Chiral ruthenium complexes induce apoptosis of tumor cell and interact with bovine serum albumin

In this study, two isomeric ruthenium(II) complexes [Ru(bpy) 2 (p‐mopip)] 2+ ( 1 ) and [Ru(bpy) 2 (o‐mopip)] 2+ ( 2 ) (bpy = 2, 2‐bipyridine; L: p‐mopip = 2‐(4‐methoxylphenyl) imidazo [4,5‐f][1,10]phenanthroline, o‐mopip = 2‐(2‐methoxylphenyl) imidazo[4,5‐f][1,10] phenan‐throline) contained OCH 3 at different positions on the phenyl ring and their enantiomers 1 , ‐2 and 1 , ‐2 displayed different properties. The cell viability of these ruthenium(II) complexes was evaluated by MTT, and complex 1 has shown significant higher anticancer potency than 1 against all the cell lines screened. Fluorescence microscopy and flow cytometric analyses demonstrated that complex 1 was able to induce apoptosis. The interactions of complexes 1 , 1 , and 1 with bovine serum albumin (BSA) were investigated by fluorescence and circular dichroism (CD) measurements. The fluorescence quenching mechanism of BSA by complexes 1 , 1 , and 1 was determined to be a static process, and the apparent binding constant K a values is as follows: Λ‐1 > 1 > Δ‐1 . The number of binding sites n for all these complexes was 1. The result of CD showed that the secondary structure of BSA molecules was changed in the presence of the ruthenium(II) complex. Chirality, 2012. © 2011 Wiley Periodicals, Inc.