Copper(II) complexes of hydroxyflavone derivatives as potential bioactive molecule to combat antioxidants: synthesis, characterization and pharmacological activities

A variety of novel copper complexes were synthesized and characterized of the formulae [Cu(L1)(OAc)], [CuL2(H2O)], [CuL3(H2O)], [CuL4(OAc)], [CuL5(H2O)] [CuL6], [CuL7], [CuL8](OAc) and [CuL9], where L1L9 represents Schiff base ligands [derived by the condensation of 5‐hydroxyflavone with 4‐aminoantipyrine (L1), o‐aminophenol (L2), o‐aminobenzoic acid (L3), o‐aminothiazole (L4), thiosemicarbazide (L5), 4‐aminoantipyrine‐o‐aminophenol (L6), 4‐aminoantipyrine‐o‐aminobenzoic acid (L7), 4‐aminoantipyrine‐o‐aminothiazole(L8) and 4‐aminoantipyrine‐thiosemicarbazide (L9)]. The spectral and magnetic results of the Cu(II) complexes exhibit square planar geometry. The DNA binding properties of copper complexes were studied by using electronic absorption spectra, viscosity and thermal denaturation experiments. The results show that the complexes were interacting with calf thymus (CT DNA). The in vitro antimicrobial activities of the investigated compounds were tested against the bacterial species and fungal species. Superoxide dismutase and antioxidant activities of the copper complexes have also been studied.