Cis-chloroammine complexes of
platinum have been shown to induce several
biological effects. These include induction of filamentous growth in Escherichia coli as well as induction of phage production from lysogenic strains of Escherichia coli. Cis-chloroammine complexes of
platinum have also been proven effective as a treatment for several animal
tumors. In general, the effectiveness of such compounds is determined by a combination of an internal polar nature coupled with an overall electrical neutrality. We have extended these studies to include other complexes of the group VIII elements. In the research reported here, complexes of
ruthenium were shown to induce filamentous growth in E. coli. Cis-Ru(NH3)3Cl3 produced this effect at a concentration of 6 mug/ml, comparable to the required concentration of cis-Pt(NH3)2Cl2 for the same effect. The charged complex, K2RuCl5 - H2O, induced filamentous growth but a significantly higher concentration of this
ruthenium complex was necessary. Several
palladium complexes were also tested. They proved to be toxic at relatively high concentrations and had no effect at lower concentrations. The proposed mechanism of action of the
platinum complexes is the hydrolysis of two cis-
chloride ligands followed by binding to
DNA which reduces the synthesis of new
DNA. The kinetic data on hydrolysis, the required cis-
chloride ligands, electrical neutrality, and the selective action on various bacteria indicate that
ruthenium and
platinum interact by a similar mechanism.