Cardiovascular Effects of the Essential Oil of Alpinia zerumbet Leaves and its Main Constituent, Terpinen-4-ol, in Rats: Role of the Autonomic Nervous System

Saad Lahlou; Charles Antonio Barros Galindo; José Henrique Leal-Cardoso; Manassés Claudino Fonteles; Gloria Pinto Duarte

doi:10.1055/s-2002-36336

Planta Med 2002; 68(12): 1097-1102
DOI: 10.1055/s-2002-36336

Original Paper

Cardiovascular Effects of the Essential Oil of Alpinia zerumbet Leaves and its Main Constituent, Terpinen-4-ol, in Rats: Role of the Autonomic Nervous System

Saad Lahlou¹ , Charles Antonio Barros Galindo¹ , José Henrique Leal-Cardoso² , Manassés Claudino Fonteles³ , Gloria Pinto Duarte¹

¹Departamento de Fisiologia e Farmacologia, Universidade Federal de Pernambuco, Recife-PE, Brasil
²Departamento de Ciências Fisiológicas, Universidade Estadual do Ceará, Fortaleza-CE, Brasil
³Faculdade de Veterinária, Universidade Estadual do Ceará, Fortaleza-CE, Brasil

Abstract

Cardiovascular effects of intravenous (i. v.) treatment with the essential oil of Alpinia zerumbet (EOAZ) were investigated in rats. Additionally this study examined (I) whether the autonomic nervous system is involved in the mediation of EOAZ-induced changes in mean aortic pressure (MAP) and heart rate (HR), and (II) whether these changes could be, at least in part, attributed to the actions of terpinen-4-ol (Trp-4-ol), the major constituent of EOAZ. In both pentobarbitone-anaesthetised and conscious rats, i. v. bolus injections of EOAZ (1 to 20 mg/kg) elicited immediate and dose-dependent decreases in MAP. In anaesthetised rats, EOAZ decreased HR only at higher doses (10 and 20 mg/kg), while changes of this parameter were not uniform in conscious rats. Hypotensive responses to EOAZ were of the same order of magnitude or duration, irrespective of whether the animal was under general anaesthesia. Pretreatment of anaesthetised rats with bilateral vagotomy did not modify significantly the hypotensive and bradycardic responses to EOAZ. In conscious rats, i. v. injections of bolus doses (1 to 10 mg/kg) of Trp-4-ol also elicited immediate and dose-dependent decreases in MAP. However, these hypotensive effects were significantly greater than those evoked by the same doses of EOAZ (1 to 10 mg/kg). Intravenous pretreatment of conscious rats with either methylatropine (1 mg/kg) or hexamethonium (30 mg/kg) had no significant effects on the EOAZ-induced hypotension. These data show that i. v. treatment with the EOAZ in either anaesthetised or conscious rats induced an immediate and significant hypotension, an effect that could be partially attributed to the actions of Trp-4-ol. The hypotension appears independent of the presence of an operational sympathetic nervous system, suggesting that the EOAZ may be a direct vasorelaxant agent.

Key words

Alpinia zerumbet - Zingiberaceae - essential oil - terpinen-4-ol - cardiovascular effects - autonomic nervous system - rat

Full Text