Photodynamic properties of lysine and arginine derivatives of bacteriopurpurinimide.

Background: O-propyloxime-N-propoxybacteriopurpurinimide methyl ester ( 3 ) is a near-infrared photosensitizer with confirmed in vivo anticancer activity. Methods: Conjugates of 3 with arginine ( 1 ) or lysine attached at an ε-amino group ( 2a ) or α-amino group ( 2b ) were studied as anticancer and antibacterial photosensitizers and compared with 3 . Results: The new conjugates preserve advanced spectral characteristics of 3 and high singlet oxygen quantum yield. They demonstrated tenfold higher photocytotoxicity for cancer cells, due to their enhanced intracellular accumulation and altered localization. Though they showed threefold decreased antibacterial photodynamic effect compared with 3 , they kill planktonic Staphylococcus aureus bacteria, and 1 destroys bacterial biofilms. Conclusion: Conjugates 1 and 2b are near-infrared photosensitizers with high anticancer and limited antibacterial activity.