Effects of sub-minimum inhibitory concentrations of lemon essential oil on the acid tolerance and biofilm formation of Streptococcus mutans
Effects of sub-minimum inhibitory concentrations of lemon essential oil on the acid tolerance and biofilm formation of Streptococcus mutans
复制标题
柠檬精油亚最低抑菌浓度对变形链球菌耐酸性和生物膜形成的影响
DOI：
10.1016/j.archoralbio.2017.12.028
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发表时间：
2018-03-01
影响因子：
3
通讯作者：
Zhang, Xiangyu
中科院分区：
文献类型：
--
作者：
Sun, Yanwei;Chen, Sijia;Zhang, Xiangyu
目的：柠檬精油(Leo)是柠檬皮中的一种次生代谢产物，几十年来一直被发现具有抑制致龋菌的作用。然而，其对主要致龋性毒力因子的影响却鲜有报道。本研究旨在研究LEO亚最低抑菌浓度对变形链球菌耐酸性和生物被膜形成的影响，并初步揭示其可能的作用机制。设计：分别采用肉汤稀释法和结晶紫染色方法研究LEO对变形链球菌耐酸性和生物被膜形成的影响。并检测了LuxS、srtA和Spap基因的表达，以探讨其可能的机制。此外，以天然致龋性因子抑制剂茶多酚(TP)和LEO的主要成分柠檬烯(LIM)为对照，评价LEO的作用效果。结果：在pH为4.0~7.0的范围内，LEO、LIM和TP的亚MIC对变形链球菌的生长均表现出剂量依赖性的抑制作用。对变形链球菌生物被膜的形成有明显的抑制作用，在1/2MIC时，对LEO、LIM和TP的抑制率分别为97.87%、94.88%和96.01%。结论：LEO的作用与LIM和TP相似或略强，提示LEO可能是一种新型的天然抗龋剂，可以抑制与细菌耐酸性和生物被膜形成相关的特定基因，而不一定影响口腔细菌的生长。
Objectives: Lemon essential oil (LEO) is a kind of secondary metabolite from lemon peels and has been found to inhibit cariogenic bacteria for decades. However, its effects on main cariogenic virulence factors are rarely reported. The present study aimed to investigate the effects of sub-minimum inhibitory concentrations (sub-MICs) of LEO on the acid tolerance and biofilm formation of Streptococcus mutans (S. mutans) and preliminarily reveal the possible underlying mechanisms.Designs: Effects of LEO on the acid tolerance and biofilm formation of S. mutans were investigated by the broth dilution method and crystal violet staining method respectively. The expression of luxS, srtA and spaP gene was also determined to explore the underlying mechanism. In addition, Tea polyphenols (TP), a major natural inhibitor of cariogenic virulence factors, and limonene (LIM), the major component of LEO, were selected as comparisons to evaluate the effects of LEO.Results: Sub-MICs of LEO, LIM and TP exhibited a dose-dependent inhibition of growth of S. mutans at pH ranging from 4.0 to 7.0. The formation of S. mutans biofilm was remarkably inhibited and the inhibitory rates of LEO, LIM and TP were 97.87%, 94.88% and 96.01% respectively at 1/2 MIC. Similarly, a down-regulation was observed in the expression of luxS, srtA and spaP gene at sub-MIC levels.Conclusions: Effects of LEO were similar or slightly stronger than LIM and TP, suggesting that LEO might represent a novel, natural anticarious agent that inhibited the specific genes associated with bacterial acid tolerance and biofilm formation without necessarily affecting the growth of oral bacteria.