Polysulfides and H2S

Oct 17, 2007 09:55 GMT  ·  By

It may not be recommended to eat garlic before going on a date, but a new research from the University of Alabama at Birmingham (UAB) has found it to be one of the best methods to decrease high blood pressure and defend yourself against cardiovascular disease.

This protective effect could be due to the interaction between garlic chemicals and red blood cells. This makes red blood cells release hydrogen sulfide (H2S), which determines the relaxation of blood vessels. Following the ingestion of two cloves of fresh garlic, the resulting H2S provoked up to 72 % vessel relaxation in rat arteries.

"This relaxation is a first step in lowering blood pressure and gaining the heart-protective effects of garlic," said lead author Dr. David Kraus, a UAB associate professor in the Departments of Environmental Health Sciences and Biology.

The "culprit" garlic's molecules believed to cause H2S release are polysulfides.

"When these garlic compounds are metabolized to H2S in the vascular system, the H2S targets membrane channels and causes smooth muscle cells to relax. So a garlic-rich diet has many good effects, and H2S may be the common mediator." said Kraus.

A previous research made by Dr. John Elrod and Dr. David Lefer, of the Albert Einstein College of Medicine revealed that H2S protects the heart from the tissue and cell damage observed in heart attack patients.

The new study is the first to connect garlic's polysulfides to increase bodily H2S production. H2S is a toxic, flammable gas, producing the smell of rotten eggs and it is also naturally synthesized by the body in small quantities. With the aging, H2S synthesis decreases.

"Exactly how H2S affords the cardiovascular system so much protection is not entirely clear, but it may involve limiting oxidative damage in cells. The role of garlic compounds in preventing platelet aggregation, which can trigger a heart attack or stroke, and in limiting cancer growth and the progression of several diseases is well documented," said Kraus.