Background: Allium sativum, the active ingredient in garlic, is known to have a beneficial effect on major cardiovascular risk factors, including dyslipidemia, blood pressure, blood glucose and insulin levels. However, the data on the significance of these effects are inconsistent due to methodological limitations, especially the use of whole garlic cloves which does not allow controlled dosing of the active compound.

Objectives: To study the effects of purified allicin on the cardiovascular system.

Methods: Spontaneously hypertensive rats treated for 6 weeks with a daily dose of 80 mg/kg/day of purified allicin added to their chow were compared to control rats that were fed regular chow. Weight, systolic blood pressure (SBP), triglycerides, cholesterol, insulin and adiponectin were measured at baseline and at the end of the study.

Results: Allicin had no effect on body weight whereas it reduced SBP significantly from 190 ± 7.5 mmHg to 168 ± 5.7 (P < 0.0001) and triglyceride levels from 96 ± 25 mg/dl to 71 ± 19 (P =0.009). Allicin had no effect on plasma cholesterol, insulin and adiponectin levels.

Conclusions: Allicin lowers blood pressure and triglyceride levels in spontaneously hypertensive rats. This effect is not mediated through weight loss.