Novel Fe II and Co II Complexes of Natural Product Tryptanthrin: Synthesis and Binding with G-Quadruplex DNA

Abstract

Tryptanthrin is one of the most important members of indoloquinoline alkaloids. We obtained this alkaloid from Isatis. Two novel F e I I and C o I I complexes of tryptanthrin were first synthesized. Single-crystal X-ray diffraction analyses show that these complexes display distorted four-coordinated tetrahedron geometry via two heterocyclic nitrogen and oxygen atoms from tryptanthrin ligand. Binding with G-quadruplex DNA properties revealed that both complexes were found to exhibit significant interaction with G-quadruplex DNA. This study may potentially serve as the basis of future rational design of metal-based drugs from natural products that target the G-quadruplex DNA.