LOS ANGELES: If dark chocolate seems to help to protect the heart, now the U.S. researchers say they have identified the molecular mechanism by which a compound found in cocoa can guard against the damage of a stroke.
The compound, a flavanol called epicatechin, triggers two built-in protective pathways in the brain, according to a report published online last week in the Journal of Cerebral Blood Flow & Metabolism.
The research team was led by Sylvain Dore, an associate professor of anesthesiology and critical care medicine and pharmacology and molecular sciences at Johns Hopkins University School of Medicine in Baltimore, reported China’s Xinhua news agency on Sunday.
A study of the cocoa-drinking Kuna Indians, living on islands off the coast of Panama, led the researchers to study epicatechin.
As an unusually low incidence of stroke and other cardiovascular disease in that population could not be explained by genetic studies, consumption of a very bitter cocoa drink that contains epicatechin was considered a contributor.
Animal studies raise the possibility that epicatechin may someday be used to treat strokes in humans, since its protective effect can be seen more than three hours after a stroke.
Existing stroke treatments typically have a shorter window of activity.
While the cardioprotective effect of dark chocolate seen in several human studies appears to open the possibility that eating lots of chocolate is healthy, “I prefer to focus on cocoa,” Dore said.
“Cocoa is not like chocolate, which is high in saturated fat and calories. Cocoa can be part of a healthy diet, combined with fruits and vegetables.”
The latest research looked at the mechanism of protection in mice that were induced to have strokes.
“We gave different doses of epicatechin in mice 90 minutes before a stroke and found that it reduced infarct (stroke damage) size,” Dore explained.
“When we gave epicatechin after a stroke, it had a protective effect up to 3.5 hours later, but not after six hours.”
Detailed studies showed that the flavanol activated two well-known pathways that shield nerve cells in the brain from damage, the Nrf2 and heme oxygenase pathways, Dore said.
Epicatechin had no protective effect in mice bred to lack those pathways.
The possibility of using epicatechin to limit human stroke damage is distant, Dore said.
“We have to be very careful. There are a lot of steps before going to human trials, potential risks and side effects. We need more work and more funding.”
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