Adukwu Emmanuel C, Bowles Melissa, Edwards-Jones Valerie, Bone Heather
Faculty of Applied Sciences, University of the West of England, Coldharbour Lane, Bristol, BS16 1QY, UK.
Manchester Metropolitan University, Manchester, UK.
Appl Microbiol Biotechnol. 2016 Nov;100(22):9619-9627. doi: 10.1007/s00253-016-7807-y. Epub 2016 Aug 26.
The aim of this study was to determine the antimicrobial effects of lemongrass essential oil (C. flexuosus) and to determine cytotoxic effects of both test compounds on human dermal fibroblasts. Antimicrobial susceptibility screening was carried out using the disk diffusion method. Antimicrobial resistance was observed in four of five Acinetobacter baumannii strains with two strains confirmed as multi-drug-resistant (MDR). All the strains tested were susceptible to both lemongrass and citral with zones of inhibition varying between 17 to 80 mm. The mean minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of citral (mic-0.14 % and mbc-0.3 % v/v) was lower than that of Lemongrass (mic-0.65 % and mbc-1.1 % v/v) determined using the microtitre plate method. Cell viability using human dermal fibroblasts (HDF; 106-05a) was determined following exposure to both compounds and a control (Grapeseed oil) using the XTT assay and the IC determined at 0.095 % (v/v) for citral and 0.126 % (v/v) for lemongrass. Grapeseed oil had no effect on cell viability. Live cell imaging was performed using the LumaScope 500 imaging equipment and changes in HDF cell morphology such as necrotic features and shrinkage were observed. The ability of lemongrass essential oil (EO) and citral to inhibit and kill MDR A. baumannii highlights its potential for use in the management of drug-resistant infections; however, in vitro cytotoxicity does suggest further tests are needed before in vivo or ex vivo human exposure.
本研究的目的是确定柠檬草精油(柔枝香茅)的抗菌作用,并确定两种受试化合物对人皮肤成纤维细胞的细胞毒性作用。采用纸片扩散法进行抗菌药敏筛选。在五株鲍曼不动杆菌中有四株观察到耐药性,其中两株被确认为多重耐药(MDR)。所有受试菌株对柠檬草和柠檬醛均敏感,抑菌圈在17至80毫米之间。使用微量滴定板法测定,柠檬醛的平均最低抑菌浓度(MIC)和最低杀菌浓度(MBC)(mic - 0.14%和mbc - 0.3% v/v)低于柠檬草(mic - 0.65%和mbc - 1.1% v/v)。使用XTT法测定人皮肤成纤维细胞(HDF;106 - 05a)在接触这两种化合物和对照(葡萄籽油)后的细胞活力,确定柠檬醛的IC为0.095%(v/v),柠檬草为0.126%(v/v)。葡萄籽油对细胞活力无影响。使用LumaScope 500成像设备进行活细胞成像,观察到HDF细胞形态的变化,如坏死特征和萎缩。柠檬草精油(EO)和柠檬醛抑制和杀灭多重耐药鲍曼不动杆菌的能力突出了其在耐药感染管理中的应用潜力;然而,体外细胞毒性确实表明在体内或体外人体接触之前还需要进一步测试。