Visible light-induced cytotoxicity of Ru,Os–polyazine complexes towards rat malignant glioma

Visible light-induced cytotoxicity of metal complexes towards rat malignant glioma. [Display omitted] •Two complexes show oxygen-mediated DNA and BSA photocleavage.•Both compounds show approximately five-fold higher cytotoxicity than cisplatin.•Compound 2 shows promising photocytotoxicity in F98 under red light irradiation. Transition metal complexes capable of visible light-triggered cytotoxicity are appealing potential candidates for photodynamic therapy (PDT) of cancer. Two monometallic polyazine complexes, [(Ph2phen)2Ru(dpp)]2+ (1) and [(Ph2phen)2Os(dpp)]2+ (2) (Ph2phen=4,7-diphenyl-1,10-phenanthroline; dpp=2,3-bis(2-pyridyl)pyrazine), were synthesized, characterized and studied as light activated drugs to kill rat malignant glioma F98 cells. Compounds 1 and 2 display strong absorption in visible spectrum, oxygen-mediated DNA and BSA photocleavage and significant photocytotoxicity under blue light irradiation along with negligible activity in the dark. Both compounds show approximately five-fold higher cytotoxicity than the traditional chemotherapeutic drug cisplatin. Furthermore, compound 2 shows promising photocytotoxicity in F98 rat malignant glioma cells within the phototherapeutic window with an IC50 value of (86.07±8.48) μM under red light (625nm) irradiation.