The results of the new study, published in the October issue of the journal Hypertension Research , add to a growing body of research reporting potential health benefits of the pine bark extract, Pycnogenol.
"This study suggests that when taking Pycnogenol, more NO is provided in response to neurotransmitters allowing for better expansion of arteries to carry more blood.
This process serves to meet the enhanced oxygen demand of the performing muscle and avoid anaerobic metabolism," said lead researcher Dr. Yukihito Higashi from the Hiroshima University Graduate School of Biomedical Sciences in Japan.
Nitric oxide (NO) is a molecule used by the endothelium (cells lining the surface of blood vessels) to signal surrounding muscle to relax, leading to a reduction in blood pressure, reduced blood clotting and protection against myocardial infarction and strokes.
The researchers performed a double-blind, randomized, placebo study with 16 young, healthy men receiving either a daily pine bark extract (180 mg Pycnogenol) or placebo for two weeks.
In order to identify the role of the extract on NO, the subjects were also infused with an inhibitor of the amino acid L-arginine was infused in patients, thereby causing a constriction of the arteries in response to the neurotransmitter acetylcholine.
After two weeks of intervention, supplementation Higashi and co-workers report that supplementation with the French maritime pine bark extracts was associated with a 42 per cent stimulation of blood flow after infusion of the inhibitor.
No significant changes in blood flow was observed in the placebo group.
"Acetylcholine stimulates the cells of arteries to produce NO from L-arginine faster," Dr. Higashi said.
"In turn, the NO causes the muscle surrounding arteries to relax, which results in an increase of blood vessel diameters.
When subjects had taken Pycnogenol the relaxation of arteries was increased by 42 per cent as compared to the group taking placebo tablets."
The research was welcomed by Frank Schonlau, director of scientific communications for Horphag Research, worldwide distributors of Pycnogenol, as "an encouraging breakthrough especially to athletes" .
"While more research is warranted… Pycnogenol seems to allow people to move faster when exercising by satisfying the enhanced muscle oxygen demand and increasing the blood flow to active muscles.
"When people are performing heavy physical activity, nerves release neurotransmitter acetylcholine to arteries supplying muscles, which makes them expand, a process that requires enhanced production of NO," he said.
Horphag Research has been very active in sponsoring and supporting studies into the potential health benefits of the pine bark extract.
The first research was conducted on the ingredient 35 years ago.
Victor Ferrari, research chief operating officer and executive vice president of Horphag Research, told NutraIngredients last year that the company ploughs $1.5m - "most of its profits" - into research each year.
The product is extracted from the bark of the Maritime pine that grows on the southern coast of France, and is currently used in over 400 dietary supplements, multi-vitamins and health products.
Source: Hypertension Research October 2007, Volume 30, Pages 775-780 "Pycnogenol, French Maritime Pine Bark Extract, Augments Endothelium-Dependent Vasodilation in Humans" Authors: K. Nishioka, T. Hidaka, S. Nakamura, T. Umemura, D. Jitsuiki, J. Soga, C. Goto, K. Chayama, M. Yoshizumi, Y. Higashi