The standardized mixture of polyphenols obtained from grape seeds contains mainly procyanidol oligomers, dimers, trimers, tetramers and oligomers up to seven units as well as small amounts of monomers (catechin and epicatechin).
Oligomers and polymers of catechin and epicatechin are found in the skin and particularly in the seeds of grapes.
These constituents are also named procyanidins, procyanidolic oligomers (PCO), leucoanthocyanins or condensed tannins. Procyanidins are constituted by a variable number of flavan units linked by B1 - B4, B5 - B8, C4 - C4 or C4 - C8 bonds.
Furthermore seeds of Vitis vinifera contain a semi-drying oil with fatty acids like palmitic, stearic, oleic and linoleic acids and also sitosterol, tocopherol and phospholipids, partly bound to lipoproteins.
Grape seed extract is a herbal preventive and therapeutic agent for vascular diseases, such as varicose veins, lymphedema and capillary fragility. It is also used in the prevention of all damages caused by free radicals.