The present study evaluated the effect of the essential oil of Mikania cordifolia (EOMc) and its major constituent limonene alone or associated with antibacterial drugs against Multidrug Resistant Bacteria (MDR). To evaluate the antibacterial activity, the minimum inhibitory concentrations (MIC) of the oil and limonene against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus were determined. The antibiotic-modulating activity was assessed using subinhibitory concentrations (MIC/8) of these substances in combination with conventional antibacterial drugs. Although no relevant antibacterial activity of the natural products was detected, both substances modulated the action of antibiotics against resistant bacteria. The EOMc demonstrated the best modulating effect against P. aeruginosa, presenting synergistic effects when associated with gentamicin and norfloxacin. In addition, the oil reduced the MIC of norfloxacin against E. coli as well as reduced the MIC of gentamicin against S. aureus. On the other hand, the best effect of limonene was obtained against S. aureus. Thus, it is concluded that the essential oil Mikania cordifolia and the isolated compound limonene do not have clinically significant antibacterial effect, but modulate the action of antibiotics against MDR bacteria.

中文翻译：

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薇甘菊和柠檬烯对MDR菌株的GC-MS-FID表征和抗菌活性。

本研究评估了Mikania cordifolia（EOMc）及其主要成分柠檬烯的精油单独使用或与抗多药耐药细菌（MDR）的抗菌药物联合使用的效果。为了评估抗菌活性，确定了油和柠檬烯对铜绿假单胞菌，大肠杆菌和金黄色葡萄球菌的最小抑制浓度（MIC）。使用这些物质的亚抑菌浓度（MIC / 8）与常规抗菌药物联合评估抗生素调节活性。尽管未检测到天然产物的相关抗菌活性，但这两种物质均调节了抗生素对耐药菌的作用。EOMc对铜绿假单胞菌具有最佳的调节作用，与庆大霉素和诺氟沙星联用时具有协同作用。另外，该油降低了诺氟沙星对大肠杆菌的MIC，以及庆大霉素对金黄色葡萄球菌的MIC。另一方面，柠檬烯对金黄色葡萄球菌具有最佳效果。因此，可以得出结论，香精油Mikania cordifolia和分离的化合物柠檬烯没有临床上显着的抗菌作用，但是可以调节抗生素对MDR细菌的作用。