Citral inhibits mycelial growth of Penicillium italicum by a membrane damage mechanism

This study investigated the anti-fungal activity and potential anti-fungal mechanisms of citral against Penicillium italicum, one of the main citrus postharvest pathogens. Results showed that citral exhibited strong anti-fungal activity against the test pathogen, with minimum inhibitory concentration and minimum fungicidal concentration of 0.50 and 1.00 μL/mL, respectively. Citral could evidently alter the morphology of P. italicum hyphae by causing loss of cytoplasm and distortion of mycelia. The membrane permeability of the P. italicum increased with increasing concentrations of citral, as evidenced by the release of cell constituents, extracellular pH, and leakage of potassium ions. Moreover, citral could induce a decrease in total lipid and ergosterol contents of P. italicum cells, indicating the disruption of membrane integrity. These results suggest that the anti-fungal activity of citral against P. italicum can be attributed to the disruption of the cell membrane integrity and membrane permeability.