Photochemical properties and photocytotoxicities against wound bacteria of sulfanyl porphyrazines with bulky peripheral substituents

Porphyrazine macrocycles with bulky peripheral phenylalkylsulfanyl substituents were subjected to photochemical studies. The singlet oxygen generation potential of these macrocycles was assessed using an indirect method with DPBF and all molecules revealed low singlet oxygen generation with quantum yields up to 0.03. In the photostability study, porphyrazine derivatives underwent photobleaching processes under light irradiation with quantum yields up to 2.45 . 10(-5). The photocytotoxicities of sulfanyl porphyrazine derivatives were researched in liposomal nanoparticles against wound bacteria, such as Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, and Streptococcus pyogenes. The most active macrocycles appeared magnesium(II) porphyrazines with 5-(3,5-dibutoxycarbonylphenoxy)pentylthio- and 2-[2-(3,5dibutoxycarbonylphenoxy)ethoxy]ethylthio-substitents. According to calculated photokilling rates obtained in the photoinactivation study, the greatest reduction of bacterial growth up to 4.7 log was noted for S. pyogenes, whereas moderate activity 2.5-2.6 log was observed against S. aureus. Low or no photocytotoxicity of studied macrocycles was noted against MRSA and S. epidermidis. (C) 2020 Elsevier B.V. All rights reserved.