Synthesis and cytotoxicity of a ruthenium nitrosyl nitric oxide donor with isonicotinic acid and a cell penetrating peptide

The syntheses and properties of trans-[Ru(NH3)4(L)(NO)](BF4)3 (L = isonicotinic acid (inaH) (I) or ina-Tat48–60 (II)) are described. Tat48–60, a cell penetrating peptide fragment of the Tat regulatory protein of the HIV virus, was linked to the ruthenium nitrosyl through inaH. I and II release NO after reduction forming trans-[Ru(NH3)4(L)(H2O)]3 +. The IC50 values against B16-F10 melanoma cells of I and II (21 μmol L− 1 and 23 μmol L− 1, respectively) are close to that of the commercially available cisplatin (33 μmol L− 1) and smaller than similar complexes. The cytotoxicity is assigned to the NO released from I and II.