Antifungal potential of Sideroxylon obtusifolium and Syzygium cumini and their mode of action against Candida albicans

Author(s)

Pereira, Jozinete Vieira ; Freires, Irlan Almeida ; Castilho, Aline Rog Eria ; da Cunha, Marcos Guilherme ; Alves, Harley da Silva ; Rosalen, Pedro Luiz

• Document type: Journal article
• Source: Pharmaceutical Biology; v. 54, n. 10, p. 2312-2319, 2016.
• Web of Science Citations: 10

Abstract

Context The emergence of resistant pathogens and toxicity of antifungals have encouraged an active search for novel candidates to manage Candida biofilms. Objective In this study, the little known species Sideroxylon obtusifolium T.D. Penn (Sapotacea) and Syzygium cumini (L.) Skeels (Myrtaceae), from the Caatinga biome in Brazil were chemically characterized and explored for their antifungal potential against C. albicans. Materials and methods We determined the effects of hydroalcoholic extracts/fractions upon fungal growth (minimum inhibitory and fungicidal concentrations, MIC/MFC), biofilm morphology (scanning electron microscopy) and viability (confocal laser scanning microscopy), proposed their mode of action (sorbitol and ergosterol assays), and finally investigated their effects against macrophage and keratinocyte cells in a cell-based assay. Data were analysed using one-way analysis of variance with Tukey-Kramer post-test (alpha = 0.05). Results The n-butanol (Nb) fraction from S. obtusifolium and S. cumini extract (Sc) showed flavonoids (39.11 +/- 6.62mg/g) and saponins (820.35 +/- 225.38mg/g), respectively, in their chemical composition and demonstrated antifungal activity, with MICs of 62.5 and 125 mu g/mL, respectively. Nb and Sc may complex with ergosterol as there was a 4-16-fold increase in MICs in the presence of exogenous ergosterol, leading to disrupted permeability of cell membrane. Deleterious effects were observed on morphology and viability of treated biofilms from concentrations as low as their MICs and higher. Sc was not toxic to macrophages and keratinocytes at these concentrations (p> 0.05), unlike Nb. Conclusions Nb and Sc demonstrated considerable antifungal activity and should be further investigated as potential alternative candidates to treat Candida biofilms. (AU)

• FAPESP's process: 13/25080-7 - Prevalence of strains of Streptococcus mutans expressing Cnm in children and adults, and the role of this glycoprotein in the pathogen-host interactions
• Grantee: Irlan de Almeida Freires
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 11/23635-6 - Isolation and pharmacological evaluation of bioactive molecules from hexane fraction of M. scutellaris geopropolis
• Grantee: Marcos Guilherme da Cunha
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 14/01723-9 - Characterization of a glass ionomer cement containing natural products: in vitro and in vivo studies
• Grantee: Aline Rogéria Freire de Castilho
• Support Opportunities: Scholarships in Brazil - Post-Doctoral