Chemistry Department, Federal University of Lavras (UFLA), Lavras, 37200-900 MG, Brazil.
Food Sciences Department, Federal University of Lavras (UFLA), Lavras, 37200-900 MG, Brazil.
FEMS Microbiol Lett. 2021 May 28;368(9). doi: 10.1093/femsle/fnab052.
Foodborne, disease-causing microorganisms are increasingly resistant to commercial antibiotics. Thus, there is a need for the development of new agents capable of acting efficiently in the control of these pathogens. Terpenoids and phenylpropanoids stand out for having high biological activity and a broad spectrum of action. The objectives of this study were to evaluate the antibacterial potential of limonene, β-citronellol, carvone, carvacrol, eugenol and trans-cinnamaldehyde and to investigate the mechanism of activity of these compounds against the bacteria Escherichia coli and Staphylococcus aureus. The terpene and phenylpropanoid compoundswere purchased and their antibacterial potential was assessed by macrodilution. The mechanism of action was verified by tests of potassium ion efflux, salt tolerance, extravasation of cellular contents, absorption of crystal violet and morphological changes analyzed by electron microscopy. Bacteriostatic and bactericidal effects caused by the compounds carvone, carvacrol, eugenol and transcinemaldehyde were observed in both species; antibacterial activity against only S. aureus was observed for β-citronelol and limonene. Reduced salt tolerance was found for strains of E. coli treated with carvacrol and S. aureus treated with β-citronelol. There was extravasation of cellular materials induced by treatments with carvone, carvacrol, eugenol and trans-cinnamaldehyde in both microorganisms. The absorption of crystal violet increased for E. coli after incubation with each treatment. Deleterious effects and morphological changes were observed. Therefore, the monoterpenes and phenylpropanoids under study are potentially applicable for antimicrobial use against E. coli and S. aureus, and the mechanism of action involves changes in membrane permeability without cell lysis.
食源性致病微生物对商业抗生素的耐药性日益增强。因此，需要开发新的能够有效控制这些病原体的药物。萜类化合物和苯丙素类化合物因其具有高生物活性和广谱作用而备受关注。本研究旨在评估柠檬烯、β-香茅醇、香芹酮、香芹酚、丁子香酚和反式肉桂醛的抗菌潜力，并研究这些化合物对大肠杆菌和金黄色葡萄球菌的作用机制。购买了萜烯和苯丙素类化合物，并通过大稀释法评估了它们的抗菌潜力。通过钾离子外排、耐盐性、细胞内容物外渗、结晶紫吸收和电子显微镜分析的形态变化测试来验证作用机制。香芹酮、香芹酚、丁子香酚和反式肉桂醛对两种细菌均表现出抑菌和杀菌作用；β-香茅醇和柠檬烯仅对金黄色葡萄球菌表现出抗菌活性。用香芹酚处理大肠杆菌和用β-香茅醇处理金黄色葡萄球菌后，其耐盐性降低。用香芹酮、香芹酚、丁子香酚和反式肉桂醛处理后，两种微生物的细胞物质均发生外渗。与每种处理物孵育后，大肠杆菌对结晶紫的吸收增加。观察到有害影响和形态变化。因此，所研究的单萜类化合物和苯丙素类化合物具有作为抗大肠杆菌和金黄色葡萄球菌的抗菌用途的潜力，其作用机制涉及到细胞膜通透性的改变而不引起细胞裂解。
