Relaxant activity of methanolic extract from seeds of Peganum harmala on isolated rat aorta.
The activity of methanolic extract from the seeds of Peganum harmala L. (MEP) on vascular smooth muscle (rat aorta) was investigated. MEP induced relaxation in aorta precontracted with noradrenaline (10(-6) M) or KCl (80 mM) (IC50 = 14.49 +/- 1.15 and 5.93 +/- 1.26 micrograms/mL, respectively) in a dose-dependent manner and this relaxant effect was not endothelium-dependent. The vasodilatory effects were potentiated by isoprenaline (10(-9) M) (1.08 +/- 0.14 micrograms/mL) and negatively affected by a non-specific inhibitor of phosphodiesterase, IBMX (10(-4) M) (20.81 +/- 1.06 micrograms/mL). Pretreatment with MEP (3, 6, 18 micrograms/ml) shifted the phenylephrine-induced dose-response curves to the right and the maximum response was attenuated, indicating that the antagonist effect of MEP on alpha 1-adrenoceptors was non-competitive. These results suggest that MEP exerts a vasodilatory effect not related to the presence of endothelium and the main mechanism may be related to the inhibition of cyclic AMP phosphodiesterase.
Berrougui
H
H
Departament of Pharmacology, Faculty of Pharmacy, C/Profesor García González s/n, 41012 Sevilla, Spain.
Herrera-Gonzalez
M D
MD
Marhuenda
E
E
Ettaib
A
A
Hmamouchi
M
M
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D000432:Methanol; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D032443:Peganum / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012639:Seeds / Q000737:chemistry; D012997:Solvents; D014662:Vasoconstrictor Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology
D010936:Plant Extracts; D012997:Solvents; D014662:Vasoconstrictor Agents; D000432:Methanol