A ruthenium(II)-trithiacyclononane curcuminate complex: Synthesis, characterization, DNA-interaction, and cytotoxic activity

Abstract

A ruthenium(II) trithiacyclononane curcuminate complex: synthesis, characterisation, DNA interaction and cytotoxic activityThe coordination of inorganic ruthenium(II) complexes to anionic oxygen-based donors is very rare. In this study, the simple, one-pot preparation of [ruthenium(II)(trithiacyclononane)(curcumin)(S-DMSO)]Cl (1) and its structural characterisation by elemental analysis, FT-IR, 1-D and 2-D NMR, ESI + -MS as well as UV-VIS and fluorescence are described. DNA thermal degradation studies showed that the complex 1 has DNA-intercalating ability, while pure curcumin is a non-intercalative compound. The in vitro cytotoxic activity of the complex 1, in comparison with that of pure curcumin, was investigated using the tumor human prostate cell line, PC-3, and the pre-neoplastic cell line, PNT-2.Results showed that complex 1 is innocuous towards normal prostate epithelial cells and, whereas curcumin is toxic in concentrations of 50 and 80 µM. On the tumour cell line PC-3, the complex 1 did not cause viability changes whereas curcumin exhibited dose-dependent inhibition. This study suggests that coordination with the trithiacyclononane ruthenium(II) scaffold stabilises the photochemical properties and biologic activity of curcumin.

Biological properties of metal complexes of curcumin

“…It appears that ruthenium complexes are often used to decrease toxicity of active ligands against normal cells by increasing their selectivity to cancer cells. For instance, the cytotoxic effects of a Ru 2+ ‐trithiacyclononane curcuminate complex showed that it was nontoxic against normal epithelial prostate cells (PNT‐2 line), while curcumin inhibited 65% of the same cells at a concentration of 80 μM . In some cases in which high cytotoxicity has been observed with certain Ru 2+ complexes of curcumin, the degree of lipophilicity of the ligand has been suggested to play a major role.…”

Curcumin Innovative Delivery Forms: Paving the ‘Yellow Brick Road’ of Antitumoral Phytotherapy

“…Analogues of curcumin arene complexes can be obtained by replacing the arene with the heterocyclic moiety of 1,4,7-tritiacyclononane (abbreviated as [9]ansS 3 ), to afford complexes with higher polarity and thus better compatibility with aqueous media. The complex [Ruthenium(II) (curcumin( [9]aneS 3 )DMSO]Cl was reported as a strong DNA-binding agent, with higher affinity than pure curcumin [254]. Cytotoxicity against the PC-3 prostate cancer cell line was, however, not observed at concentrations as high as 80 mM.…”