Salsola imbricata attenuates type 2 diabetes mellitus in rats by regulating oxidative stress and insulin signaling

Abstract

Objective: To evaluate the antidiabetic effect of Salsola imbricata (S. imbricata) leaf extract against high-fat-diet/streptozocin-induced alterations in diabetic rats and to explore the underlying mechanisms involved in insulin secretion. Methods: The total phytochemical content of ethyl acetate extract of S. imbricata was analyzed by HPLC. In vitro antioxidant and antidiabetic activities were determined. Ethyl acetate extract of S. imbricata (250 and 500 mg/kg) was administered to diabetic rats for 21 days. Serum glucose, serum insulin, fasting blood glucose, body weight, and homeostasis model assessment of insulin resistance were measured. The hepatic malondialdehyde and antioxidant enzyme activities including superoxide dismutase, catalase, and glutathione peroxidase were evaluated. Sandwich ELISA kits were used to measure pro-inflammatory cytokines IL-6 and tumor necrosis factor-α (TNF-α) in liver tissue homogenate. Pdx-1, Ins-1, and Ins-2 expression levels were assessed using qRT-PCR. Results: S. imbricata had potent antioxidant (IC50=11.75 µg/ mL) and antidiabetic activity (IC50=28.10 µg/mL). HPLC analysis showed the presence of gallic acid, p-coumaric acid, salicylic acid, chlorogenic acid, caffeic acid, and quercetin. S. imbricata extract significantly (P<0.05) reduced blood glucose levels with marked improvement in insulin sensitivity and reduced insulin resistance. S. imbricata leaf extract improved malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase levels in hepatic tissue. S. imbricata leaf extract also decreased levels of TNF-α and IL-6 (P<0.05). qRT-PCR revealed the upregulation of insulin signaling transduction genes (Pdx-1, Ins-1, Ins-2). Conclusions: S. imbricata ethyl acetate extract exhibits pronounced antidiabetic activity in rats by improving insulin resistance via modulation of insulin signaling pathway and alleviating oxidative stress.