Tao Lei, Liang Yan, Xia Zhi, Wang Xinsheng, Wang Xiaodong, Chao Zhe, Guo Jie
Lanzhou Vocational Technical College, School of Health, Lanzhou, China.
College of Agronomy, Henan Agricultural University, Zhengzhou, China.
Front Pharmacol. 2025 Apr 8;16:1579283. doi: 10.3389/fphar.2025.1579283. eCollection 2025.
Oregano essential oils (OEOs) and their biological active components are of great interest due to their potent pharmaceutical and antibacterial activities. OEOs were extracted from wild and cultivated oregano with white or purple flower using our extraction process. We investigated the antibacterial effects of OEOs and the main active components, carvacrol and thymol. The synergistic effects of carvacrol and thymol were evaluated using checkerboard assay, time-kill assays and systemic infection mice model. The synergistic mechanism was also revealed using scanning electron microscopy (SEM) assay and DAPI/PI staining. Essential oil extracted from wild and cultivated oregano with white flower exhibited potent antibacterial activities against standard strains of Gram-positive and -negative bacteria, with minimum inhibitory concentrations (MICs) range from 0.25-1 mg/mL. The antibacterial activities of carvacrol were obvious higher than that of thymol with MICs values of 0.005-0.04 mg/mL. Carvacrol combining with tobramycin exhibited highly promising synergistic effects (with FICI = 0.25 against and 0.125 against MRSA) which were further confirmed by the time-kill assays. In the systemic infection mice model, carvacrol combining with tobramycin exhibited potent antibacterial effects, with significantly improving the survival rate of mice, reducing the MRSA load and alleviating the pathological changes in the lungs of the infected mice. Preliminary explorations for synergistic mechanism suggested that the enhanced antibacterial potential of tobramycin might be attributed to carvacrol with the ability to perforate membrane and induce holes on it.
牛至精油（OEOs）及其生物活性成分因其强大的药用和抗菌活性而备受关注。采用我们的提取工艺从开白花或紫花的野生和栽培牛至中提取OEOs。我们研究了OEOs以及主要活性成分香芹酚和百里香酚的抗菌作用。使用棋盘法、时间杀菌试验和全身感染小鼠模型评估香芹酚和百里香酚的协同作用。还通过扫描电子显微镜（SEM）试验和DAPI/PI染色揭示了协同机制。从开白花的野生和栽培牛至中提取的精油对革兰氏阳性和阴性标准菌株表现出强大的抗菌活性，最低抑菌浓度（MICs）范围为0.25 - 1毫克/毫升。香芹酚的抗菌活性明显高于百里香酚，其MICs值为0.005 - 0.04毫克/毫升。香芹酚与妥布霉素联合表现出非常有前景的协同作用（对大肠杆菌的FICI = 0.25，对耐甲氧西林金黄色葡萄球菌的FICI = 0.125），时间杀菌试验进一步证实了这一点。在全身感染小鼠模型中，香芹酚与妥布霉素联合表现出强大的抗菌作用，显著提高了小鼠的存活率，降低了耐甲氧西林金黄色葡萄球菌载量，并减轻了感染小鼠肺部的病理变化。对协同机制的初步探索表明，妥布霉素抗菌潜力的增强可能归因于香芹酚具有穿透膜并在其上形成孔洞的能力。
