Effect of Aqueous Garlic (Allium sativum L.) Extract on Acetylcholine and Isosorbide-Induced Relaxation of Isolated Aorta in Rat

The hypotensive effect of garlic has been well-documented in human subjects and animals. Since endothelial activity regulates vascular reactivity in physiological and pathophysiological conditions, the aim of the present study was to investigate the effect of garlic on endothelium-dependent and independent relaxation of rat aorta for elucidation of mechanism of the garlic anti-hypertensive effect. Four and eight weeks after treatment with garlic extract, aortic rings were studied for relaxation response to acetylcholine and isosorbide dinitrate. The obtained results showed that endotheliumdependent relaxation response of aortic rings to acetylcholine, from rats treated with garlic for 4 and 8 weeks, increases about 5-24% and 3-27%, respectively compared to controls. But, endotheliumindependent relaxation response to isosorbide showed no difference in all groups. Moreover, the relaxant effect of garlic extract was time-dependent. The obtained findings strongly suggest that garlic exerts its relaxant effect through endothelium by production and/or releasing of endothelium-derived relaxing factor. Iran. Biomed. J. 7 (1): 23-27, 2003