Ruthenium tetrazene complexes bearing glucose moieties on their periphery: Synthesis, characterization, andin vitrocytotoxicity

Ruthenium tetrazene complexes with general formula [Cp*RuCl(1,4-R2N4)] (Cp* = eta(5)-C5Me5), where R = benzyl (1), 2-fluorobenzyl (2),beta-d-glucopyranosyl-unprotected (3a) and acyl-protected (3b-d), 2-acetamido-beta-d-glucopyranosyl-unprotected (4a) and acyl-protected (4b-d), propyl-beta-d-glucopyranoside-unprotected (5a), andO-acetylated (5b), were synthesized and characterized using nuclear magnetic resonance and electrospray ionization-mass spectrometry. In addition, the molecular structure of3bwas determined using X-ray crystallography. The cytotoxicity of complexes against ovarian (A2780, SK-OV-3) and breast (MDA-MB-231) cancer cell lines and noncancerous cell line HEK-293 was evaluated and compared to cisplatin activity. The carbohydrate-modified complexes bearing acyl-protecting groups exhibited higher efficacy (in low micromolar range) than unprotected ones, where the most active4dwas superior to cisplatin up to five times against all investigated cancer cell lines; however, no significant selectivity was achieved. The complex induced apoptotic cell death at low micromolar concentrations (0.5 mu M for A2780 and HEK293; 2 mu M for SK-OV-3 and MDA-MB-231).