Effects of hydroalcoholic extract of saffron petal on blood pressure and heart rate in hypertension induced by angiotensin II and L-NAME in anesthetized rats

Abstract

The saffron petals are a by-product part of the saffron flower with a cardiovascular effect. This study evaluated the effect of the saffron petal on hypertension induced by angiotensin II (AII) and NG-nitro-L-arginine methyl ester (L-NAME, a NOS inhibitor). Rats were divided into 11 groups: 1) Control, 2) AII (50.00 ng kg^-1), 3) Losartan+ AII, 4) L-NAME (10.00 mg kg^-1), 5) sodium nitroprusside (SNP) + L-NAME, 6, 7) Saffron petals extract; 8, 9) saffron petals (100 and 200 mg kg^-1) + AII and 10,11) saffron petals (100 and 200 mg kg^-1) + L-NAME. Hypertension induced by intravenous injection of AII and L-NAME in separate groups. In treated groups, 30 min before injection of AII or L-NAME rats received two doses of extract via intraperitoneal administration. The femoral artery was cannulated and cardiovascular parameters recorded by a transducer connected to power lab apparatus. Maximal changes (∆) of mean arterial pressure (MAP), systolic blood pressure (SBP) and heart rate (HR) from baseline were calculated and compared to with those in hypertensive and control groups. Results showed that both AII and L-NAME significantly increased SBP and MAP than control, however, HR in AII was decreased and in the L-NAME group increased. Pre-treatment with saffron petals could significantly attenuate the cardiovascular responses induced by both AII and L-NAME. However, the effect of the extract in AII hypertensive rats was more effective than L-NAME groups. The findings showed that the hydroalcoholic extract of the saffron petals had an antihypertensive effect that mainly was mediated by inhibition of AII activity.

Keywords: Angiotensin II; Hypertension; L-NAME; Saffron petal.

Fig. 1

A recording sample of cardiovascular responses induced by intravenous administration of A) AII alone, B) AII + saffron petal (SP) 200 mg kg^-1, C) L-NAME alone and D) L-NAME + saffron petal 200 mg kg^-1. The line indicates time of injection. PBP: Pulsatile blood pressure, MAP: Mean arterial pressure, HR: Heart rate

Fig. 2

Effects of two doses (100 and 200 mg kg^-1) of hydroalcoholic extract of saffron petal (SP) on A) Heart rate, B) Systolic blood pressure and C) Mean arterial pressure in angiotensin II (AII) hypertensive rats. The data are expressed as mean ± SEM. Los: Losartan

Fig. 3

Effects of two doses (100 and 200 mg kg^-1) of hydro-alcoholic extract of saffron petal (SP) on A) Heart rate, B) Systolic blood pressure and C) Mean arterial pressure in L-NAME hypertensive rats. The data are expressed as mean ± SEM.  SNP: Sodium nitroprusside