Eleven new quinoxaline derivatives were designed and synthesized as modified VEGFR-2 inhibitors of our previous work. The synthesized compounds were tested against three human cancer cell lines (HepG-2, MCF-7 and HCT-116). Compounds 11g, 11e and 11c were the most potent members against the tested cells. Compound 11g (IC₅₀ = 4.50, 2.40, and 5.90 μM) was the most potent member compared to doxorubicin (IC₅₀ = 8.29, 9.65, and 7.68 μM) and sorafenib (IC₅₀ = 7.33, 9.41, and 7.23 μM) against HepG-2 and HCT-116, and MCF-7 cell lines, respectively. Compound 11e showed better anti-proliferative activities than doxorubicin and sorafenib with IC₅₀ values of 5.34, 4.19, and 6.06 μM, against HepG-2 and HCT-116 and MCF-7 cell lines, respectively. In addition, the most active anti-proliferative derivatives 11c, 11e, 11f, and 11g were selected to evaluate their inhibitory activities against VEGFR-2. The tested compounds displayed good inhibitory activity with IC₅₀ values ranging from 0.75 to 1.36 μM. Among them, compound 11g was the most active member with an IC₅₀ value of 0.75 μM, compared to the reference drug; sorafenib (IC₅₀ = 1.29 μM). Moreover, docking studies revealed that the synthesized compounds have good binding patterns against the prospective molecular target; VEGFR-2. In addition, in silico, ADMET and toxicity studies showed a high level of drug likeness for the synthesized compounds.

The discovery of drugs capable of inhibiting SARS-CoV-2 is a priority for human beings due to the severity of the global health pandemic caused by COVID-19. To this end, repurposing of FDA-approved drugs such as NSAIDs against COVID-19 can provide therapeutic alternatives that could be utilized as an effective safe treatment for COVID-19. The anti-inflammatory activity of NSAIDs is also advantageous in the treatment of COVID-19, as it was found that SARS-CoV-2 is responsible for provoking inflammatory cytokine storms resulting in lung damage. In this study, 40 FDA-approved NSAIDs were evaluated through molecular docking against the main protease of SARS-CoV-2. Among the tested compounds, sulfinpyrazone 2, indomethacin 3, and auranofin 4 were proposed as potential antagonists of COVID-19 main protease. Molecular dynamics simulations were also carried out for the most promising members of the screened NSAID candidates (2, 3, and 4) to unravel the dynamic properties of NSAIDs at the target receptor. The conducted quantum mechanical study revealed that the hybrid functional B3PW91 provides a good description of the spatial parameters of auranofin 4. Interestingly, a promising structure–activity relationship (SAR) was concluded from our study that could help in the future design of potential SARS-CoV-2 main protease inhibitors with expected anti-inflammatory effects as well. NSAIDs may be used by medicinal chemists as lead compounds for the development of potent SARS-CoV-2 (M^pro) inhibitors. In addition, some NSAIDs can be selectively designated for treatment of inflammation resulting from COVID-19.