Adil Mohd, Singh Kunal, Verma Praveen K, Khan Asad U
Medical Microbiology and Molecular Biology Laboratory, Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India.
National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India.
J Glob Antimicrob Resist. 2014 Dec;2(4):286-292. doi: 10.1016/j.jgar.2014.05.006. Epub 2014 Jul 6.
Streptococcus mutans is well documented as a major aetiological agent of dental caries. The ability to form a biofilm on tooth surfaces is the major virulence factor of this bacterium. The objective of this study was to evaluate the effect of eugenol on suppression of biofilm- and quorum sensing (QS)-related genes of S. mutans and to determine its putative mode of action. Eugenol was evaluated for its inhibitory activity against virulence properties such as adherence and biofilm formation. Morphological changes in the architecture of S. mutans and in the biofilm were analysed and observed using confocal laser scanning microscopy and transmission electron microscopy. The effects of eugenol on expression of biofilm- and QS-related genes (gtfB, gtfC, comDE, smu630, vicR, brpA, ftf, relA, gbpB and spaP) were checked by quantitative real-time PCR (qRT-PCR). The present data revealed that eugenol at a sub-minimum inhibitory concentration (sub-MIC) significantly downregulated the expression of tested genes but did not affect bacterial growth. These results suggest that a sub-MIC of eugenol can effectively suppress virulence genes. Thus, the results indicated that eugenol can inhibit caries-associated biofilm and showed its therapeutic potential against oral biofilm.
变形链球菌是公认的龋齿主要病因菌。在牙齿表面形成生物膜的能力是该细菌的主要毒力因子。本研究的目的是评估丁香酚对变形链球菌生物膜相关基因和群体感应（QS）相关基因的抑制作用，并确定其可能的作用方式。评估了丁香酚对诸如黏附及生物膜形成等毒力特性的抑制活性。使用共聚焦激光扫描显微镜和透射电子显微镜分析并观察了变形链球菌及其生物膜结构的形态变化。通过定量实时PCR（qRT-PCR）检测丁香酚对生物膜相关基因和QS相关基因（gtfB、gtfC、comDE、smu630、vicR、brpA、ftf、relA、gbpB和spaP）表达的影响。目前的数据显示，亚最小抑菌浓度（sub-MIC）的丁香酚显著下调了受试基因的表达，但不影响细菌生长。这些结果表明，亚最小抑菌浓度的丁香酚可有效抑制毒力基因。因此，结果表明丁香酚可抑制与龋齿相关的生物膜，并显示出其对口腔生物膜的治疗潜力。
