Antifungal activity of curcumin-mediated photodynamic inactivation against Fusarium graminearum on maize

The natural curcumin-mediated photodynamic inactivation (PDI) was developed, and its inactivation potency against Fusarium graminearum in vitro and in vivo was systematically investigated by fluorescence probe assay, trypan blue staining, scanning electron microscope (SEM), confocal laser scanning microscopy (CLSM), etc. Results showed that under the irradiation of blue LED, the photosensitizer of curcumin was excited to generate massive reactive oxygen species (ROS) in the cells of F. graminearum, and the PDI completely inactivated their mycelia and spores under the treatment of 150 mu M curcumin and 10.8 J/cm(2) irradiation. Further analysis found that the PDI ruptured the cellular microstructures, damaged the cell membrane by increasing its permeability and oxidizing the lipids, degraded the intracellular DNA and proteins inside the spores of F. graminearum. Meanwhile, the PDI also potently killed >99.99% spores of F. graminearum on maize under the treatment of 200 mu M curcumin and 10.8 J/cm(2) irradiation. Moreover, the PDI suppressed the production of zearalenone (ZEN), and residual ZEN could not be detected after the storage of maize for 10 days. Therefore, this study systematically explored the inactivation efficiency of curcumin-mediated PDI against both the mycelia and spores of F. graminearum, which provides a valid and promising method to control the fungal hazards in grains.