Preliminary Characterization of the Vasorelaxant Effect of Thymus atlanticus (Ball) Roussine using Optical Methods

Abstract

Background: Thymus atlanticus (Ball) Roussine is a Moroccan endemic thyme species that is traditionally used as an aromatic and medicinal plant. Several studies have demonstrated its pharmacological significance and therapeutic value. Objective: The current study aimed to assess the vasorelaxant effect of the aqueous extract of this species. Methods: The contractility of isolated rat aortas was investigated using the multi-well organ bath technique. This method was adapted and validated in our experimental conditions using epinephrine and hydralazine as vasoconstrictive and vasodilator agents, respectively. The application of 10 μM epinephrine induced a clear vasoconstriction of the aorta rings (Lumen reduction = 31.8±0.4%). However, hydralazine induced a dose-dependent relaxation with an EC50 value of 6.1±1.2 mM. For the aqueous extract of T. atlanticus, the aortic rings were precontracted with epinephrine, and then increasing concentrations (0.125-1 mg/mL) of this extract were added cumulatively. Results: The results have indicated T. atlanticus extract to have a significant vasodilatory effect in a dose-dependent manner (EC50 = 0.52±0.03 mg/mL). Conclusion: The findings provide preliminary evidence of the vasorelaxant effect of the aqueous extract of T. atlanticus using a low-cost optical approach. However, the cellular and molecular mechanisms underlying this effect have yet to be revealed.