Endothelium-dependent and -independent effect of aqueous extract of garlic on vascular reactivity on diabetic rats.

Garlic has been well known for its protective effects against cardiovascular disease. In this study, the effect of aqueous extract of garlic on the vascular reactivity of thoracic aorta from streptozotocin (STZ)-diabetic rats was investigated in the presence and absence of endothelium. Although, 8-weeks of treatment with garlic extract had no significant effect on the concentration of serum glucose, but it significantly attenuated the abnormality in vascular reactivity to noradrenaline (NA) and acetylcholine (Ach). In addition, the endothelium-independent relaxation response to isosorbide dinitrate (ISD) was not affected by diabetes or garlic treatment. The results suggest that garlic treatment of STZ-diabetic rats can prevent the development of abnormal contractility through an endothelium-dependent and -independent mechanism.