Department of Public Health and Microbiology, University of Turin, Turin, Italy.
Planta Med. 2012 Oct;78(15):1633-5. doi: 10.1055/s-0032-1315153. Epub 2012 Aug 7.
The essential oils have started to be recognized for their potential antimicrobial role only in recent years. Clinical experience showed that the efficacy of antimicrobial agents depends not only on their direct effect on a given microorganism but also on the functional activity of the host immune system. Since data on the effects of essential oils on the innate immune system are scanty and fragmentary, the aim of this study was to evaluate the influence of thyme (red) essential oil (EO), at subinhibitory/inhibitory concentrations, on intracellular killing activity by human polymorphonuclear granulocytes (PMNs) against Candida albicans. In order to provide a frame of reference for the activity of this EO, its in vitro killing activity in the absence of PMNs was also evaluated.Results showed that EO at subminimal inhibitory (subMIC)/minimal inhibitory (MIC) concentrations significantly enhanced intracellular killing of C. albicans in comparison with EO-free controls and was comparable to the positive control (fluconazole). In in vitro killing assays without PMNs, we observed progressive growth of the yeast cells in the presence of EO subMIC/MIC concentrations. A positive antifungal interaction with phagocytes could explain why this EO, which appeared to be only fungistatic in time-kill assays, had efficacy in killing yeast cells once incubated with PMNs.
近年来，人们才开始认识到精油具有潜在的抗菌作用。临床经验表明，抗菌剂的疗效不仅取决于其对特定微生物的直接作用，还取决于宿主免疫系统的功能活性。由于关于精油对先天免疫系统影响的数据稀少且零散，本研究旨在评估百里香（红）精油（EO）在亚抑菌/抑菌浓度下对人多形核粒细胞（PMN）对白色念珠菌的细胞内杀伤活性的影响。为了为这种精油的活性提供参考框架，还评估了其在不存在 PMN 的情况下的体外杀伤活性。结果表明，与无 EO 对照和阳性对照（氟康唑）相比，EO 在亚最小抑菌浓度（subMIC）/最小抑菌浓度（MIC）浓度下显著增强了对白色念珠菌的细胞内杀伤作用。在没有 PMN 的体外杀伤试验中，我们观察到在 EO subMIC/MIC 浓度存在下，酵母细胞逐渐生长。与吞噬细胞的阳性抗真菌相互作用可以解释为什么这种 EO 在时间杀伤试验中似乎只是抑菌剂，但一旦与 PMN 孵育，就具有杀死酵母细胞的功效。
