Department of Biology and Ecology, Faculty of Science and Mathematics, University of Niš, Višegradska 33, 18000, Niš, Serbia.
Eur J Clin Microbiol Infect Dis. 2012 Jun;31(6):1015-25. doi: 10.1007/s10096-011-1400-1. Epub 2011 Sep 8.
The purpose of this study was to investigate the inhibitory/bactericidal activity and cell membrane effects of the hydrodistilled essential oil of Inula helenium L. roots against Staphylococcus aureus. Additionally, detailed chemical investigation was done in order to pinpoint the most active oil constituents and also the parts of these molecules responsible for their antimicrobial effect. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using the broth microdilution method. The membrane-active nature of this oil was investigated by measuring the culture turbidity, leakage of phosphates, and 260-nm-absorbing material, together with lysis of the exposed cells. Finally, the effect of the oil on the cells was visualized using scanning electron microscopy (SEM). The chemical composition of the essential oil was analyzed using gas chromatography-mass spectrometry (GC-MS) and preparative medium-pressure liquid chromatography (MPLC). Chemical modification of the oil was performed using catalytic hydrogenation (H(2), Pd/C) and reduction with NaBH(4). The MIC and MBC values were 0.01 μl mL(-1) and 0.02 μl mL(-1), respectively. Membrane damage was demonstrated through increased permeability (phosphates and nucleic acid leakage), followed by lysis of the exposed cells, captured on SEM images. The most active constituents were alantolactone, isoalantolactone, and diplophyllin. The essential oil showed very potent antistaphylococcal activity, with obvious membrane-damaging effects. Sesquiterpene lactones were found to be the most active principles of the oil, whose eudesmane core olefinic bonds, along with the α,β-methylene-lactone ring, are essential structural parts responsible for the exhibited antimicrobial activity.
本研究旨在探讨土木香根水蒸馏精油对金黄色葡萄球菌的抑菌/杀菌活性和细胞膜效应。此外，还进行了详细的化学研究，以确定最具活性的油成分，以及这些分子中负责其抗菌作用的部分。采用肉汤微量稀释法测定最小抑菌浓度（MIC）和最小杀菌浓度（MBC）。通过测量培养物浊度、磷酸盐泄漏和 260nm 吸收物质，以及暴露细胞的溶解，研究了该油的膜活性性质。最后，使用扫描电子显微镜（SEM）观察油对细胞的影响。使用气相色谱-质谱联用仪（GC-MS）和制备型中压液相色谱（MPLC）分析精油的化学成分。使用催化氢化（H₂，Pd/C）和 NaBH₄还原对油进行化学修饰。MIC 和 MBC 值分别为 0.01μl mL⁻¹和 0.02μl mL⁻¹。通过增加通透性（磷酸盐和核酸泄漏），随后通过 SEM 图像捕获暴露细胞的溶解，证明了细胞膜损伤。最活跃的成分是土木香内酯、异土木香内酯和二叶亭。该精油表现出很强的抗葡萄球菌活性，并具有明显的破坏细胞膜的作用。倍半萜内酯被发现是该油最具活性的成分，其艾烷核心烯烃键以及α，β-亚甲基-内酯环是负责表现出抗菌活性的必需结构部分。
