Study on antitumor activity of three ruthenium arene complexes in vitro

Three ruthenium arene complexes, namely {[(η 6 - p -cymene)Ru(Cl)] 2 (dpb)}(PF 6 ) 2 ( 1 ), [(η 6 - p -cymene)Ru( dpb )Cl](PF 6 ) ( 2 ) and [(η 6 - p -cymene) Ru( dpb )py](PF 6 ) ( 3 ) (dpb = 2,3-bis(2-pyridyl)benzo-quinoxaline, py = pyridine), were synthesized and their antitumor properties were introduced. Complexes 1-3 were characterized by 1 H NMR, MS, and elemental analysis . As a binuclear ruthenium structure, the absorption of metal ligand electron transfer (MLCT) of 1 extended to 700 nm. Complex 1 was significantly hydrolyzed under dark conditions. The cytotoxicity in vitro study showed that complexes 1 and 2 are more toxic to human lung cancer cells (A549) and human cervial cancer cells (Hela) than cisplatin . Moreover, there was almost no cross-resistance between complex 1-2 and cisplatin. Under the irradiation at 478 nm, complexes 1-3 all produced singlet oxygen ( 1 O 2 ), and the 1 O 2 quantum yield of complex 1 in PBS is the highest among complexes 1-3 . Complex 1 also produced 1 O 2 under 600 nm light irradiation . DNA gel electrophoresis showed that 1 caused the photocleavage of plasmid DNA. The hydrolysis rate of complex 1 was accelerated under light (λ > 600 nm). And the phototoxicity of complex 1 to Hela cells under light (λ > 600 nm) was much greater than its dark toxicity, which may be due to its generation of 1 O 2 and the promotion of its hydrolysis under long-wave light irradiation.