Cardiovascular effects of ginger aqueous extract and its phenolic constituents are mediated through multiple pathways

TY - JOUR

T1 - Cardiovascular effects of ginger aqueous extract and its phenolic constituents are mediated through multiple pathways

AU - Ghayur, M N

AU - Gilani, A H

AU - Afridi, M B

AU - Houghton, P J

PY - 2005/10

Y1 - 2005/10

N2 - Ginger is a world known food plant which is equally reputed for its medicinal properties. We report here the hypotensive, endothelium-dependent and independent vasodilator and cardio-suppressant and stimulant effects of its aqueous extract (Zo(.)Cr). Zo(.)Cr, which tested positive for saponins, flavonoids, amines, alkaloids and terpenoids, induced a dose-dependent (3.0-10.0 mg/kg) fall in the arterial blood pressure (BP) of anaesthetized rats which was partially blocked by atropine (1 mg/kg). In isolated endothelium-intact rat aorta, Zo(.)Cr (0.01-5.0 mg/ml) relaxed the phenylephrine (1 mu M)-induced contractions, effect partially blocked by atropine (1 mu M). Zo-Cr inhibited the K (80 mM)-induced contractions and also shifted the Ca++ dose-response curves to the right, similar to verapamil, indicating Ca++ antagonist activity. An atropine-resistant and L-NAME-sensitive vasodilator activity was also noted from ginger phenolic constituents 6-, 8- and 10-gingerol, while 6-shogaol showed a mild vasodilator effect. In guinea-pig atria, Zo-Cr (0.1-5.0 mg/ml) inhibited the force and rate of atrial contractions. Pretreatment with atropine blocked the inhibitory effect and a stimulatory effect was unmasked which was resistant to propranolol and verapamil but sensitive to ryanodine, blocker of Ca++ release from intracellular stores. Later at doses >= 1.0 mg/ml, the extract completely suppressed the atrial tissue, effect resistant to glibenclamide, pyrilamine, aminophylline and L-NAME. These data indicate that the aqueous ginger extract lowers BP through a dual inhibitory effect mediated via stimulation of muscarinic receptors and blockade of Ca++ channels and this study provides sound mechanistic basis for the use of ginger in hypertension and palpitations. (c) 2005 Elsevier Inc. All rights reserved

AB - Ginger is a world known food plant which is equally reputed for its medicinal properties. We report here the hypotensive, endothelium-dependent and independent vasodilator and cardio-suppressant and stimulant effects of its aqueous extract (Zo(.)Cr). Zo(.)Cr, which tested positive for saponins, flavonoids, amines, alkaloids and terpenoids, induced a dose-dependent (3.0-10.0 mg/kg) fall in the arterial blood pressure (BP) of anaesthetized rats which was partially blocked by atropine (1 mg/kg). In isolated endothelium-intact rat aorta, Zo(.)Cr (0.01-5.0 mg/ml) relaxed the phenylephrine (1 mu M)-induced contractions, effect partially blocked by atropine (1 mu M). Zo-Cr inhibited the K (80 mM)-induced contractions and also shifted the Ca++ dose-response curves to the right, similar to verapamil, indicating Ca++ antagonist activity. An atropine-resistant and L-NAME-sensitive vasodilator activity was also noted from ginger phenolic constituents 6-, 8- and 10-gingerol, while 6-shogaol showed a mild vasodilator effect. In guinea-pig atria, Zo-Cr (0.1-5.0 mg/ml) inhibited the force and rate of atrial contractions. Pretreatment with atropine blocked the inhibitory effect and a stimulatory effect was unmasked which was resistant to propranolol and verapamil but sensitive to ryanodine, blocker of Ca++ release from intracellular stores. Later at doses >= 1.0 mg/ml, the extract completely suppressed the atrial tissue, effect resistant to glibenclamide, pyrilamine, aminophylline and L-NAME. These data indicate that the aqueous ginger extract lowers BP through a dual inhibitory effect mediated via stimulation of muscarinic receptors and blockade of Ca++ channels and this study provides sound mechanistic basis for the use of ginger in hypertension and palpitations. (c) 2005 Elsevier Inc. All rights reserved

U2 - 10.1016/j.vph.2005.07.003

DO - 10.1016/j.vph.2005.07.003

M3 - Article

VL - 43

SP - 234

EP - 241

JO - VASCULAR PHARMACOLOGY

JF - VASCULAR PHARMACOLOGY

IS - 4

ER -