Astragalus adscendens extract shows antidiabetic effects through controlling oxidative stress, inflammation and apoptosis in streptozotocin-induced diabetic rats

Objective: To assess the effect of oral treatment of methanolic extract of the aerial parts of Astragalus adscendens in streptozotocin-induced diabetic rats. Methods: In order to induce diabetes, rats intraperitoneally received streptozotocin at 65 mg/kg. Sixty adult male Wistar rats were allocated into six groups (10 rats per each) including the healthy control group, the diabetic group as well as the diabetic group treated with Astragalus adscendens methanolic extract at 50, 100, and 200 mg/kg per day or glibenclamide (0.6 mg/kg/day) for 28 d. The effects of Astragalus adscendens methanolic extract on the levels of glucose, insulin, alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, creatinine, urea, uric acid, total protein, albumin, triglyceride, cholesterol, α-amylase, oxidant/antioxidant enzymes, and inflammatory cytokines were evaluated. Real time-PCR was also used for measuring the gene expression of caspase-3, Bcl2, and Bax. Results: The levels of glucose, cholesterol, triglyceride, creatinine, urea, uric acid, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, bilirubin, and malondialdehyde considerably declined (P<0.001) in diabetic rats after treatment with Astragalus adscendens methanolic extract especially at a dose of 200 mg/kg. In addition, treatment with Astragalus adscendens methanolic extract noticeably increased the level of insulin, total protein, and albumin as well as improved the activities of catalase, glutathione peroxidase, and superoxide dismutase, as well as the expression levels of TNF-α, IL-1β, caspase-3, Bcl2 and Bax (P<0.001) compared to the diabetic control group. The extract also inhibited α-amylase in a dose-dependent manner with an IC50 value of 19.6 µg/mL. Conclusions: Astragalus adscendens methanolic extract shows potent antidiabetic, anti-inflammatory, anti-apoptotic, and antioxidant effects in diabetic rats. However, more studies are needed to verify the underlying mechanism of the effect of this plant extract and test its efficacy in clinical trials.