Ammodaucus leucotrichus Acts as an Antihypertensive and Vasorelaxant Agent Through sGC and Prostaglandin Synthesis Pathways

Background: Ammodaucus leucotrichus is a medicinal plant used in traditional medicine to treat various ailments, including hypertension. Aims: The study aimed to determine the antihypertensive activity of Ammodaucus leucotrichus. Objective: The study aimed to investigate the antihypertensive and vasorelaxant activities of the aqueous extract of Ammodaucus leucotrichus fruits (ALAE) in rats. Methods: ALAE was prepared to study its antihypertensive effect in L-NAME (Nω-L-arginine methyl ester)-induced hypertensive rats and its vasorelaxant activity in isolated thoracic aortas of rats. The acute and subchronic effects of ALAE on systolic, diastolic, mean arterial pressure, and heart rate (HR) were evaluated after oral administration of ALAE (60 and 100 mg/kg body weight) for 6 h for the acute experiment and over 7 days for the subchronic test. Isolated thoracic aortic rings were prepared to examine the vasorelaxant action of ALAE. Several common pharmacological agents were used to test potential pathways implicated in vasorelaxant action. Results: The results showed that ALAE reduced blood pressure parameters (systolic, mean, and diastolic blood pressure) in L-NAME-induced hypertension rats after repeated oral treatment over seven days without affecting normotensive rats. Furthermore, in thoracic aortic rings pre-contracted with epinephrine (EP) (10 μM) or KCl (80 mM), ALAE (0.250-1.625 mg/ml) showed a vasorelaxant effect. In isolated rat thoracic aortas, blockage of soluble guanylyl cyslase with blue methylene (P < 0.01) partially decreased this vasorelaxant effect. In addition, blockage of the prostaglandin synthesis pathway with indomethacin (P<0.05) also reduced the vasorelaxant activity of ALAE. Pretreatment of aortic rings with glibenclamide, propanolol, L-NAME, MLN-4760, or nifedipine did not affect ALAE-induced vasorelaxation. Conclusion:Ammodaucus leucotrichus is a prescient medicinal plant, able to act as an antihypertensive agent. Moreover, the results suggest that the extract increased cGMP in NO-independent manner.