Wang Xu-Dong, Bai Jia-Li, Ma Zhen-Jia, Fan Jie, Kong Wei-Bao, Wang Jun-Long, Zhang Ji, Liang Jun-Yu
College of Life Science, Northwest Normal University, Lanzhou, 730070, Gansu, People's Republic of China.
College of Medicine, Northwest Minzu University, Lanzhou, Gansu, People's Republic of China.
Curr Microbiol. 2025 Jul 2;82(8):359. doi: 10.1007/s00284-025-04333-8.
In light of concerns regarding milk quality deterioration and the rising threat of bacterial resistance, developing alternative treatments to antibiotics for mastitis has become imperative. Clove oil (CEO), a well-established natural antimicrobial, has not been extensively investigated for its synergistic potential when combined with Elsholtzia EO. Essential oils (EOs) from the plants were extracted using steam distillation. Gas chromatography-mass spectrometry (GC-MS) results showed that the main component of CEO was eugenol (76.59%), the main component of Elsholtzia densa EO was limonene (22.05%), the main component of Elsholtzia ciliata EO was carvone (31.63%), the main component of Elsholtzia fruticosa EO (EfEO) was eucalyptol (40.1%), and the main component of Elsholtzia stauntonii EO was cuminol (27.60%). Antimicrobial assays demonstrated CEO's superior efficacy against bovine mastitis pathogens (MIC: 1.875-7.5 mg/mL), while CEO/EfEO combination exhibited marked synergy (FICI ≤ 0.75). Further studies on the antimicrobial mechanisms of CEO, EfEO, and the CEO/EfEO combination showed that they were able to affect the integrity of the bacterial cell wall and increase membrane permeability. Such effect led to the leakage of biomolecules, including proteins and nucleic acids, accompanied by a concurrent decline in intracellular ATPase activity. The results of antioxidant activity assay showed that CEO exhibited stronger antioxidant capacity than EfEO. Cytotoxicity assessments conducted in bovine mammary epithelial cells delineated safe therapeutic windows, with EC values ranging from 0.120 to 0.148 mg/mL for CEO and 0.261-0.286 mg/mL for EfEO. Furthermore, the combined application of CEO and EfEO resulted in a reduction of the EC value. These findings indicate that CEO and EfEO represent a promising phytotherapeutic alternative, offering a potential solution to the growing challenge of antibiotic resistance in dairy production systems.
鉴于对牛奶质量下降的担忧以及细菌耐药性威胁的不断上升，开发乳腺炎抗生素替代治疗方法已变得势在必行。丁香油（CEO）是一种公认的天然抗菌剂，但其与香薷精油联合使用时的协同潜力尚未得到广泛研究。采用水蒸气蒸馏法从植物中提取精油（EOs）。气相色谱 - 质谱（GC - MS）结果表明，CEO的主要成分是丁香酚（76.59%），密花香薷精油的主要成分是柠檬烯（22.05%），细叶香薷精油的主要成分是香芹酮（31.63%），木香薷精油（EfEO）的主要成分是桉叶油素（40.1%），海州香薷精油的主要成分是对异丙基苯甲醚（27.60%）。抗菌试验表明，CEO对牛乳腺炎病原体具有优异的疗效（MIC：1.875 - 7.5 mg/mL），而CEO/EfEO组合表现出显著的协同作用（FICI≤0.75）。对CEO、EfEO及CEO/EfEO组合抗菌机制的进一步研究表明，它们能够影响细菌细胞壁的完整性并增加膜通透性。这种作用导致包括蛋白质和核酸在内的生物分子泄漏，同时细胞内ATP酶活性下降。抗氧化活性测定结果表明，CEO的抗氧化能力比EfEO更强。在牛乳腺上皮细胞中进行的细胞毒性评估确定了安全治疗窗口，CEO的EC值范围为0.120至0.148 mg/mL，EfEO的EC值范围为0.261 - 0.286 mg/mL。此外，CEO和EfEO的联合应用导致EC值降低。这些发现表明，CEO和EfEO是一种有前景的植物治疗替代方案，为应对乳制品生产系统中日益严重的抗生素耐药性挑战提供了潜在解决方案。
