Researchers from the University of Alabama at Birmingham have reported in the October 19th Proceedings of the National Academy of Sciences that a compound called allicin is responsible for garlic's heart health benefits.1 Allicin has long been believed to be the active component in garlic. The new research confirms the compound's mechanism of action. Allicin rapidly breaks down to form organic polysulphides (diallyl sulfide, diallyl disulfide, diallyl trisulfide, and ajoene), when these polysulfides come in contact with red blood cells, the red blood cells begin emitting hydrogen sulphide. The hydrogen sulphide triggers the blood vessels to relax, increasing blood flow to the heart and other tissues.
In the initial stages of the study, the researchers extracted juice from fresh garlic and added minute amounts of the juice to the red blood cells; the cells immediately began emitting hydrogen sulphide. As the study progressed and was refined the researchers were able to determine the compounds involved in the reaction and that the reaction occurred at the surface of the cells. The researchers then used intact aorta rings from rats under physiologically relevant oxygen levels as a model for blood vessels. Once again hydrogen sulfide was released and the vessel tension was reduced in a dose-dependant manner. A 200 micromole solution reduced vascular tension by about 40 percent while a 500 micromole solution reduce the tension by about 75 percent. Based on these finding and that garlic is one of the few plants that contain allyl-substituted sulfur compounds, the researchers stated that "hydrogen sulphide production from these garlic-derived organic polysulphides provides the basis for the long-term beneficial effects obtained from the habitual consumption of garlic."
Learn more about the potential heart benefits of garlic here.
1. Benavides, G. A., G. L. Squadrito, et al. (2007). "Hydrogen sulfide mediates the vasoactivity of garlic." Proc Natl Acad Sci U S A.
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