Inhibitory mechanism and application of cinnamon essential oil against Aspergillus flavus

Aspergillus flavus produces highly toxic and carcinogenic aflatoxins that cause severe economic losses and pose a serious threat to public health. Cinnamon essential oils (CEO) have recently attracted attention as promising alternative antifungal agents. In this study, the inhibition mechanism of CEO on A. flavus was investigated, and its application in the prevention of A. flavus in coix seeds was explored for the first time. The results showed that mycelial growth, spore germination, and aflatoxin synthesis of A. flavus were completely inhibited after treatment with 0.5 μL/mL of CEO. Morphological, physiological, and biochemical changes after CEO treatment were also analyzed to elucidate the inhibitory mechanism. Transcriptomic analysis showed that some genes involved in conidiophore development (flbA and abaA), ergosterol synthesis (CYP51, Erg1, Erg3, Erg7, Erg9, Erg24, and Erg25), aflatoxin biosynthesis (aflR, aflO, aflT, aflJ, aflW, and aflY), and oxidative stress (Pbs2, Ste20, CAT, atfB, mtfA, PacC, ppoC, and gprM) were significantly regulated. Moreover, A. flavus infection in coix seeds was effectively inhibited by 20.0 μL/g of CEO. This study shed important light on the processes underlying the antifungal mechanism of CEO and affirmed the possibility of using CEO as a green anti-aflatoxigenic agent in the preservation of coix seed.