Laboratory of Microbiology and Molecular Biology (LMBM), Department of Biological Chemistry/CCBS/URCA, Brazil.
Laboratory of Pharmacology and Molecular Chemistry (LFQM), Department of Biological Chemistry/CCBS/URCA, Brazil.
Food Chem. 2021 Feb 1;337:127776. doi: 10.1016/j.foodchem.2020.127776. Epub 2020 Aug 5.
Staphylococcus aureus is a Gram-positive bacterium responsible for a number of diseases and has demonstrated resistance to conventional antibiotics. This study aimed to evaluate the antibacterial activity of eugenol and its derivatives allylbenzene, 4-allylanisole, isoeugenol and 4-allyl-2,6-dimethoxyphenol against the S. aureus NorA efflux pump (EP) in association with norfloxacin and ethidium bromide. The antibacterial activity of the compounds was assessed using the broth microdilution method to determine the minimum inhibitory concentration (MIC). A reduction in the MIC of ethidium bromide (a substrate for several efflux pumps) or norfloxacin was used as a parameter of EP inhibition. Molecular modeling studies were used to predict the 3D structure and analyze the interaction of selected compounds with the binding pocket of the NorA efflux pump. Except for 4-allylanisole and allylbenzene, the compounds presented clinically effective antibacterial activity. When associated with norfloxacin against the SA 1199B strain, 4-allyl-2,6-dimethoxyphenol eugenol and isoeugenol caused significant reduction in the MIC of the antibiotic, demonstrating synergistic effects. Similar effects were observed when 4-allyl-2,6-dimethoxyphenol, allylbenzene and isoeugenol were associated with ethidium bromide. Together, these findings indicate a potential inhibition of the NorA pump by eugenol and its derivatives. This in vitro evidence was corroborated by docking results demonstrating favorable interactions between 4-allyl-2,6-dimetoxypheno and the NorA pump mediated by hydrogen bonds and hydrophobic interactions. In conclusion, eugenol derivatives have the potential to be used in antibacterial drug development in strains carrying the NorA efflux pump.
金黄色葡萄球菌是一种革兰氏阳性细菌,可导致多种疾病,并已表现出对传统抗生素的耐药性。本研究旨在评估丁香酚及其衍生物烯丙基苯、4-烯丙基苯甲醚、异丁香酚和 4-烯丙基-2,6-二甲氧基苯酚对金黄色葡萄球菌 NorA 外排泵(EP)与诺氟沙星和溴化乙锭联合的抗菌活性。使用肉汤微量稀释法评估化合物的抗菌活性,以确定最小抑菌浓度(MIC)。溴化乙锭(几种外排泵的底物)或诺氟沙星的 MIC 降低被用作 EP 抑制的参数。分子建模研究用于预测所选化合物的 3D 结构,并分析它们与 NorA 外排泵结合口袋的相互作用。除了 4-烯丙基苯甲醚和烯丙基苯外,这些化合物表现出具有临床疗效的抗菌活性。当与诺氟沙星联合用于 SA 1199B 株时,4-烯丙基-2,6-二甲氧基苯酚、丁香酚和异丁香酚导致抗生素 MIC 显著降低,表现出协同作用。当 4-烯丙基-2,6-二甲氧基苯酚、烯丙基苯和异丁香酚与溴化乙锭联合使用时,也观察到类似的效果。这些发现表明丁香酚及其衍生物可能抑制 NorA 泵。这些体外证据得到了对接结果的证实,结果表明 4-烯丙基-2,6-二甲氧基苯酚与 NorA 泵之间存在有利的相互作用,由氢键和疏水相互作用介导。总之,丁香酚衍生物有可能在携带 NorA 外排泵的菌株中用于开发抗菌药物。