Microwave-assisted synthesis and in vitro and in silico studies of pyrano[3,2-c]quinoline-3-carboxylates as dual acting anti-cancer and anti-microbial agents and potential topoisomerase II and DNA-gyrase inhibitors

Abstract

A microwave-assisted method was utilized to synthesize novel pyranoquinolone derivatives as dual acting topoisomerase II/DNA gyrase inhibitors with apoptosis induction ability for halting lung cancer and staphylococcal infection. Herein, the designed rationale was directed toward mimicking the structural features of both topoisomerase II and DNA gyrase inhibitors as well as endowing them with apoptosis induction potential. The absolute configuration of the series was assigned using X-ray diffraction analysis. Cytotoxic activity against NSCLC A549 cells showed that ethyl 2-amino-9-bromo-4-(furan-2-yl)-5-oxo-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carboxylate (IC₅₀ ≈ 35 μM) was the most potent derivative in comparison to the positive control Levofloxacin and was selected for further investigation to assess its selectivity (SI = 1.23). Furthermore, in vitro antibacterial screening revealed the potential activity of this bromo derivative against Staphylococcus aureus. Mechanistic studies showed that the aforementioned compound exhibited promising inhibitory activity against topoisomerase II (IC₅₀ = 45.19 μM) and DNA gyrase (IC₅₀ = 40.76 μM) compared to reference standards. In addition, the previous compound induced a A549 cell apoptosis by 38.49-fold and it also increased the total apoptosis by 20.4% compared to a 0.53% increase in the control. Docking simulations postulated its interactions and suggested well fitting into its molecular targets.