Synthesis, DNA-binding study, and antioxidant activity of 14-aryl-14H-dibenzo[a,j]xanthene derivatives

A simple and efficient one-pot method for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthene derivatives using Ni(ClO4)(2)center dot 6H(2)O as a catalyst is described. DNA-binding properties of 14-aryl-14H-dibenzo[a,j]xanthene derivatives 1a, 1j, 1l, 1m, and 1n were investigated using calf thymus DNA by electronic absorption spectroscopy and fluorescence spectroscopy. Binding constant (K (b)) with DNA was calculated from the absorption measurements. The spectral changes observed such as hypochromicity, red shift, and isosbestic point are consistent with the intercalation mode of binding of the chromophore into the stack DNA base pairs. Among the five, compound 1n with strong electron donating substituents on the phenyl ring shows better intercalative binding with DNA. Investigations of antioxidant properties show that the dibenzo[a,j]xanthene 1m with -OH group substitution has high radical scavenging properties against DPPH and ABTS(+).