Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Institute of Traditional Chinese Medicine & Natural Products, Wuhan University, Wuhan, PR China.
PLoS One. 2012;7(1):e30147. doi: 10.1371/journal.pone.0030147. Epub 2012 Jan 17.
The essential oil extracted from the seeds of dill (Anethum graveolens L.) was demonstrated in this study as a potential source of an eco-friendly antifungal agent. To elucidate the mechanism of the antifungal action further, the effect of the essential oil on the plasma membrane and mitochondria of Aspergillus flavus was investigated. The lesion in the plasma membrane was detected through flow cytometry and further verified through the inhibition of ergosterol synthesis. The essential oil caused morphological changes in the cells of A. flavus and a reduction in the ergosterol quantity. Moreover, mitochondrial membrane potential (MMP), acidification of external medium, and mitochondrial ATPase and dehydrogenase activities were detected. The reactive oxygen species (ROS) accumulation was also examined through fluorometric assay. Exposure to dill oil resulted in an elevation of MMP, and in the suppression of the glucose-induced decrease in external pH at 4 µl/ml. Decreased ATPase and dehydrogenase activities in A. flavus cells were also observed in a dose-dependent manner. The above dysfunctions of the mitochondria caused ROS accumulation in A. flavus. A reduction in cell viability was prevented through the addition of L-cysteine, which indicates that ROS is an important mediator of the antifungal action of dill oil. In summary, the antifungal activity of dill oil results from its ability to disrupt the permeability barrier of the plasma membrane and from the mitochondrial dysfunction-induced ROS accumulation in A. flavus.
本研究表明，从莳萝（Anethum graveolens L.）种子中提取的精油可能是一种环保型抗真菌剂的来源。为了进一步阐明其抗真菌作用的机制，研究了精油对黄曲霉（Aspergillus flavus）质膜和线粒体的影响。通过流式细胞术检测到质膜损伤，并通过抑制麦角固醇合成进一步验证。精油导致黄曲霉细胞形态发生变化，麦角固醇数量减少。此外，还检测了线粒体膜电位（MMP）、外介质酸化以及线粒体 ATP 酶和脱氢酶活性。通过荧光测定法还检查了活性氧物质（ROS）的积累。暴露于莳萝油会导致 MMP 升高，并抑制 4 µl/ml 时葡萄糖诱导的外部 pH 值降低。还观察到 A. flavus 细胞中 ATP 酶和脱氢酶活性呈剂量依赖性降低。线粒体的上述功能障碍导致 A. flavus 中 ROS 积累。通过添加 L-半胱氨酸可防止细胞活力降低，这表明 ROS 是莳萝油抗真菌作用的重要介质。总之，莳萝油的抗真菌活性源自其破坏质膜通透性屏障的能力以及诱导 A. flavus 中 ROS 积累的线粒体功能障碍。
