The synthesis of hybrid "cationic
metalloporphyrin-
intercalator" molecules is reported. These molecules are based on
9-methoxyellipticine as
intercalator and tris-(4-N-methylpyridiniumyl)metalloporphyrins having a 4-aminophenyl or a 4-hydroxyphenyl group for the attachment of the linker. The effect of the length of linker (7-13 bonds), the chemical nature of the linking group (with a carboxamido or an
ether function), the position of amino group between the two parts of hybrid molecules, the number of
intercalator moieties (ellipticinium) covalently attached to the
metalloporphyrin, and the nature of the central
metal atom (Mn, Fe, Zn) on the
biological activity of these hybrid molecules were studied. In addition, these molecules have a high affinity for
double-stranded DNA (affinity constant of hybrid molecule 9Mn,Me = 2.3 x 10(9) M-1 for poly[
d(A-T)] and 2.8 x 10(8) M-1 for
poly[d(G-C)] and are cytotoxic against murine
leukemia cells L1210 in vitro (IC50 of 9Mn,Me = 0.8 microM). Their cytotoxicities are dependent on the nature of central atom.
Iron derivatives are less active than
manganese analogues and the corresponding
zinc derivatives are nearly inactive despite their same affinity for
nucleic acids. These highly water-soluble hybrid molecules could be considered as efficient
bleomycin models based on a cationic
metalloporphyrin.