Photodynamic activity and photoantimicrobial chemotherapy studies of ferrocene-substituted 2-thiobarbituric acid

[Display omitted] •Ferrocene conjugate photo-generates hydroxyl radical upon exposure to light.•The conjugate is photocytotoxic against MCF-7 cancer cells under 595 nm LED light.•DCFDA assay shows photo-generation of ROS by the conjugate in MCF-7 cells.•The ferrocene conjugate exhibit remarkable PACT activity. A ferrocene-substituted thiobarbituric acid (FT) has been synthesized to explore its photophysical properties and photodynamic and photoantimicrobial chemotherapy activities. FT has an intense metal-to-ligand charge transfer (MLCT) band at ca. 575 nm. The ferrocene moiety of FT undergoes photooxidation to form a ferrocenium species which in turn produces hydroxyl radical in an aqueous environment, which was confirmed via the bleaching reaction of p-nitrosodimethylaniline (RNO). FT exhibits efficient PDT activity against MCF-7 cancer cells with an IC50 value of 5.6 μM upon irradiation with 595 nm for 30 min with a Thorlabs M595L3 LED (240 mW cm−2). Photodynamic inactivation of Staphylococcus aureus and Escherichia coli by FT shows significant activity with log reduction values of 6.62 and 6.16 respectively, under illumination for 60 min at 595 nm. These results demonstrate that ferrocene-substituted thiobarbituric acids merit further study for developing novel bioorganometallic PDT agents.