Anti-diabetic Properties of Thymoquinone is unassociated with Glycogen Phosphorylase Inhibition

Background: Nigella sativa L. (Black seed), is commonly used by traditional healers as a remedy for more than four thousand years. The antidiabetic property of N. sativa seeds oil is attributable to the presence of Thymoquinone (TQ). On the other hand many studies have been designed to investigate the possible effects of the TQ in Streptozotocin (STZ) and nicotinamide (NA)-induced diabetes in rats. Aim of the study: The aim of this study was to elucidate the mechanisms underlying the glucose lowering effects of thymoquinone. Methods: In vitro and in silico using glycogen phosphorylase (GPa) enzyme assay and docking tools were used. Results: Oral administration of TQ for 60 days, dose dependently improved the glycemic status in STZ-NA induced diabetic rats. GPa activity was measured in the direction of glycogen synthesis by the release of phosphate from glucose-1-phosphate. TQ at a concentration of 0.05 Mm inhibits GPa activity by only 14.9%. Conclusion: These results show that TQ at 60 mg/kg b.w is associated with potential antihyperglycemic effects. Furthermore, anti-diabetic properties of TQ are unassociated with glycogen phosphorylase inhibition.