Antihyperglycemic, hypolipidemic and antioxidant activities of total saponins extracted from Aralia taibaiensis in experimental type 2 diabetic rats

Abstract

Ethnopharmacological relevance: As a well-known traditional Chinese medicine the root bark of Aralia taibaiensis has multiple pharmacological activities, including relieving rheumatism, promoting blood circulation to arrest pain, inducing diuresis to reduce edema, and antidiabetic action. It has long been used as a folk medicine for the treatment of traumatic injury, rheumatic arthralgia, nephritis, edema, hepatitis and diabetes mellitus in China.

Aim of study: To evaluate the antihyperglycemic, hypolipidemic and antioxidant activities of total saponins extracted from Aralia taibaiensis (SAT) in experimental type 2 diabetic mellitus (T2DM) rats.

Materials and methods: Acute toxicity was studied in rats to determine the safe oral dose of SAT. Then, SAT was given orally to normal and streptozotocin-nicotinamide induced T2DM rats at 80, 160 and 320 mg/kg doses for a series of 28 days to determine the antihyperglycemic activity. Glibenclamide (600 μg/kg), a standard antidiabetic drug, was used as a positive control drug. At the end of treatment, biochemical parameters and antioxidant levels were measured to evaluate the hypolipidemic and antioxidant activities of SAT.

Results: Oral administration of SAT did not exhibit toxicity and death at a dose not more than 2000 mg/kg. SAT dose-dependently improved the symptoms of polydipsia, polyuria, polyphagia and weight loss in diabetic rats. Compared with diabetic control group, administration of 320 mg/kg SAT resulted in significant (P<0.05) fall in the levels of fasting blood glucose, glycosylated hemoglobin, creatinine, urea, alanine transarninase, aspartate aminotransferase, total cholesterol, triglycerides, low density lipoprotein cholesterol and malondialdehyde, but significant (P<0.05) increase in the levels of serum insulin, superoxide dismutase and reduced glutathione. However, SAT did not have any effect on the normal rats.

Conclusions: SAT had excellent antihyperglycemic, hypolipidemic and antioxidant activities in T2DM rats and might be a promising drug in the therapy of diabetes mellitus and its complications.

Keywords: Antihyperglycemic activity; Antioxidant activity; Aralia taibaiensis; Hypolipidemic activity; Saponins; Type 2 diabetic mellitus.