Berenil acts as a poison of eukaryotic topoisomerase II.

The ability of the anti-trypanosomal drug berenil to interfere with the activities of eukaryotic type II topoisomerases is evaluated using two different types of reactions catalyzed by the enzyme: the relaxation of naturally supercoiled DNA and the decatenation of kinetoplast DNA (kDNA). The results indicate that berenil acts as an inhibitor of the catalytic activity, but the inhibiting ability appears to be smaller than for other minor-groove binding ligands.