Suhr K I, Nielsen P V
Mycology Group, Biocentrum-DTU, Technical University of Denmark, Kgs. Lyngby, Denmark.
J Appl Microbiol. 2003;94(4):665-74. doi: 10.1046/j.1365-2672.2003.01896.x.
To study how antifungal activity of natural essential oils depends on the assay method used.
Oils of bay, cinnamon leaf, clove, lemongrass, mustard, orange, sage, thyme and two rosemary oils were tested by two methods: (1) a rye bread-based agar medium was supplemented with 100 and 250 microl l-1 essential oil and (2) real rye bread was exposed to 136 and 272 microl l-1 volatile oil in air. Rye bread spoilage fungi were used for testing. Method 1 proved thyme oil to be the overall best growth inhibitor, followed by clove and cinnamon. On the contrary, orange, sage and rosemary oils had very limited effects. Mustard and lemongrass were the most effective oils by the volatile method, and orange, sage and one rosemary showed some effects. Oil compositions were analysed by gas chromatography-mass spectrography.
Antifungal effects of the essential oils depended on the application method. Larger phenolic compounds such as thymol and eugenol (thyme, cinnamon and clove) had best effect applied directly to medium, whereas smaller compounds such as allyl isothiocyanate and citral (mustard and lemongrass) were most efficient when added as volatiles.
This study proves that the method used for screening essential oils as potential antimicrobials should correspond with the application sought.
研究天然香精油的抗真菌活性如何取决于所使用的测定方法。
通过两种方法对月桂、肉桂叶、丁香、柠檬草、芥菜、橙子、鼠尾草、百里香精油以及两种迷迭香精油进行了测试：（1）在以黑麦面包为基础的琼脂培养基中添加100和250微升/升的香精油；（2）将真正的黑麦面包暴露于空气中136和272微升/升的挥发油中。使用黑麦面包腐败真菌进行测试。方法1证明百里香精油是总体上最佳的生长抑制剂，其次是丁香和肉桂。相反，橙子、鼠尾草和迷迭香精油的效果非常有限。通过气相色谱-质谱联用仪分析了油的成分。
香精油的抗真菌效果取决于应用方法。较大的酚类化合物如百里酚和丁香酚（百里香、肉桂和丁香）直接应用于培养基时效果最佳，而较小的化合物如异硫氰酸烯丙酯和柠檬醛（芥菜和柠檬草）作为挥发物添加时效率最高。
本研究证明，用于筛选作为潜在抗菌剂的香精油的方法应与所寻求的应用相对应。
