DNA breakage by tannic acid and Cu(II): generation of active oxygen species and biological activity of the reaction.

Tannic acid was shown to reduce oxygen to superoxide anion. In the presence of Cu(II), the hydroxyl radical and hydrogen peroxide were formed. Strand scission reaction was shown to account for the biological activity of tannic acid as assayed by bacteriophage inactivation. The inactivating activity occurs through the Fenton pathway for free radical production and subsequent DNA cleavage by these radicals.