Effect of Standardized Hydroalcoholic Extract of Saffron Stamen on High Blood Pressure and Baroreflex Sensitivity in Anesthetized Rats

Abstract

Objective: The stamen is a byproduct of saffron (Crocus sativus) flowers. Herein, its cardiovascular effects were evaluated on hypertension induced by angiotensin II (AngII) and NG-nitro-Larginine methyl ester (L-NAME), as well as baroreflex sensitivity (BRS).

Methods: Rats were randomly divided into 10 groups: 1) control, 2) AngII (50 ng/kg, i.v.), 3) losartan (10 mg/kg, i.p.) + AngII, 4) L-NAME (10 mg/kg, i.v.), 5) sodium nitroprusside (SNP) (50 mg/kg, i.p.) + L-NAME, 6, 7) saffron stamen extract (SS) (100 and 200 mg/kg, i.p.) + AngII and 8, 9) SS (100 and 200 mg/kg) + L-NAME, and 10) SS (200 mg/kg) + phenylephrine (Phen, i.v.). The treated rats first received two doses of SS, 30 min after the injection of L-NAME, AngII, and Phen in separate groups. The cardiovascular parameters were recorded by the PowerLab apparatus via an angiocatheter inserted into the femoral artery. The maximal changes (Δ) of mean arterial pressure (MAP), systolic blood pressure (SBP), and heart rate (HR) in the treated groups were compared with those of the hypertensive and control groups. The changes in MAP and HR induced by Phen were used for BRS evaluation.

Results: The SS extract did not significantly affect the basal cardiovascular parameters. The injection of AngII significantly increased the MAP and SBP (P<0.01-P<0.001) with no significant effect on the HR. The SS extract significantly attenuated the pressor effect induced by AngII (P<0.001). Increased MAP and SBP induced by L-NAME (P<0.001) were also significantly attenuated by the SS extract (P<0.01). The effect of SS extract on L-NAME was significantly higher than that of AngII (P<0.05). Moreover, BRS was significantly improved by the SS extract.

Conclusion: Our findings provide evidence that the SS extract has anti-hypertensive effects that are probably mediated by an inhibitory effect on AngII, increasing nitric oxide production, or improving baroreflex sensitivity.

Keywords: L-NAME; Saffron stamen; angiotensin II; baroreflex sensitivity.; hypertension.