Exploration of the Main Antibiofilm Substance of Lactobacillus plantarum ATCC 14917 and Its Effect against Streptococcus mutans .

Dental plaque, a complex biofilm system established by cariogenic bacteria such as (), is the initiator of dental caries. Studies have found that the cell-free supernatant (CFS) of could inhibit biofilm formation. However, the main antibiofilm substance of the CFS that acts against is unclear. The present study found that the CFS of () ATCC 14917 had the strongest antibiofilm effect among the five tested oral . Further bioassay-guided isolation was performed to identify the main antibiofilm substance. The antibiofilm effect of the end product, named , was observed and the structure of it was elucidated by using Q-TOF MS, 2D NMR and HPLC. The results showed that several components in the CFS had an antibiofilm effect; however, the effect of was the strongest, as it could reduce the generation of exopolysaccharides and make the biofilm looser and thinner. After structure elucidation and validation, was identified as a mixture of lactic acid (LA) and valine. Additionally, LA was shown to be the main antibiofilm substance in . In summary, this study found that the antibiofilm effect of the CFS against was attributable to the comprehensive effect of multiple components, among which LA played a dominant role.