Effect of a Metal Ion in Modulating the Binding Interaction of a Dietary Flavonoid with Bovine Serum Albumin and DNA: A Spectroscopic and Theoretical Approach

Plant-derived flavonoids are an excellent option as a potential substitute to synthetic products in food industries, and flavonoid-metal complexes exhibit better functional properties than free tlavonoids. Here, an iron(II) complex of rutin, a dietary flavonoid, has been synthesized and characterized. A comparative assessment of the interaction of rutin and its iron(II) complex with the transport protein [bovine serum albumin (BSA)] and deoxyribonucleic acid (DNA) has been performed. The interaction process has been characterized using multispectroscopic techniques and has been further supported by theoretical studies. We have evidenced the alteration in the interacting mode of rutin with BSA upon complexation with Fe(II). Also, rutin interacts with DNA via minor groove binding, while the complex interacts with DNA through a mixed mode involving both groove binding and intercalative binding. Interestingly, the antioxidant activity of the metal complex has been found to he enhanced, and it also provides better protection against UV radiation-induced cell damage than rutin alone.