Antioxidant and antidiabetic activities of Terminalia bellirica fruit in alloxan induced diabetic rats

Excessive production of free radicals in the living system leads to oxidative stress which is associated with degenerative disorders including diabetes. Diabetes is increasing at a rapid pace despite the availability of synthetic anti-hyperglycemic drugs in the market. Hence antioxidant and anti-diabetic compounds of natural origin have attracted attention for drug development. The aim of the present study was to investigate the phytochemical composition, antioxidant potential, α-amylase inhibitory and antidiabetic activity of aqueous (AQ) and ethyl acetate (EA) extracts of Terminalia bellirica fruit. Chemical methods were employed for phytochemical analysis. Antioxidant activities of extracts were measured using in vitro assays viz., DPPH free radical scavenging, reducing power, hydroxyl radical scavenging and phosphomolybdate assays. The antidiabetic potential was measured by in vitro α-amylase inhibitory activity and in vivo serum biochemical assays in alloxan-induced diabetic rats. Chemical analysis showed the presence of phenols, flavonoids, alkaloids, terpenoids, saponins and glycosides as a major phytochemical in AQ and EA extracts of T. bellirica fruit. Quantitatively EA extract showed the presence of higher content of phenolics and flavonoids as compared to AQ extract. Further EA extract exhibited considerable free radical scavenging abilities in DPPH and HRSA assays (up to 94%), reducing power assay and appreciable total antioxidant power in phosphomolybdate assay (78 μgPGE/g). The EA extract exhibited comparatively better α-amylase inhibitory activity (IC50 43.5 μg/ml) as compared to AQ extract (IC50 74.8 μg/ml). The activity was comparable to standard drug acarbose. Antidiabetic activity of extracts was studied in alloxan-induced diabetic rats by monitoring the body weight, blood glucose, lipid profile and other biochemical parameters for 28 days. In diabetic rats both the extracts showed a restorative effect on body weight and blood biomarkers such as glucose, creatinine, total protein, total cholesterol, LDL, HDL, triglyceride, urea and uric acid. The ethyl acetate extract also exhibited superiority over the aqueous extracts during in vivo antidiabetic assays. The results revealed that T. bellirica fruit extracts possess antioxidant, α-amylase inhibitory and antidiabetic activities and hence it could be useful for the management of hyperglycemia and oxidative stress.