Synthesis, DNA binding, photo-induced DNA cleavage and cell cytotoxicity studies of a family of light rare earth complexes

A family of light rare earth complexes, [RE(acac)3(dpq)] (RE = La (1), Ce (2), Pr (3), Nd (4), Sm (5)) and [RE(acac)3(dppz)].CH3OH (RE = La (6), Ce (7), Pr (8), Nd (9), Sm (10) viz. acetylacetonate (acac), dipyrido[3,2-d:20,30-f]quinoxaline (dpq), dipyrido[3,2-a:20,30-c] phenazine (dppz)), have been synthesized and structurally characterized. Binding interactions of these complexes with CT-DNA and their photo-induced DNA cleavage activity with pBR 322 DNA are also investigated. These complexes have strong DNA binding interaction (Kb ≈ 105 M− 1 and Kapp ≈ 105 M− 1)and the binding propensity to CT-DNA decrease with the order: dppz complexes > dpq complexes. Furthermore, DNA photocleavage experiments indicate that these complexes are efficient DNA cleaving agents in UV-A (365 nm) and ambient light in the absence of any external reagents. Hydroxyl radical (HO
• ) and singlet oxygen (1O2) are the major cleavage active species from the machanistic studies. Moreover, cell cytotoxicity studies of these complexes on HeLa, K562 and MDA-MB-231 cells indicate that they have the potential to act as effective metal-based anti-cancer drugs.

A family of light rare earth complexes, [RE(acac)3(dpq)] and [RE(acac)3(dppz)]CH3OH have been synthesized and their DNA binding and photo-induced DNA cleavage activity are investigated.The light rare earth metal elements have less effect in the DNA binding, DNA cleavage and cytotoxicity.Figure optionsDownload as PowerPoint slide