Antidiabetic activity of corn steep liquor extract of Curculigo pilosa and its solvent fractions in streptozotocin-induced diabetic rats

The rhizome of Curculigo pilosa (CP) prepared with Corn steep liquor (CSL), is traditionally used in the treatment of diabetes mellitus. In this study, antidiabetic activity of the CSL extract and its fractions (butanol and methanol) were evaluated in streptozotocin-induced diabetic rats. Diabetes mellitus was induced by single intraperitoneal administration of streptozotocin (50 mg/kg) and diabetic rats were treated with 300 mg/kg bodyweight of the extract(s) for 28 days. Antidiabetic effect was monitored by plasma blood glucose, oral glucose tolerances test (OGGT), body weight and heamatological indices. Also serum urea, creatinine, cholesterol, high density lipoprotein, bilirubin, alkaline phosphatase, aspartate and alanine transaminases were evaluated. The levels of hepatic glutathione, catalase, superoxide dismutase, lipid peroxidation, nitric oxide and hydrogen peroxide were assessed; also histopathology of the hepatic tissues was examined. Oral administration of the extract resulted in significant (p < 0.05) reduction of plasma blood glucose (29.32% crude extract and 22.96% butanol fraction) and also increased body weight (20.61% crude extract, 13.44% butanol fraction and 6.23% methanol fraction) of diabetic rats. The heamotogical indices, plasma parameters and hepatic oxidative stress in diabetic rats were returned to near normalcy following treatment with the extract(s). The GC-MS analysis of the extract revealed the presence of stilbene, a proven antidiabetic agent, which might be responsible for the antidiabetic activity. The results obtained suggest that the CSL extract of CP could be used in management of diabetes mellitus thus providing scientific validation of its use as an antidiabetic agent.