Attenuating potential of leaf extracts of alstonia scholaris on altered glycemic index, lipid, hepatic and renal parameters in streptozotocin induced diabetic rats

Alstonia scholaris (Apocynaceae) is an important constituent of numerous and widely used therapeutic formulations of Ayurveda, the traditional Indian system of medicine. Present study was aimed to determine the potential of leaf extracts of A. scholaris administration in attenuating the glycemic index [mean blood glucose (MBG), per cent glycosylated haemoglobin fraction (HbA1c)], lipid profile [total cholesterol (TC), triglycerides (TG), low and high density lipoproteins (LDL and HDL)], hepatic [transaminases, phosphatases, dehydrogenases] and renal indices [plasma proteins, blood urea nitrogen (BUN), creatinine (CR), uric acid (UA)] in streptozotocin (STZ) induced diabetic rats. Administration of STZ increased (P<0.05) the levels of MBG, HbA1c fraction which indicated the induction of diabetes in rats. Enhanced (P<0.05) TC, TG, LDL, total oxidant status (TOS), oxidative stress index (OSI), malondialdehyde (MDA) levels, hepatic and renal indices were observed in blood of diabetic rats. However, levels of HDL, protein profile, total antioxidant status (TAS), glutathione (GSH), total thiols (TTH) and activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione-s-transferase (GST) and glucose-6-phosphate dehydrogenase (G6PDH) were significantly reduced in diabetic rats. Repeated oral administration of ethanolic leaf extract of A. Scholaris reduced the levels of MBG, HbA1c and TC in diabetic rats. While it restored OSI, TTH, GSH, CAT, SOD, GST and MDA levels; it also increased activities of G6PDH and GPx in diabetic rats compared to untreated diabetic rats. These findings indicated that A. Scholaris leaf extracts possess antidiabetic potential against STZ induced diabetes in rats. Overall, the ethanolic leaf extract of A. Scholaris displayed greater antidiabetic capacity than its aqueous counterpart.