Complex formation of rutin and quercetin with copper alters the mode of inhibition of Ribonuclease A

► Synthesis and characterizations of rutin and quercetin Cu(II) complexes. ► Rutin enhanced the ribonucleolytic activity of RNase A whereas others show inhibition properties. ► Mode of inhibition of the compounds determined from kinetic experiment - Ki values in the μM range. ► Binding modes of these compounds with RNase A investigated by different spectroscopic methods. ► The stability of RNase A in presence of the compounds was determined from melting point studies.