Abstract: Certain proanthocyanidins found in various wines, grape juice, and other plant extracts exhibit endothelium-dependent vasorelaxing activity that involves increased nitric oxide production by endothelial cells. The smallest procyanidins (PCs) possessing substantial EDR activity were isolated from grape seeds. A dimer di-gallate (epicatechin-galloyl-epicatechin-gallate) was purified from concord grape seed extracts by Toyopearl TSK-40 gel chromatography, HPLC and electrospray FTMS. Further characterization was achieved using tannase treatment and acid thiolysis. This compound had an EC50 for vasorelaxation of 0.67±0.04 ?g/ml when tested for endothelium-dependent relaxing activity in phenylephrine pre-contracted rat aortic rings.

Abstract: The present invention is an isolated compound and method of inducing endothelium-dependent relaxation in blood vessels including the step of introducing isolated procyanidins having a preponderance of (−)-epicatechins to a patient wherein the procyanidins are preferably galloylated. To achieve both bioavailability and potency, it is also preferred that the number of epicatechins monomers forming each procyanidin is between two and five. More specifically, isolated epicatechin-(4-8)-epicatechin-(4-8)-epicatechin-gallate (C1-gallate) is administered to the patient.