The berries contain a unique and complex chemical composition and are all rich in flavonoids, polyphenols and anthocynanins. The anthocyanins are responsible for the red, purple and blue pigments of the berries and hold the most promising properties for human health. Since anthocyanins have been shown to be powerful anti-oxidants, scientific reports about their anti-inflammatory, anti-ulcerative, anti-viral, and anti-cancer properties is not surprising, albeit more work needs to be done.
In recent years, the simple chemical nitric oxide (NO) has been shown to play an enormous role in the function of all arteries in health and disease. NO is produced by endothelial cells, which line the inner surface of all blood vessels. NO is a potent relaxing agent of arterial smooth muscle. It plays a major role in keeping the blood pressure of an individual from becoming dangerously high and in preventing blood vessels from spasming. In addition, NO inhibits the development of blood clots and the early processes of atherosclerosis.
Superoxide belongs to a family of reactive chemicals known as oxygen radicals, reactive oxygen species (ROS) or “oxidants,” as they are commonly referred to in lay literature. These radicals generally promote spasm, blood clot formation and atherosclerosis in arteries. Oxygen radical generation has been shown to be increased in a variety of cardiovascular diseases and also appears to play a detrimental role in cancers, diabetes and inflammatory conditions. Vitamins C and E are known to scavenge or “soak up” superoxide, but evidence that these vitamins can play a preventative or curative role in human disease is not strong.
Currently, the consequences of the reaction of NO with superoxide are not fully understood. There is evidence to suggest that such reactions may be beneficial or harmful to processes in the body. It is reasonable to assume however, that any factor that promotes the arterial endothelial NO system and/or suppresses the effects of oxygen radicals in the body has the potential to yield marked cardiovascular benefits to an individual, as well as potentially have positive impacts other major human diseases.
Four Studies
Accordingly, a cluster of new studies examining the effects of the berries on arteries is the basis of a new research investigation, “Characterization of Coronary Arterial Reactivity of Berry Anthocyancins,” conducted by David R. Bell, Ph. D. and Kristin Gochenaur, B.S., both of the Indiana University School of Medicine, Fort Wayne, Indiana. They will present their findings during the American Physiological Society (APS) annual meeting, which is being held as part of the Experimental Biology conference. More than 14,000 scientific investigators are attending the gathering, which begins April 20-24, 2002 at the Ernest N. Morial Convention Center, New Orleans, LA.
Methodology
The researchers conducted four investigations into potential coronary vascular activity of extracts prepared from elderberry, chokeberry and bilberry. The test arteries used in the investigations were porcine coronary arteries, which share similar a physiology to those in humans. The researchers investigated whether or not:
· solutions prepared from the three berry extracts possess direct endothelium-dependent or -independent vasoactivity in coronary arteries;
· endothelium-dependent, NO mediated relaxation or direct NO mediated relaxation of coronary arteries is modified in the presence of a physiological concentration of the three berry extracts;
· endothelium-dependent, NO mediated relaxation or direct NO mediated relaxation of coronary arteries is modified following either short term or overnight incubation of the arteries with a physiological concentration of the three berry extracts; and
· impaired endothelium-dependent, NO mediated relaxation of coronary arteries following exposure to superoxide is alleviated by concurrent exposure of the arteries to a physiological concentration of the three berry extracts.
Results
They found that:
· Extracts from chokeberry and bilberry, but not elderberry, produce a direct dose-dependent relaxation of porcine coronary arteries, with chokeberry extract being the most potent. This relaxation was totally dependent on the vascular endothelium because the extracts did not significantly contract or relax arteries in which the endothelium was removed.
· Relaxation of coronary arteries to an agent that releases NO from the arterial endothelium, as well as that in response to NO itself, were not altered by either the presence, short term exposure or overnight exposure to a physiological concentration of any of the extracts.
· A physiological concentration of chokeberry extract totally protected the coronary arteries from oxidant injury. Extracts from bilberry and elderberry provided partial, but not complete, protection against oxidant injury.
Conclusions
Berry extracts, in concentrations likely to be seen in the human blood stream following reasonable ingestion of these compounds, can stimulate the coronary arterial NO system. This is potentially important because of the pivotal role this system has in maintaining normal arterial function.
Furthermore, the variation in direct coronary vasoactivity and oxidative protective effect of the three different extracts, which were normalized for total anthocyanin content, strongly suggests that an individual component, or combination of components, in the berries is responsible for their vascular effects. In particular, chokeberry extract appears to possess potentially strong beneficial properties with regards to the function of coronary arteries in health and disease.
The American Physiological Society (APS) is one of the world’s most prestigious organizations for physiological scientists. These researchers specialize in understanding the processes and functions underlying human health and disease. Founded in 1887 the Bethesda, MD-based Society has more than 10,000 members and publishes 3,800 articles in its 14 peer-reviewed journals each year.
Contact: Donna Krupa
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APS Newsroom: April 20-24, 2002
Morial Convention Center, New Orleans
Room: Level 2, Room B211
Telephone: 504.670.6534