Evaluation of vascular effects of aqueous Crocus sativus petals’ extract in the hypertensive rats

Background and Aim: Crocus sativus (C. sativus) petals attenuates smooth muscle tension and blood pressure in control animals. However the antihypertensive effect and its mechanisms haven’t been recognized. This study investigates the antihypertensive effects of C. sativus petals’ aqueous extract in hypertensive rats and also responses of the rat isolated perfused mesenteric bed. Materials and Methods: The interventional experimental study was performed on 20 male rats (divided to 5 and 15 rats for in vivo and in vitro studies respectively). Hypertension was induced by DOCA-salt injection (20 mg/kg, twice weekly, for 5 weeks, S.C) and water was replaced by NaCl (1%). Five weeks later, animals were anaesthetized with sodium thiopental (30 mg intraperitoneal). Then systemic arterial blood pressure was measured by cannulation of carotid artery following administration of different doses of aqueous extract of C. sativus. Isolated mesenteric beds precontracted with KCl (40 mM), and the tension was measured in presence of different concentrations of the aqueous extract. Finally, various doses of C. sativus extract were applied after incubation by L-NAME or indomethacin. The mesentry was perfused with pump and the recordings were done by physiograph. Results: Mean arterial blood pressure in hypertensive rats was 231±6 mmHg. Administration of aqueous extracts of C. sativus reduced the blood pressure in a dose–dependent manner. In mesenteric beds preparation, addition of C. sativus reduced the contractile effects of KCl. Incubation with L-NAME but not indomethacin abolished hypotension effect of the extract. Conclusion: It was proposed that the antihypertensive effects of C. sativus petals’ extract are through the reduction in total peripheral resistance following nitric oxide production.