For the samples in this test, researchers used Bronson Vitamins brand of 50 mg extract capsules, which were purchased in the United States. When converted to the amount of antioxidants contained within 100 grams of the capsules, the ORAC value of grape seed extract was 108,130.
The most common source of grape seeds are from wine making, as they are discarded during the process, so supplement manufacturers purchase them. The type or species of grape is not reported on Bronson Vitamins website for this product, which is typical among other supplement companies, too. Most likely, red and/or purple grape seeds were used.
Even though a specific brand was used in this test, any authentic source of grape seed extract would be expected to achieve a similar ORAC.
Research Support, Non-U.S. Gov't: Carlsen MH, Halvorsen BL, Holte K, et al. Nutrition Journal NIH Jan 2010