Lima Emília Maria França, de Almeida Felipe Alves, Pinto Uelinton Manoel
Food Research Center (FoRC), Laboratory of Food Microbiology, Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo (USP), São Paulo, SP, Brazil.
Department of Microbiology, Institute of Biotechnology Applied to Agriculture (BIOAGRO), Federal University of Viçosa (UFV), Viçosa, MG, Brazil.
World J Microbiol Biotechnol. 2025 Jan 11;41(2):32. doi: 10.1007/s11274-025-04255-4.
Bacteria coordinate gene expression in a cell density-dependent manner in a communication process called quorum sensing (QS). The expression of virulence factors, biofilm formation and enzyme production are QS-regulated phenotypes that can interfere in human health. Due to this importance, there is great interest in inhibiting QS, comprising an anti-virulence strategy. This work aimed to evaluate the effect of selected phenolic compounds on the inhibition of QS-regulated phenotypes in Pseudomonas aeruginosa PAO1, using concentrations that do not interfere in bacterial growth. This is one of the main premises for studying the effect of compounds on QS. Firstly, an in-silico study with the LasR and RhlR proteins of P. aeruginosa by molecular docking of 82 phenolic compounds was performed. Then, a screening with 13 selected phenolic compounds was performed, using biosensor strains P. aeruginosa lasB-gfp and P. aeruginosa rhlA-gfp, which emit fluorescence when the QS system is activated. From this assay, eight compounds were selected and evaluated for inhibition of pyocyanin, rhamnolipids, proteases, elastase, and motility. The compounds variably inhibited the evaluated virulence factors. The greatest inhibitions were observed for swarming motility, achieving inhibition rates of up to 50% for baicalein (500 µM) and curcumin (50 µM). Notably, curcumin showed satisfactory inhibition for all phenotypes even at lower concentrations (12.5 to 50 µM) compared to the other compounds (125 to 500 µM). Four compounds - rosmarinic acid, baicalein, curcumin, and resveratrol - were finally tested against biofilm formation observed by optical microscopy. This study demonstrated that phenolic compounds exhibit strong in silico binding to P. aeruginosa LasR and RhlR proteins and variably inhibit QS-regulated phenotypes in vitro. Although no biofilm inhibition was observed, future studies combining compounds and exploring molecular mechanisms are recommended. These findings highlight the biotechnological potential of phenolic compounds for future applications in the food, clinical, and pharmaceutical fields.
细菌在一种称为群体感应（QS）的通讯过程中以细胞密度依赖的方式协调基因表达。毒力因子的表达、生物膜形成和酶的产生都是受QS调控的表型，它们会干扰人类健康。鉴于其重要性，人们对抑制QS的研究兴趣浓厚，这构成了一种抗毒力策略。本研究旨在评估所选酚类化合物对铜绿假单胞菌PAO1中QS调控表型的抑制作用，所使用的浓度不会干扰细菌生长。这是研究化合物对QS作用效果的主要前提之一。首先，通过对82种酚类化合物进行分子对接，对铜绿假单胞菌的LasR和RhlR蛋白进行了计算机模拟研究。然后，使用生物传感器菌株铜绿假单胞菌lasB-gfp和铜绿假单胞菌rhlA-gfp进行筛选，这两种菌株在QS系统激活时会发出荧光。从该试验中，选择了8种化合物并评估其对绿脓菌素、鼠李糖脂、蛋白酶、弹性蛋白酶和运动性的抑制作用。这些化合物对所评估的毒力因子有不同程度的抑制作用。观察到对群体运动性的抑制作用最大，黄芩苷（500µM）和姜黄素（50µM）的抑制率高达50%。值得注意的是，与其他化合物（125至500µM）相比，姜黄素即使在较低浓度（12.5至50µM）下对所有表型也表现出令人满意的抑制作用。最后，对迷迭香酸、黄芩苷、姜黄素和白藜芦醇这四种化合物针对光学显微镜下观察到的生物膜形成进行了测试。本研究表明，酚类化合物在计算机模拟中与铜绿假单胞菌LasR和RhlR蛋白具有很强的结合力，并在体外对QS调控的表型有不同程度的抑制作用。虽然未观察到生物膜抑制作用，但建议未来开展化合物组合及探索分子机制的研究。这些发现突出了酚类化合物在食品、临床和制药领域未来应用的生物技术潜力。
