CNRS UMR 6134 SPE, Université de Corse, BP 52, 20250 Corte, France.
Molecules. 2018 Aug 23;23(9):2125. doi: 10.3390/molecules23092125.
Quorum sensing (QS) is a bacterial communication mechanism used to express various survival or virulence traits leading to enhanced resistance. is a commonly used strain that highlights anti-QS action of bioactive substances. Here, we wanted to see if 12 selected essential oils (EO) could exert anti-QS activity. We measured the sublethal minimal QS inhibitory concentration (MQSIC) by assessing violacein production of along with bacterial growth. To confirm the QS disruption, we also proceed to surface bacterial observations using scanning electron microscopy (SEM). We showed that menthenolide extracted and isolated from a plant endemic to occidental Mediterranean Sea islands, ssp. , acts as an inhibitor of violacein production and biofilm formation. Measured MQSIC was much lower than the minimal inhibitory concentration (MIC): 0.10 mg·mL vs. 3.00 mg·mL. Moreover, disturbance of QS-related traits was confirmed by the degradation of biofilm matrix. There is a clear structure⁻activity relationship between menthenolide and anti-QS activity. Indeed, its isomer molecule (mintlactone) exerts a poor anti-QS action. These results indicate that inhibition of violacein production and biofilm formation by menthenolide might be related to a disruption in the QS mechanism.
群体感应 (QS) 是一种细菌通讯机制，用于表达各种生存或毒力特征，从而增强抗性。 是一种常用的菌株，突出了生物活性物质的抗 QS 作用。在这里，我们想看看 12 种精选的精油 (EO) 是否具有抗 QS 活性。我们通过评估 对紫色素产生的影响以及细菌生长来测量亚致死最小 QS 抑制浓度 (MQSIC)。为了确认 QS 中断，我们还使用扫描电子显微镜 (SEM) 对表面细菌进行了观察。我们表明，从地中海西部岛屿特有植物中提取和分离的薄荷酮内酯作为一种抑制紫色素产生和生物膜形成的抑制剂。测定的 MQSIC 远低于最小抑菌浓度 (MIC)：0.10 mg·mL 对 3.00 mg·mL。此外，通过生物膜基质的降解证实了与 QS 相关特征的干扰。薄荷酮内酯和抗 QS 活性之间存在明显的结构-活性关系。事实上，它的异构体分子（薄荷内酯）表现出较差的抗 QS 作用。这些结果表明，薄荷酮内酯抑制紫色素产生和生物膜形成可能与 QS 机制的破坏有关。
