Antihyperglycaemic, antihyperlipidaemic and β cell regenerative effects of Spondias pinnata (Linn. f.) Kurz. bark extract on streptozotocin induced diabetic rats

IntroductionIn Sri Lanka, Spondias pinnata (Linn. f.) Kurz (Family: Anacardiaceae) is popular in traditional Ayurvedic medicine for the treatment of diabetes mellitus. This study investigated the effect of aqueous bark extract of S. pinnata on antihyperglycaemic, antihyperlipidaemic activities and β-cell regenerative potential in streptozotocin induced diabetic rats. Dose, long term effects and acute toxicity were also investigated.MethodologyA series of experimental studies were conducted using S. pinnata. Diabetes was induced in rats by injecting them with streptozotocin (65 mg/kg, ip). Control rats were either healthy untreated, or diabetes induced untreated rats which only received distilled water. Diabetic rats were treated with different dose to identify the optimum effective dose of S. pinnata. having identified the optimum dose (1.00 g/kg) and glibenclamide (0.50 mg/kg) was given daily for 30 days. The assessment of biochemical parameters, histopathology and immunohistochemistry of the pancreas occurred at 30 days.ResultsThe percentage of glycosylated hemoglobin decreased together with a concomitant increase in the concentration of serum insulin and C-peptide in S. pinnata treated diabetic rats (p < 0.05). Serum lipid parameters improved for S. pinnata treated diabetic rats (p < 0.05). Islet cell regeneration in S. pinnata treated diabetic rats was noted by the percentage increase in insulin secreting β-cells and increase in islet profile diameter in the pancreas. A significant (p < 0.05) dose dependent improvement in glucose tolerance with optimum effectiveness at 1.00 g/kg was shown for the S. pinnata treated diabetic rats. No toxicity was observed.ConclusionsResults revealed that aqueous bark extract of S. pinnata exerted antihypelipidaemic and insulinotropic effects through increased biosynthesis of insulin in streptozotocin induced diabetic rats. Histopathology and immunohistochemistry confirmed that S. pinnata extract was able to induce β-cell regeneration in the pancreas of diabetic rats.