UBC Theses and Dissertations
Synthesis and characterization of ruthenium maltolato, sulfoxide, and nitroimidazole complexes as potential anticancer agents Wu, Adam
The anticancer properties of Ru sulfoxide and imidazole complexes, including cis-RuCl₂(DMSO)₃(DMSO), trans-RuCl₂(DMSO)₄, and [trans-Ru(Im)(DMSO)Cl₄]⁻ have previously been studied by other groups (DMSO and DMSO = S-bonded and O-bonded dimethylsulfoxide, respectively; Im = imidazole). This thesis work concerns the use of Ru maltolato complexes in this regard; maltol (3-hydroxy-2-methyl-4-pyranone), being a non-toxic, water-soluble food additive, is suitable for biological use. [diagrams not included] Several Ru[sup II] bis(maltolato) and bis(ethylmaltolato) complexes with ancillary monodentate and bidentate sulfoxide ligands (DMSO, TMSO, and BESE) have been synthesized and well characterized, as well as a Ru[sup II] BESE-metronidazole complex, RuCl₂(BESE)(metro)₂ (TMSO = tetramethylenesulfoxide, BESE = 1,2- bis(ethylsulfinyl)ethane, metro = metronidazole). Some Ru[sup III] maltolato complexes have also been synthesized in order to compare their anticancer activities to those of related Ru[sup II] complexes. The Ru complexes were characterized by a variety of spectroscopic techniques, including NMR, UV-vis, IR, and MS; elemental analysis and solution conductivity data were also collected. Cyclic voltammetry was used to determine the reduction potentials of various Ru complexes. X-ray crystallographic structures were determined for cis-Ru(ma)₂(S,R-BESE), trans-RuCl₂(R,R-BESE)(metro)₂, and trans- [Ru(ma)₂(metro)₂](CF₃S0₃) (ma = maltolato). The sulfoxide ligands are exclusively S-bonded as observed in the IR and ¹H NMR spectra, and in the first two X-ray structures. Of the complexes tested, Ru(ma)₃ and Ru(etma)₃ (etma = ethylmaltolato) exhibit the best anticancer activities against human breast cancer cells (MDA435/LCC6) in the in vitro MTT assay (a colorimetric determination of cancer cell viability), in terms of the lowest IC₅₀ values of 150 and 80 μM, respectively, IC₅₀ being the drug concentration that kills 50 % of the cancer cells relative to the control. The Ru[sup II] maltolato-sulfoxide complexes also showed some anticancer activities, with Ru(etma)₂(DMSO)₂ being the most potent (IC₅₀ = 470 μM). The ethylmaltolato complexes are generally more effective than the corresponding maltolato complexes. Further anticancer testing of Ru maltolato complexes is encouraged from these preliminary results.
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