Multispectroscopic studies of the interaction of calf thymus DNA with the anti-viral drug, valacyclovir

The present study investigated the binding interaction between an antiviral drug, valacyclovir and calf thymus DNA (CT-DNA) using emission, absorption, circular dichroism, viscosity and DNA melting studies. In fluorimetric studies, thermodynamic enhancement constant (KD) and bimolecular enhancement constant (KB) were calculated at different temperatures and demonstrated that fluorescence enhancement is not initiated by a dynamic process, but instead by a static process that involves complex DNA formation in the ground state. Further, the enthalpy and entropy of the reaction between the drug and CT-DNA showed that the reaction is exothermic and enthalpy-favored. In addition, detectable changes in the circular dichroism spectrum of CT-DNA in the presence of valacyclovir indicated conformational changes in the DNA double helix following interaction with the drug. All these results prove that this antiviral drug interacts with CT-DNA via an intercalative mode of binding.

In this study the interaction between CT-DNA and an antiviral drug, valacyclovir, has been investigated and it has been found that the drug can intercalate into DNA double helix.Figure optionsDownload as PowerPoint slideHighlights
► Reposition drugs approved for other indications as anticancer agents.
► The antiviral drug, valacyclovir, exhibits a high binding affinity for CT-DNA.
► Provide greater insight into the use of antiviral drugs as anticancer.