Organic grape seed concentrate and acerola powder Vino C® – OPC is a dietary supplement made from grape seed concentrate and acerola powder, offered in capsule form. It provides a synergistically complementary combination of nutrients from grape seeds and acerola cherries. Vino C® – OPC primarily supplies high-quality natural vitamin C from acerola cherries, and also contains OPCs (oligomeric proanthocyanidins), which are polyphenols found in grape seeds.