Garlic oil may help release protective compounds for the heart during a heart attack, during cardiac surgery, or for congestive heart failure. The active compound is diallyl trisulfide, which can deliver hydrogen sulfide gas to the heart. In studies in mice when a coronary artery is tied off there is 61% less damage when diallyl trisulfide is administered. It lowers free radical levels in the mitochondria by turning down mitochondrial function and lowering free radical production.
Garlic has many other compound such as allicin, which helps reduce blood pressure, has an anticoagulant effect, and may also lower cholesterol and blood sugar levels. There are three "gasotransmitters," nitric oxide, hydrogen sulfide, and carbon dioxide, that affect blood flow in large and small arteries.
The key substance in hydrogen sulfide is sulfur. There are three amino acids high in sulfur: cysteine, methionine, and taurine. Foods high in these substances include eggs, garlic, and many cruciferous veggies, as well as fruits such as blueberries, cheries and grapes.