With an upsurge in multidrug resistant bacteria backed by biofilm defence armours, there is a desperate need of new antibiotics with a non-traditional mechanism of action. Targeting bacteria by misguiding them or halting their communication is a new approach that could offer a new way to combat the multidrug resistance problem. Quorum sensing is considered to be the achilles heel of bacteria that has a lot to offer. Since, both quorum sensing and biofilm formation have been related to drug resistance and pathogenicity, in this study we synthesised new derivatives of citral with antiquorum sensing and biofilm disrupting properties. We previously reported antimicrobial and antiquorum sensing activity of citral and herein we report the synthesis and evaluation of citral and its derivatives (CD1-CD3 ) for antibacterial, antibiofilm and antiquorum sensing potential against Chromobacterium violaceum using standard methods. Preliminary results revealed that CD1 is the most active of all the derivatives. Qualitative and quantitative evaluation of antiquorum sensing activity at sub-inhibitory concentrations of these compounds also revealed high activity for CD1 followed by CD2, CD3 and citral. These compounds also inhibit biofilm formation at subinhibitory concentrations without causing any bacterial growth inhibition. These results were replicated by RT-qPCR with down regulation of the quorum sensing genes when C. violaceum was treated with these test compounds. Overall, the results are quite encouraging, revealing that biofilm and quorum sensing are interrelated processes and also indicating the potential of these derivatives to impede bacterial communication and biofilm formation.

中文翻译：

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柠檬醛及其衍生物抑制紫色色杆菌中的群体感应和生物膜形成

随着由生物膜防御装甲支持的多重耐药菌的激增，迫切需要具有非传统作用机制的新型抗生素。通过误导细菌或停止它们的交流来靶向细菌是一种新方法，可以提供一种新的方法来对抗多药耐药性问题。群体感应被认为是细菌的致命弱点。由于群体感应和生物膜形成都与耐药性和致病性有关，因此在本研究中，我们合成了具有抗群体感应和生物膜破坏特性的柠檬醛新衍生物。我们之前报道了柠檬醛的抗菌和抗微生物活性，在此我们报告了柠檬醛及其衍生物（CD1-CD3）的合成和评价用于抗菌，使用标准方法对紫色色杆菌的抗生物膜和抗微生物感应潜力。初步结果表明，CD1 是所有衍生物中最活跃的。在这些化合物的亚抑制浓度下对 Antiquorum 感应活性的定性和定量评估也揭示了 CD1 的高活性，其次是 CD2、CD3 和柠檬醛。这些化合物还在亚抑制浓度下抑制生物膜形成，而不会引起任何细菌生长抑制。这些结果通过 RT-qPCR 复制，当用这些测试化合物处理紫葡萄时，群体感应基因下调。总的来说，结果相当令人鼓舞，