<p>GLP-1 mediates the modulating effect of thymoquinone on feeding behaviors in diabetic rats</p>

Abstract

Background: Thymoquinone (TQ) is a safe nutrient isolated from the seeds or volatile oil extract of Nigella sativa . In addition to its benefits in glucose regulation, TQ improves feeding disorders in diabetic animals. Glucagon-like peptide-1 (GLP-1) analogs improve glycemic control and ameliorate obesity or hyperphagia. Therefore, the present study aimed to investigate the role of GLP-1 in TQ-induced anorexia. Method: Type 2 diabetes was induced in rats by nicotinamide and streptozotocin injection. TQ was orally administered to diabetic rats at different doses for 45 days. Following TQ treatment, changes in serum glucose levels, GLP-1 concentration, body weight, food intake, and water intake were determined. To further explore the interaction between GLP-1 and TQ, the inhibitor of dipeptidyl peptidase 4, sitagliptin and the GLP-1 receptor antagonist exendin 9–39 (Ex 9–39) were separately administered to TQ- or vehicle-treated diabetic rats. Results: TQ treatment attenuated hyperglycemia and reduced hyperphagy and water intake in streptozotocin-induced diabetic rats in a dose-dependent manner. Moreover, TQ treatment elevated plasma GLP-1 levels compared to those in control rats. The effects of TQ were enhanced by treatment with sitagliptin and reduced by the injection of Ex 9–39 into the brain. In contrast, similar treatment with another antioxidant (either ascorbic acid or N-acetylcysteine) produced the same anorexic effect as TQ without changing the plasma GLP-1 levels in diabetic rats. Therefore, TQ attenuated hyperphagy while increasing plasma GLP-1 levels and had antioxidant-like effects. Conclusion: TQ increased endogenous GLP-1 levels to reduce hyperphagy in diabetic rats.

Effect of Nigella Sativa Oil on Oxidative Stress, Inflammatory, and Glycemic Control Indices in Diabetic Hemodialysis Patients: A Randomized Double-Blind, Controlled Trial

“…Insulin secretion is affected by a variety of factors. NS can increase insulin secretion by increasing GLP1 secretion [46,47], stimulating beta-adrenergic receptors [48], proliferating and regenerating pancreatic beta cells [49,50], and decreasing serum glucagon [51,52]. In addition, black seed can increase the sensitivity of insulin receptors by increasing the production of p-IRS and p-AKT and decreasing leptin secretion [32,53].…”

Effects of Nigella sativa, Camellia sinensis, and Allium sativum as Food Additives on Metabolic Disorders, a Literature Review

“…Researchers reported that administration of 50 and 100 mg/kg/day of TQ could reduce the level of glucose, HOMA-IR, and food and water intake in diabetic rats. These effects of TQ were carried out through enhancing the endogenous level of glucagon-like peptide 1 ( Lee et al, 2019 ).…”

Therapeutic perspective of thymoquinone: A mechanistic treatise

“…Thymoquinone being potent anticancer agent significantly lowers the hypoxia‐inducible factor‐1α (HIF‐1α) expression, inhibits interaction between HSP90 and HIF‐1α, and boosts HIF‐1α protein degradation in hypoxic cancer cells. It also suppresses the downstream genes of HIF‐1α, exhibited alterations in concentrations of lactate, glucose, and ATP levels, which further linked with disturbance of anaerobic metabolic and induction of apoptosis (Lee, Kuo, et al, 2019; Lee, Kim, et al, 2019). Thymoquinone also suppresses the cancer cell stages and the activation of PI3K/Akt pathway in oral squamous cell carcinoma (Ren & Luo, 2019).…”

“…Glucagon‐like peptide‐1 (GLP‐1) analogs have been found to improve the glycemic control, while administration of streptozotocin is used to induce the diabetes in experimental subjects. In diabetic rats, supplementation of thymoquinone by using oral route in dose‐dependent manner exhibited elevation in plasma GLP‐1 levels by lowering the hypergaphy (Harphoush et al., 2019; Lee et al, 2019; Lee, Kim, et al, 2019). In diet‐induced obesity mouse model, supplemented thymoquinone at the rate of 20 mg/kg BW per day prevented diabetic phenotype via lowering the glucose concentration, fasting insulins, serum cholesterol, triglycerides, and inflammatory markers resistin and MCP‐1, improving the glucose tolerance and insulin sensitivity, and enhancing the phosphorylated Akt level, whereas it phosphorylated SIRT‐1 in skeletal muscle and phosphorylated SIRT‐1 and AMPKα in liver (Shpetim et al, 2017).…”