oligomeric proanthocyanidins →
ολιγομερείς προανθοκυανιδίνεςProanthocyanidins, also known as OPCs (oligomeric proanthocyanidins) or condensed tannins, are a subgroup of the flavonoid class of polyphenols. In essence, they are oligomer chains of flavanols, such as the flavan-3-ol epicatechin.[citation needed]
They were discovered in 1948 by Jacques Masquelier, who developed and later patented techniques for the extraction of proanthocyanidins from pine needles and grape seeds.
https://en.wikipedia.org/wiki/Proanthocyanidins