Editors' ChoiceCardiovascular Homeostasis

Vasorelaxation with Garlic? It’s a Gas

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Science's STKE  20 Nov 2007:
Vol. 2007, Issue 413, pp. tw423
DOI: 10.1126/stke.4132007tw423

Garlic is reputed to have various beneficial effects on health, and its consumption has been correlated with a decrease in several risk factors for cardiovascular disease. Noting that garlic is rich in organosulfur compounds and that hydrogen sulfide (H2S), like nitric oxide and carbon monoxide, may act as a gaseous signaling molecule in the cardiovascular system (see Lefer), Benavides et al. investigated the possibility that polysulfide compounds in garlic might provide a source of vascular H2S. Using a polarographic H2S sensor, they showed that addition of garlic juice to human red blood cells (RBCs) elicited H2S production. Glucose, which enabled the maintenance of the pool of reduced RBC glutathione, promoted sustained production of H2S in the presence of garlic; moreover, glutathione plus garlic produced H2S even in the absence of RBCs. Experiments with membrane-permeant and -impermeant thiol-blocking reagents indicated that H2S production involved exofacial RBC membrane thiols, as well as intracellular thiols. H2S produced in the presence of either garlic or garlic-derived polysulfides elicited relaxation of precontracted rat aortic rings, an effect that did not require a functional endothelium. Thus, the authors propose that garlic produces beneficial vasoactive effects by promoting the production of H2S.

G. A. Benavides, G. L. Squadrito, R. W. Mills, H. D. Patel, T. S. Isbell, R. P. Patel, V. M. Darley-Usmar, J. E. Doeller, D. W. Kraus, Hydrogen sulfide mediates the vasoactivity of garlic. Proc. Natl. Acad. Sci. U.S.A. 104, 17977-17982 (2007). [Abstract] [Full Text]

D. J. Lefer, A new gaseous signaling molecule emerges: Cardioprotective role of hydrogen sulfide. Proc. Natl. Acad. Sci. U.S.A. 104, 17907-17908 (2007). [Full Text]

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