BODIPY‐Based Photosensitizers as Potential Anticancer and Antibacterial Agents: Role of the Positive Charge and the Heavy Atom Effect

Abstract

Abstract Boron‐dipyrromethene derivatives, including cationic and iodinated analogs, were obtained and subjected to physicochemical and in vitro photodynamic activity studies. Iodinated derivatives revealed a substantial heavy atom effect manifested by a bathochromic shift of the absorption band by about 30 nm and fluorescence intensity reduced by about 30–35 times, compared to that obtained for non‐iodinated ones. In consequence, singlet oxygen generation significantly increased with Φ Δ values in the range 0.69–0.97. The in vitro photodynamic activity was evaluated on Gram‐positive Staphylococcus aureus , Gram‐negative Escherichia coli , and on human androgen‐sensitive prostate adenocarcinoma cells (LNCaP). The novel cationic, iodinated BODIPY, demonstrated the highest activity toward all studied cells. An excellent cytotoxic effect was found against LNCaP cells with an IC 50 value of 19.3 nM, whereas the viability of S. aureus was reduced by >5.6 log 10 at 0.25 μM concentration and by >5.3 log 10 in the case of E. coli at 5 μM. Thus, this analog seems to be a very promising candidate for the application in both anticancer and antimicrobial photodynamic therapy.