Silver enhances the in vitro antifungal activity of the saponin, CAY-1

Anthony J. De Lucca, Stephen Boue, Tin Sien, Thomas E. Cleveland, Thomas J. Walsh

Research output: Contribution to journalArticlepeer-review


The fungicidal properties of purified CAY-1, dissolved silver ion and ethylenediamine tetraacetic acid (EDTA) separately were studied in vitro as were the abilities of silver and EDTA to enhance CAY-1 fungicidal properties. Non-germinated and germinating conidia of Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Fusarium verticillioides (Fusarium moniliforme), Fusarium oxysporum and Fusarium solani were incubated separately with CAY-1 (0-24.8μgml-1), silver (0-111.1μgml-1), and EDTA (0-2400μgml-1). Controls consisted of non-germinated or germinated conidia in test medium. To assess combined activity, compounds, based on the sub-lethal doses of each as defined in the initial experiments, were combined and tested in bioassays. Controls for the mixed sets consisted of non-germinated or germinated conidia only or with the sub-lethal CAY-1 test concentrations. The minimum inhibitory concentrations (MICs) for CAY-1 and silver, both separate and combined, were determined. Viability assays showed CAY-1 activity only against the germinating conidia of A. flavus, A. niger and F. solani. Silver was active against the germinating conidia of all fungi and the non-germinated conidia of F. oxysporum and F. solani. Combined silver and CAY-1 produced significant viability loss at concentrations not effective separately. EDTA was not fungicidal separately and did not enhance CAY-1 fungicidal properties. MIC data showed that CAY-1 plus silver had an additive effect. Results indicate that dissolved silver was fungicidal in vitro and enhanced the fungicidal properties of CAY-1 at concentrations ineffective when tested separately. Published 2009. This article is a US Government work and is in the public domain in the USA.

Original languageEnglish (US)
Pages (from-to)e1-e9
Issue number4
StatePublished - Jul 1 2011


  • Aspergillus
  • CAY-1
  • Fungicidal
  • Fusarium
  • Saponin
  • Silver

ASJC Scopus subject areas

  • Dermatology
  • Infectious Diseases


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