白及提取物抗变异链球菌致龋效果的研究

目的研究白及提取物对变异链球菌粘附、生物膜形成及活性的影响,评价其抗龋效果。方法市售白及95%乙醇浸提;纸片法、打孔法测定直接抑菌作用;液体稀释法检测MIC;结晶紫法研究亚抑菌浓度提取物对变异链球菌粘附能力及生物膜总量的影响;采用荧光显微镜和激光共聚焦显微镜观察常态牙菌斑生物膜生长过程中及药物处理后牙菌斑生物膜中死菌和活菌的构成,研究其对牙菌斑生物膜结构和活性的影响;运用扫描电镜观察白及药液对变异链球菌生物膜的影响。结果白及提取物具有一定的抑菌作用,MIC为16~62 mg/m L;结晶紫法定量研究生物膜结果显示白及药液作用4 h对变异链球菌的粘附均有抑制作用,抑制率为28.63%~60.08%;作用20 h对生物膜总量抑制率达77.08%;白及药液作用20 h,荧光染色显示生物膜活性明显被抑制,抑制率达62.03%;梯度浓度白及药液分别作用20 h后,激光共聚焦显微镜下观察到随着药液浓度增加,绿色的活菌、团块状结构减少,生物膜形成明显被抑制;扫描电镜下可见药液作用后细菌间粘性物质减少。结论高浓度白及提取液对变异链球菌有直接抑菌作用,亚抑菌浓度能抑制其粘附和生物膜的形成,进而具有抗龋作用。

The anti-caries effect of Bletilla striata extract against Streptococcus mutans

Abstract: Objective To study the effect of Bletilla striata extract on the adhesion, the biofilm formation and vitality of Streptococcus mutans, and evaluate its anti-caries effect. Methods Dilution method was adopted to measure the minimal inhibitory concentration (MIC) of Bletilla striata extract. The adhesion and total amount of the biofilm of Streptococcus mutans was tested with crystal violet staining. The vitality of Streptococcus mutans in the biofilm was observed with fluorescence microscope. The structure of the biofilm was observed by using scanning electron microscopy. Results The MIC of Bletilla striata extract against S.mutans was 16 - 62 mg/mL. The adhesion of Streptococcus mutans was inhibited by Bletilla striata extract after culture for 4 h, the inhibition rate was 28.63% - 60.08%. The total amount of biofilm was inhibited at a rate of 77.08%, after 20 hours of cultivation; the inhibition rate was up to 62.03%. Scanning electron microscopy showed that Bletilla striata obviously reduced the amount of live bacteria and inhibited the formation of biofilm. Conclusion Bletilla striata extract has an anti-caries effect on Streptococcus mutans by inhibiting the adhesion of the pathogen and the formation of its biofilm.