Effect of Salvia rhytidea Benth. extract on serum glucose, gut alphaglucosidase in healthy and streptozotocin-induced diabetic rats

Abstract

Salvia rhytidea Benth. is one of the endemic species in Iran which has been used as anti-diabetic in traditional medicine. The aim of this study was to evaluate the hypoglycemic effect of Salvia rhytidea Benth. methanol extract on healthy and induced diabetic rats. Determination of alphaglucosidase activity also was the other objective. Aerial parts of the plant were extracted after authentication with methanol 80% by macerating method. The methanol extract was evaporated under reduced pressure to evaporate its methanol content then lyophilized and stored in screw cap vials. Plant LD50 was determined 4.9 g/kg. Diabetes was induced by single i.p injection of a freshly prepared streptozotocin (STZ) solution (55 mg:kg in normal saline) to overnight fasted male wistar rats. Test animals received extract at doses of 0/5,1 ,2 g/kg. Negative and positive control groups received normal saline and glibenclamid respectively. Serum glucose levels were determined at various points of time (0, 60, 120 and 180min after injection). Results showed that Salvia rhytidea extract was suppressed the elevated blood glucose at doses of 0.5, 1 and 2 g/kg body weight for 180 min. At 0.5 g/kg body weight was found to be comparable to glibenclamide, a reference drug. Blood glucose lowering effect of extract in dose of 1 g/kg was higher than glibenclamide at dose of 20mg/kg. At dose of 0.5g/kg, plant extract exhibited similar activity with glibenclamide.Our studies indicates that the leaves of this plant possess significant antihyperglycemic potential.