Anti-candida potential of red fruits: Antifungal and anti-biofilm effects

In the context of the prevention of dental caries, the cranberry fruit (Vaccinium macrocarpon), thanks to its richness in high molecular weight polyphenols, previously demonstrated anti-cariogenic properties, inhibiting biofilm formation of cariogenic bacteria. The antifungal activity of a dry extract of this fruit and three other red fruits (Rubus idaeus, Vaccinium myrtillus and Malpighia punicifolia) was assessed on Candida albicans and C. glabrata yeasts, which are oral cavity commensals, with a planktonic mode of growth. Moreover, the activity of these fruit extracts was studied against Candida spp. biofilms. A first approach was to evaluate the ability of yeasts to adhere to untreated polystyrene surfaces and to form biofilms in YNB medium supplemented with fruit extracts (0.02–40mg/mL). A second approach was to pretreat the polystyrene surfaces by fruit extracts (2–40mg/mL) and then to evaluate the ability of yeasts to both adhere to these surfaces and form biofilms. The MIC determination of the four extracts showed a lack of antifungal activity. Regarding the anti-adhesion and anti-biofilm effects, in the case of the first approach, a significant anti-adhesion activity was obtained with cranberry extract, using concentrations ≥1.25mg/mL (C. albicans) and ≥2.5mg/mL (C. glabrata). Its activity was studied on five other strains of C. albicans and C. glabrata in the second approach. In conclusion, this preliminary work demonstrated the anti-adhesion potency of cranberry extract on Candida spp, but this activity was strain-dependent.