Reactions of Ru(III)-drugs KP1019 and KP418 with guanine, 2'-deoxyguanosine and guanosine: a DFT study.

Ruthenium (Ru)-based anticancer drugs are considered to be novel alternatives of platinum-based drugs. They exhibit potent cytotoxicity against the cancer cells and hence are useful for the treatment of cancer. Herein, the density functional theory calculations in the gas phase and aqueous media are carried out to study the reactions of two Ru(III)-based drugs such as KP1019 and KP418 with the N7 site of guanine (G), 2'-deoxyguanosine (dGua), and guanosine (Gua) to understand their reactivity against the DNA and RNA. All the reactions are found to be exothermic. The activation free energies and rate constants of these reactions indicate that KP1019 and KP418 would react with the dGua more readily than Gua. Hence, the binding of these drugs with the DNA would be more preferred as compared to RNA. It is further found that among these drugs, KP1019 would be more reactive than KP418 in agreement with the experimental observation. Thus, this study is expected to aid in the future development of potent anticancer drugs.