Effects Of Lemon Essential Oil On Surface Hydrophobicity,Adherence And SrtA Transcription Of Streptococcus Mutans

Objective: Streptococcus mutans has the most significant relationship with dental caries,which also plays an important role in the early biofilm formation. Many surface proteins(such as surface protein spa P) are anchored to the cell wall envelope by sortase A, which is coded by the gene srtA. Enzyme sortase A plays an important role in the adhesion to tooth surface. The aim of this study was to investigate the inhibitory ability of lemon essential oil(LEO), limonene(LIM) and tea polyphenol(TP) against the cell surface hydrophobicity, adherence and srtA?spa P gene expression levels of S. mutans.Content: To investigate the effect of LEO, LIM and TP on the cell surface hydrophobicity, adherence and srtA?spa P gene expression levels of S. mutans in vitro experiments, and the possible mechanism of the effects of natural plant products on them was also discussed.Methods: 1.The minimal inhibitory concentration of LEO, LIM and TP on S.mutans(inhibitory concentration Minimal, MIC) was determined. The effect of LEO on the growth of HUVECs was detected by MTT assay.2. Determining the effect of the three kinds of natural products on the cell surface hydrophobicity and adherence of S.mutans.Select five concentrations following MIC as experiment concentrations,and blank control group is BHI liquid medium without any drugs. Microbial adhesion to hydrocarbons(MATH) is used to determine the effect of them on the cell surface hydrophobicity of S.mutans. The effect of different concentrations of plant products on the adherence of S.mutans to the hard tissue surface of was determined by a classical 96-cell microtitre plate production assay using crystal violet staining method.3. Determine the effects of the three kinds of natural products on the srtA and spa P gene transcription level of S.mutans.Using real-time fluorescence quantitative PCR method, the expression levels of srtA and spa P genes of S.mutans after treatment with different concentrations of plant products were determined.Results: 1. MIC of LEO, LIM and TP were 4.5 mg/ml, 21 mg/ml, 4 mg/ml. LEO(1/2MIC?1/20MIC)had inhibitory effect on the HUVECs.2. The cell surface hydrophobicity of S.mutans is 76.725%.LEO, LIM and TP(sub-MIC levels) could inhibit the cell surface hydrophobicity of S.mutans in a dose-dependent manner. In the 1/2MIC concentrations, the extent of inhibitory effect on the cell surface hydrophobicity is LEO > LIM > TP,(F=91.041,P<0.05). In the sub-MIC levels, the extent of inhibitory effect of LEO on the cell surface hydrophobicity is better than LIM.3. LEO, LIM and TP(sub-MIC levels) could inhibit the adherence of S.mutans. This difference in the 1 / 2MIC concentrations was not statistically significant,(F=1.43,P>0.05).4. In the 1/2MIC(2.25mg/ml)~ 1/20000MIC(0.000225mg/ml), LEO could inhibit the cell surface hydrophobicity of S.mutans in a dose-dependent manner. However, LEO could inhibit the adherence of S.mutans in 1/2MIC(2.25mg/ml)~ 1/200MIC(0.0225mg/ml), not Below the concentration 1/2000MIC(0.00225mg/ml).5. LEO, LIM and TP(In the 1/2MIC~ 1/200MIC) could inhibit the srtA gene transcription level of S.mutans in a dose-dependent manner. With the increase of the concentration of LEO?LIM?TP,srtA gene m RNA expression levels reduce.6.The extent of inhibitory effect of LEO on transcriptional expression of srtA gene is better than LIM?TP?Conclusions: LEO, LIM and TP(sub-MIC levels) has inhibitory effect on the cell surface hydrophobicity, adherence and srtA gene expression levels of S.mutans.