Antioxidative activities of alpha-mangostin in high-fat/high-glucose diet and streptozotocin-induced insulin-resistant rodents

Abstract

Insulin resistance (IR), of which pathomechanism is mainly mediated by oxidative stress, leads to impaired insulin secretion and multisystem damages. Recent evidence suggests that alpha-mangostin (α-MG) is a potential candidate to ameliorate oxidative stress; hence, this study aims to evaluate the antioxidative properties of α-MG in IR-induced rats. A total of 36 male Wistar rats were divided into six groups, i.e., control, control + a-MG (200 mg/kg), IR, IR + metformin, and IR + various doses of α-MG (100 and 200 mg/kg) which were administered via oral gavage for 8 weeks. IR was induced by administering high-fat/high-glucose diet for 11 weeks followed by a single streptozotocin injection (35 mg/kg, i.p.). Malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH) activities were assayed to assess the oxidative stress between groups. Welch's analysis of variance and Kruskal-Wallis test were used to compare the data. This study demonstrated that α-MG remarkably decreased MDA and increased SOD as well as GSH activities in the heart, liver, and kidney tissues of IR model. Furthermore, α-MG also upregulated SOD activity in heart tissues in a dose-dependent manner. Besides its antioxidative effects, the administration of α-MG at 200 mg/kg was also associated with the upregulation of skeletal glucose transporter type 4 expression (2.50 ± 0.43 vs. control, 3.65 ± 0.36 ng/ml; p < 0.05). These findings suggest that α-MG yielded the potent antioxidative properties against IR rats.