Proanthocyanidin

Proanthocyanidin (also known as oligomeric proanthocyanidin (OPC), pycnogenol, leukocyanidin and leucoanthocyanin) is a class of flavonoids. It was discovered in 1936 by Professor Jacques Masquelier and called Vitamin P, although this name did not gain official category status and has since fallen out of usage. It was Masquelier who first developed techniques for the extraction of Proanthocyanidins from certain plant species.