Interactions with HSA, anticancer and antiallergic activity of binuclear μ‐oxo bridged ruthenium acetate compounds

Abstract

AbstractThe μ‐oxo bridged ruthenium acetate 1 [Ru2O(CH3COO)2(5‐CH3‐1,10‐phen)2(py)2](PF6)2 (5‐CH3‐1,10‐phen=5‐methyl‐1,10‐phenanthroline; py=pyridine) is presented. Its electronic and infrared spectra, as well as its cyclic voltammograms are all consistent with the proposed structure. Regarding biological properties, we collected data for 1 and its analog [Ru2O(CH3COO)2(1,10‐phen)2(py)2](PF6)2 (2) to infer the role of phenantroline methylation. The HSA fluorescence is quenched by 1 and the presence of variable concentrations of it did not affect the τ1/2 values for the HSA excited state lifetime (mean τ1/2 values=3.56, 3.46, and 3.32 ns at 298, 304, and 310 K respectively). Circular dichroism showed that the HSA α‐helix content decreased only 5 % upon interaction with 1, which formed a ground‐state adduct with HSA, not changing the protein structure to a significant extent. Interaction between 1 and DNA was weak; Benesi‐Hildebrand constants were in the order of 102 M−1. We probed the allergenic potential/antiallergic activity of 1, observing that 200 μM inhibited mast cell degranulation by about 80 %, while cell viability remained unaltered throughout the measurement (2 h). Therefore, 1 has antiallergic potential and is not an allergen. Regarding its anticancer activity, at all the employed concentrations, 1 was more cytotoxic than 2 against B16F10 murine melanoma cancer cells. At 25 μM, 1 reduced cell viability to less than 14 %, while 2 reduced cell viability to only 78 %.