The photodynamic anticancer and antibacterial activities of Sn(IV) tetra(4-methylbenzoate)chlorins

The emergence of antibacterial resistance and the high mortality rates associated with cancer have led to increased interest in the development of photodynamic antibacterial chemotherapy (PACT) and photodynamic therapy (PDT), which depend on the generation of reactive oxygen species by a photosensitizer. In this study, meso-tetra(4-methylbenzoate)chlorin (1-Chl) and its Sn(IV) derivatives with hydroxyl (2-SnOH) and 3-pyridyloxy [3-Sn(3-PyO)] axial ligands were synthesized and characterized for study in this context. The trans-axial ligands of 2-SnOH and 3-pyridyloxy 3-Sn(3-PyO) were introduced to decrease aggregation. The singlet oxygen quantum yields range from 0.49 to 0.67 in DMSO, with 2-SnOH exhibiting the highest value. PACT activity studies were performed against Staphylococcus aureus (S. aureus) and Escherichia coli using 625 and 660 nm Tholabs light-emitting diodes (1.4 and 1.7 mW/cm 2 for 75 min). 2-SnOH exhibited significant PACT activity against S. aureus with Log[Formula: see text] reduction values greater than 3. PDT activity studies against a triple-negative breast cancer cell line were conducted, and 1-Chl, 2- SnOH, and 3-Sn(3-PyO) chlorins had IC[Formula: see text] values of 7.0, 3.2, and 3.5 [Formula: see text]M, respectively, while the phototoxicity index (PI) values were found to be greater than 17, 25, and 31.