There are over 500 difference species of barberry (Berberis) and with the exception of Australia, they're native to just about every temperate and subtropical region in the world.The best known is the Berberis vulgaris which goes by the name European barberry, though you can find it in North America, Asia, and Middle East too. This sample actually came from Iran, where they call it zereshk (Persian barberries). The red are most common but dark blue barberries are seen with other species.Keep in mind the antioxidants are so high because these tests were using the dried fruit. When fresh, expect about 1/5th the ORAC value.
Research Support, Non-U.S. Gov't: Carlsen MH, Halvorsen BL, Holte K, et al. Nutrition Journal NIH 2010