Antihyperglycemic Activity of the Various Extracts of Costus speciosus Rhizomes

Costus speciosus is known to possess antidiabetic properties and used in local health traditions in India but the validation of drug is not done. The activity of various fractions of drug is also not reported. In view of its immense potential in andiabetic properties, systematic study was conducted with an objective to evaluate the antihyperglycemic activity of petroleum ether, chloroform, methanolic, and aqueous extracts of C. speciosus rhizomes on over night fasted, Streptozotocin (STZ) induced diabetic rats. Blood glucose level (BGL) monitored at 0, 30, 60, 120 and 240 minutes suggested that all extracts of C. speciosus resulted in reduction of BGL significantly except pet ether extract. Aqueous extract and methanolic extracts reduced initial BGL of 387 to 120 mg/dl and 303 to 161 mg/ dl respectively at the end of 240 minutes. Similar studies conducted with oral glucose tolerance test (OGTT) confirmed the above findings suggesting that aqueous extract and methanolic extracts of C. speciosus were highly effective in bringing down the BGL from 590 to 96 mg/dl and 570 to 128 mg/dl respectively at the end of 240 minutes, which was on par with the glibenclamide. Results from multiple dose studies wherein the drug was administered for 14 days also confirmed the above findings and the serum lipid profiles high density lipoproteins (HDL), low density lipoproteins (LDL) and very low density lipoproteins (VLDL) were found to be optimum in aqueous or methanolic extracts on par with normal healthy rats or standard drug glibenclamide treated rats.