Araújo Nara Juliana Santos, Silva Camila Aparecida Pereira, Bezerra Vanessa Lima, Oliveira-Tintino Cicera Datiane Morais, Alencar Gabriel Gonçalves de, Costa Maria do Socorro, Silva Ana Raquel Pereira da, Santos Josefa Sayonara Dos, Camara Kamila Correa, Facundo Heberty diTarso Fernandes, Ferreira Lívia Pereira, Coutinho Henrique Douglas Melo, Barbosa Filho José Maria, Domiciano Carolina Bandeira, Araújo-Neto José Bezerra de, Andrade-Pinheiro Jacqueline Cosmo
Graduate Program in Biochemistry and Molecular Biology, Federal University of Cariri, Barbalha, Ceará, 63.090-684, Brazil.
Laboratory of Applied Microbiology-LAMAP, Federal University of Cariri, Barbalha, Ceará, 63.090-684, Brazil.
ChemistryOpen. 2025 Jul 22:e2500227. doi: 10.1002/open.202500227.
Antimicrobial resistance remains one of the major challenges to global public health, compromising the effectiveness of treatments and contributing to increased morbidity and mortality associated with bacterial infections. Among the mechanisms involved, efflux pumps-such as NorA, expressed in resistant strains of Staphylococcus aureus-are particularly noteworthy. These transport proteins actively expel antibiotics from the cell, reducing their intracellular concentration. In this context, natural compounds have been explored as potential resistance inhibitors, with a focus on the triterpene lupeol, known for its pharmacological properties. This study evaluates the activity of lupeol against the NorA efflux pump using in vitro assays and in silico modeling. The minimum inhibitory concentration (MIC) is determined by broth microdilution, and pump inhibition is assessed via ethidium bromide-induced fluorescence. SYTOX Green assays indicated that lupeol does not compromise bacterial membrane integrity. Although lupeol presented a MIC ≥ 1024 μg mL, it demonstrates significant inhibition of NorA activity. Molecular docking reveals a binding energy of -7.112 kcal mol and interactions with key residues of the protein, outperforming the CCCP control. These findings suggest that lupeol acts as a modulator of bacterial resistance, with potential application as a therapeutic adjuvant in the treatment of infections caused by multidrug-resistant S. aureus.
抗生素耐药性仍然是全球公共卫生面临的主要挑战之一，它损害了治疗效果，并导致与细菌感染相关的发病率和死亡率上升。在涉及的机制中，耐药菌株金黄色葡萄球菌中表达的NorA等外排泵尤其值得关注。这些转运蛋白能将抗生素主动排出细胞，降低其细胞内浓度。在这种情况下，天然化合物已被探索作为潜在的耐药性抑制剂，重点是具有药理特性的三萜类化合物羽扇豆醇。本研究使用体外试验和计算机模拟评估羽扇豆醇对NorA外排泵的活性。通过肉汤微量稀释法测定最低抑菌浓度（MIC），并通过溴化乙锭诱导的荧光评估泵抑制作用。SYTOX Green试验表明羽扇豆醇不会损害细菌膜的完整性。虽然羽扇豆醇的MIC≥1024μg/mL，但它对NorA活性有显著抑制作用。分子对接显示结合能为-7.112kcal/mol，并与该蛋白的关键残基相互作用，优于CCCP对照。这些发现表明羽扇豆醇可作为细菌耐药性的调节剂，在治疗耐多药金黄色葡萄球菌引起的感染方面具有作为治疗佐剂的潜在应用价值。
