Sub-lethal concentrations of Muscari comosum bulb extract suppress adhesion and induce detachment of sessile yeast cells

Abstract

The formation of yeast biofilm on food industry equipment can lead to serious hygiene problems and economic losses due to food spoilage and equipment impairment. This study explored the ability of a sub-lethal concentration of the bulb extract of Muscari comosum to modulate adhesion of Candida albicans and subsequent biofilm development by this fungus. The HPLC profile of the ethanolic bulb extract showed phenolic constituents, which were found to undergo Folin-Ciocalteu reagent reduction. Prior to the adhesion tests, it was shown that up to 4000 mg l⁻¹ of natural extract did not adversely affect fungal growth nor did it act as a carbon energy source for C. albicans. Mathematical models predicted that 4000 mg l⁻¹ and 700 mg l⁻¹ of bulb extract would cause more than 98% reduction in fungal coverage on abiotic surfaces, without killing the planktonic cells. When added to C. albicans biofilm, the natural extract was shown to induce the dispersion of sessile cells in a dose-dependent manner.

Keywords:

• Muscari comosum
• Candida albicans
• sub-lethal concentration of extract
• experimental design
• adhesion
• dispersion agent

Acknowledgements

This work was partially supported by Fondazione Cariplo, grant no. 2011-0277.