Antifungal activity of organotin compounds with functionalized carboxylates evaluated by the microdilution bioassay in vitro

Abstract

We investigated the susceptibility of 96 well-characterized strains of yeast-like and filamentous fungi towards new organotin compounds: (1) [Sn(C₄H₉)₃(OOCC₆H₄SO₃H-2)], (2) Sn(C₄H₉)₃{OOC(CH₂)₃P(C₆H₅)₃}]Br, and (3) [Sn(C₆H₅)₃[OOC(CH₂)₃N(CH₃)₃}]Cl. In the case of yeast-like fungi, the in vitro susceptibility tests were carried out according to the Clinical Laboratory Standards Institute (CLSI, formerly NCCLS) reference method M27-A2, while for filamentous fungi the investigations were conducted according to the M38-A and M38-P methods. The organotin complexes 1, 2 and 3 are active antifungal agents. Minimal inhibitory concentrations (MIC) were in the range of 0.25–4.68 μg/ml for all tested fungal strains. Considerably larger differences were found for minimal fungicidal concentrations (MFC). In the case of yeast-like fungi, the fungicidal effect was generally observed at organotin compounds concentrations of 2.34–9.37 μg/ml. The MFC values for filamentous fungi were considerably higher and were in the range of 18.74–50 μg/ml. In conclusion, organotin compounds 1, 2 and 3 showed high fungistatic and fungicidal activities against different species of pathogenic and nonpathogenic fungi. However, they were also highly cytotoxic towards two mammalian cell lines.

Keywords:

• Organotin compounds
• antifungal activity
• broth microdilution
• yeast
• filamentous fungi

Acknowledgements

The authors are grateful to the Ministry of Science and Higher Education for the support to this research (Grants: PBZ –Min- 015/P05/2004; 1016/S/IGiM/09 and No 3 T09A 01029).Declaration of interest : The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

This paper was first published online on Early Online on 01 February 2010.