Fern extracts potentiate fluconazole activity and inhibit morphological changes in Candida species

Asian Pacific Journal of Tropical Biomedicine Available online 5 October 2017 In Press, Accepted Manuscript Author links open overlay panelMaria A.Freitas1Antonia T.L.Santos1Antonio J.T.Machado1Ana Raquel P.Silva1Fábia F.Campina1Maria S.Costa1Gioconda M.A.B.Martins1Maria Flaviana B.Morais-Braga1Saulo R.Tintino1Irwin R.A.Menezes1JaimeRibeiro-Filho1Altevir P.Medeiros2Adeliana S.Oliveira3Patrício B.Maracajá4Henrique D.M.Coutinho1 Show more https://doi.org/10.1016/j.apjtb.2017.09.018Get rights and content Open Access funded by Hainan Medical University Under a Creative Commons licenseopen access Abstract Objective To investigate the antifungal activity of the fern species Lygodium venustum and Pityrogramma calomelanos (P. calomelanos) against Candida albicans and Candida tropicalis strains. Methods The microdilution method was used to evaluate the antifungal activity, as well as the modulating effects of ethanolic extracts of these plants in combination with fluconazole. The minimum inhibitory concentration (MIC), minimum fungicide concentration and morphological changes were also determined. Results The extract obtained from Lygodium venustum presented a MIC > 8 192 μg/mL, while the extract obtained from and P. calomelanos presented a MIC = 8 192 μg/mL, indicating that they present weak antifungal activity. However, combination of the extracts with Fluconazole potentiated the antifungal activity of this drug. At different experimental conditions, such as concentration of the extract and type of strain, the extracts inhibited hyphae and pseudohyphae formation, indicating that these fern species can affect the morphology of the fungi. Conclusions The extracts obtained from the fern species Lygodium venustum and P. calomelanos dose not present significant antifungal activity. However, P. calomelanos potentiates the activity of fluconazole and both extracts inhibits the morphological changes in Candida species, indicating that they have potential pharmacological activity as modulators of fungal biology. Therefore, novel studies are required to characterize the interference of these extracts in the virulence and pathogenicity of Candida species as well as the potential of fern species to treat fungal infections. Key words DimorphismCandida speciesFernsLygodium venustumPityrogramma calomelanos