Effects of Salvia mirzayanii extract administration on hyperglycemia improvement in diabetic rats: The role of GLUT4, PEPCK and G6Pase genes

Diabetes is a dangerous metabolic disorder by increasing incidence in human societies worldwide. Recently, much attention has been focused on the development of hypoglycemic agents, particularly the derivatives of herbal drugs, in the treatment of diabetes. This research aimed to study the anti-diabetic effect of Salvia mirzayanii in the diabetic rat models. First, the plant material was extracted from the leaves, and orally administered to the rats. After treating the animals with the aqueous extract of S. mirzayanii at a dose of 600 mg/kg, animal body weight for 12 weeks, fasting blood glucose, oral glucose tolerance test (OGTT), and body weight changes were examined. To analyze the anti-diabetic function of S. mirzayanii, we measured the expression of glucose transporter-4 (GLUT4), phosphoenolpyruvate carboxykinase (PEPCK), and glucose 6-phosphatase (G6Pase) genes in healthy and streptozotocin (STZ)-diabetic rats. The expression levels of the genes of interest in muscle and liver tissues were determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry (IHC). There were no significant differences in fasting blood glucose and OGTT between normal control (NC) group and the diabetic control (DC) group treated with S. mirzayanii. In contrast, there was a significant difference with the untreated DC (P < 0.05). The treatment of diabetic rats with S. mirzayanii significantly increased the expression of GLUT4 in the muscle and decreased the expression levels of PEPCK and G6Pase in the liver compared to the DC group (P < 0.05). These findings clearly show that S. mirzayanii can improve hyperglycemia by increasing the GLUT4 expression, and inhibiting the gluconeogenesis pathway in the liver. In general, the obtained results provided a new insight into the efficacy of S. mirzayanii aqueous extract as an anti-diabetic herbal medicine

Comparative study of anti-diabetic effects of insulin, epigenin and Salvia mirzayanii extract in streptozotocin-induced diabetic male rats

803-809The use of hypoglycemic medications for diabetes has several limitations, such as adverse reactions and high rates of secondary failure. These adverse effects have forced patients with diabetes to use herbal medicines that have a similar degree of potency without side effects. So, there has been a growing interest in hypoglycemic agents from natural products, in particular, those derived from plant materials. In other words, searching for better agents from herbs or natural products to treat diabetes is duly needed. The purpose of this study was to compare the anti-diabetic effects of Salvia mirzayanii extract with insulin and epigenin in diabetic male rats. The plant material was initially extracted and administered orally to the animals. After treatment of rats with insulin, epigenin or aqueous extract of S. mirzayanii, oral glucose tolerance test (OGTT), fasting blood glucose and animal weight changes were examined. To analyze the molecular function of insulin, epigeninand S. mirzayanii, expression of glucose transporter-4 (GLUT4), phosphoenol pyruvate carboxykinase (PEPCK) and glucose 6-phosphatase (G6Pase) genes in healthy and streptozotocin (STZ)-diabetic male rats were studied as well. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was performed for all groups and the data were normalized using the formula 2-ΔΔCt.Statistical analysis was performed by one-way analysis of variance. In fasting blood glucose and OGTT, there was no significant difference between the normal control group and the diabetic groups treated with insulin, epigenin and S. mirzayanii. But there was a significant difference with the uncontrolled diabetic group (P < 0.05). Meanwhile, the uncontrolled diabetic group gained less weight compared to the other groups. RT-qPCR of beta-actin, GLUT4, G6Pase and PEPCK genes yielded products with lengths of 228, 140, 79 and 151 bp, respectively. In gene expression studies, there was a significant difference between the mRNA levels of GLUT4, G6Pase and PEPCK in control groups and the groups treated with insulin, epigenin and S. mirzayanii. The greatest effect on increasing the mRNA expression of GLUT4 was related to insulin, epigenin and S. mirzayanii, respectively. The greatest effect in reducing the mRNA expression of PEPCK was related to insulin, epigenin and S. mirzayanii, respectively. The greatest effect in reducing the mRNA expression of G6Pase was also related to insulin, but the effect of epigenin and S.mirzayaniiwas almost the same. Overall, obtained results show that S. mirzayanii can be utilized as a herbal medicationwith insulin and epigenin mimetic-activity