A series of novel metal complexes of 4-aminoantipyrine quinoxaline (4-AAPQ) Schiffbase derived from 4-aminoantipyrine and quinoxaline-2-carboxaldehyde were synthesized. The structural and properties of these compounds were characterized by spectral methods (IR, mass, 1 H NMR, 13 C NMR, UV–Vis), mo- lar conductance, and elemental analysis. The binding stoichiometry mode was confirmed as 1:1 (metal: ligand) by analytical, and spectral data. The type of coordination of the metal to azomethine nitrogen and quinoxaline nitrogen atoms of the ligand were determined by spectral data. In this case, the ligand acts as a bidentate donor with the coordination number of four in prepared complexes. The synthesized compounds were tested for two types of cancer cell lines consisting of human colon cancer (HT-29) and breast cancer (MCF-7), as well as one normal cell line containing human foreskin fibroblast (HFF) using MTT cell viability assay. A comparative study of the IC 50 values indicates that 4-AAPQ-Cu (II)/ and Mn(II) complexes exhibit higher activity than related Schiffbase ligand on the MCF-7 cell line. Also, 4-AAPQ- Mn(II)/ and -Zn(II) complexes were the most active compounds with the highest inhibition against HT-29 cell line after 48 h. Molecular docking studies of 4-AAPQ Cu(II) within the c-kit active site as a validated target displayed 344.33 nM and -8.82 kcal/mol for inhibition constant (Ki) and free energy of binding, respectively.
