Manganese(II), copper(II) and silver(I) complexes containing 1,10-phenanthroline/1,10-phenanthroline-5,6-dione against Candida species.

Background: New chemotherapeutics are urgently required to treat Candida infections caused by drug-resistant strains. Methods: The effects of 16 1,10-phenanthroline (phen)/1,10-phenanthroline-5,6-dione/dicarboxylate complexed with Mn(II), Cu(II) and Ag(I) were evaluated against ten different Candida species. Results: Proliferation of Candida albicans , Candida dubliniensis , Candida famata , Candida glabrata , Candida guilliermondii , Candida kefyr , Candida krusei , Candida lusitaniae , Candida parapsilosis and Candida tropicalis was inhibited by three of six Cu(II) (MICs 1.52-21.55 μM), three of three Ag(I) (MICs 0.11-12.74 μM) and seven of seven Mn(II) (MICs 0.40-38.06 μM) complexes. Among these [Mn ₂ (oda)(phen) ₄ (H ₂ O) ₂ ][Mn ₂ (oda)(phen) ₄ (oda) ₂ ].4H ₂ O, where oda = octanedioic acid, exhibited effective growth inhibition (MICs 0.4-3.25 μM), favorable activity indexes, low toxicity against Vero cells and good/excellent selectivity indexes (46.88-375). Conclusion: [Mn ₂ (oda)(phen) ₄ (H ₂ O) ₂ ][Mn ₂ (oda)(phen) ₄ (oda) ₂ ].4H ₂ O represents a promising chemotherapeutic option for emerging, medically relevant and drug-resistant Candida species.