Method: The dried and finely ground turmeric was extracted with methanol at room temperature for 24 h and concentrated under vacuum. A part of the methanol extract was suspended in 70% aqueous methanol and fractioned serially for n-hexane, chloroform and ethyl acetate fraction. To select the most active anti-biofilm fraction, a glycolytic pH-drop assay, HPLC qualitative and quantitative analysis were performed. To compare the anti-biofilm activity and curcuminoid contents of the fractions, the linearity of calibration curve was determined using the experimental parameters, the final pH from glycolytic pH-drop assay and content of curcuminoids. To assess the influence of the most active anti-biofilm fraction and curcuminoids on the virulence factors of S. mutans biofilm cells, glycolytic pH drop, sucrose-dependent adherence, acid-killing and F-ATPase activity assays were performed using 74 h old S. mutans biofilms. S. mutans biofilms were formed on saliva-coated hydroxyapatite discs.
Result: The most active anti-biofilm fraction and curcuminoids, which are the main components of turmeric, had inhibitory effects on the virulence properties of S. mutans biofilms, such as bacterial adherence, acidogenicity and aciduricity (250 µg/ml of the most active anti-biofilm fraction, 50 µg/ml of curcuminoids).
Conclusion: These results suggest that the separated turmeric fraction and curcuminoids may be useful for controlling dental biofilms and subsequent dental caries formation.