Department of Food Quality and Safety, College of Food Science and Engineering, Tonghua Normal University, 134000 Tonghua, PR China.
Department of Food Quality and Safety, College of Food Science and Engineering, Jilin University, 130062 Changchun, PR China.
J Med Microbiol. 2019 Apr;68(4):657-666. doi: 10.1099/jmm.0.000949. Epub 2019 Mar 18.
Zedoary turmeric oil (ZTO), the steam extract of Curcuma zedoaria Rosc was researched for its chemical composition, antibacterial activity, and mechanism for countering two major food-borne pathogenic species, Listeria monocytogenes and Staphylococcus aureus.
Gas chromatography-mass spectrometry (GC-MS) was used to analyse and characterize the chemical composition of ZTO. Its MICs for the two bacterial species and growth curves were measured. Western blot and real-time reverse-transcription (RT)-PCR assays were utilized to elaborate the mechanism of the antibacterial effect of ZTO by examining the expression levels of virulence-related extracellular proteins. ELISA was used to explore the biological relevance.
GC-MS revealed high contents of curzerene, eucalyptol, germacrone and (-)-g-elemene representing 28.45, 10.94, 10.77 and 10.54 %, respectively, of the whole components. The MICs of ZTO that combatted L. monocytogenes and S. aureus were similar (1-2 mg ml ). After adding ZTO at increasing concentrations, there was an evident reduction in the transcription of hly, iap, hla, sea, seb and agrA in a dose-dependent manner. Furthermore, TNF-α accumulation in RAW264.7 cells stimulated by L. monocytogenes and S. aureus supernatants was restricted by a 1/4 MIC of ZTO.
Overall, L. monocytogenes and S. aureus were comparably susceptible to ZTO. These data demonstrated that ZTO's antimicrobial property was mediated by the repression of the production of virulence factors involved in L. monocytogenes and S. aureus pathogenesis, a finding that can potentially further progress in the development of new anti-virulence drugs.
莪术油（ZTO）是姜黄的水蒸气提取物，研究其化学成分、抗菌活性及其对抗两种主要食源性病原体——单核细胞增生李斯特菌和金黄色葡萄球菌的机制。
采用气相色谱-质谱联用（GC-MS）分析和鉴定 ZTO 的化学成分。测定其对两种细菌的 MIC 值和生长曲线。利用 Western blot 和实时 RT-PCR 检测 ZTO 抑制细菌毒力相关胞外蛋白表达水平，阐述其抗菌作用机制。ELISA 用于探讨其生物学相关性。
GC-MS 揭示了 ZTO 中含有高含量的莪术烯、桉油精、姜黄烯和 (-)-g-榄香烯，分别占总成分的 28.45%、10.94%、10.77%和 10.54%。ZTO 对单核细胞增生李斯特菌和金黄色葡萄球菌的 MIC 值相似（1-2mg/ml）。随着 ZTO 浓度的增加，hly、iap、hla、sea、seb 和 agrA 的转录明显减少，呈剂量依赖性。此外，ZTO 以 1/4 MIC 浓度抑制单核细胞增生李斯特菌和金黄色葡萄球菌上清液刺激 RAW264.7 细胞中 TNF-α的积累。
总体而言，单核细胞增生李斯特菌和金黄色葡萄球菌对 ZTO 具有相似的敏感性。这些数据表明，ZTO 的抗菌特性是通过抑制与单核细胞增生李斯特菌和金黄色葡萄球菌发病机制相关的毒力因子的产生来介导的，这一发现可能会进一步推动新型抗毒力药物的开发。
