Background: Candidiasis is one of the most prevalent and important opportunistic fungal infections of the oral cavity caused by Candida yeast species like Candida albicans, C. glabrata, and C. krusei. In addition, several bacteria can cause oral infections. The inhibition of microbial biofilm is the best way to prevent oral infections.
Objectives: The aim of the present study is to evaluate the antifungal, antimicrobial, and anti-biofilm properties of ginger (Zingiber officinale) extract against Candida species and some bacterial pathogens and the extract's effects on biofilm formation.
Materials and methods: Ginger ethanolic extract as a potential mouthwash was used to evaluate its effect against fungi and bacteria using the microdilution method, and biofilm was evaluated using the crystal violet staining method and dead/alive staining. MTT assay was used to evaluate the possible cytotoxicity effects of the extract.
Results: The minimum inhibitory concentrations (MICs) of ginger extract for evaluated strains were 40, 40, 20, 20, 20, 20, 10, and 5 mg/mL for Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Bacillus cereus, Acinetobacter baumannii, C. albicans, and C. krusei, respectively. Ginger extract successfully inhibited biofilm formation by A. baumannii, B. cereus, C. krusei, and C. albicans. MTT assay revealed no significant reduction in cell viability after 24 hours. The minimum inhibitory biofilm concentrations (MIBCs) of ginger extract for fungi strains (C. krusei and C. albicans) were greater than those of fluconazole and nystatin (P = 0.000).
Conclusions: The findings of the present study indicate that ginger extract has good antifungal and antibiofilm formation by fungi against C. albicans and C. Krusei. Concentrations between 0.625 mg/mL and 5 mg/mL had the highest antibiofilm and antifungal effects. Perhaps, the use of herbal extracts such as ginger represents a new era for antimicrobial therapy after developing antibiotic resistance in microbes.
Keywords: Antifungal; Antimicrobial; Biofilms; C. krusei; Candida albicans; Zingiber officinale.