Bilberry and blueberry anthocyanins act as powerful intracellular antioxidants in mammalian cells

► Antioxidant activity of berry anthocyanins was assayed in four different cell lines. ► Anthocyanins acted as intracellular antioxidants at very low concentrations. ► The assay can serve as a model of anthocyanins' absorption and distribution. ► These data explain the high bioactivity of berry anthocyanins.