Effects of hippadine on the blood pressure and heart rate in male spontaneously hypertensive Wistar rats.

Ethnopharmacological relevance: Hippadine is an alkaloid isolated from Crinum macowanii. Crinum macowanii is used in South Africa to treat oedema, 'heart disease', rheumatic fever, cancer and skin diseases, and belongs to the plant family Amaryllidaceae, assumed to have originated in the South African region. The aim of this study was to evaluate the effect of hippadine, an alkaloid extracted from Crinum macowanii, on the blood pressure (BP) and heart rate (HR) in anaesthetized male spontaneously hypertensive Wistar rats (SHR); and to find out if α1 and or β1 adrenoceptors contribute to its effects.

Materials and methods: Hippadine (2.5-12.5 mg/kg), adrenaline (0.05-0.20 mg/kg), atenolol (0.5-40 mg/kg) and prazosin hydrochloride (100-500 μg/kg) were infused intravenously, and the BP and HR measured via a pressure transducer connecting the femoral artery and the PowerLab. Adrenaline increased the systolic, diastolic and mean arterial BP, while hippadine, atenolol and prazosin respectively decreased the systolic, diastolic and mean arterial BP. Increases in HR were observed with both adrenaline and prazosin, while reductions in HR were observed with atenolol and hippadine. Infusion of adrenaline in rats pre-treated with atenolol (30 mg/kg), prazosin (400 μg/kg), and hippadine (10 mg/kg) led to similar increases in BP and HR in all groups. All changes in HR or BP were significant (p<0.05) and dose dependent.

Conclusion: Hippadine decreases the BP and HR in SHR, and these effects may be due to α1 and β1 adrenoceptor inhibition.