Grape skin
OPC's (Oligomeric Proanthocyanidins) are a set of bioflavonoid complexes that perform as free radical scavengers in the human body. Many names refer to this set of bioflavonoids, including PCO's (Oligomeric Procyanidolic Complexes), leuco anthocyanin, anthocyanidin and still others. We will refer to them as OPC's for the duration of this discussion.

OPC's are types of bioflavonoids, very powerful ones. Bioflavonoids are parts of plants that are actually assimilated into our body tissues when we consume them. It was, in fact, this very ability that led to their discovery. OPC bioflavonoids were first noticed in the laboratory because they have the uncanny ability to strengthen blood vessel walls within hours after taking them! The person responsible for their discovery was a French scientist named Dr. Jacques Masquelier, who first tested bioflavonoid containing peanuts on lab animals and discovered that their blood vessel walls would double in strength only hours after eating them. His discovery was made in 1948. In 1951, this same doctor extracted OPC's from pine bark.

In 1970, Dr. Masquelier obtained yet another patent for these bioflavonoids - a far more potent product. It is the grape seed extract that you may have heard about, and it is a powerful substance indeed.