Hypoglycemic and β-cells regenerative effects of Aegle marmelos (L.) Corr. bark extract in streptozotocin-induced diabetic rats

The aim of this study was to examine the antidiabetic potential of Aegle marmelos (L.) Corr. (Rutaceae) bark in a diabetic rat model. Dose dependent effects of methanol extract of Aegle marmelos bark (AM) (200 and 400 mg/kg) on blood glucose, plasma insulin, glycated haemoglobin (HbA1c), total protein, hepatic glycogen, marker enzymes of hepatic function and carbohydrate metabolism were evaluated in (streptozotocin) STZ-induced diabetic rats by oral administration for 30 days. Structural integrity of pancreatic islets was assessed by routine histology while, their functional status was assessed by immunolocalization for insulin. High-performance liquid chromatography (HPLC) study established that AM contained antihyperglycemic constituents, aegelin (1.27% w/w) and lupeol (0.29% w/w). AM at 200 and 400 mg/kg showed significant reduction in blood glucose level by 19.14% and 47.32%, respectively in diabetic rats. AM treatment significantly increased insulin level, and produced similar effects on other biochemical parameters. Histological studies showed the regenerative effect of AM on the β-cells of diabetic rats. Immunohistochemical observations in the extract treated diabetic rats showed increased insulin-immunoreactive β-cells. These findings suggest that A. marmelos bark extract has the therapeutic potential in STZ-induced hyperglycemia; hence it can be used in the treatment of diabetes mellitus.