TY - JOUR T1 - Cytotoxicity of Ferrocenyl–Ethynyl Phosphine Metal Complexes of Gold and Platinum JF - Anticancer Research JO - Anticancer Res SP - 825 LP - 829 VL - 31 IS - 3 AU - ELEANOR FOURIE AU - ELIZABETH ERASMUS AU - JANNIE C. SWARTS AU - ALEXANDER JAKOB AU - HEINRICH LANG AU - GISELA K. JOONE AU - CONSTANCE E.J. VAN RENSBURG Y1 - 2011/03/01 UR - http://ar.iiarjournals.org/content/31/3/825.abstract N2 - Background: Ferrocene derivatives may possess antineoplastic activity. Those with low ferrocenyl reduction potentials often have the highest anticancer activity, as cell components have to oxidise them to the active ferrocenium species before cytotoxicity can be recorded. Some gold(I) complexes also possess anticancer activity. This study examined the cytotoxicity of ferrocenyl-ethynyl and ruthenocenyl-ethynyl complexes of gold and platinum. The results were related to the ease of iron oxidation in the ferrocenyl fragment and compared with the cytotoxicity of cisplatin, [(H3N)2PtCl2] and [Au(PPh2CH2CH2PPh2)2]Cl. Materials and Methods: Ferrocene-containing gold and platinum complexes of the type Fc-C≡C-PPh2, 1, and Fc-C≡C-PPh2→M with Fc=ferrocenyl (FeII(η5-C5H5) (η5-C5H4)), Ph=phenyl (C6H5) and M=Au-Cl, 2, Au-C≡C-Fc, 3, or Au-C≡C-Rc, 4 (Rc=ruthenocenyl, (RuII(η5-C5H5) (η5-C5H4)) and the complex [(Fc-C≡C-PPh2)2PtCl2], 5, were investigated. Cytotoxicity tests were determined on the HeLa (human cervix epitheloid) cancer cell line, ATCC CCL-2. Cell survival was measured by means of the colorometric 3-(4,5-dimethylthiazol-2-yl)-diphenyltetrazolium bromide assay. Results: The IC50 values of compounds 1-4 from four experiments causing 50% cell growth inhibition, ranged between 4.6 and 27 μmol dm−3. Drug activity was inversely proportional to the sum of all formal reduction potentials, Eo’, of the ferrocenyl groups of the Fc-C≡C-PPh2 and Fc-C≡C-ligands coordinated to the gold centre. The Fc-C≡C-PPh2→Au-Cl complex, compound 2, was most cytotoxic with IC50=4.6 μmol dm−3 , demonstrating the beneficial effect the Cl− ion has on the cytotoxicity of these neutral gold complexes. The platinum complex [(Fc-C≡C-PPh2)2PtCl2], compound 5, resembling the structure of cisplatin, in principle should exhibit good cytotoxicity, but was not tested due to its total insolubility in any biocompatible medium. ER -