Context: Salvianolic acids are the most abundant water-soluble compounds extracted from the herb Salvia miltiorrhiza L. (Lamiaceae) with antioxidant and protective effects.
Objective: This study evaluates the antidiabetic effect of salvianolic acid B (Sal B) in multiple low-dose streptozotocin (MLDS)-induced diabetes in rat.
Materials and methods: Rats were divided into control, Sal B40-treated control, diabetic, Sal B20-, and Sal B40-treated diabetic groups. Sal B was daily administered at doses of 20 or 40 mg/kg (i.p.), started on third day post-STZ injection for 3 weeks. Serum glucose and insulin level and some oxidative stress markers in pancreas were measured in addition to the oral glucose tolerance test (OGTT), histological assessment, and apoptosis determination.
Results: After 3 weeks, treatment of diabetic rats with Sal B20 and Sal B40 caused a significant decrease of the serum glucose (p < 0.05-0.01) and improvement of OGTT. Meanwhile, serum insulin was significantly higher in Sal B20- and Sal B40-treated diabetics (p < 0.01) and treatment of diabetics with Sal B40 significantly lowered malondialdehyde (MDA) (p < 0.05), raised glutathione (GSH) (p < 0.05), and activity of catalase (p < 0.01) with no significant change of nitrite. Furthermore, the number of pancreatic islets (p < 0.05) and their area (p < 0.01) was significantly higher and apoptosis reactivity was significantly lower (p < 0.05) in the Sal B40-treated diabetic group versus diabetics.
Discussion and conclusion: Three-week treatment of diabetic rats with Sal B exhibited antidiabetic activity which is partly exerted via attenuation of oxidative stress and apoptosis and augmentation of antioxidant system.
Keywords: Apoptosis; langerhans islet; oral glucose tolerance test; oxidative stress; pancreas; serum insulin.