<i>In Vitro</i> Inhibitory Effect of Vanillin on <i>Candida</i> Biofilm

Abstract

Vanillin is a major constituent of vanilla seeds which is used as a flavoring agent in both food and non-food industries. Previous reports have showed that vanillin had antimicrobial properties against food spoilage bacteria, yeasts, and molds. However, investigations about its effect on oral pathogenic yeasts are scarcely found. Objective: This study aims to determine the effect of vanillin on candida biofilm formation in vitro. Method: Vanillin (Sigma-Aldrich, UK) was prepared in 99.7% ethyl alcohol and diluted to concentrations of 0.5-20 mM. Biofilms of Candida albicans (ATCC 10231 and 2 clinical strains) were grown on the bottom of 96-well plate with Yeast Nitrogen Base (YNB) medium supplemented with 100 mM glucose in a shaking incubator at 37oC for 24 h. After washing, each concentration of vanillin was added with YNB supplemented with 200 mM glucose. The plate was incubated in shaking incubator for another 24 h at 37oC. Evaluation of biofilm was assessed through the XTT reduction assay. A solution of 0.2% chlorhexidine gluconate solution and 99.7% ethyl alcohol were used as positive and negative controls respectively. Result: It was found that 75-80% candida biofilm reduction was demonstrated at concentrations of 10.5-20 mM vanillin whereas chlorhexidine exhibited 94% biofilm reduction. Conclusion: Our results indicate that vanillin is a promising agent that can be used to cure candida infection in the oral cavity. Further studies are required to evaluate its effect on other yeast strains and cytotoxicity before consideration for usage in patients.