Abstract: This study explored the antifungal activity and potential mechanism of action of dihydromyricetin (DMY) against Aspergillus flavus. The minimum inhibitory concentration (MIC) of DMY against the spore germination and mycelial growth of A. flavus was 4 mg/mL. Calcofluor white (CW) and propidium iodide (PI) staining proved that DMY treatment destroyed the cell wall and membrane of A. flavus. Compared with the control group, the release of A. flavus cell content (expressed as OD260 nm) in the 1/2 MIC and MIC groups increased by 4.14 and 6.93 times, respectively, and both the extracellular pH and relative conductivity increased. The inhibition rate of A. flavus respiration by DMY at MIC was as high as 25.82%. These results indicated that DMY exerted antifungal activity against A. flavus via disrupting the integrities of the cell wall and membrane and interfering with respiratory metabolism. In addition, DMY could effectively inhibit the germination of A. flavus spores on peanuts and corn kernels. Therefore, DMY can be used as an effective natural antifungal compound in the preservation of grains and agricultural products.

Key words: dihydromyricetin; Aspergillus flavus; antifungal mechanism; peanuts; corn