Extracts from French maritime pine bark may inhibit an enzyme linked to glucose absorption 190 times more than a synthetic medication, says new research from Germany that could offer significant benefits for diabetics if the results can be translated from the lab to humans.
The results of the new study, published on-line in the journal Diabetes Research and Clinical Practice, add to a growing body of research reporting anti-diabetic effects of the pine bark extract, Pycnogenol.
Diabetes mellitus type II is a serious disease with rising prevalence," said lead researcher Dr. Petra Hogger. "This study is crucial for those suffering with the disease because it affirms that Pycnogenol brand pine bark extract is more effective than [a] prescription medication and supports the abundance of other research done on Pycnogenol and diabetes."
In the US, there are over 20 million people with diabetes, equal to seven percent of the population. The total costs are thought to be as much as $132 billion, with $92 billion being the cost of medication paid to pharmaceutical companies, according to 2002 American Diabetes Association figures.
Hogger and co-researcher Angelika Schafer from Wurzburg University tested Pycnogenol brand pine tree extract, a green tea extract (Emil Flachsmann) and the synthetic compound acabrose (Glucobay, Bayer Vital) for their ability to inhibit alpha-glucosidase, an enzyme found in the large intestine that is involved in the metabolism of carbohydrates and the production of glucose. By inhibiting the activity of the enzyme it could be possible to prevent typical high-glucose peaks in the blood stream after a meal.
The in vitro study used an assay of alpha-glucosidase activity with equal concentrations of each sample and report that the most potent inhibition of the alpha-glucosidase was achieved by the pine bark extract (quantity required 50 percent inhibition five micrograms per millilitre), followed by the green tea extract (20 micrograms per millilitre) and finally the acarbose (one milligram per millilitre).
“Since the alpha-glucosidase enzymes are located in the duodenum the intact pine bark extract constituents could exert inhibitory effects on alpha-glucosidase before a secondary metabolism of the procyanidin oligomers by bacteria occurs of the lower intestinal tract,” wrote the researchers.
“Our results contribute to the explanation of clinical anti-diabetic effects of Pycnogenol,” they said. To identify which compounds in pine bark extract may be behind the inhibiting effects, the researchers tested four different fractions (phenol carbonic acids and monomeric polyphenols; dimeric and trimeric procyanidins; tetrameric up to hexameric procyanidins; and higher oligomeric compounds). The latter of these fractions inhibited the enzyme's activity by 94 percent.
“The results obtained assign a novel, local effect to oligomeric procyanidins and contribute to the explanation of glucose-lowering effects of pine bark extract observed in clinical trials with diabetic patients,” wrote the researchers.
Horphag Research, manufacturer of Pycnogenol brand pine tree bark extract was the funding source behind this latest study.
A. Schafer, P. Hogger; Oligomeric procyanidins of French maritime pine bark extract (Pycnogenol) effectively inhibit alpha-glucosidase; Diabetes Research and Clinical Practice. Diabetes Res Clin Pract. 2007 Jul;77(1):41-6. Epub 2006 Nov 13. Published on-line ahead of print, doi: 10.1016/j.diabres.2006.10.011.