Synthesis and molecular docking studies of some novel Schiff bases incorporating 6-butylquinolinedione moiety as potential topoisomerase IIβ inhibitors

A series of novel pyranoquinolinone-based Schiff's bases were designed and synthesized. They were evaluated for topoisomerase IIβ (TOP2B) inhibitory activity, and cytotoxicity against breast cancer cell line (MCF-7) for the development of novel anticancer agents. A molecular docking study was employed to investigate their binding and functional properties as TOP2B inhibitors, using the D iscovery S tudio 2.5 software, where they showed very interesting ability to intercalate the DNA–topoisomerase complex. Compounds 2a , 2c and 2f showed high docking score values (82.36% −29.98 kcal mol −1 for compound 2a , 78.18% −26.98 kcal mol −1 for compound 2c and 78.65, −28.11 kcal mol −1 for compound 2f ) and revealed the highest enzyme inhibition activity. The best hit compounds exhibited highly potent TOP2B inhibitors with submicromolar IC50 at 5 µM compared to the reference doxorubicin.