Cuminaldehyde in cumin essential oils prevents the growth and aflatoxin B1 biosynthesis of Aspergillus flavus in peanuts

ABSTRACT The contamination of food with Aspergillus flavus has caused serious economic losses and posed a great threat to human and animal health. Cumin, a condiment and flavoring in many dishes, was showed to have great potential to prevent A. flavus contamination in the present study. By using cumin essential oil (CEO), the occurrence of A. flavus contamination on peanuts was prevented during the storage period even up to 9 months. We further identified cuminaldehyde as the predominant component in CEO with great inhibitory activity to both the growth of A. flavus and aflatoxin B1 (AFB1) biosynthesis. The data showed that the minimum inhibitory concentration (MIC) of cuminaldehyde to conidial growth was 0.64 μL/mL, and the mycelia exposed to 0.80 μL/mL cuminaldehyde reduced AFB1 production by more than 99% in comparison to the control. RNA-Seq profiles showed that some genes, involving the synthesis pathway of ergosterol and AFB1, were significantly down-regulated in the transcription by cuminaldehyde. Further investigation confirmed a significantly reduced cellular ergosterol content in the presence of cuminaldehyde, and the qRT-RCR results were also in agreement with that by RNA-Seq, indicating down-regulated expressions of those genes involving ergosterol and AFB1 synthesis. Taken together, our study strongly supported cuminaldehyde as a potential agent for the prevention of A. flavus contamination.