Abstract

The solubilities in water (W) and in 3 mol.L(-1) aqueous acetonitrile at 298.15 K of thiophene-2-, furan-2- and pyrrole-2-carboxaldehyde phenylhydrazone along with their nitro and 2,4-dinitro derivatives, referred to as PCT, PCF, PCP, NPCT, NPCF, NPCP, DPCT, DPCF and DPCP, respectively, are reported. The standard Gibbs energy of transfer from W to solvent mixtures (Delta G(W-mix)(transf)) was estimated for each solute. The results indicate that the transfer process for all systems is a spontaneous process. Calculations under the scaled-particle theory suggest that the work of cavity creation (Delta Delta G(c)), which is associated with the transfer of the phenylhydrazone from W to mix, dominates the magnitude of Delta G(W-mix)(transf). UV spectroscopic measurements suggest that these compounds bind calf thymus(CT)-DNA via intercalation mode in a buffer-3 mol.L(-1) acetonitrile solution. The binding constant (K(b)) depends on the nitro-substitution on the phenyl moiety and the electronegativity of the heteroatom in the heterocyclic ring. The corresponding Gibbs energy of binding (Delta G(DNA-B)(0)) of phenylhydrazone derivatives to CT-DNA shows a marked dependence with Delta Delta G(c). The anticancer activity on human breast cancer cell lines MDA-231, MDA-435 and HT-29 human colon adenocarcinoma cell line was evaluated for the compounds NPCT, NPCF, DPCT and PCT.