Synthesis, characterization and in vitro antitumor activity of new palladium(II) complexes with (S,S)-R(2)edda-type esters

Abstract

Six palladium(II) complexes with (S,S)-R(2)edda-type esters ((S,S)-R2edda-type; (S,S)-eddch = (S,S)-ethylenediamine-N,N'-di-2-(3-cyclohexyl)propanoate, R = Me, Et, n-Pr, 1-3; (S,S)-pddch = (S,S)-propylenediamine-N,N'-di-2-(3-cyclohexyl)propanoate, R = Et, n-Pr, 4, 5; and (S,S)-eddip = (S,S)-ethylenediamne-N,N'-di-2-propanoate, R = i-Am, 6) were synthesized, characterized by IR, NMR spectroscopy, ESI-MS and elemental analysis. DFT calculations indicate that in case of 1-4, the most stable isomers are with (S,S)- and (R,S)-configuration of nitrogen atoms, but for complex 6 (R,R)- and (R,S)-N,N'-configured isomers. Furthermore, complex 5 was obtained as (S,S)-N,N' configured isomer. Cytotoxicity study was performed against human cervical adenocarcinoma (HeLa), human alveolar basal adenocarcinoma (A549) and non-cancerous human fetal lung fibroblast (MRC-5) cell lines using colorimetric MTT assay. From the investigated palladium(II) complexes 2, 3 and 5 exhibited highest cytotoxic potential against HeLa (IC50: 28.5 +/- 3.9, 29.5 +/- 1.3 and 34.3 +/- 3.2, respectively).