidiabetic, antihyperlipidaemic and antioxidant activities were investigated in STZ - NA-induced diabetic rats. Diabetic rats were orally administered with glibenclamide (10 mg/kg b.wt), EFSD (200, 400 and 800 mg/kg b.wt) for 28 d. Further, changes in the blood glucose level (BGL), biochemical parameters, antioxidants were observed and histology of pancreas was performed. Results No toxicity and lethality were observed. Results of the following parameters are represented by treated versus disease control (STZ + NA) groups. BGL (161.33 ± 22.8 versus 476.17 ± 56.58 mg/dl), glycosylated haemoglobin (5.285 ± 0.19 versus 8.05 ± 0.55%), urea (40.32 ± 1.96 versus 75.37 ± 2.91 mg/dl), uric acid (1.2 ± 0.07 versus 2.16 ± 0.05 mg/dl), total cholesterol (89.3 ± 5.14 versus 139.7 ± 5.95 mg/dl) and triglycerides (79.65 ± 2.52 versus 108.9 ± 3.61 mg/dl) were significantly decreased, whereas haemoglobin (11.75 ± 0.73 versus 7.95 ± 0.42 g/dl), high-density lipoprotein cholesterol (14.2 ± 1.11 versus 6.97 ± 0.84 mg/dl), total protein (45%) and liver glycogen (87%) were significantly increased in EFSD-treated diabetic group. Significant changes were observed in the enzymatic and non-enzymatic antioxidants in EFSD-treated groups (p < 0.001). Histopathological examination showed the regeneration of β-cells in Islets of Langerhans. Conclusion This study confirms the antidiabetic, antihyperlipidaemic and antioxidant activities of S. densiflorum fruits.
Keywords: blood glucose level; diabetes induction; diabetes mellitus; medicinal plant; β-Cell restoration.