A specific inhibitor of type I DNA-topoisomerase of Trypanosoma cruzi: dimethyl-hydroxy-ellipticinium.

2-6 dimethyl-9-hydroxyellipticinium inhibited the relaxation of supercoiled DNA by the type I topoisomerase of T. cruzi. Since DNA relaxed in the presence of an intercalating drug prior to electrophoresis became supercoiled when the ligand was removed, we analysed the topoisomerisation in gels containing another ligand, chloroquine. The inhibition which is reported here, concerning a type I topoisomerase, is of an exceptional efficiency.