Streptococcus mutans Raw sequence reads. Streptococcus mutans

Lonicera japonica flos (LJF) is a traditional Chinese herb with multi-functions and has been consumed as a tea for thousands of years. In this work, it was investigated for the inhibitory effect and mechanism of Streptococcus mutans (S. mutans), a primary oral pathogen. The inhibitory effect of LJF samples from different origins was examined, and the active extracts of LJF from Henan were validated for their inhibitory activity in terms of the change of surface characteristics such as adherence, hydrophobicity, and auto-aggregate ability, and the production of exopolysaccharides (EPS) and quorum-sensing signaling molecule AI-2. The conjoint analysis of transcriptomic and untargeted metabolomics showed that two-component systems (TCS), quorum sensing (QS), and phosphotransferase system (PTS) were the three main pathways related to S. mutans biofilm formation. It was found that LJF inhibited biofilm formation mainly by reducing WIG and WSG. Where the sensing histidine VicK was expressed disorderly and AI-2 sensing was blocked by LJF. Then the response regulator transcriptional factor was inhibited, leading to the down-regulated glycosyltransferase by the gtf family and decrease in WIG and WSG. This is the first exploration of the inhibitory effect and mechanism of LJF on S. mutans. The results can serve as a theoretical basis for the application of LJF in functional food, oral health care, and relevant areas.