Effects of tyrosol and farnesol on Candida albicans biofilm

Abstract

The present in vitro study examined the effects of the quorum-sensing molecules farnesol and tyrosol on the development of Candida albicans biofilm in order to elucidate their role as novel adjuvants in oral hygiene. The investigation was conducted in C. albicans ATCC 10231 and C. albicans isolates from dentures and was performed in flat-bottomed 96-well polystyrene plates. Yeast growth and their capacity to form biofilms were evaluated following 24 and 48 h incubations at 37°C in Sabouraud broth supplemented with 0.001–3 mM farnesol and/or 1–20 mM tyrosol. Yeast growth was assessed by turbidimetry and biofilms were quantitated by crystal violet staining, under aerobic and anaerobic conditions. The viability of the fungal cells was controlled by the culture of planktonic cells and by examination of the biofilms using fluorescence microscopy following staining with fluorescein diacetate and ethidium bromide. Farnesol at 3 mM exerted a stronger action when added at the beginning of biofilm formation (>50% inhibition) than when added to preformed biofilms (<10% inhibition). Similarly, tyrosol at 20 mM had a greater effect on biofilm formation (>80% inhibition) than on preformed biofilms (<40% inhibition). Despite significant reductions in attached biomass, yeast growth varied little in the presence of the investigated molecules, as corroborated by the turbidimetry, culture of supernatants on solid culture medium followed by counting of colony-forming units and viability tests using fluorescence microscopy. At the highest tested concentration, the molecules had a greater effect during the initial phases of biofilm formation. The effect of farnesol during anaerobiosis was not significantly different from that observed during aerobiosis, unlike that of tyrosol during anaerobiosis, which exhibited slightly reduced yeast biofilm inhibition. In conclusion, the present study demonstrated the specific anti-biofilm effect, independent of fungicidal or fungistatic action, of farnesol and tyrosol, as tested in C. albicans ATCC 10231 and 6 strains isolated from dentures. Prior to suggesting the use of these molecules for preventive purposes in oral hygiene, further studies are required in order to clarify the metabolic pathways and cellular mechanisms involved in their antibiofilm effect, as well as the repercussions on the oral microbiome.

Abrogation of pathogenic attributes in drug resistant Candida auris strains by farnesol

“…In comparison to other non-auris Candida species where lower concentrations of farnesol were reported to have anti-biofilm effects, our results showed higher concentrations are required to inhibit biofilm formation and development. Sebaa and co-workers (2019) reported anti-biofilm activity of farnesol against C. albicans ATCC 10231 and 6 other strains isolated from dentures [42]. In the same study, it was reported that 3 mM farnesol exerted stronger action when added at the beginning of biofilm formation (>50% inhibition) than when added to 24h mature biofilms (<10% inhibition), and therefore concluded farnesol had a greater effect during the initial phases of biofilm formation.…”

Potential antibiofilm activity of farnesol-loaded poly(DL-lactide-co-glycolide) (PLGA) nanoparticles against Candida albicans

“…However, this effect was independent of the fungistatic or fungicidal effect. The researchers stated that by the addition of exogenous quorumsensing molecules, the related mechanism may be disrupted or the adhesion of microorganisms on the surface may be limited (Sebaa et al 2019). On the other hand, farnesol, a hydrophobic drug, has been reported to have antimicrobial effects against certain pathogens such as S. mutans.…”

Yeast biofilm in food realms: occurrence and control

“…Recently, the effect of farnesol against C. tropicalis and other yeasts isolated from fruit juice filtration membranes in mono-and multispecies biofilms was assessed (Agustín et al 2019). Similarly, the combination of tyrosol with other antifungals (amphotericin B, itraconazole, and fluconazole) showed a synergistic effect against C. albicans and C. tropicalis biofilms (Sebaa et al 2019). By contrast, nitric oxide (NO), a recognized QSM, enhanced the biofilm formation of S. cerevisiae through FLO11-independent mechanisms (Yan and Bassler 2019).…”