Standardized Hebal Blend. Combats Free Radicals. Rich Source of OPCs. Antioxidant Supreme combines essential vitamins with key herbs well-known for their high level of free radical scavenging activity. In particular the OPCs (Oligomeric proanthocyanidins) found in pine bark and grape seed extracts provide an advanced level of antioxidant support. Standardized extracts are guaranteed to contain a specific quantity of a known marker compound and are laboratory tested to insure consistent potency.