Silver Nanoparticles Stabilized with Propolis Show Reduced Toxicity and Potential Activity Against Fungal Infections

Abstract

Aim: Elucidate the antifungal efficacy of biologically synthesized silver nanoparticles with ethanolic propolis extract (AgNPs PE) against the planktonic forms and biofilms of clinically important fungi. Materials & methods: AgNPs were synthesized, characterized and evaluated for cytotoxicity, mutagenicity and antimicrobial activity. Results: AgNPs PE displayed a colloidal appearance, good stability and size of 2.0–40.0 nm. AgNPs PE demonstrated lower cytotoxicity and nonmutagenic potential. In addition, AgNPs PE displayed antifungal properties against all tested isolates, inhibiting growth at concentrations lower than the cytotoxic effect. Mature biofilms treated for 48 h with AgNPs PE showed significant reduction of viable cells, metabolic activity and total biomass. Conclusion: This is the first time that AgNPs have been synthesized from an ethanolic extract of propolis only, proving antifungal, antibiofilm, atoxic and nonmutagenic properties.

Keywords::

• antibiofilm
• Candida sp.
• cytotoxicity
• ethanolic propolis extract
• Fusarium sp.
• Microsporum sp.
• mutagenicity
• nanomedicine
• Trichophyton sp.

Supplementary data

To view the supplementary data that accompany this paper please visit the journal website at: www.tandfonline.com/doi/suppl/10.2217/fmb-2020-0173

Author contributions

B Kischkel was responsible for conceptualization, acquisition of data, data analysis and writing original draft, PF Castilho, KMP Oliveira and PST Rezende were responsible for acquisition of data; ML Bruschi, TIE Svidzinski and M Negri were responsible for conceptualization and writing – review and editing.

Acknowledgments

We thank the Complex of Research Support Centers (COMCAP), Universidade Estadual de Maringá, in particular the central microscopy (CMI) for their assistance in image acquisition and advanced materials analysis center (CAM).

Financial & competing interests disclosure

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number 421620/2018-8, Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP), grants number 2018/26402-1 and Financiadora de Estudos e Projetos (FINEP/CONCAP). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Funded writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have followed the principles outlined in the Declaration of Helsinki for all human experimental investigations. Routine care of the subjects was not modified; the fungal isolates from human samples collected in the study were part of routine clinical practice. The participants were in accordance with the ethical standards of the Research Ethics Committee of Universidade Estadual de Maringá, approved with judgment numbers 615.643/2014 and 44.896515.5.0000.0104. Furthermore, the authors registered the use of propolis in the Brazilian National System for Genetic Heritage and Associated Traditional Knowledge Management (SisGen) under the number AC7A2F5.

Data sharing statement

The authors certify that this manuscript reports original research data. Individual data that underlie the results reported in this article are available from the corresponding author following publication, including the study report and study protocol. Additional data are available upon reasonable request.

Additional information

Funding

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant number 421620/2018-8, Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP), grants number 2018/26402-1 and Financiadora de Estudos e Projetos (FINEP/CONCAP). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.