Nanostructured TiO2 Catalyzed Microwave Assisted Synthesis of Fused Quinolines-DNA Binding, Molecular Docking and Antioxidant Activity

The use of nanostructured TiO2 as mixed phase photocatalyst in the synthesis of 2H-pyrano/2H-thiopyrano [2,3-b]quinoline-2-carboxylic acid (2a/2b) is described. The binding modes of 2a/2b with ds DNA fragments d(CGCGAATTCGCG) were predicted by molecular docking studies. The lowest energy was found in the compound 2b with a binding energy of -7.44 Kcal/mol and inhibition constant of 5.39 x e-6. The interaction study with CT DNA was carried out by absorption spectra, (Kb constant obtained for 2a is 3.5x106 and for 2b it is 2.9x105), viscosity and thermal denaturation methods. The in vitro antioxidant activities were evaluated. Finally, the results showed that the intercalated 2a/2b compounds are strong antioxidants and they protect oxidative DNA damage from harmful free radicals.