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

In this study, two isomeric ruthenium(Pi) 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 -OCH3 at different positions on the phenyl ring and their enantiomers Delta-1, -2 and Delta-1, -2 displayed different properties. The cell viability of these ruthenium(II) complexes was evaluated by MTT, and complex Delta-1 has shown significant higher anticancer potency than Delta-1 against all the cell lines screened. Fluorescence microscopy and flow cytometric analyses demonstrated that complex Delta-1 was able to induce apoptosis. The interactions of complexes Delta-1, 1, and Delta-1 with bovine serum albumin (BSA) were investigated by fluorescence and circular dichroism (CD) measurements. The fluorescence quenching mechanism of BSA by complexes Delta-1, 1, and Delta-1 was determined to be a static process, and the apparent binding constant K-a values is as follows: Delta-1 >1 > Delta-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 24:174-180, 2012. (c) 2011 Wiley Periodicals, Inc.