Comparison of antiplatelet activity of garlic tablets with cardio-protective dose of aspirin in healthy volunteers: a randomized clinical trial

Document Type: Original Research Article


1 Department of Pharmacotherapy, Faculty of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran

2 Department of phytopharmaceuticals , Faculty of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran

3 Department of Cardiology, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran


Objective: Some of the adverse effects of aspirin including peptic ulcers, gastrointestinal bleeding and aspirin resistance compelled researchers to find a suitable alternative with fewer adverse effects. In this clinical trial, we aimed to find the effective antiplatelet dose of garlic.
Materials and Methods: This randomized controlled clinical trial (RCT) was conducted on 62 healthy volunteers of 20-50 years old. All volunteers used 80 mg aspirin per day for 1 week and at the end of this time, platelet aggregation (PA) induced by 4 agonists acting in aggregation pathway including adenosinediphosphate (20 μmol/l), epinephrine (20 μmol/l), collagen(0.19 mg/ ml) and arachidonic acid (0.5mg/ ml) was measured by Light Transmittance Aggregometry (LTA) in all participants. After one month washout period, volunteers were randomized into 3 groups and each received 1, 2 or 3 garlic tablets (1250 mg) a day for 1 month. After one month, PA was examined in all groups.
Results: The mean ±SD of the age of all volunteers was 28.60 ± 9.00 years. In addition, 52.00 % of our volunteers were male and 48.00% of them were female. Garlic tablet didnot have significant effect on PA at any dose. However, 30% of volunteers in the group that used 3 garlic tablets/day reported adverse effect (i.e. bleeding). No significant association between sex, age and PA was observed.
Conclusion:  In this study, we were unable to determine the effective anti-platelet dose of garlic which that could be equal to that of aspirin anti-platelet activity, as assessed LTA method.


Main Subjects

Afzal M, Ali M, Thomson M, Armstrong D. 2000. Garlic and its medicinal potential. Inflammopharmacology, 8: 123-148.

Agarwal KC. 1996. Therapeutic actions of garlic constituents. Med Res Rev, 16:111-124.

Angiolillo DJ, Suryadevara S, Capranzano P, Zenni MZ, Guzman LA, Bass TA. 2009. Antiplatelet drug response variability and the role of platelet function testing: a practical guide for interventional cardiologists.Cathet Cardiovasc Interv, 73: 1-14.

Angiolillo DJ. 2009. Variability in responsiveness to oral antiplatelet therapy. Am J Cardiol, 103: 27A-34A.

Apitz-Castro R, Escalante J, Vargas R, Jain Mk.  1986. Ajoene, the antiplatelet principle of garlic, synergistically potentiates the antiaggregatory action of prostacyclin, forskolin, indomethacin and dypiridamole on human platelets. Thromb Res, 42: 303-311.

Bordia A, Verma S, Srivastava K. 1998. Effect of garlic (Allium sativum) on blood lipids, blood sugar, fibrinogen and fibrinolytic activity in patients with coronary artery disease. Prostaglandins Leukot Essent Fatty Acids, 58: 257-263.

Ernst E. 1986. Cardiovascular effects of garlic (Allium sativum): a review. Pharmatherapeutica, 5: 83-89.

Farré AJL, Tamargo J, Mateos-cáceres PJ, Azcona L, Macaya C. 2010. Old and new molecular mechanisms associated with platelet resistance to antithrombotics. Pharmaceut Res, 27: 2365-2373.

Gupta N, Porter TD. 2001. Garlic and garlic-derived compounds inhibit human squalene monooxygenase. J Nutr, 131: 1662-1667.

Hiyasat B, Sabha D, Grötzinger K, Kempfert J, Rauwald JW, Mohr FW, Dhein S. 2009. Antiplatelet activity of Allium ursinum and Allium sativum. Pharmacology, 83: 197-204.

Jain AK, Vargas R, Gotzkowsky S, Mcmahon FG. 1993. Can garlic reduce levels of serum lipids? A controlled clinical study. Am J Med, 94: 632-635.

Johnson J, Decker S, Zaharevitz D, Rubinstein L, Venditti J, Schepartz S, Kalyandrug S, Christian M, Arbuck S, Hollingshead M. 2001.Relationships between drug activity in NCI preclinical in vitro and in vivo models and early clinical trials. Br J Canc, 84:1424.

Kuliczkowski W, Witkowski A, Polonski L, Watala C, Filipiak K, Budaj A, Golanski J, Sitkiewicz D, Pregowski J. Gorski J. 2009. Interindividual variability in the response to oral antiplatelet drugs: a position paper of the Working Group on antiplatelet drugs resistance appointed by the Section of Cardiovascular Interventions of the Polish Cardiac Society, endorsed by the Working Group on Thrombosis of the European Society of Cardiology. Eur Heart J, 30: 426-435.

Kushner FG, Hand M, Smith SC, King SB, Anderson JL, Antman EM, Bailey SR, Bates ER, Blankenship JC, Casey DE. 2009. focused updates: ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction (updating the 2004 guideline and 2007 focused update) and ACC/AHA/SCAI guidelines on percutaneous coronary intervention (updating the 2005 guideline and 2007 focused update): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol, 54: 2205-2241.

Lau BH, Adetumbi MA, Sanchez A. 1983. Allium sativum (garlic) and atherosclerosis: a review. Nutr Res, 3: 119-128.

Lawson LD, Ransom DK, Hughes BG. 1992. Inhibition of whole blood platelet-aggregation by compounds in garlic clove extracts and commercial garlic products. Thromb Res, 65: 141-156.

Longo D, Fauci A, Kasper D, Hauser S. 2011. Harrison's Principles of Internal Medicine, 18, New York, McGraw-Hill Professional.

Makheja A, Bailey J. 1990. Antiplatelet constituents of garlic and onion. Agents actions, 29: 360-363.

Schaffer EM, Liu JZ, Green J, Dangler CA, Milner JA. 1996. Garlic and associated allyl sulfur components inhibit N-methyl-N-nitrosourea induced rat mammary carcinogenesis. Canc Lett, 102: 199-204.

Scharbert G, Kalb ML.,Duris M, Marschalek C, Kozek-Langenecker SA. 2007. Garlic at dietary doses does not impair platelet function. Anesth Analg, 105: 1214-1218.

Sendl A. 1995. Allium sativum and Allium ursinum: Part 1 Chemistry, analysis, history, botany. Phytomedicine, 1: 323-339.

Srivastava K. 1993. Antiplatelet principles from a food spice clove (Syzgiumaromaticum L). Prostaglandins Leukot Essent Fatty Acids, 48: 363-372.

Steiner M, Li W. 2001. Aged garlic extract, a modulator of cardiovascular risk factors: a dose-finding study on the effects of AGE on platelet functions. J Nutr, 131: 980S-984S.

Wagner H, Wierer M, Fessler  B. 1987. Effects of garlic constituents on arachidonate metabolism. Planta Med, 53: 305-306.