RESUMO
To overcome the poor water solubility of curcumin, a curcumin-ß-cyclodextrin (Cur-ß-CD) complex was prepared as a novel photosensitizer. Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) were used to verify the formation of Cur-ß-CD. Furthermore, the ROS generation capacity and photodynamic bactericidal effect were measured to confirm this Cur-ß-CD complex kept photodynamic activity of curcumin. The result showed Cur-ß-CD could effectively generate ROS upon blue-light irradiation. The plate count assay demonstrated Cur-ß-CD complex possess desirable photodynamic antibacterial effect against food-borne pathogens including Staphylococcus aureus, Listeria monocytogenes and Escherichia coli. The cell morphology determined by scanning electron microscope (SEM) and transmission electron microscope (TEM) showed Cur-ß-CD could cause cell deformation, surface collapse and cell structure damage of the bacteria, resulting in the leakage of cytoplasmic; while agarose gel electrophoresis and SDS-PAGE further illustrated the inactivation mechanisms by Cur-ß-CD involve bacterial DNA damage and protein degradation.
