Major components in Lilac and Litsea cubeba essential oils kill Penicillium roqueforti through mitochondrial apoptosis pathway

Agriculture products spoilage caused by mold not only causes huge economic losses, but also poses a safety hazard to human health. Although essential oils (EOs) are widely used for agriculture products antisepsis, little is known about the synergistic antifungal mechanisms of their major components. In this paper, the synergistic mechanism of eugenol and citral (SEC) on Penicillium roqueforti was studied. The results showed that SEC caused irreversible damage to the cell membrane of P. roqueforti, resulting in significant changes in membrane protein conformation and fatty acid content, among which citral had a greater effect on fatty acid content than eugenol. Through the analysis of mitochondrial morphology and membrane potential, it was found that SEC treatment resulted in serious collapse of mitochondria and significant increase of membrane potential. In this process, the contribution rate of eugenol was higher than that of citral. Further analysis of the tricarboxylic acid cycle (TCA) pathway showed that SEC could inhibit the activity of key enzymes and the production of energy charge in the TCA pathway, resulting in significant down-regulation of gene expression of three key molecules (succinate dehydrogenase, isocitrate dehydrogenase and fumarate hydratase). In conclusion, these results indicated that SEC could kill P. roqueforti through the tricarboxylic acid cycle.