A comparative study on DNA/BSA binding, DNA photocleavage and antioxidant activities of water soluble peripherally and non-peripherally tetra-3-pyridin-3-ylpropoxy-substituted Mn(III), Cu(II) phthalocyanines

Abstract

In this study, peripherally and non-peripherally tetra-3-pyridin-3-ylpropoxy substituted Mn(III), Cu(II) phthalocyanines and their water soluble derivatives were synthesized and characterized. To determine DNA binding mode and cleavage pathway of water soluble phthalocyanines 2a, 3a, 2b and 3b were used CT-DNA and supercoiled pBR322 plasmid DNA. The DNA binding of water soluble phthalocyanines monitored using electronic absorption titration, competitive ethidium bromide, thermal denaturation that the water soluble phthalocyanines could bind to CT-DNA via intercalation mode in order 3a > 3b > 2a > 2b. The water soluble phthalocyanines cleaved supercoiled pBR322 plasmid DNA via photocleavage mechanism induced by singlet oxygen under irradiation at 600 nm for 3a, 700 nm for 3b and 750 nm for 2a and 2b. In addition, the binding experiment of BSA showed that water soluble phthalocyanines could bind to blood plasma proteins through a static quenching mechanism. Non-peripheral tetra-substituted water soluble Cu(II) phthalocyanine 3b showed high radical scavenging activities than other water soluble phthalocyanines due to metal ion and non-peripheral position. All of these experiments claimed that non-peripheral tetra-substituted water soluble Cu(II) phthalocyanine 3b have anticancer agent potential due to efficiently biological properties.